WorldWideScience

Sample records for cambium

  1. Nonparallelism of cambium cells in neighboring rows

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    Wiesław Włoch

    2014-02-01

    Full Text Available The periclinal walls of cambial cells in neighboring lineages (rows may not be parallel when viewed in their radial aspect. This lack of longitudinal parallelism may be so extensive that in active cambium pairs of cells from neighboring rows may be in contact only along restricted segments. This means that the initial cells, rather than farming a continuous layer, may be arranged in an irregular network pattern from which some parts project inward or outward from the layer of their mutual cantacts. The longitudinal nonparallelism of cambial cells becomes more pronounced during symplasitic radial growth. Unequal periclinal divisions counteract this, and in initial cells abscission of the parts projecting from the layer of mutual contact occurs. When the cambium passes from a period of activity to a Period of rest a continuous layer of initials is reestabhshed. This involves elongation by intrusive growth of those cells previously shortened as the result of irregular periclinal divisions. The division walls in cambial cells may be warped, that is they change their orientation along the longitudinal direction perhaps even similar to an aircraft propeller. A division wall may thus be periclinal in one part of the cell and anticlinal in another.

  2. Transition areas in the domain patterns of storeyed cambium of Tilia cordata Mill.

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    Wiesław Włoch

    2014-02-01

    Full Text Available The occurrence of interlocked grain, generated by storeyed cambium, was observed in the wood of linden. The inclination of the grain changed periodically every two to four years. In general, the direction of the change of grain was compatible with the occurrence of configuration Z or S of cellular events. 1f, in the cambium during the generation of a growth ring, the domain border did not pass the examined area, the events were of one configuration type only, otherwise, there were two types of events aggregated into microareas. The microareas were the result of unsynchronous activities of groups of cambium cells. A growth ring area through which a domain border passed during the year under consideration was called the transition area.

  3. Upward movement of the domain pattern in the cambium producing wavy grain in Picea excelsa

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    Z. Hejnowicz

    2015-05-01

    Full Text Available The cambium which produces wavy-grained xylem in spruce differs from normal cambium by a higher frequency of oblique anticlinal divisions and a higher rate of intrusive growth of fusiform initials. Since the orientation, either to the left or to the right, of the divisions and the overlaps achieved by the growting tips is uniform within the areas called domains, the domain pattern of the cambium is reflected in the pattern of grain undulations in the xy1em. The domain pattern moves longitudinally about 0.7 mm during the production of l mm of xylem. A visible expression of the movement is the obliquity of undulation lines on the radial face of the wavy xylem.

  4. Time-variable frequency of events in domains of Tilia cambium

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    Wiesław Włoch

    2014-02-01

    Full Text Available In the cambium of linden, producing xylem with interlocked grain, domains active, as regards the occurrence of events, and inactive ones can be distinguished. The area of the cambium investigated was an assemblage of small domains among which at certain periods domains Z, and, at another period, domains S were active. The inclination of the grain was changing in the direction corresponding to the type of the active domains. Alternative occurrence of periods of activity of Z and S domains led to the formation of interlocked grain in the xylem, with a much longer wave than the height of a pair domains.

  5. Alnus subcordata C.A.M. Cambium Cells Dynamics Along Transport Corridors in Hyrcanian Forests

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    Aidin Parsakhoo

    2009-01-01

    Full Text Available Problem statement: In this study, we considered transport corridors and sampling aspects to be the major indicators of ecological effects on Alder (Alnus subcordata cambium cells dynamics. Approach: Thus, 240 cores were taken from forest-facing and road-facing trunk of Alder trees along Amre, Neka and Darab Kola transport corridors in hyrcanian Forests of Iran. Results showed that the roads corridor had significant effects on Alnus subcordata annual rings (p = 0.04 and bark growth (pResults: In Darab Kola and Neka the bark thickness in road-facing aspect was significantly (pConclusion: Cambium cells dynamic diagram in production of annual rings indicated that the Alnus subcordata at commence of growth had been produced wide rings but in continuance the rings width reduced. This reduction was obviously for road-facing cores. Soil compaction, drainage structures, natural hazards and etc caused the thinner rings to be produced by cambium cells in road-facing aspect.

  6. Seasonal activity of cambium in some tropical trees. 111. Salvadora persica L.

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    G. S. Paliwal

    2015-05-01

    Full Text Available Seasonal activity of cambium has been investigated in Salvadora persica L., one of the commonest evergrenn tree of northern India, from March, 1974 to February, 1975 in the main stem and the branch. Secondary vascular cambium behaves abnormally on the xylem side, by producing xylem and phloem in succession, resulting in the formation of interxylary phloem. It has a storied (sitratified cambium organization, comprising short fusiform and isodiametric ray initials. The fusiform initials show characteristically beaded cell walls due to the presence of primary pit fields and are uninucleate. These are highly vacuolate during the active period. The cambial activity starts in the month of March, reaches the peak in August and finally slows down in the main stem. In an young branch, however, it is initiated in March-April and reaches the peak in July and then declines till November. It once again showed an upward trend gradually. It appears that the initiation of the combial activity in this tree takes place by a hormone produced in the newly formed leaves, coupled with the high rainfall, enhanced relative humidity, optimum temperature, and short-day conditions. Size measurements for the fusiform initials showed considerable variations during the span of a year. A comparision of the organization of three types of phloem 'normal', 'included' and 'internal' occurring in this plant has also bean presented.

  7. The parenchymo-vascular cambium and its derivative tissues in stems and roots of Bougainvillaea glabra Choisy (Nyctaginaceae

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    Z. Puławska

    2015-05-01

    Full Text Available In the shoots and roots of Bougainmllaea, the parenchymo-vascular cambium produces thinwalled secondary parenchyma to one side and the secondary vascular bundles embedded in the "conjunctive tissue" to the other. Periclinal division of a single cambial cell in one radial row brings about periclinal divisions of the adjacent cells of the neighbouring rows. Anticlinal division of a single cambial cell at one level, on the other hand, causes anticlinal. divisions of the adjacent cells of the overlying and underlying tiers.

  8. Ratio of fusiform and ray initials in the vascular cambium of Madhuca indica J.F. Gmel.

    Science.gov (United States)

    Bhat, Saima; Siddiqui, M Badruzzaman

    2007-02-01

    The anatomical studies of the vascular cylinder revealed in tangential longitudinal plane have fusiform initials and ray initials arranged in non-stratified manner like majority of dicots. It is generally believed that fusiform initials constitute more than 90% of the vascular cambium but contrary to above reports, 60 to 83% fusiform initials have been observed in different tropical tree and in certain extreme cases their proportion may fall as low as 25%. Keeping in view the above variations, the present communication aims at presenting the proportions of the fusiform initials which was found to be 65% mean tangential area in the cambial zone of presently investigated species. PMID:19069530

  9. The storeyed and non-storeyed arrangement of rays in the storeyed cambium of Tilia cordata Mill.

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    Wiesław Włoch

    2014-02-01

    Full Text Available Due to restructuring of the cellular arrangement, rays in storeyed cambium undergo transformations, that is, uniting and splitting on the borders of storeys, when their height during development exceeds that of the storeys of fusiform cells. The primordial rays on the cambium surface have a non-storeyed arrangement. Prolonged predominance of splitting over uniting can lead to a situation in which the height of the rays does not exceed that of fusiform cell storeys. A storeyed arrangement of rays is thus formed. The maintenance of a given arrangement of rays in successive annual growths is the result of the cumulation of several traits, such as: 1 the seriation of rays, 2 the magnitude of grain inclination, 3 the rate of the restructuring of the cell arrangement. For example, the quicker a storeyed arrangement of rays will be formed the less the rays are seriated, the quicker the cells are restructured and the greater the inclination of their arrangement. The magnitude of the inclination of the grain and the rate of cell restructuring are traits connected with the arrangement of fusiform cells. The seriate nature of rays, however, is characteristic of rays and, moreover, it is a characteristic individual trait. It seems that the seriation of rays can play a valuable role in taxonomic analysis.

  10. Increase of xylan synthetase activity during xylem differentiation of the vascular cambium of sycamore and poplar trees.

    Science.gov (United States)

    Dalessandro, G; Northcote, D H

    1981-01-01

    The activity of a β-(1-4)-xylan synthetase, a membrane-bound enzymic system, was measured in particulate enzymic preparations (1,000 g and 1,000-100,000 g pellets) obtained from homogenates of cambial cells, differentiating xylem cells and differentiated xylem cells isolated from actively growing trees of sycamore (Acer pseudoplatamus) and poplar (Populus robusta). The specific activity (nmol of xylan formed min(-1) mg(-1) of protein) as well as the activity calculated on a per cell basis (nmol of xylan formed min(-1) cell(-1)) of this enzymic system, markedly increased as cells differentiate from the vascular cambium to xylem. This increase is closely correlated with the enhanced deposition of xylan occurring during the formation of secondary thickening. The possible control of xylan synthesis during the biogenesis of plant cell wall is discussed.

  11. Changes in enzymic activities of nucleoside diphosphate sugar interconversions during differentiation of cambium to xylem in sycamore and poplar.

    Science.gov (United States)

    Dalessandro, G; Northcote, D H

    1977-02-15

    During the transition from primary wall formation to secondary thickening there is a marked shift in the synthesis of pectin, hemicellulose and cellulose. The activities of the enzymes [UDP-D-galactose 4-epimerase (EC 5.1.3.2)8 UDP-l-arabinose 4-epimerase (EC 5.1.3.5), UDP-D-glucose dehydrogenase (EC 1.1.1.22) and UDP-D--glucuronate decarboxylase (EC 4.1.1.35)] were measured in cambial cells, differentiating xylem cells and differentiated xylem cells isolated from sycamore and poplar trees, and phloem cells from poplar. At the final stage of the differentiation of cambium to xylem there was a decrease in activity of the enzymes directly involved in producing the soluble precursors of pectin (DUP-D-galactose 4-epimerase and UDP-L-arabinose 4-epimerase and an increase in those producing the precursors of hemicellulose (UDP-D-glucose dehydrogenase and UDP-D-glucuronate decarboxylase). These results strongly suggest ahat the changes were correlated with the differences observed in the chemical composition of the wall during development. The changes found in the catalytic activity of the enzymes of nucleoside diphosphate sugar interconversion exert a coarse control over the synthesis of pectin and hemicelluloses. The tissues at all stages of development contained the necessary enzyme activities to produce all the precursors of pectin and hemicellulose, even at the final stage of differentiation when no pectin was formed.

  12. The intrusive growth of initial cells in re-arangement of cells in cambium of Tilia cordata Mill.

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    Wiesław Włoch

    2014-02-01

    Full Text Available In the cambium of linden producing wood with short period of grain inclination change (2-4 years, the intensive reorientation of cells takes place. This is possible mainly through an intrusive growth of cell ends from one radial file entering space between tangential walls of neighboring file and through unequal periclinal divisions that occur in the "initial surface". The intrusive growth is located on the longitudinal edge of a fusiform cell close to the end, and causes deviation of cell ends in a neighbouring file from the initial surface. Unequal periclinal division divides a cell with a deviated end into two derivatives, unequal in size. The one of them, which inherits the deviated end, leaves the initial surface becoming a xylem or phloem mother cell. This means that the old end is eliminated. The intensity of intrusive growth and unequal periclinal divisions is decisive for the velocity of cambial cell reorientation. The oriented intrusive growth occurs only in the initial cells. For that reason, changes in cell-ends position do not occur within one packet of cells but are distinct between neighbouring packets.

  13. Size variation in the vascular cambium and its derivatives in two Alstonia species Variação em tamanho do cambio vascular e seus tecidos derivados em duas espécies de Alstonia

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    Moin A. Khan

    2007-09-01

    Full Text Available Two tropical tree species viz. Alstonia venenata Br. and Alstonia neriifolia Don. (Apocynaceae were investigated to detect size variation in different elements of the cambium and its derivative tissues. Although these two species were grown under identical climatic and edaphic conditions, fusiform initial dimensions and the elements derived from them were larger in A. venenata than in A. neriifolia. Ray initials are rectangular in A. venenata but isodiametric in A. neriifolia. An appreciable increase in length was observed in the phloem and xylem ray cells when compared to the mother cells. Maximum elongation was observed in xylem fibers during differentiation from the respective fusiform initials.Duas espécies de árvores tropicais (Alstonia venenata Br. e Alstonia neriifolia Don. - Apocynaceae foram estudadas para detectar variação em tamanho de diversos elementos do cambio e seus tecidos derivados. Embora as condições de clima e edaficas destas duas espécies fossem identicas, as dimensões das iniciais fusiformes e os elementos derivados destas foram maiores em A. venenata do que em A. neriifolia. As iniciais radiais são retangulares em A. venenata porem são isodiamêtricas em A. neriifolia. Foi observado aumento substancial no comprimento das células do floema e xilema quando comparadas com as células mãe. Alongamento máximo foi observado nas fibras do xilema durante a diferenciação das respectivas iniciais fusiformes.

  14. Behavioral responses of leaves and vascular cambium of Prosopis cineraria (L.) Druce to different regimes of coal-smoke pollution

    Energy Technology Data Exchange (ETDEWEB)

    Iqbal, M.; Mahmooduzzafar; Aref, I.M.; Khan, P.R. [Hamdard University, New Delhi (India). Faculty of Science

    2010-07-01

    The foliar and cambial responses of Prosopis cineraria to five different coal-smoke regimes in Delhi, India, were studied using the monthly collections of leaves and cambial blocks as well as the data on SO{sub 2}, NO{sub 2} and particulate concentrations from each of the five study sites. Coal-smoke inhibited pigment concentration, NR activity and sugar content and promoted stomatal index and the nitrate and sulfur contents. Stomatal conductance was low, leading to a drop in the net photosynthetic rate. Cambial activity started quite late and the annual increment of wood was reduced despite a prolonged active phase, possibly due to a distinctly retarded rate of cambial cell division. Vessel proportion in the wood increased but the size of vessel elements and fibers decreased. Such studies may help in identifying trees suitable for cultivation in the pollution-affected areas.

  15. Intra-annual dynamics of non-structural carbohydrates in the cambium of mature conifer trees reflects radial growth demands.

    Science.gov (United States)

    Simard, Sonia; Giovannelli, Alessio; Treydte, Kerstin; Traversi, Maria Laura; King, Gregory M; Frank, David; Fonti, Patrick

    2013-09-01

    The presence of soluble carbohydrates in the cambial zone, either from sugars recently produced during photosynthesis or from starch remobilized from storage organs, is necessary for radial tree growth. However, considerable uncertainties on carbohydrate dynamics and the consequences on tree productivity exist. This study aims to better understand the variation in different carbon pools at intra-annual resolution by quantifying how cambial zone sugar and starch concentrations fluctuate over the season and in relation to cambial phenology. A comparison between two physiologically different species growing at the same site, i.e., the evergreen Picea abies Karst. and the deciduous Larix decidua Mill., and between L. decidua from two contrasting elevations, is presented to identify mechanisms of growth limitation. Results indicate that the annual cycle of sugar concentration within the cambial zone is coupled to the process of wood formation. The highest sugar concentration is observed when the number of cells in secondary wall formation and lignification stages is at a maximum, subsequent to most radial growth. Starch disappears in winter, while other freeze-resistant non-structural carbohydrates (NSCs) increase. Slight differences in NSC concentration between species are consistent with the differing climate sensitivity of the evergreen and deciduous species investigated. The general absence of differences between elevations suggests that the cambial activity of trees growing at the treeline was not limited by the availability of carbohydrates at the cambial zone but instead by environmental controls on the growing season duration.

  16. Dicty_cDB: Contig-U12722-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available ) GQ02809.SP6_D22 GQ028 - Cambium / phloem scrappin... 48 0.63 1 ( EX315666 ) GQ02809.B7_D22 GQ028 - Cambium / phloem scrap...ping... 48 0.63 1 ( EX312653 ) GQ02804.SP6_F06 GQ028 - Cambium / phloem scrap...pin... 48 0.63 1 ( EX312312 ) GQ02804.B7_F06 GQ028 - Cambium / phloem scrapping... 48 0.63 1 ( AC

  17. Dicty_cDB: Contig-U11082-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available 58 ) GQ02811.B7_D08 GQ028 - Cambium / phloem scrapping... 46 3e-05 3 ( EX312195 ) GQ02804.B7_A02 GQ028 - Cambium / phloem scrap...ping... 46 3e-05 3 ( EX313127 ) GQ02805.B7_M12 GQ028 - Cambium / phloem scrapping... 46 3...GQ031 - Xylem Scrapings (Normalize... 46 3e-05 3 ( EX317077 ) GQ02811.B7_E03 GQ028 - Cambium / phloem scrapp

  18. Dicty_cDB: Contig-U15430-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available rmalize... 48 1.4 1 ( EX321443 ) GQ02817.SP6_D02 GQ028 - Cambium / phloem scrappin... 48 1.4 1 ( EX321074 ) ...GQ02817.B7_D02 GQ028 - Cambium / phloem scrapping... 48 1.4 1 ( EX319276 ) GQ0281...4.SP6_A05 GQ028 - Cambium / phloem scrappin... 48 1.4 1 ( EX318985 ) GQ02814.B7_A05 GQ028 - Cambium / phloem scrap

  19. Dicty_cDB: Contig-U11967-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available 9.SP6_A14 GQ028 - Cambium / phloem scrappin... 42 9e-05 2 ( EX328735 ) GQ02829.B7..._A14 GQ028 - Cambium / phloem scrapping... 42 9e-05 2 ( EX326205 ) GQ02824.SP6_M13 GQ028 - Cambium / phloem scrap

  20. Dicty_cDB: Contig-U15927-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available ondary xylem of girdled... 54 0.031 1 ( EX318935 ) GQ02813.SP6_N02 GQ028 - Cambium / phloem scrappin... 54 0....031 1 ( EX318604 ) GQ02813.B7_N02 GQ028 - Cambium / phloem scrapping... 54 0.031 1 ( EX317857 ) GQ02812.B7_...I07 GQ028 - Cambium / phloem scrapping... 54 0.031 1 ( EX314053 ) GQ02806.SP6_H13... GQ028 - Cambium / phloem scrappin... 54 0.031 1 ( EX313703 ) GQ02806.B7_H13 GQ028 - Cambium / phloem scrapp

  1. Dicty_cDB: Contig-U04603-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available appin... 44 8.6 1 ( EX318360 ) GQ02813.B7_B23 GQ028 - Cambium / phloem scrap...ping... 44 8.6 1 ( EX315990 ) GQ02809.SP6_C18 GQ028 - Cambium / phloem scrappin... 44 8....6 1 ( EX315638 ) GQ02809.B7_C18 GQ028 - Cambium / phloem scrapping... 44 8.6 1 ( EX315442 ) GQ02808.SP6_J18 ...GQ028 - Cambium / phloem scrappin... 44 8.6 1 ( EX315097 ) GQ02808.B7_J18 GQ028 - Cambium / phloem scrap... ( EX344349 ) GQ03102.B7_I10 GQ031 - Xylem Scrapings (Normalize... 44 8.6 1 ( EX318692 ) GQ02813.SP6_B23 GQ028 - Cambium / phloem scr

  2. Dicty_cDB: Contig-U06545-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available GQ02803.SP6_N23 GQ028 - Cambium / phloem scrappin... 58 4e-04 1 ( EX311897 ) GQ0...2803.B7_N23 GQ028 - Cambium / phloem scrapping... 58 4e-04 1 ( EX310949 ) GQ02801.SP6_H09 GQ028 - Cambium / phloem scrap...pin... 58 4e-04 1 ( EX310884 ) GQ02801.SP6_E04 GQ028 - Cambium / phloem scrappin... 58 4e-04 1 (... EX310628 ) GQ02801.B7_H09 GQ028 - Cambium / phloem scrapping... 58 4e-04 1 ( EX3...10566 ) GQ02801.B7_E04 GQ028 - Cambium / phloem scrapping... 58 4e-04 1 ( AL929353 ) Plasmodium falciparum s

  3. Cambium generation and cellulose physical structure by growth stage and plant sex in ‘Yunma No.1’ hemp stalk%生长期和植株性别对‘云麻1号’麻秆部分物理特性的影响

    Institute of Scientific and Technical Information of China (English)

    王齐玮; 吴宁; 杜官本; 吴章康; 李晓平; 徐宝

    2015-01-01

    利用广角X-射线衍射仪和显微镜研究了生长期和植株性别对‘云麻1号’工业大麻Cannabis sativa ‘Yunma No.1’麻秆形成层分生、纤维素相对结晶度和晶胞尺寸的影响.结果表明:在整个生长期内大麻秆茎部的纤维中,大麻纤维的相对结晶度随着生长期不断变化而变化,但整个生长期内变化幅度都不是很大;生长期为19~35 d,晶胞大小为0.230~0.245 nm,在生长期42~186 d,晶胞的大小较前面有所下降,大约为0.137 nm,并且基本保持不变;同一生长期,雌株的细胞层数比雄株的细胞层数略多;生长期77~91 d时,雄株的相对结晶度要高于雌株,而在生长期98~186 d,雌株的相对结晶度高于雄株;在77~186 d的生长期中,雌雄株晶胞尺寸的变化范围为0.136~0.150 nm.晶胞尺寸与生长期,细胞层数和相对结晶度之间没有显著的相关性.

  4. Dicty_cDB: Contig-U10553-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available abelii mRNA; EST DKFZp470M2011_r1 (from clo... 48 0.34 1 ( EX328636 ) GQ02828.SP6_M06 GQ028 - Cambium / phloem scrap...pin... 48 0.34 1 ( EX328273 ) GQ02828.B7_M06 GQ028 - Cambium / phloem scrapping... 48 0.34 1 ( EX327...971 ) GQ02827.SP6_O02 GQ028 - Cambium / phloem scrappin... 48 0.34 1 ( EX327671 )... GQ02827.B7_O02 GQ028 - Cambium / phloem scrapping... 48 0.34 1 ( BX936281 ) Zebrafish DNA sequence *** SEQU

  5. The activity of uridine diphosphate-D-glucose: Nicotinamide-adenine dinucleotide oxidoreductase in cambial tissue and differentiating xylem isolated from sycamore trees.

    Science.gov (United States)

    Rubery, P H

    1972-06-01

    The activity of UDPGlc: NAD oxidoreductase is measured in enzyme preparations obtained from sycamore cambium and xylem tissue. The activity of this enzyme is greater in xylem than in cambium whether expressed on a specific activity basis or on a per-cell basis. It is suggested that, in developing xylem, direct oxidation of UDPGlc may contribute significantly to the biosynthesis of polysaccharide precursors.

  6. Dicty_cDB: Contig-U12140-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available B12.5pR Populus active cambium cDNA library... 46 3.6 1 ( BU823926 ) UB58DPB12 Populus tremula cambium cDNA library Po...._1( AK221351 |pid:none) Arabidopsis thaliana mRNA for hypo... 55 5e-06 AC015447_3( AC015447 |pid:none) Arabi

  7. Dicty_cDB: Contig-U15912-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available P5323RG8.T0 Acorn worm normalized juvenile pE... 56 3e-10 4 ( EX320945 ) GQ02816.SP6_N15 GQ028 - Cambium / phloem scrap...pin... 68 5e-09 2 ( EX320576 ) GQ02816.B7_N15 GQ028 - Cambium / phloem scrap

  8. Dicty_cDB: Contig-U02375-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available Cryptomeria japonica cDNA clone: CMFL031_P02, 5'e... 44 4.9 1 ( EX314727 ) GQ02807.SP6_I05 GQ028 - Cambium / phloem scrap...pin... 44 4.9 1 ( EX314403 ) GQ02807.B7_I05 GQ028 - Cambium / phloem scrap

  9. Dicty_cDB: Contig-U05055-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available 8.SP6_G24 GQ030 - Xylem planings - daytime ... 44 10.0 1 ( EX316108 ) GQ02809.SP6_I08 GQ028 - Cambium / phloem scrap...pin... 44 10.0 1 ( EX315761 ) GQ02809.B7_I08 GQ028 - Cambium / phloem scrapping... 44 10.0 1 ( DQ074

  10. Dicty_cDB: Contig-U01890-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available protein LOC443612, mR... 52 1e-06 2 ( EX326292 ) GQ02825.B7_A20 GQ028 - Cambium / phloem scrapping... 62 4e...2825.SP6_A20 GQ028 - Cambium / phloem scrappin... 62 6e-05 1 ( FK908043 ) EST_lsal_evj_932496 lsalevj mixed_

  11. Dicty_cDB: Contig-U10652-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available WS03820.C21_M12 SS-B-23 Picea sitchensis cDNA clo... 62 3e-05 1 ( EX321390 ) GQ02817.SP6_A20 GQ028 - Cambium / phloem scrap...pin... 62 3e-05 1 ( EX321020 ) GQ02817.B7_A20 GQ028 - Cambium / phloem scrap

  12. Dicty_cDB: Contig-U13795-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available ) GQ03212.B7_H17 GQ032 - Shoot tip (Normalized libr... 54 0.006 1 ( EX320896 ) GQ02816.SP6_L13 GQ028 - Cambium / phloem scrap...pin... 54 0.006 1 ( EX320527 ) GQ02816.B7_L13 GQ028 - Cambium / phloem scrap

  13. Dicty_cDB: Contig-U14675-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available P(XYZ) lettuce perennis Lac... 46 2e-15 6 ( EX317051 ) GQ02811.B7_D01 GQ028 - Cambium / phloem scrapping... ...) WS0099.B21.1_L03 IS-B-N-A-10 Picea engelmannii x ... 74 5e-13 3 ( EX317416 ) GQ02811.SP6_D01 GQ028 - Cambium / phloem scrap

  14. Dicty_cDB: Contig-U05088-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available Shoot tip (Normalized li... 44 6.9 1 ( EX314035 ) GQ02806.SP6_G17 GQ028 - Cambium / phloem scrappin... 44 6....9 1 ( EX313684 ) GQ02806.B7_G17 GQ028 - Cambium / phloem scrapping... 44 6.9 1 ( EV276953 ) GLMCY94TF JCVI-

  15. Dicty_cDB: Contig-U10799-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available 66 2e-11 2 ( EX313750 ) GQ02806.B7_J14 GQ028 - Cambium / phloem scrapping... 50 2e-11 3 ( AF026545 ) Pneumoc...ive growth ... 50 3e-11 3 ( EX314098 ) GQ02806.SP6_J14 GQ028 - Cambium / phloem scrap

  16. Dicty_cDB: Contig-U16300-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available . 74 1e-24 5 ( EX321078 ) GQ02817.B7_D06 GQ028 - Cambium / phloem scrapping... 58 1e-24 6 ( DY264647 ) IC0AA...ary xyle... 74 5e-19 5 ( EX328679 ) GQ02828.SP6_O05 GQ028 - Cambium / phloem scrap...B7_N21 GQ038 - Stem - Active growth Picea... 74 1e-18 4 ( EX328548 ) GQ02828.SP6_I10 GQ028 - Cambium / phloem scrap... ( EX317133 ) GQ02811.B7_G11 GQ028 - Cambium / phloem scrapping... 68 2e-17 4 ( EX359273 ) GQ03201.B7_K15 GQ...u... 62 3e-17 4 ( EX328318 ) GQ02828.B7_O05 GQ028 - Cambium / phloem scrapping... 74 3e-17 3 ( CK739401 ) US

  17. Dicty_cDB: Contig-U04870-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available Q032 - Shoot tip (Normalized libr... 46 0.17 2 ( EX311742 ) GQ02803.B7_F05 GQ028 - Cambium / phloem scrappin...820.B7_F01 GQ028 - Cambium / phloem scrapping... 46 0.17 2 ( EX373838 ) GQ03228.B7_N08 GQ032 - Shoot tip (No...Normalized libr... 46 0.18 2 ( EX314238 ) GQ02807.B7_A02 GQ028 - Cambium / phloem scrapping... 46 0.19 2 ( E... ) GQ03203.B7_A07 GQ032 - Shoot tip (Normalized libr... 46 2.6 1 ( EX323619 ) GQ02820.SP6_F01 GQ028 - Cambium / phloem scrap...pin... 46 2.6 1 ( EX314565 ) GQ02807.SP6_A02 GQ028 - Cambium / phloem scrap

  18. Dicty_cDB: Contig-U06838-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available .SP6_M18 GQ029 - Xylem scrapings - AT NITE... 48 0.29 1 ( EX332407 ) GQ02904.B7_M18 GQ029 - Xylem scrapings ...- AT NITE ... 48 0.29 1 ( EX320804 ) GQ02816.SP6_H13 GQ028 - Cambium / phloem scrap...pin... 48 0.29 1 ( EX320433 ) GQ02816.B7_H13 GQ028 - Cambium / phloem scrapping... 48 0.29 1 ( EX318356 ) ...GQ02813.B7_B18 GQ028 - Cambium / phloem scrapping... 48 0.29 1 ( EX316825 ) GQ02810.SP6_J03 GQ028 - Cambium / phloem scrap...pin... 48 0.29 1 ( EX316470 ) GQ02810.B7_J03 GQ028 - Cambium / phloem scrap

  19. Dicty_cDB: Contig-U15039-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available Q02828.SP6_G20 GQ028 - Cambium / phloem scrappin... 40 1e-07 3 ( DR476779 ) WS00968.C21_G22 IS-B-N-A-10 Pice...6_M13 GQ028 - Cambium / phloem scrappin... 40 2e-07 3 ( CB089832 ) gp29d06.g1 Cycad Leaf Library (NYBG) Cyca... 3 ( EX328280 ) GQ02828.B7_M13 GQ028 - Cambium / phloem scrapping... 40 2e-07 3 (...: Clean ROOTS systems - P trea... 40 2e-07 3 ( EX312157 ) GQ02803.SP6_N22 GQ028 - Cambium / phloem scrappin...... 40 2e-07 3 ( EX311896 ) GQ02803.B7_N22 GQ028 - Cambium / phloem scrapping... 4

  20. Dicty_cDB: Contig-U00877-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available ( FD738267 ) WS03943.C21_P02 SS-B-24 Picea sitchensis cDNA clo... 34 1.5 2 ( EX318804 ) GQ02813.SP6_G23 GQ028 - Cambium / phloem scra..... 36 1.5 2 ( EX316698 ) GQ02810.SP6_D03 GQ028 - Cambium / phloem scrappin... 34 ...1.5 2 ( EX318475 ) GQ02813.B7_G23 GQ028 - Cambium / phloem scrapping... 34 1.5 2 ( DN200103 ) USDA-FP_138167

  1. Genetic and hormonal regulation of cambial development.

    Science.gov (United States)

    Ursache, Robertas; Nieminen, Kaisa; Helariutta, Ykä

    2013-01-01

    The stems and roots of most dicot plants increase in diameter by radial growth, due to the activity of secondary meristems. Two types of meristems function in secondary plant body formation: the vascular cambium, which gives rise to secondary xylem and phloem, and the cork cambium, which produces a bark layer that replaces the epidermis and protects the plant stem from mechanical damage and pathogens. Cambial development, the initiation and activity of the vascular cambium, leads to an accumulation of wood, the secondary xylem tissue. The thick, cellulose-rich cell walls of wood provide a source of cellulose and have the potential to be used as a raw material for sustainable and renewable energy production. In this review, we will discuss what is known about the mechanisms regulating the cambium and secondary tissue development. PMID:22551327

  2. Dicty_cDB: Contig-U09330-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available ylem planings - daytime a... 60 1e-04 1 ( EX331539 ) GQ02903.B7_A06 GQ029 - Xylem scrapings - AT NITE ... 60... 1e-04 1 ( EX323057 ) GQ02819.SP6_M07 GQ028 - Cambium / phloem scrappin... 60 1e-04 1 ( EX322713 ) GQ02819.B...7_M07 GQ028 - Cambium / phloem scrapping... 60 1e-04 1 ( AV999726 ) Ciona intesti

  3. Comparative Root and Stem Anatomy of Four Rare Onobrychis Mill. (Fabaceae Taxa Endemic in Turkey

    Directory of Open Access Journals (Sweden)

    Mehmet TEKİN

    2015-09-01

    Full Text Available Four endemic taxa of Onobrychis Mill. genus, some of them being classified in the endangered threat category, were investigated for root and stem anatomy. Onobrychis quadrijuga, O. argyrea subsp. argyrea, O. tournefortii and O. albiflora were studied in regard to specific anatomy for the first time within the hereby study. Anatomical characters as the size and shape of the periderm, cortex, cambium cells in root and epidermis, collenchyma, cortex, cambium and pith cells in stem belonging to these four Onobrychis taxa were determined in detail. Based on the roots and stems measurements and analysis, specific anatomical differences between species were revealed.

  4. Dicty_cDB: Contig-U05491-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available e... 34 1.3 2 ( AF218854 ) Mus musculus cytochrome P450 arachidonic acid epo... 46 1.4 2 ( AL935317 ) Zebraf...sculus 4 days embryo whole body cDNA, RIKEN... 46 1.9 1 ( BU822411 ) UB37DPB03 Populus tremula cambium cDNA library Po.

  5. Dicty_cDB: Contig-U05050-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available A librar... 48 0.57 1 ( BU820098 ) UA51CPC05 Populus tremula cambium cDNA library Po... 48 0.57 1 ( BA000026...Full=Vesicle-trafficking protein SEC22b; AltNa... 48 4e-04 AY850353_1( AY850353 |pid:none) Magnaporthe grisea protein transpo.

  6. Repellence of the red bud borer (Resseliella oculiperda) to grafted apple trees by impregnation of budding tape with essential oils

    NARCIS (Netherlands)

    Tol, van R.W.H.M.; Linden, van der A.; Swarts, H.J.; Visser, J.H.

    2007-01-01

    The red bud borer Resseliella oculiperda (Rübs.) is a pest insect of apple trees when rootstocks are grafted with scion buds by shield budding. The female midges are attracted to the wounds of the grafted buds where they lay their eggs. The larvae feed on the cambium and destroy the buds completely

  7. Strigolactone analogues and their use

    KAUST Repository

    Al-Babili, Salim

    2015-03-17

    Novel compounds of formula (I) their use as germination trap for parasitic weeds, for the regulation of branching, tillering and root development, for enhancement of cambium growth, for the regulation of hyphal growth of mycorrhizal fungi and compositions comprising compounds of formula (I) and insecticides and/or fungicides.

  8. Dicty_cDB: SHH135 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available and phloem from mature trees Picea glauca cDNA clone GenomeQuebec_Id:GQ00610_L03 5', mRNA sequence. 44 1e-0...RNA, partial cds. 1265 0.0 1 DV977319 |DV977319.1 GQ00610.B3.1_L03 GQ006: Cambium

  9. Dicty_cDB: Contig-U14381-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available _J09 GQ031 - Xylem Scrapings (Normaliz... 44 9.0 1 ( EX331458 ) GQ02902.SP6_M12 GQ029 - Xylem scrapings - AT... NITE... 44 9.0 1 ( EX316044 ) GQ02809.SP6_F04 GQ028 - Cambium / phloem scrappin... 44 9.0 1 >( AU038582 ) D

  10. Dicty_cDB: Contig-U15059-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available 689 ) GQ02819.B7_L06 GQ028 - Cambium / phloem scrapping... 56 1e-13 2 ( EX426360 ) GQ03813.B7_B24 GQ038 - St...-13 4 ( EX332277 ) GQ02904.B7_G20 GQ029 - Xylem scrapings - AT NITE ... 54 2e-12 2 ( BJ400850 ) Dictyosteliu

  11. Dicty_cDB: Contig-U09222-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available . 50 0.071 1 ( EX330315 ) GQ02901.B7_H16 GQ029 - Xylem scrapings - AT NITE ... 50... 0.071 1 ( EX312476 ) GQ02804.B7_M18 GQ028 - Cambium / phloem scrapping... 50 0.071 1 ( CE507331 ) tigr-gss-

  12. Dicty_cDB: Contig-U15294-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available ngs (Normalize... 46 5.5 1 ( EX334633 ) GQ02907.SP6_G12 GQ029 - Xylem scrapings - AT NITE... 46 5.5 1 ( EX31...6004 ) GQ02809.SP6_D08 GQ028 - Cambium / phloem scrappin... 46 5.5 1 ( EX309517 )

  13. Dicty_cDB: Contig-U04691-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available lem Scrapings (Normalize... 50 0.11 1 ( EX335210 ) GQ02908.SP6_C04 GQ029 - Xylem scrapings - AT NITE... 50 0....11 1 ( EX334873 ) GQ02908.B7_C04 GQ029 - Xylem scrapings - AT NITE ... 50 0.11 1... ( EX331900 ) GQ02903.SP6_D04 GQ029 - Xylem scrapings - AT NITE... 50 0.11 1 ( EX331595 ) GQ02903.B7_D04 GQ029 - Xylem scrap...ings - AT NITE ... 50 0.11 1 ( EX319300 ) GQ02814.SP6_B05 GQ028 - Cambium / phloem scrappin...... 50 0.11 1 ( EX319007 ) GQ02814.B7_B05 GQ028 - Cambium / phloem scrapping... 50

  14. Molecular Mechanisms for Vascular Development and Secondary Cell Wall Formation

    Science.gov (United States)

    Yang, Jung Hyun; Wang, Huanzhong

    2016-01-01

    Vascular tissues are important for transporting water and nutrients throughout the plant and as physical support of upright growth. The primary constituents of vascular tissues, xylem, and phloem, are derived from the meristematic vascular procambium and cambium. Xylem cells develop secondary cell walls (SCWs) that form the largest part of plant lignocellulosic biomass that serve as a renewable feedstock for biofuel production. For the last decade, research on vascular development and SCW biosynthesis has seen rapid progress due to the importance of these processes to plant biology and to the biofuel industry. Plant hormones, transcriptional regulators and peptide signaling regulate procambium/cambium proliferation, vascular patterning, and xylem differentiation. Transcriptional regulatory pathways play a pivot role in SCW biosynthesis. Although most of these discoveries are derived from research in Arabidopsis, many genes have shown conserved functions in biofuel feedstock species. Here, we review the recent advances in our understanding of vascular development and SCW formation and discuss potential biotechnological uses. PMID:27047525

  15. The effect of cambial zone isolation upon the autolytic system in maturing tracheids of pine (Pinus silvestris L.

    Directory of Open Access Journals (Sweden)

    Jacek Zakrzewski

    2014-02-01

    Full Text Available The autolytic protease system in maturing tracheids of the main stem of Pinus silvestris was investigated after separation (using surgical methods of the cambial zone from the layer of differentiating xylem, in combination with decapitation and IAA application. Separation of the cambium prevented autolysis of the protoplast in maturing tracheids, although the specific activity of proteases was little reduced. It was found that a radial or longitudinal concentration gradient of exogenously applied auxin was not responsible for autolysis, but that it could influence the level of extracted protein, and proteolytic activity. Similarly, decapitation modified, only to small degree, the effects of the cambium separation. Thus, the data from this experiment lead to the conclusion that integration of all cells in the region of xylem formation is a crucial factor for the start of autolytic protoplast breakdown. Possible involvement of auxin waves in the transfer of the positional information for this process is suggested.

  16. AINTEGUMENTA and the D-type cyclin CYCD3;1 regulate root secondary growth and respond to cytokinins.

    Science.gov (United States)

    Randall, Ricardo S; Miyashima, Shunsuke; Blomster, Tiina; Zhang, Jing; Elo, Annakaisa; Karlberg, Anna; Immanen, Juha; Nieminen, Kaisa; Lee, Ji-Young; Kakimoto, Tatsuo; Blajecka, Karolina; Melnyk, Charles W; Alcasabas, Annette; Forzani, Celine; Matsumoto-Kitano, Miho; Mähönen, Ari Pekka; Bhalerao, Rishikesh; Dewitte, Walter; Helariutta, Ykä; Murray, James A H

    2015-01-01

    Higher plant vasculature is characterized by two distinct developmental phases. Initially, a well-defined radial primary pattern is established. In eudicots, this is followed by secondary growth, which involves development of the cambium and is required for efficient water and nutrient transport and wood formation. Regulation of secondary growth involves several phytohormones, and cytokinins have been implicated as key players, particularly in the activation of cell proliferation, but the molecular mechanisms mediating this hormonal control remain unknown. Here we show that the genes encoding the transcription factor AINTEGUMENTA (ANT) and the D-type cyclin CYCD3;1 are expressed in the vascular cambium of Arabidopsis roots, respond to cytokinins and are both required for proper root secondary thickening. Cytokinin regulation of ANT and CYCD3 also occurs during secondary thickening of poplar stems, suggesting this represents a conserved regulatory mechanism. PMID:26340943

  17. AINTEGUMENTA and the D-type cyclin CYCD3;1 regulate root secondary growth and respond to cytokinins

    Directory of Open Access Journals (Sweden)

    Ricardo S. Randall

    2015-10-01

    Full Text Available Higher plant vasculature is characterized by two distinct developmental phases. Initially, a well-defined radial primary pattern is established. In eudicots, this is followed by secondary growth, which involves development of the cambium and is required for efficient water and nutrient transport and wood formation. Regulation of secondary growth involves several phytohormones, and cytokinins have been implicated as key players, particularly in the activation of cell proliferation, but the molecular mechanisms mediating this hormonal control remain unknown. Here we show that the genes encoding the transcription factor AINTEGUMENTA (ANT and the D-type cyclin CYCD3;1 are expressed in the vascular cambium of Arabidopsis roots, respond to cytokinins and are both required for proper root secondary thickening. Cytokinin regulation of ANT and CYCD3 also occurs during secondary thickening of poplar stems, suggesting this represents a conserved regulatory mechanism.

  18. Radiosensitivity of different tissues from carrot root at different phases of growth in culture

    International Nuclear Information System (INIS)

    The present work compares the effect of γ-radiation dose and time in culture on the growth of cambium and phloem carrot (Daucus carota) root explants. It was found that the phloem is more radiosensitive than the cambium and that both tissues were more radiosensitive when irradiated on excision at the G1 phase rather than at the end of the lag phase on the ninth day of growth in culture when cells were predominantly at the G2 phase. The nuclear volumes of cells from both tissues were similar but were larger at the end of the more radioresistant lag phase than those of the G1 phase on excision. However, nuclear volume could not account for the differences in radiosensitivity between either the tissues or irradiation times in culture

  19. ANATOMY OF GYNURA AURANTIACA (BLUME) SCH.BIP. EX DC. (ASTERACEAE)

    OpenAIRE

    Rodica BERCU

    2014-01-01

    The paper presents a detailed histoanatomical description, of the vegetative organs (root, stem and leaf) and photographs as well of Gynura aurantiaca (Blume) Sch.Bip. ex DC. It was observed that the root have typical primary dictos structure. The stem has a differentiated in two regions cortex and the stele comprise one ring of open collateral vascular bundles with secondary xylem due to the cambium activity. The petiole anatomy is quite similar in its basic structure with the stem. The blad...

  20. Role of Cytokinin and Auxin in Shaping Root Architecture: Regulating Vascular Differentiation, Lateral Root Initiation, Root Apical Dominance and Root Gravitropism

    OpenAIRE

    Aloni, R; ALONI, E.; Langhans, M.; ULLRICH, C. I.

    2006-01-01

    • Background and Aims Development and architecture of plant roots are regulated by phytohormones. Cytokinin (CK), synthesized in the root cap, promotes cytokinesis, vascular cambium sensitivity, vascular differentiation and root apical dominance. Auxin (indole-3-acetic acid, IAA), produced in young shoot organs, promotes root development and induces vascular differentiation. Both IAA and CK regulate root gravitropism. The aims of this study were to analyse the hormonal mechanisms that induce ...

  1. Non-destructive heat treatment of trees to stop disease progression

    OpenAIRE

    Lammeren, van, A.A.M.; Keijzer, de, S.; Ketelaar, M.J.; Kuik, van, A.J.

    2014-01-01

    Some bacterial species are major pathogens of trees. Establishment, growth and the quality of trees can be affected by these disease outbreaks. Infected trees exhibit extensive necrosis of phloem and cambium, which can ultimately lead to dieback. The endophytic localization of and ability of these pathogens to create a protective matrix render them poorly accessible to control agents. The present invention provides methods and apparatus for controlling or stopping bacterial infections in tree...

  2. Bio-ecological Peculiarities of Taxus baccata L. in Decorative Gardening of Eastern Georgia

    OpenAIRE

    Tamar Nadiradze

    2014-01-01

    The article discusses contemporary bio-ecological conditions of Taxus baccata L. in its natural distribution area of Georgia, particularly in Batsara National Preserve. Contemporary bio-ecological conditions of Taxus baccata L. spread in decorative gardening of eastern Georgia have also been studied based on the samples of the collection (47 pieces) of Tsinandali Arboretum. We have studied the periods of bud opening, vegetation ending, starting and finishing of cambium action, sprout woode...

  3. Bio-ecology of Taxus Baccata l. in Kakheti

    OpenAIRE

    Tamar Nadiradze

    2013-01-01

    The article discusses the bio-ecology of Taxus baccata L. in Kakheti (eastern Georgia), particularly in Tsinandali Park. Yew (Taxus baccata L.) preserved in Tsinandali Park (Telavi region, Georgia) was chosen as an object for long-lasting observation over plant vegetation. Vegetation of 47 new specimens were studied during the period 2001-2010. It was observed the buds opening, the vegetation finishing, the cambium active periods beginning and finishing, the sprout stiffen process, the rate a...

  4. Missing rings in Pinus halepensis

    OpenAIRE

    Novak, Klemen; De Luis, Martin; Saz, Miguel Angel; Longares, Luis Alberto; Serrano-Notivoli, Roberto; Raventós, Josep; Čufar, Katarina; Gričar, Jožica; Di Filippo, Alfredo; Piovesan, Gianluca; Rathgeber, Cyrille; Papadopoulos, Andreas; Kevin T. Smith

    2016-01-01

    Climate predictions for the Mediterranean Basin include increased temperatures, decreased precipitation, and increased frequency of extreme climatic events (ECE). These conditions are associated with decreased tree growth and increased vulnerability to pests and diseases. The anatomy of tree rings responds to these environmental conditions. Quantitatively, the width of a tree ring is largely determined by the rate and duration of cell division by the vascular cambium. In the Mediterranean cli...

  5. WOX4 and WOX14 act downstream of the PXY receptor kinase to regulate plant vascular proliferation independently of any role in vascular organisation

    OpenAIRE

    Etchells, J. P.; Provost, C. M.; Mishra, L; Turner, S. R.

    2013-01-01

    In plants, the cambium and procambium are meristems from which vascular tissue is derived. In contrast to most plant cells, stem cells within these tissues are thin and extremely long. They are particularly unusual as they divide down their long axis in a highly ordered manner, parallel to the tangential axis of the stem. CLAVATA3-LIKE/ESR-RELATED 41 (CLE41) and PHLOEM INTERCALATED WITH XYLEM (PXY) are a multifunctional ligand-receptor pair that regulate vascular cell division, vascular organ...

  6. The effect of cambial zone isolation upon the autolytic system in maturing tracheids of pine (Pinus silvestris L.)

    OpenAIRE

    Jacek Zakrzewski; Krzysztof Rakowski

    2014-01-01

    The autolytic protease system in maturing tracheids of the main stem of Pinus silvestris was investigated after separation (using surgical methods) of the cambial zone from the layer of differentiating xylem, in combination with decapitation and IAA application. Separation of the cambium prevented autolysis of the protoplast in maturing tracheids, although the specific activity of proteases was little reduced. It was found that a radial or longitudinal concentration gradient of exogenously ap...

  7. PHYSICAL, MORPHOLOGICAL PROPERTIES AND RAMAN SPECTROSCOPY OF CHESTNUT BLIGHT DISEASED CASTANEA SATIVA MILL. WOOD

    Directory of Open Access Journals (Sweden)

    Gokhan Gunduz

    2016-03-01

    Full Text Available In this study, some of the physical and anatomical properties of Chestnut Blight Diseased (CBD wood were investigated, and the study also included observations using Raman spectroscopy. The objective of these investigations was to determine the extent of the damage that is done to the wood of the diseased chestnut trees, which must be removed from the forest and used in the manufacture of industrial products. It was indicated that most of the adverse effects of the disease were in the vascular cambium. There was a clear indication of deterioration of the wood in the last growth ring next to vascular cambium. In the diseased secondary xylem region next to vascular cambium; vessel diameter, vessel frequency and vessel element length had a decrease, and vessel and other cells were irregular compared to healthy wood. Spores were detected and identified as Cryphonectria parasitica (Murrill. Annual ring properties (annual growth ring width, latewood percentage, etc. were similar in diseased wood compared to healthy wood. The Raman spectroscopy results showed no significant changes in the structure of the cell wall or its components. After removing the diseased parts, unlimited usage of formerly wood is possible. Heat treatment of the wood is suggested before use in the interest of sanitation and dimensional stability.

  8. Influence of Temperature on Cambial Activity and Cell Differentiation in Quercus Sessiliflora and Acer Pseudoplatanus of Different Ages

    Directory of Open Access Journals (Sweden)

    Jožica Gričar

    2013-06-01

    Full Text Available We evaluated the response of active cambium of sessile oak (Quercus sessiliflora and sycamore maple (Acer pseudoplatanus to experimentally increased (20–22 °C and decreased (9–11 °C temperatures. Heating and cooling experiments on 150-year old Q. sessiliflora were performed during the growth season of 2007 and on 30-year old A. pseudoplatanus in 2008. In 2009, heating experiment was carried out on 30-year old Q. sessiliflora. For each treatment, two trees were selected of each species and sampled at 21-day intervals during the vegetation period and investigated by means of light microscopy. Continuously elevated temperatures slightly promoted the development of xylem cells in old Q. sessiliflora trees in the first month of cambial activity. However, no effect of elevated or decreased temperature was detected in the timing and dynamics of wood and phloem formation. The applied treatments, therefore, had no visible impact on the structure or width of the xylem or phloem increments in 2007. On the other hand, heating young A. pseudoplatanus trees provoked the development of epicormic shoots two months after the onset of the experiment and finally the death of trees. The cambium of those trees did not reactivate in 2008; xylem and phloem increments were consequently not formed. Low temperature treatments slowed down cell production at the very beginning of the growing season, but no alterations in wood or phloem formation dynamics or structure were observed later. The heating of young Q. sessiliflora trees caused the development of epicormic shoots and the death of trees four months after the experiment. The pattern of their dying was similar as in A. pseudoplatanus but with a two month delay. The observations indicate that tree age, thickness of dead bark and duration of the applied treatments influence the response of cambium. The development of dead bark is species specific and it occurs earlier in Q. sessiliflora than in A. pseudoplatanus

  9. Histo-anatomy of the stem of Solanum tuberosum L.

    Directory of Open Access Journals (Sweden)

    Monica SIPOS

    2008-05-01

    Full Text Available The paper reveals the anatomical structure of the stem of Solanum tuberosum L. in the incipient stages of the ontogenetic development (the popular denomination „sprout”. Cross sections of the stem of this species were performed. The appearance of the secondary structure – even in this early ontogenetic stage – was confirmed by the presence of the cambium and the tissues generated by this. As a result, at the potato, the purely primary structure of the stem is of a short duration.

  10. Wood Chemical Composition in Species of Cactaceae: The Relationship between Lignification and Stem Morphology

    OpenAIRE

    Jorge Reyes-Rivera; Gonzalo Canché-Escamilla; Marcos Soto-Hernández; Teresa Terrazas

    2015-01-01

    In Cactaceae, wood anatomy is related to stem morphology in terms of the conferred support. In species of cacti with dimorphic wood, a unique process occurs in which the cambium stops producing wide-band tracheids (WBTs) and produces fibers; this is associated with the aging of individuals and increases in size. Stem support and lignification have only been studied in fibrous tree-like species, and studies in species with WBTs or dimorphic wood are lacking. In this study, we approach this pro...

  11. Influences of environmental factors on the radial profile of sap flux density in Fagus crenata growing at different elevations in the Naeba Mountains, Japan.

    Science.gov (United States)

    Kubota, Mitsumasa; Tenhunen, John; Zimmerman, Reiner; Schmidt, Markus; Adiku, Samuel; Kakubari, Yoshitaka

    2005-05-01

    Sap flux density was measured continuously during the 1999 and 2000 growing seasons by the heat dissipation method in natural Fagus crenata Blume (Japanese beech) forests growing between 550 and 1600 m on the northern slope of the Kagura Peak of the Naeba Mountains, Japan. Sap flux density decreased radially toward the inner xylem and the decrease was best expressed in relation to the number of annual rings from the cambium, or in relation to the relative depth between the cambium and the trunk center, rather than as a function of absolute depth. The relative influences of radiation, vapor pressure deficit and soil water on sap flux density during the growing season were similar for the outer and inner xylem, and at all sites. Measurements of soil water content and water potential at a depth of 0.25 m demonstrated that sap flux density responded similarly and sensitively to water potential changes in this soil layer, despite large differences in rooting depth at different elevations, localizing one important control point in the functioning of this forest ecosystem. Identification of the relative influences of radiation, vapor pressure deficit and drying of the upper soil layer on sap flux density provides a framework for in-depth analysis of the control of transpiration in Japanese beech forests. In addition, the finding that the same general controls are operating on sap flux density despite climate gradients and large differences in overall forest stand structure will enhance understanding of water use by forests along elevation gradients.

  12. Study on Rooting Culture and Rooting Anatomy of Tree Peony 'Wulong Pengsheng' Regenerated Shoots%牡丹‘乌龙捧盛’组培苗生根及生根解剖学研究

    Institute of Scientific and Technical Information of China (English)

    贾文庆; 徐小博; 刘会超; 李纪元

    2013-01-01

    The tissue-cultured seedlings of tree peony ‘ Wulong Pengsheng' were used to study the effects of different plant growth regulators,culture methods,and holdfast on rooting.The morphological structure change during rooting was also observed using the method of paraffin section.The result showed that the best combination of plant growth regulators for rooting was IBA 3.0 mg · L-1 + NAA 0.6 mg · L-1.The treatment under the temperature of 4℃ for ten days was benefit to rooting,and the rate could reach 75.67%.It was identified that the adventitious root primordia of shoot in vitro originated from the vascular cambium cells,especially,the cross areas of cambium and pith ray and they started to differentiate at the 5th day and lasted to the 12th day.If the shoots were cultured in the root inducing medium for 12 days,it would lead to not only descend of rooting rate,but also showing callus of stem base,and leaf senescent.However,if they were transferred into the medium without hormone in time,the root primordial protruded the epidermis and developed normally after 5 days' culture.

  13. 气候变化对树木木质部生长影响的研究进展%Advances in Research on the Effect of Climatic Change on Xylem Growth of Trees

    Institute of Scientific and Technical Information of China (English)

    程瑞梅; 刘泽彬; 封晓辉; 肖文发

    2015-01-01

    Objective]Growth of trees is strongly influenced by climatic factors. The changes of xylem cells of trees record more detailed information compared to the tree-ring widths,and could enrich the present knowledge extracted from the traditional dendroclimatological or dendroecological studies. Our aim is to provide a reference for studying the global change using the characteristics of trees xylem cells.[Method]This paper summarizes the process of xylem formation,the research methods of studying the responses of xylem growth to climatic factors and the effect of climatic change ( temperature,precipitation,solar radiation,photoperiod and increasing atmospheric CO2 ) on trees cambial activity and xylem growth. [Result]At present,there are two methods to study the response of xylem growth to climatic factors at cell level: pinning and microcoring. Pinning was mainly used to study the response of cambium to injury or records the xylem growth increment of tropical trees,and microcoring can be used to observe the changes of the number of cambium cells in different stages and the xylem formation process. Recent research demonstrated that the formation of xylem went through four stages: cambial reactivation,cell radial enlargement,secondary wall thickening and lignification,the formation of mature xylem cells, and each stage was affected by climatic factors. The changes of xylem growth of trees were significantly correlated with some climatic factors,such as temperature,precipitation,solar radiation,photoperiod and increasing atmospheric CO2 . Temperature mainly affects the cambium activity at early stage of tree growth,and changes the time of reactivation of the cambium,cell division rate and active period. But temperature will not change the sequence of xylem cell differentiation and seasonal growth pattern. Precipitation mainly affects the rate of the cambium cell division, the duration of cambium cell division in the growing season and the tracheid diameter. Inadequate

  14. MRI links stem water content to stem diameter variations in transpiring trees.

    Science.gov (United States)

    De Schepper, Veerle; van Dusschoten, Dagmar; Copini, Paul; Jahnke, Siegfried; Steppe, Kathy

    2012-04-01

    In trees, stem diameter variations are related to changes in stem water content, because internally stored water is depleted and replenished over a day. To confirm this relationship, non-invasive magnetic resonance imaging (MRI) was combined with point dendrometer measurements in three actively transpiring oak (Quercus robur L.) trees. Two of these oak trees were girdled to study the stem increment above the girdling zone. MRI images and micrographs of stem cross-sections revealed a close link between the water distribution and the anatomical features of the stem. Stem tissues with the highest amount of water were physiologically the most active ones, being the youngest differentiating xylem cells, the cambium and the youngest differentiating and conductive phloem cells. Daily changes in stem diameter corresponded well with the simultaneously MRI-measured amount of water, confirming their strong interdependence. MRI images also revealed that the amount of water in the elastic bark tissues, excluding cambium and the youngest phloem, contributed most to the daily stem diameter changes. After bark removal, an additional increase in stem diameter was measured above the girdle. This increase was attributed not only to the cambial production of new cells, but also to swelling of existing bark cells. In conclusion, the comparison of MRI and dendrometer measurements confirmed previous interpretations and applications of dendrometers and illustrates the additional and complementary information MRI can reveal regarding water relations in plants. PMID:22268159

  15. Transcript Accumulation Dynamics of Phenylpropanoid Pathway Genes in the Maturing Xylem and Phloem of Picea abies during Latewood Formation

    Institute of Scientific and Technical Information of China (English)

    Giovanni Emiliani; Maria Laura Traversi; Monica Anichini; Guido Giachi; Aiessio Giovannelli

    2011-01-01

    In temperate regions,latewood is produced when cambial activity declines with the approach of autumnal dormancy.The understanding of the temporal (cambium activity vs dormancy) and spatial (phloem,cambial region,maturing xylem) regulation of key genes involved in the phenylpropanoid pathway during latewood formation represents a crucial step towards providing new insights into the molecular basis of xylogenesis.In this study,the temporal pattern of transcript accumulation of 12 phenylpropanoid genes (PAL1,C4H3I5,C4H4,4CL3,4CL4,HCT1,C3H3,CCoAOMT1,COMT2,COMT5,CCR2) was analyzed in maturing xylem and phloem of Picea abies during latewood formation.Quantitative reverse transcription-polymerase chain reaction analyses revealed a well-defined RNA accumulation pattern of genes involved in the phenylpropanoid pathway during latewood formation.Differences in the RNA accumulation patterns were detected between the different tissue types analyzed.The results obtained here demonstrated that the molecular processes involved in monolignol biosynthesis are not restricted to the cambial activity timeframe but continued after the end of cambium cell proliferation.Furthermore,since it has been shown that lignification of maturing xylem takes place in late autumn,we argue on the basis of our data that phloem could play a key role in the monolignol biosynthesis process.

  16. The Role of DNA Methylation in Xylogenesis in Different Tissues of Poplar.

    Science.gov (United States)

    Wang, Qingshi; Ci, Dong; Li, Tong; Li, Peiwen; Song, YuePeng; Chen, Jinhui; Quan, Mingyang; Zhou, Daling; Zhang, Deqiang

    2016-01-01

    In trees, xylem tissues play a key role in the formation of woody tissues, which have important uses for pulp and timber production; also DNA methylation plays an important part in gene regulation during xylogenesis in trees. In our study, methylation-sensitive amplified polymorphism (MSAP) analysis was used to analyze the role cytosine methylation plays in wood formation in the commercially important tree species Populus tomentosa. This analysis compared the methylation patterns between xylem tissues (developing xylem and mature xylem) and non-xylem tissues (cambium, shoot apex, young leaf, mature leaf, phloem, root, male catkin, and female catkin) and found 10,316 polymorphic methylation sites. MSAP identified 132 candidate genes with the same methylation patterns in xylem tissues, including seven wood-related genes. The expression of these genes differed significantly between xylem and non-xylem tissue types (P vascular tissues (cambium, phloem, and developing xylem) did not have distinct expression patterns in xylem and non-xylem tissue. Also, bisulfite sequencing and transcriptome sequencing of MYB, NAC and FASCICLIN-LIKE AGP 13 revealed that the location of cytosine methylation in the gene might affect the expression of different transcripts from the corresponding gene. The expression of different transcripts that produce distinct proteins from a single gene might play an important role in the regulation of xylogenesis. PMID:27462332

  17. Changes of Cold Hardiness Indexes of Korla Fragrant Pear's Different Organs with Air Temperature during Over-wintering Period%越冬期间库尔勒香梨不同器官抗寒指标随气温的变化

    Institute of Scientific and Technical Information of China (English)

    艾克来木·艾合买提; 阿不来提·买买提; 巴特尔·巴克; 阿丽腾·吐尔孙哈力; 萨吉旦·阿卜杜克日木; 祖力克艳·麻那甫

    2016-01-01

    以越冬期间库尔勒香梨花芽、树干、枝条等器官为材料,测定了不同器官形成层组织抗氧化酶(SOD、CAT、POD )活性、可溶性蛋白含量、相对电导率等抗寒指标,同时监测了果园气温和树干阳阴面形成层温度,并采用隶属函数评价不同器官抗寒性,分析越冬期气温对新疆库尔勒香梨不同器官抗寒指标和抗寒性的影响。结果表明:(1)在库尔勒香梨越冬期间,不同器官同一抗寒指标和同一器官不同抗寒指标随气温、树干阳阴面形成层温度差的变化趋势有所不同,但总体上抗寒指标均与气温呈负相关关系,而与树干阳阴面形成层温度差均呈正相关关系。(2)各器官形成层可溶性蛋白含量与其抗氧化酶活性呈正相关关系,SOD、CAT 活性与POD活性呈正相关关系,并以CAT与POD活性相关性最强。(3)利用隶属函数法综合分析结果显示,贡献率最大的是CAT活性和可溶性蛋白含量,不同器官抗寒性强弱顺序为花芽组织>树干阴面形成层>枝条形成层>树干阳面形成层。研究发现,库尔勒香梨各器官形成层POD和CAT活性在越冬期间较低气温和较强烈形成层温度变化时较高,并以SOD对低温伤害和形成层温度变化最敏感;整个越冬期抗寒性强的器官表现出较高的可溶性蛋白含量和较低的相对电导率;形成层温度变化与抗寒生理指标变化之间具有较好的相关性,在一定范围内能够反映机体受到的低温冻害程度。%During over wintering period ,with the flower bud ,trunk cambium and branch as material ,we determined the cold hardiness indexes ,antioxidant enzyme activities (SOD ,CAT ,POD) ,soluble protein content and relative conductivity ,of different organs and tissues ,simultaneously monitored the orchard air temperature and trunk cambium temperature ,evaluated the cold resistance of different organs by using

  18. Bio-ecological Peculiarities of Taxus baccata L. in Decorative Gardening of Eastern Georgia

    Directory of Open Access Journals (Sweden)

    Tamar Nadiradze

    2014-03-01

    Full Text Available The article discusses contemporary bio-ecological conditions of Taxus baccata L. in its natural distribution area of Georgia, particularly in Batsara National Preserve. Contemporary bio-ecological conditions of Taxus baccata L. spread in decorative gardening of eastern Georgia have also been studied based on the samples of the collection (47 pieces of Tsinandali Arboretum. We have studied the periods of bud opening, vegetation ending, starting and finishing of cambium action, sprout woodening process, time and rate of growing in height, and regularities of accumulation-transformation of storage carbohydrates. The studies revealed that the Yew growth duration is affected by the snowless winter and frequent droughts increased in the last decades as they cause the lack of water in soils and badly affect the plant growth. Regularities of accumulation-transformation of storage carbohydrates and the studies of sprout woodening and cambium action peculiarities prove the strong ability of frost-resistance. In order to conserve this endangered species (Taxus baccata L. it’s needful to introduce it widely in decorative gardening.

  19. Biological basis of tree-ring formation: a crash course

    Directory of Open Access Journals (Sweden)

    Cyrille Barthélémy Karl Rathgeber

    2016-05-01

    Full Text Available Wood is of crucial importance for man and biosphere. In this mini review, we present the fundamental processes involved in tree-ring formation and intra-annual dynamics of cambial activity, along with the influences of the environmental factors. During wood formation, new xylem cells produced by the cambium are undergoing profound transformations, passing through successive differentiation stages, which enable them to perform their functions in trees. Xylem cell formation can be divided in five major phases: (1 the division of a cambial mother cell that creates a new cell; (2 the enlargement of this newly formed cell; (3 the deposition of its secondary wall; (4 the lignification of its cell wall; and finally, (5 its programmed cell death. In most regions of the world cambial activity follows a seasonal cycle. At the beginning of the growing season, when temperature increases, the cambium resumes activity, producing new xylem cells. These cells are disposed along radial files, and start their differentiation program according to their birth date, creating typical developmental strips in the forming xylem. The width of these strips smoothly changes along the growing season. Finally, when climatic conditions deteriorate (temperature or water availability in particular, cambial activity stops, soon followed by cell enlargement, and later on by secondary wall deposition. Without a clear understanding of the xylem formation process, it is not possible to comprehend how annual growth rings and typical wood structures are formed, recording seasonal variations of the environment as well as extreme climatic events.

  20. 巨尾桉韧皮部周皮形成过程的研究%Study on the periderm forming process in Eucalyptus grandis × E.urophylla phloem

    Institute of Scientific and Technical Information of China (English)

    刘喜明; 陈瑞英; 陈居静; 于再君

    2013-01-01

    周皮具有重要的保护作用和商业价值,采用石蜡切片法对4年生巨尾桉韧皮部周皮形成过程的微观结构进行研究.结果表明:周皮形成于每年的2月下旬至5月上旬,距树皮外表面900 μm深度附近的位置,并随树龄增长而加深.依据细胞形态结构特征和发生顺序,将周皮形成过程划分为6个阶段.(1)细胞脱分化前:将会形成周皮的位置,细胞处于相对静止状态;(2)细胞脱分化期:将会形成周皮的位置,细胞发生脱分化,逐步恢复分裂能力;(3)木栓形成层形成期:脱分化后的细胞开始分裂,形成木栓形成层并逐渐连续;(4)木栓层形成期:木栓形成层向外分生木栓层,向内分生栓内层;(5)径向伸展层形成期:木栓形成层发生径向伸展,变异为径向伸展层;(6)木栓层细胞分离期:部分木栓层细胞发生脱落,落皮层从局皮上分离.在径向伸展层形成期,木栓形成层细胞径向壁发生先破裂解体再重构的现象,为细胞伸展过程中的细胞壁化学键断裂学说提供了直观证据.%Periderm has important role in protection and high values in commerce.The microstructure of pefiderm forming process in 4 years old Eucalyptus grandis × E.urophylla phloem was studied by paraffin method,the results showed as follows.The periderm formed from late February to early May every year,it lay about 900 μm under outermostlayer,and became deeper with age.Based on the cell morphological structure features and sequence,the periderm forming process was divided into six stages.(1) Before cell dedifferentiating stage,the parenchymal cells where periderm would emerge were static.(2) At cell dedifferentiating stage,the parenchymal cells were dedifferentiating to regain fission ability.(3) Cork cambium forming stage,the parenchymal cells were dividing to forming cork cambium.(4)Cork forming stage,the cork cambium dividing cork cells outward and phelloderm inward.(5) Radial expanded layer forming stage

  1. The Function of CLE Peptide Hormone-Mediated Signaling Transduction in the Development and Differentiation of Plant Vascular System%CLE多肽激素信号转导在植物维管系统发育分化中的作用

    Institute of Scientific and Technical Information of China (English)

    王旭; 杨少辉; 王洁华

    2011-01-01

    多肽激素参与植物的生长、发育及抗逆等许多生命过程,特别是作为信号分子在细胞与细胞之间的短距离信息交流中起着关键作用.原形成层/形成层细胞通过分裂与分化,在保持自身分生活性的同时,不断生成木质部和韧皮部细胞.近年来研究表明,CLE多肽激素及其类受体激酶通过独特的信号转导机制决定着维管形成层细胞的命运,在调节维管系统的发育方面具有重要的作用.以维管组织为重点,着重介绍CLE多肽激素在控制和影响拟南芥原形成层/形成层细胞分裂和分化方面的信号通路.尽管目前还不清楚CLE多肽激素如何影响木本植物维管形成层的起始、维持及分化,但随着杨树全基因组序列的获得,采用功能基因组学研究策略,将进一步了解林木植物中控制维管形成层细胞分生和分化的重要基因,从而实现调控次生维管系统发育、改良材性的目标.%Peptide hormones are involved in plant growth, development, stress resistance and many other life processes, and especially play a key role as signaling molecules in the short-range cell-cell communication. The procambium/ cambium cells continuously generate xylem and phloem cells through division and differentiation, while maintaining their own proliferation activity. Recent studies have shown that CLE peptide hormones and their receptor kinases could determine the vascular cambium cell fate through a unique signaling transduction mechanism, therefore they are important in regulating the development of vascular system. Focusing on vascular tissue, this review introduces the CLE peptide hormone signaling pathway in controlling and influencing the division and differentiation of procambium/cambium cells in Arabidopsis. It is still unclear how CLE peptides affect the initiation, maintenance and differentiation of vascular cambium cell in woody plants. However, with the poplar genome sequence information

  2. Does the structure of wood contribute to understanding the oaks decline phenomenon?

    Directory of Open Access Journals (Sweden)

    Mirela Tulik

    2014-04-01

    Full Text Available Vascular cambium is a meristematic tissue which produces wood centriphugaly and phloem centripetaly. In the structure of wood and phloem, data concerning developmental processes taking place in the cambium is recorded. The history of the cambium is encoded in the dimensions, numbers and arrangements of the wood and phloem cells. For investigations, the wood is usually preferred because it is durable and such data could remain unchanged for centuries, whereas in the phloem due to distorted processes, it deranges after a few years. In broadleaves, the wood is composed of vessels, tracheids, fibers and parenchyma cells. The process of the wood formation consists of the cambial cell derivatives expansion, lignification of its walls and programmed cell death. Since the seventies of the nineteenth century, the process of declining oaks taking place in Europe on a regular basis has been observed. Oak decline is a complex process that involves interactions of both biotic and abiotic factors leading to increased trees mortality. The main goal of the studies is the examination of the structure of wood in declining oaks (Quercus robur L. in respect to physiological (conductive role of this tissue. It is known that on the level of the wood structure, water transport efficiency depends on the diameter of vessels - the main elements of the hydraulic conductivity system. Any reduction of the vessels lumen causes the reduction of the water transport to the organs of the trees body and, therefore, influences organisms survival rate. Anatomical analyses were carried out on wood samples (comprising all annual rings formed during the 30-40 years life of the analyzed trees collected at breast height from the main stem of healthy, weakened and dead oaks. The anatomical traits of the wood like as the width of the annual increments, the diameter and density of early wood vessels were measured. The results which are described in the paper by Tulik (2014 revealed that

  3. ANATOMY OF GYNURA AURANTIACA (BLUME SCH.BIP. EX DC. (ASTERACEAE

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    Rodica BERCU

    2014-06-01

    Full Text Available The paper presents a detailed histoanatomical description, of the vegetative organs (root, stem and leaf and photographs as well of Gynura aurantiaca (Blume Sch.Bip. ex DC. It was observed that the root have typical primary dictos structure. The stem has a differentiated in two regions cortex and the stele comprise one ring of open collateral vascular bundles with secondary xylem due to the cambium activity. The petiole anatomy is quite similar in its basic structure with the stem. The blade presents a heterogenous and hypostomatic mesophyll and a number of vascular bundles in the midrib zone. Remarkable is the presence of the filamentous, uniseriate non-glandular hairs in the stem, petiole and leaf blade. The mechanical tissue is present in the stem, petiole and blade as well.

  4. MORFOANATOMIA DA RIZOGÊNESE ADVENTÍCIA EM MINIESTACAS DE Eucalyptus grandis x Eucalyptus urophylla

    Directory of Open Access Journals (Sweden)

    Patrícia Bueno Goulart

    2014-01-01

    Full Text Available The present work aimed to accomplish the histological analysis of the events involved in the adventitious rooting pattern of four Eucalyptus grandis x Eucalyptus urophylla clones. The mini-cuttings were collected from a mini-stump and the rooting experiments were set up under mini-hedge indoor semi-hydroponics by means of intermittent flooding fertirrigation. For histological analyses, the proximal ends of the mini- cuttings were collected after 0, 1, 2, 4, 6, 8, 10, and 12 days after planting them at greenhouse. After fixation with FAA 70% , the samples were dehydrated in a graded ethanol series and infiltrated overnight in metracrilate resin, and finally embedded in resin. It was verified the endogenous origin of adventitious root primordia from vascular cambium, and in some cases, the formation and proliferation of calli at the proximal end of the mini-cuttings within 8 to 12 days.

  5. Dicty_cDB: Contig-U04515-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available _L3A_SL1 Nippo... 46 0.008 2 ( FG287049 ) 1108770728167 New World Screwworm Egg 9261 ESTs C... 46 0.009 2 ( ...FG294927 ) 1108770721339 New World Screwworm Larvae 9387 EST... 46 0.009 2 ( FG28...9781 ) 1108793305302 New World Screwworm Egg 9261 ESTs C... 46 0.009 2 ( CK096156 ) UA48BPF09.3pR Populus do...09 1 ( BU819882 ) UA48BPF09 Populus tremula cambium cDNA library Po... 54 0.009 1 ( FG288449 ) 1108793271723 New World... Screwworm Egg 9261 ESTs C... 46 0.010 2 ( FG299008 ) 1108793324740 New World Screwworm Larvae 938

  6. ANATOMICAL STUDIES ON SCOPOLIA CARNIOLICA JACQ. VEGETATIVE ORGANS

    Directory of Open Access Journals (Sweden)

    Cristina STEFANESCU

    2006-08-01

    Full Text Available Scopolia carniolica Jacq. is a medicinal species of Solanaceae, harvested from the Romanian spontaneous flora for its atropine and scopolamine content. We have analyzed the anatomical structure of the vegetative organs (rhizome, root, stem and leaf and the biometrical parameters of the leaf blade (vascular islet, stomatal index and palisade ratio, in order to establish the main specific characters and differential elements useful for the correct identification and for avoiding the impurification of medicinal products. The characteristic structures for the rhizome and root are the secondary ones, mainly with parenchyma elements and lacking in mechanical fibres; the stem has a primary becoming secondary structure, bicolateral vascular bundles with cambium in the interior and between them and endoderma as starch layer. The sand cells are characteristic for rhizome, root and stem structures. On the leaf surface were identified protector multicellular trichomes and specific secretory and glandular ones.

  7. Response of Some Malus Мill. Species Representatives to Extreme Low Temperatures in Baikal Siberia

    Directory of Open Access Journals (Sweden)

    Yu.M. Batuyeva

    2016-05-01

    Full Text Available The paper presents the results of study of maximal frost resistance of apple-tree varieties of Novosibirsk, Krasnoyarsk, Buryat, Canadian selection by the method of artificial freezing. The research found virtually all apple-tree varieties to withstand the temperature as low as -45оС without serious damage to bark, cambium and wood; with only Melba variety exhibiting significant bark damage. Apple-tree varieties of Buryat ACRI selection, regardless of cultivation location, demonstrated high tissue resistance to critical low negative temperatures. The investigated forms of Malus baccata L. Borkh, are characterized by high frost resistance in the middle of winter regardless of their location. Critical temperatures of -50о and -55оС proved lethal for Lada, Krasnaya Grozd’ varieties, as well as for Melba variety of Canadian selection.

  8. Xylem Phenology of Fagus sylvatica in Rarău Mountains (Eastern Carpathians, Romania

    Directory of Open Access Journals (Sweden)

    Anca SEMENIUC

    2014-06-01

    Full Text Available The cambium activity and the tree ring formation of European beech (Fagus sylvatica L. from the Rarău Mountains was monitored during 2009, 2010 and 2011 in a beech - coniferous stand, representative for Eastern Carpathian mixed forests. Wood microcores were collected weekly from five trees and prepared in order to describe the different phases of wood formation. Four phases of tree ring development were quantified, in number of cells and phase duration: cambial phase, cell enlargement, cell wall thickening and cell maturation. The onset of the cambial activity took place in the first week of May 2009, one week later in 2010 and in the last week of April 2011. The beech tree ring development period varies between 127 days in 2009 and 137 days in 2011.

  9. The use of plants as regular food in ancient subarctic economies: a case study based on Sami use of Scots pine innerbark.

    Science.gov (United States)

    Bergman, Ingela; Östlund, Lars; Zackrisson, Olle

    2004-01-01

    This study combines ethnological, historical, and dendroecological data from areas north of the Arctic Circle to analyze cultural aspects of Sami use of Scots pine (Pinus sylvestris L.) inner bark as regular food. Bark was peeled in June when trees were at the peak of sapping, leaving a strip of undamaged cambium so the tree survived. As a result, it is possible to date bark-peeling episodes using dendrochronology. The paper argues that the use of Scots pine inner bark reflects Sami religious beliefs, ethical concerns, and concepts of time, all expressed in the process of peeling the bark. A well-developed terminology and a set of specially designed tools reveal the technology involved in bark peeling. Consistent patterns with respect to the direction and size of peeling scars found across the region demonstrate common values and standards. Peeling direction patterns and ceremonial meals relating to bark probably reflect ritual practices connected to the sun deity, Biejvve.

  10. Auxin apical control of the auxin polar transport and its oscillation - a suggested cellular transduction mechanism

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    Tomasz J. Wodzicki

    2014-02-01

    Full Text Available The proposed hypothesis concerns the transduction of auxin molecular signals arriving from the apoplast at the plasma membrane or recognized by the proteineous receptors of the responding cell, to the concentration gradients oscillating in the supracellular space, associated usually with the specific plant growth and differentiation. Acting as an agonist from outside the target cell auxin stimulates in this cell: (1 the liberation of auxin from the cytosolic pool of its conjugates directly into the basipetal efflux; (2 the synthesis of new auxin which restores the cytosolic reserve of auxin conjugates. The functioning of such a system may be effective in a series of processes initiated by the changing concentration of cytosolic calcium. The hypothesis suggests a molecular mechanism for the development and effective operation of the morphogenetic field in the supracellular space of the plant body, such as the field resulting from auxin waves discovered in cambium.

  11. Crecimiento secundario inusual en raíz principal de Pfaffia gnaphalioides (L. Fil. Mart. (Amaranthaceae Secondary and unusual growth in main root of Pfaffia gnaphalioides (L. Fil. Mart. (Amaranthaceae

    Directory of Open Access Journals (Sweden)

    Mónica Alicia Grosso

    2007-03-01

    Full Text Available Raíces de Pfaffia se comercializan como "ginseng brasilero" y extractos crudos de raíces de Pfaffia glomerata tienen actividad analgésica y desinflamatoria. Pfaffia gnaphalioides es herbácea perenne y crece en el área serrana del sur de la Provincia de Córdoba, Argentina. El objetivo de este trabajo es estudiar el crecimiento secundario inusual en raíz principal de Pfaffia gnaphalioides. Se estudió en invernáculo la forma de crecimiento durante los dos primeros años relacionando la parte aérea y subterránea. Se realizaron calicatas in situ para analizar el sistema radical. La raíz principal desarrolla raíces laterales, plagiótropas, con yemas que forman brotes aéreos de innovación. En cortes transversales de raíz principal se observa desarrollo secundario inusual. Un meristema lateral produce corteza secundaria hacia afuera y tejido conjuntivo y una sucesión de cambia vascular hacia adentro. Cuando cada cambium vascular es producido, el meristema lateral que se encuentra hacia afuera de éste tiende a permanecer quiescente, retornando a la actividad cuando el cambium vascular interno a éste permanece menos activo. Los cordones vasculares secundarios están dispuestos en anillos concéntricos sin radios parenquimáticos. La presencia de abundante parénquima conteniendo almidón en la estructura inusual de raíz en Pfaffia gnaphalioides, constituye una buena adaptación a condiciones xéricas.Pfaffia roots have been commercialized as "brazilian ginseng" and crude extracts of Pfaffia glomerata roots have analgesic and disinflamatory activity. Pfaffia gnaphalioides is a perennial herb and grows in southern Córdoba, Argentina. The objective of this work is to analyze root systems in Pfaffia gnaphalioides. Growth of above and belowground organs was observed for two years in a greenhouse. Belowground organs were analyzed in situ in hillcountry shrublands, by digging soil pits. The root system is characterized by presence of a main

  12. The Woody-Preferential Gene EgMYB88 Regulates the Biosynthesis of Phenylpropanoid-Derived Compounds in Wood

    Science.gov (United States)

    Soler, Marçal; Plasencia, Anna; Lepikson-Neto, Jorge; Camargo, Eduardo L. O.; Dupas, Annabelle; Ladouce, Nathalie; Pesquet, Edouard; Mounet, Fabien; Larbat, Romain; Grima-Pettenati, Jacqueline

    2016-01-01

    Comparative phylogenetic analyses of the R2R3-MYB transcription factor family revealed that five subgroups were preferentially found in woody species and were totally absent from Brassicaceae and monocots (Soler et al., 2015). Here, we analyzed one of these subgroups (WPS-I) for which no gene had been yet characterized. Most Eucalyptus members of WPS-I are preferentially expressed in the vascular cambium, the secondary meristem responsible for tree radial growth. We focused on EgMYB88, which is the most specifically and highly expressed in vascular tissues, and showed that it behaves as a transcriptional activator in yeast. Then, we functionally characterized EgMYB88 in both transgenic Arabidopsis and poplar plants overexpressing either the native or the dominant repression form (fused to the Ethylene-responsive element binding factor-associated Amphiphilic Repression motif, EAR). The transgenic Arabidopsis lines had no phenotype whereas the poplar lines overexpressing EgMYB88 exhibited a substantial increase in the levels of the flavonoid catechin and of some salicinoid phenolic glycosides (salicortin, salireposide, and tremulacin), in agreement with the increase of the transcript levels of landmark biosynthetic genes. A change in the lignin structure (increase in the syringyl vs. guaiacyl, S/G ratio) was also observed. Poplar lines overexpressing the EgMYB88 dominant repression form did not show a strict opposite phenotype. The level of catechin was reduced, but the levels of the salicinoid phenolic glycosides and the S/G ratio remained unchanged. In addition, they showed a reduction in soluble oligolignols containing sinapyl p-hydroxybenzoate accompanied by a mild reduction of the insoluble lignin content. Altogether, these results suggest that EgMYB88, and more largely members of the WPS-I group, could control in cambium and in the first layers of differentiating xylem the biosynthesis of some phenylpropanoid-derived secondary metabolites including lignin. PMID

  13. Variability in radial sap flux density patterns and sapwood area among seven co-occurring temperate broad-leaved tree species.

    Science.gov (United States)

    Gebauer, Tobias; Horna, Viviana; Leuschner, Christoph

    2008-12-01

    Forest transpiration estimates are frequently based on xylem sap flux measurements in the outer sections of the hydro-active stem sapwood. We used Granier's constant-heating technique with heating probes at various xylem depths to analyze radial patterns of sap flux density in the sapwood of seven broad-leaved tree species differing in wood density and xylem structure. Study aims were to (1) compare radial sap flux density profiles between diffuse- and ring-porous trees and (2) analyze the relationship between hydro-active sapwood area and stem diameter. In all investigated species except the diffuse-porous beech (Fagus sylvatica L.) and ring-porous ash (Fraxinus excelsior L.), sap flux density peaked at a depth of 1 to 4 cm beneath the cambium, revealing a hump-shaped curve with species-specific slopes. Beech and ash reached maximum sap flux densities immediately beneath the cambium in the youngest annual growth rings. Experiments with dyes showed that the hydro-active sapwood occupied 70 to 90% of the stem cross-sectional area in mature trees of diffuse-porous species, whereas it occupied only about 21% in ring-porous ash. Dendrochronological analyses indicated that vessels in the older sapwood may remain functional for 100 years or more in diffuse-porous species and for up to 27 years in ring-porous ash. We conclude that radial sap flux density patterns are largely dependent on tree species, which may introduce serious bias in sap-flux-derived forest transpiration estimates, if non-specific sap flux profiles are assumed.

  14. A contribution to understanding the structure of amphivasal secondary bundles in monocotyledons

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    Joanna Jura-Morawiec

    2014-04-01

    Full Text Available Secondary growth of monocotyledonous plants is connected with the activity of the monocot cambium that accumulates most of the derivatives inner to the cambial cylinder. These derivatives differentiate into (a secondary bundles with the amphivasal arrangement, i.e. xylem composed of tracheids surrounds the phloem cells and (b the parenchymatous secondary conjunctive tissue in which the bundles are embedded. The amphivasal secondary bundles differ in the arrangement of xylem cells as visible on single cross sections through the secondary body of the monocots. Apart from the bundles with typical ring of tracheids also the bundles where tracheids do not quite surround the phloem are present. We aimed to elucidate the cross sectional anatomy of the amphivasal secondary bundles with the use of the serial sectioning method which allowed us to follow very precisely the bundle structure along its length. The studies were carried out with the samples of secondary tissues collected from the stem of Dracaena draco L. growing in the greenhouses of the Polish Academy of Sciences Botanical Garden – CBDC in Powsin and the Adam Mickiewicz University Botanical Garden. The material was fixed in a mixture of glycerol and ethanol (1:1; v/v, dehydrated stepwise with graded ethanol series and finally embedded in epon resin. Afterwards, the material was sectioned with microtome into continuous series of thin (3 μm sections, stained with PAS/toluidine blue and examined under the light microscope. The results, described in details in Jura‑Morawiec & Wiland-Szymańska (2014, revealed novel facts about tracheids arrangement. Each amphivasal bundle is composed of sectors where tracheids form a ring as well as of such where tracheids are separated by vascular parenchyma cells. We hypothesize that strands of vascular parenchyma cells locally separating the tracheids enable radial transport of assimilates from sieve elements of the bundle towards the sink tissues, e

  15. Living on the edge: contrasted wood-formation dynamics in Fagus sylvatica and Pinus sylvestris under Mediterranean conditions

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    Edurne eMartinez Del Castillo

    2016-03-01

    Full Text Available Wood formation in European beech (Fagus sylvatica L. and Scots pine (Pinus sylvestris L. was intra-annually monitored to examine plastic responses of the xylem phenology according to altitude in one of the southernmost areas of their distribution range, i.e. in the Moncayo Natural Park, Spain. The monitoring was done from 2011 to 2013 at 1180 and 1580 m a.s.l., corresponding to the lower and upper limits of European beech forest in this region. Microcores containing phloem, cambium and xylem were collected biweekly from twenty-four trees from the beginning of March to the end of November to assess the different phases of wood formation. The samples were prepared for light microscopy to observe the following phenological phases: onset and end of cell production, onset and end of secondary wall formation in xylem cells and onset of cell maturation. The temporal dynamics of wood formation widely differed among years, altitudes and tree species. For Fagus sylvatica, the onset of cambial activity varied between the first week of May and the third week of June. Cambial activity then slowed down and stopped in summer, resulting in a length of growing season of 48–75 days. In contrast, the growing season for Pinus sylvestris started earlier and cambium remained active in autumn, leading to a period of activity varying from 139-170 days. The intra-annual wood-formation pattern is site and species-specific. Comparison with other studies shows a clear latitudinal trend in the duration of wood formation, positive for Fagus sylvatica and negative for Pinus sylvestris.

  16. Bayesian phylogeny of sucrose transporters: Ancient origins, differential expansion and convergent evolution in monocots and dicots

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    Duo ePeng

    2014-11-01

    Full Text Available Sucrose transporters (SUTs are essential for the export and efficient movement of sucrose from source leaves to sink organs in plants. The angiosperm SUT family was previously classified into three or four distinct groups, Types I, II (subgroup IIB and III, with dicot-specific Type I and monocot-specific Type IIB functioning in phloem loading. To shed light on the underlying drivers of SUT evolution, Bayesian phylogenetic inference was undertaken using 41 sequenced plant genomes, including seven basal lineages at key evolutionary junctures. Our analysis supports four phylogenetically and structurally distinct SUT subfamilies, originating from two ancient groups (AG1 and AG2 that diverged early during terrestrial colonization. In both AG1 and AG2, multiple intron acquisition events in the progenitor vascular plant established the gene structures of modern SUTs. Tonoplastic Type III and plasmalemmal Type II represent evolutionarily conserved descendants of AG1 and AG2, respectively. Type I and Type IIB were previously thought to evolve after the dicot-monocot split. We show, however, that divergence of Type I from Type III SUT predated basal angiosperms, likely associated with evolution of vascular cambium and phloem transport. Type I SUT was subsequently lost in monocots along with vascular cambium, and independent evolution of Type IIB coincided with modified monocot vasculature. Both Type I and Type IIB underwent lineage-specific expansion. In multiple unrelated taxa, the newly-derived SUTs exhibit biased expression in reproductive tissues, suggesting a functional link between phloem loading and reproductive fitness. Convergent evolution of Type I and Type IIB for SUT function in phloem loading and reproductive organs supports the idea that differential vascular development in dicots and monocots is a strong driver for SUT family evolution in angiosperms.

  17. Cytokinin and Auxin Display Distinct but Interconnected Distribution and Signaling Profiles to Stimulate Cambial Activity.

    Science.gov (United States)

    Immanen, Juha; Nieminen, Kaisa; Smolander, Olli-Pekka; Kojima, Mikiko; Alonso Serra, Juan; Koskinen, Patrik; Zhang, Jing; Elo, Annakaisa; Mähönen, Ari Pekka; Street, Nathaniel; Bhalerao, Rishikesh P; Paulin, Lars; Auvinen, Petri; Sakakibara, Hitoshi; Helariutta, Ykä

    2016-08-01

    Despite the crucial roles of phytohormones in plant development, comparison of the exact distribution profiles of different hormones within plant meristems has thus far remained scarce. Vascular cambium, a wide lateral meristem with an extensive developmental zonation, provides an optimal system for hormonal and genetic profiling. By taking advantage of this spatial resolution, we show here that two major phytohormones, cytokinin and auxin, display different yet partially overlapping distribution profiles across the cambium. In contrast to auxin, which has its highest concentration in the actively dividing cambial cells, cytokinins peak in the developing phloem tissue of a Populus trichocarpa stem. Gene expression patterns of cytokinin biosynthetic and signaling genes coincided with this hormonal gradient. To explore the functional significance of cytokinin signaling for cambial development, we engineered transgenic Populus tremula × tremuloides trees with an elevated cytokinin biosynthesis level. Confirming that cytokinins function as major regulators of cambial activity, these trees displayed stimulated cambial cell division activity resulting in dramatically increased (up to 80% in dry weight) production of the lignocellulosic trunk biomass. To connect the increased growth to hormonal status, we analyzed the hormone distribution and genome-wide gene expression profiles in unprecedentedly high resolution across the cambial zone. Interestingly, in addition to showing an elevated cambial cytokinin content and signaling level, the cambial auxin concentration and auxin-responsive gene expression were also increased in the transgenic trees. Our results indicate that cytokinin signaling specifies meristematic activity through a graded distribution that influences the amplitude of the cambial auxin gradient. PMID:27426519

  18. Relationships between mountain pine and climate in the French Pyrenees (Font-Romeu studied using the radiodensitometrical method

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    Rolland, Cristian

    1994-12-01

    Full Text Available A radiodensitometrical study was carried out on 46 Pinus uncinata (Ramond in Font-Romeu (French Pyrenees. Correlation functions with monthly climatical data were calculated using separately the ring-widths, the earlywood and the latewood densities. The Mountain Pine shows narrow rings (1.5 mm and a high sensitivity to climate (M.S. = 0.221, but it does not seem to suffer from drought despite the dryness of the climate (788 mm rainfall per year. This species is more sensitive to temperature than to precipitation, since temperature governs latewood formation. A hot spring and a mild autumn with maximum temperatures above threshold levels will extend the growing period. A warm autumn also increases the latewood density, whereas cold nights during the previous year's autumn are unfavourable to growth because they may affect the cambium and bud initiations.

    [es] Se ha llevado a cabo un trabajo densitométrico sobre 46 Pinus uncinata (Ramond en Font-Romeu (Cerdaña francesa. Las funciones de correlación con el clima han sido calculadas sucesivamente con el espesor de los anillos de crecimiento, la densidad de la madera temprana y de la madera tardía. Esta especie produce anillos de crecimiento delgados (1.5 mm y presenta una elevada sensibilidad con el clima (S.M. = 0.221 pero no parece afectada por la falta de lluvia aunque el clima es más xérico (788 mm/ año. La madera tardía parece muy sensible a las temperaturas. Una primavera cálida ejerce un efecto favorable y un otoño suave con temperaturas máximas superiores a límites críticos permite continuar su desarollo. De la misma manera un otoño caliente aumenta la densidad de la madera tardía aunque las noches frías durante el otoño precedente son desfavorables para el crecimiento porque pueden afectar al Inicio de las yemas y del cambium.
    [fr] Une étude radiodensitométrique de46 Pinus uncinata (Ramond a été réalisée à Font-Romeu (Pyrénées Françaises. Les

  19. Allocation of 14C assimilated in late spring to tissue and biochemical stem components of cork oak (Quercus suber L.) over the seasons.

    Science.gov (United States)

    Aguado, Pedro L; Curt, M Dolores; Pereira, Helena; Fernández, Jesús

    2012-03-01

    Carbon distribution in the stem of 2-year-old cork oak plants was studied by (14)CO(2) pulse labeling in late spring in order to trace the allocation of photoassimilates to tissue and biochemical stem components of cork oak. The fate of (14)C photoassimilated carbon was followed during two periods: the first 72 h (short-term study) and the first 52 weeks (long-term study) after the (14)CO(2) photosynthetic assimilation. The results showed that (14)C allocation to stem tissues was dependent on the time passed since photoassimilation and on the season of the year. In the first 3 h all (14)C was found in the polar extractives. After 3 h, it started to be allocated to other stem fractions. In 1 day, (14)C was allocated mostly to vascular cambium and, to a lesser extent, to primary phloem; no presence of (14)C was recorded for the periderm. However, translocation of (14)C to phellem was observed from 1 week after (14)CO(2) pulse labeling. The phellogen was not completely active in its entire circumference at labeling, unlike the vascular cambium; this was the tissue that accumulated most photoassimilated (14)C at the earliest sampling. The fraction of leaf-assimilated (14)C that was used by the stem peaked at 57% 1 week after (14)CO(2) plant exposure. The time lag between C photoassimilation and suberin accumulation was ∼8 h, but the most active period for suberin accumulation was between 3 and 7 days. Suberin, which represented only 1.77% of the stem weight, acted as a highly effective sink for the carbon photoassimilated in late spring since suberin specific radioactivity was much higher than for any other stem component as early as only 1 week after (14)C plant labeling. This trend was maintained throughout the whole experiment. The examination of microautoradiographs taken over 1 year provided a new method for quantifying xylem growth. Using this approach it was found that there was more secondary xylem growth in late spring than in other times of the year

  20. Advances in Research on the Effect of Climatic Change on Xylem Growth of Trees%气候变化对树木木质部生长影响的研究进展

    Institute of Scientific and Technical Information of China (English)

    程瑞梅; 刘泽彬; 封晓辉; 肖文发

    2015-01-01

    浓度升高对树木木质部细胞的影响,研究结果并不一致,一些研究认为,CO2浓度升高影响细胞的分裂速率和细胞的扩张而不是次生细胞壁的加厚,从而造成早材生长轮宽度明显增加,但也有研究表明,CO2浓度升高并没有引起早材细胞结构较大的变化,相反晚材生长环的宽度却明显增加。【结论】随着研究理论和技术手段的不断成熟,极端灾害下树木木质部细胞的生长特征、不同树种木质部细胞的生长对气候变化的响应以及多种气候因子对树木木质部生长的综合影响将成为今后研究的主要方向。%Objective]Growth of trees is strongly influenced by climatic factors. The changes of xylem cells of trees record more detailed information compared to the tree-ring widths,and could enrich the present knowledge extracted from the traditional dendroclimatological or dendroecological studies. Our aim is to provide a reference for studying the global change using the characteristics of trees xylem cells.[Method]This paper summarizes the process of xylem formation,the research methods of studying the responses of xylem growth to climatic factors and the effect of climatic change ( temperature,precipitation,solar radiation,photoperiod and increasing atmospheric CO2 ) on trees cambial activity and xylem growth. [Result]At present,there are two methods to study the response of xylem growth to climatic factors at cell level: pinning and microcoring. Pinning was mainly used to study the response of cambium to injury or records the xylem growth increment of tropical trees,and microcoring can be used to observe the changes of the number of cambium cells in different stages and the xylem formation process. Recent research demonstrated that the formation of xylem went through four stages: cambial reactivation,cell radial enlargement,secondary wall thickening and lignification,the formation of mature xylem cells, and each stage was

  1. Allocation of 14C assimilated in late spring to tissue and biochemical stem components of cork oak (Quercus suber L.) over the seasons.

    Science.gov (United States)

    Aguado, Pedro L; Curt, M Dolores; Pereira, Helena; Fernández, Jesús

    2012-03-01

    Carbon distribution in the stem of 2-year-old cork oak plants was studied by (14)CO(2) pulse labeling in late spring in order to trace the allocation of photoassimilates to tissue and biochemical stem components of cork oak. The fate of (14)C photoassimilated carbon was followed during two periods: the first 72 h (short-term study) and the first 52 weeks (long-term study) after the (14)CO(2) photosynthetic assimilation. The results showed that (14)C allocation to stem tissues was dependent on the time passed since photoassimilation and on the season of the year. In the first 3 h all (14)C was found in the polar extractives. After 3 h, it started to be allocated to other stem fractions. In 1 day, (14)C was allocated mostly to vascular cambium and, to a lesser extent, to primary phloem; no presence of (14)C was recorded for the periderm. However, translocation of (14)C to phellem was observed from 1 week after (14)CO(2) pulse labeling. The phellogen was not completely active in its entire circumference at labeling, unlike the vascular cambium; this was the tissue that accumulated most photoassimilated (14)C at the earliest sampling. The fraction of leaf-assimilated (14)C that was used by the stem peaked at 57% 1 week after (14)CO(2) plant exposure. The time lag between C photoassimilation and suberin accumulation was ∼8 h, but the most active period for suberin accumulation was between 3 and 7 days. Suberin, which represented only 1.77% of the stem weight, acted as a highly effective sink for the carbon photoassimilated in late spring since suberin specific radioactivity was much higher than for any other stem component as early as only 1 week after (14)C plant labeling. This trend was maintained throughout the whole experiment. The examination of microautoradiographs taken over 1 year provided a new method for quantifying xylem growth. Using this approach it was found that there was more secondary xylem growth in late spring than in other times of the year

  2. Injertos en chiles tipo Cayene, jalapeño y chilaca en el noroeste de Chihuahua, México Grafting in Cayenne, jalapeño and chilaca chili peppers in northwestern Chihuahua, Mexico

    Directory of Open Access Journals (Sweden)

    Pedro Osuna-Ávila

    2012-07-01

    Full Text Available En semillas cosechadas por los agricultores se estudió la influencia en la sincronización de los diámetros de tallos en injertos comunes y recíprocos utilizando los tipos de chiles, jalapeño, chilaca y Cayene como injertos y el criollo de Morelos CM-334 como portainjerto. El grosor del tallo del CM 334 presentó mayor compatibilidad con el chile tipo jalapeño y con el tipo chilacay fue muy distante con el grosor del tallo del tipo de chile Cayene. La formación de callo abundante entre la unión de los injertos ensayados mostró buena aptitud y afinidad lo cual permitió la conexión firme del cambium con el patrón. Los porcentajes de supervivencia de los injertos fueron 90% con los chiles lo cual está dentro del rango aceptable a nivel comercial. El usar el CM 334 como un portainjerto resistente a P .capsici podría formar parte del manejo integrado para controlar la marchitez en estos tipos de chiles comerciales. El injerto reciproco puede ser usado para estudiar genes asociados con procesos de regulación de señales a distancia capaces de moverse de la raíz al brote como ramificaciones, floración, resistencia sistémica y respuestas a estrés abiótico.In seeds harvested by farmers, the influence on the timing of the diameters of stems was studied in common and reciprocal grafts using chilies, jalapeño, chilaca and Cayenne as grafts and, landrace Morelos CM-334 as the rootstock. CM 334's stem diameter showed high compatibility with jalapeño and chilaca, and was very distant with Cayenne. Abundant callus formation between the unions of the tested grafts showed good aptitude and affinity which allowed the firm connection of the vascular cambium. The rates of graft survival were of 90% with chilies, which is within the acceptable range for commercially purposes. Using CM 334 as a rootstock resistant to P. capsici could be part of an integrated control for wilt in these types of commercial chilies. The reciprocal graft can be used to

  3. Intrusive growth of primary and secondary phloem fibres in hemp stem determines fibre-bundle formation and structure.

    Science.gov (United States)

    Snegireva, Anastasia; Chernova, Tatyana; Ageeva, Marina; Lev-Yadun, Simcha; Gorshkova, Tatyana

    2015-05-27

    Plant fibres-cells with important mechanical functions and a widely used raw material-are usually identified in microscopic sections only after reaching a significant length or after developing a thickened cell wall. We characterized the early developmental stages of hemp (Cannabis sativa) stem phloem fibres, both primary (originating from the procambium) and secondary (originating in the cambium), when they still had only a primary cell wall. We gave a major emphasis to the role of intrusive elongation, the specific type of plant cell growth by which fibres commonly attain large cell length. We could identify primary phloem fibres at a distance of only 1.2-1.5 mm from the shoot apical meristem when they grew symplastically with the surrounding tissues. Half a millimeter further downwards along the stem, fibres began their intrusive elongation, which led to a sharp increase in fibre numbers visible within the stem cross-sections. The intrusive elongation of primary phloem fibres was completed within the several distal centimetres of the growing stem, before the onset of their secondary cell wall formation. The formation of secondary phloem fibres started long after the beginning of secondary xylem formation. Our data indicate that only a small portion of the fusiform cambial initials (hemp, but may be applied to many other species.

  4. INTELLIGENCE, COGNITION AND LANGUAGE OF GREEN PLANTS

    Directory of Open Access Journals (Sweden)

    Anthony eTrewavas

    2016-04-01

    Full Text Available A summary definition of some 70 descriptions of intelligence provides a definition for all other organisms including plants that stresses fitness. Barbara McClintock, a plant biologist, posed the notion of the ‘ thoughtful cell’ in her Nobel prize address. The systems structure necessary for a thoughtful cell is revealed by comparison of the interactome and connectome. The plant root cap, a group of some 200 cells that act holistically in responding to numerous signals, likely possesses a similar systems structure agreeing with Darwin’s description of acting like the brain of a lower organism. Intelligent behaviour requires assessment of different choices and taking the beneficial one. Decisions are constantly required to optimise the plant phenotype to a dynamic environment and the cambium is the assessing tissue diverting more or removing resources from different shoot and root branches through manipulation of vascular elements. Environmental awareness likely indicates consciousness. Spontaneity in plant behaviour, ability to count to five and error correction indicate intention. Volatile organic compounds are used as signals in plant interactions and being complex in composition may be the equivalent of language accounting for self and alien recognition by individual plants. Game theory describes competitive interactions. Interactive and intelligent outcomes emerge from application of various games between plants themselves and interactions with microbes. Behaviour profiting from experience, another simple definition of intelligence, requires both learning and memory and is indicated in the priming of herbivory, disease and abiotic stresses.

  5. Intelligence, Cognition, and Language of Green Plants.

    Science.gov (United States)

    Trewavas, Anthony

    2016-01-01

    A summary definition of some 70 descriptions of intelligence provides a definition for all other organisms including plants that stresses fitness. Barbara McClintock, a plant biologist, posed the notion of the 'thoughtful cell' in her Nobel prize address. The systems structure necessary for a thoughtful cell is revealed by comparison of the interactome and connectome. The plant root cap, a group of some 200 cells that act holistically in responding to numerous signals, likely possesses a similar systems structure agreeing with Darwin's description of acting like the brain of a lower organism. Intelligent behavior requires assessment of different choices and taking the beneficial one. Decisions are constantly required to optimize the plant phenotype to a dynamic environment and the cambium is the assessing tissue diverting more or removing resources from different shoot and root branches through manipulation of vascular elements. Environmental awareness likely indicates consciousness. Spontaneity in plant behavior, ability to count to five and error correction indicate intention. Volatile organic compounds are used as signals in plant interactions and being complex in composition may be the equivalent of language accounting for self and alien recognition by individual plants. Game theory describes competitive interactions. Interactive and intelligent outcomes emerge from application of various games between plants themselves and interactions with microbes. Behavior profiting from experience, another simple definition of intelligence, requires both learning and memory and is indicated in the priming of herbivory, disease and abiotic stresses.

  6. Ectopic expression a tomato KNOX Gene Tkn4 affects the formation and the differentiation of meristems and vasculature.

    Science.gov (United States)

    Yan, Fang; Hu, Guojian; Ren, Zhenxin; Deng, Wei; Li, Zhengguo

    2015-12-01

    The KNOTTED-LIKE HOMEODOMAIN genes are involved in maintenance of the shoot apical meristem which produces the whole above-ground body of vascular plants. In this report, a tomato homolog gene, named as Tkn4 (a nucleus targeted transcription factor) was identified and characterized. By performing RT-PCR, the transcript level of Tkn4 was separately found in stem, root, stamen, stigma, fruit and sepal but hardly visible in the leaf. Besides, Tkn4 was induced by a series of plant hormones. Overexpression of Tkn4 gene in tomato resulted in dwarf phenotype and strongly repressed the formation of shoot apical meristem, lateral meristem and cambiums in transgenic lines. The transgenic lines had wrinkled leaves and anatomic analysis showed that there was no obvious palisade tissues in the leaves and the layer of cells changed in vascular tissue (xylem and phloem). To explore the regulation network of Tkn4, RNA-sequencing was performed in overexpression lines and wild type plants, by which many genes related to the synthesis and the signal transduction of cytokinin, auxin, gibberellin, ethylene, abscisic acid, and tracheary element differentiation or extracellular matrix synthesis were significantly regulated. Taken together, our results demonstrate that Tkn4 plays important roles in regulating the biosynthesis and signal transduction of diverse plant hormones, and the formation and differentiation of meristems and vasculature in tomato.

  7. Identification of microRNAs Involved in Regeneration of the Secondary Vascular System in Populus tomentosa Carr

    Science.gov (United States)

    Tang, Fang; Wei, Hairong; Zhao, Shutang; Wang, Lijuan; Zheng, Huanquan; Lu, Mengzhu

    2016-01-01

    Wood formation is a complex developmental process primarily controlled by a regulatory transcription network. MicroRNAs (miRNAs) can modulate the expression of target genes involved in plant growth and development by inducing mRNA degradation and translational repression. In this study, we used a model of secondary vascular system regeneration established in Populus tomentosa to harvest differentiating xylem tissues over time for high-throughput sequencing of small RNAs. Analysis of the sequencing data identified 209 known and 187 novel miRNAs during this regeneration process. Degradome sequencing analysis was then performed, revealing 157 and 75 genes targeted by 21 known and 30 novel miRNA families, respectively. Gene ontology enrichment of these target genes revealed that the targets of 15 miRNAs were enriched in the auxin signaling pathway, cell differentiation, meristem development, and pattern specification process. The major biological events during regeneration of the secondary vascular system included the sequential stages of vascular cambium initiation, formation, and differentiation stages in sequence. This study provides the basis for further analysis of these miRNAs to gain greater insight into their regulatory roles in wood development in trees. PMID:27303419

  8. Morphophysiological Behavior and Cambial Activity in Seedlings of Two Amazonian Tree Species under Shade

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    Monyck Jeane dos Santos Lopes

    2015-01-01

    Full Text Available Variations in light intensity can lead to important anatomical and morphophysiological changes in plants. Aiming to increase knowledge about the Amazonian tree species, this study examines the influence of shade on the cambial activity and development of Parkia gigantocarpa Ducke and Schizolobium parahyba var. amazonicum (Huber ex Ducke Barneby seedlings. Seedlings of the two species were grown in a nursery under four shade intensities (treatments: full sun, low, moderate, and high shade (resp., 0%, 23%, 67%, and 73% of shade, or 2000, 1540, 660, and 540 µmol·m−2·s−1 obtained with polyethylene screens. We measured plant height, stem diameter, biomass production, stomatal conductance (gs, transpiration (E, photosynthesis (A, and cambial activity (CA (xylem, cambium, and phloem. Also, we calculated the Dickson Quality Index (DQI. The highest values of biomass production, gs,  E, A, and DQI, were found under full sun, in P. gigantocarpa, and under low shade intensity in S. parahyba. In both species high shade intensity reduced CA. We concluded that the CA and the physiological and morphological attributes work together, explaining the radial growth and increasing seedlings quality, which optimized efficient seedling production under full sun, in P. gigantocarpa, and under low shade intensity in S. parahyba.

  9. The separation and distribution of simple and condensed leucoanthocyanins of the tea plant (Camellia sinensis L.).

    Science.gov (United States)

    Forrest, G I; Bendall, D S

    1969-08-01

    1. Leucoanthocyanin monomers of high mobilities in aqueous solvents on thinlayer chromatograms, assumed to be structurally simple, were characteristic of mature bulky tissues, whereas members of lower mobility were confined to young vegetative and floral tissues. 2. Flavylogens were separated by gel filtration on Sephadex columns into monomeric, oligomeric and polymeric fractions. 3. The polymeric fraction from young brown stems was heterogeneous, one-half having a molecular weight of about 3400, one-third a molecular weight between 3600 and 17000, and the remainder a molecular weight of over 17000. 4. Leaves had low flavylogen concentrations; only monomers were present. Stem tissues were rich in polymers, which increased with the age of the young stem and decreased inwards through the wood. The maximal flavylogen concentrations were in the phloem and cambium from mature stems, where all three fractions were richly present. The periderm tissue and, to a lesser extent, the seed coat were characterized by a very high polymer/monomer ratio, exhibiting a much higher degree of polymerization than the wood. Root tissues contained high concentrations of monomers. 5. In general, there was an inverse correlation between the extent of polymerization and the complexity of the monomers present. 6. The results are in favour of the thesis that the function of the flavanols is, after polymerization to condensed tannins, to impregnate dead structural tissues and thereby to protect them from infection and decay.

  10. Intelligence, Cognition, and Language of Green Plants.

    Science.gov (United States)

    Trewavas, Anthony

    2016-01-01

    A summary definition of some 70 descriptions of intelligence provides a definition for all other organisms including plants that stresses fitness. Barbara McClintock, a plant biologist, posed the notion of the 'thoughtful cell' in her Nobel prize address. The systems structure necessary for a thoughtful cell is revealed by comparison of the interactome and connectome. The plant root cap, a group of some 200 cells that act holistically in responding to numerous signals, likely possesses a similar systems structure agreeing with Darwin's description of acting like the brain of a lower organism. Intelligent behavior requires assessment of different choices and taking the beneficial one. Decisions are constantly required to optimize the plant phenotype to a dynamic environment and the cambium is the assessing tissue diverting more or removing resources from different shoot and root branches through manipulation of vascular elements. Environmental awareness likely indicates consciousness. Spontaneity in plant behavior, ability to count to five and error correction indicate intention. Volatile organic compounds are used as signals in plant interactions and being complex in composition may be the equivalent of language accounting for self and alien recognition by individual plants. Game theory describes competitive interactions. Interactive and intelligent outcomes emerge from application of various games between plants themselves and interactions with microbes. Behavior profiting from experience, another simple definition of intelligence, requires both learning and memory and is indicated in the priming of herbivory, disease and abiotic stresses. PMID:27199823

  11. Concentration of radiocesium in the wild Japanese monkey (Macaca fuscata over the first 15 months after the Fukushima Daiichi nuclear disaster.

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    Shin-ichi Hayama

    Full Text Available Following the massive earthquake that struck eastern Japan on March 11, 2011, a nuclear reactor core meltdown occurred at the Fukushima Daiichi Nuclear Power Plant, operated by Tokyo Electric Power Company, and was followed by the release of large amounts of radioactive materials. The objective of this study was to measure the concentration of radiocesium (134Cs and (137Cs in the muscle of Japanese monkeys (Macaca fuscata inhabiting the forest area of Fukushima City and to determine the change in concentration over time as well as the relationship with the level of soil contamination. Cesium concentrations in the muscle of monkeys captured at locations with 100,000-300,000 Bq/m(2 were 6,000-25,000 Bq/kg in April 2011 and decreased over 3 months to around 1,000 Bq/kg. However, the concentration increased again to 2,000-3,000 Bq/kg in some animals during and after December 2011 before returning to 1,000 Bq/kg in April 2012, after which it remained relatively constant. This pattern of change in muscle radiocesium concentration was similar to that of the change in radiocesium concentration in atmospheric fallout. Moreover, the monkeys feed on winter buds and the cambium layer of tree bark potentially containing higher concentrations of radiocesium than that in the diet during the rest of the year. The muscle radiocesium concentration in the monkeys related significantly with the level of soil contamination at the capture locations.

  12. Ontogenetic histological changes in the wood of mango (Mangifera indica L. cv Deshi) exposed to coal-smoke pollution

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, M.C.; Iqbal, M. [Dept. of Botany, New Delhi (India)

    2005-11-01

    Trees of Mangifera indica L. cv Deshi growing at two sites, one heavily polluted due to coal-smoke emanating from a thermal power plant and the other free from such pollution, were examined across their boles (from pith to cambium) to trace ontogenetic changes induced by coal-smoke pollutants in the wood structure with special reference to vessels and fibres. Wood formation was hampered in the polluted environment, as evident from the width of annual rings, indicating an adverse influence of coal-smoke pollutants on the cambial activity. The pollutants inhibited dimensional growth of tracheal elements and promoted frequency and grouping of vessels since early growth stages. The increasing vessel number per square millimeter of wood and the decreasing dimensions of vessel elements and fibres resulted in low values for vulnerability and mesomorphic ratios in the polluted trees. The ratio of the length of fibres to that of vessel elements also decreased. With the growing age, the decline in vulnerability ratio and mesomorphic ratio was enhanced whereas that in the fibre/vessel-element length ratio was minimized.

  13. Socio-ecological implications of modifying rotation lengths in forestry.

    Science.gov (United States)

    Roberge, Jean-Michel; Laudon, Hjalmar; Björkman, Christer; Ranius, Thomas; Sandström, Camilla; Felton, Adam; Sténs, Anna; Nordin, Annika; Granström, Anders; Widemo, Fredrik; Bergh, Johan; Sonesson, Johan; Stenlid, Jan; Lundmark, Tomas

    2016-02-01

    The rotation length is a key component of even-aged forest management systems. Using Fennoscandian forestry as a case, we review the socio-ecological implications of modifying rotation lengths relative to current practice by evaluating effects on a range of ecosystem services and on biodiversity conservation. The effects of shortening rotations on provisioning services are expected to be mostly negative to neutral (e.g. production of wood, bilberries, reindeer forage), while those of extending rotations would be more varied. Shortening rotations may help limit damage by some of today's major damaging agents (e.g. root rot, cambium-feeding insects), but may also increase other damage types (e.g. regeneration pests) and impede climate mitigation. Supporting (water, soil nutrients) and cultural (aesthetics, cultural heritage) ecosystem services would generally be affected negatively by shortened rotations and positively by extended rotations, as would most biodiversity indicators. Several effect modifiers, such as changes to thinning regimes, could alter these patterns. PMID:26744047

  14. A preliminary investigation into the use of Red Pine (Pinus Resinosa) tree cores as historic passive samplers of POPs in outdoor air

    Science.gov (United States)

    Rauert, Cassandra; Harner, Tom

    2016-09-01

    The suitability of Red Pine trees (Pinus Resinosa) to act as passive samplers for persistent organic pollutants (POPs) in outdoor air and to provide historic information on air concentration trends was demonstrated in this preliminary investigation. Red Pine tree cores from Toronto, Canada, were tested for polycyclic aromatic hydrocarbon (PAHs), alkylated-PAHs, nitro and oxy-PAHs, polybrominated diphenyl ethers (PBDEs) and novel brominated flame retardants (novel BFRs). The PBDEs and novel BFRs demonstrated a similar relative contribution in cores representing 30 years of tree growth, to that reported in contemporary air samples. Analysis of tree ring segments of 5-15 years resulted in detectable concentrations of some PAHs and alk-PAHs and demonstrated a transition from petrogenic sources to pyrogenic sources over the period 1960-2015. A simple uptake model was developed that treats the tree rings as linear-phase passive air samplers. The bark infiltration factor, IFBARK, is a key parameter of the model that reflects the permeability of the bark to allow chemicals to be transferred from ambient air to the outer tree layer (cambium). An IFBARK of about 2% was derived for the Red Pine trees based on tree core and air monitoring data.

  15. The acropetal effects of indole-3-acetic acid in isolated shoot segments of Acer pseudoplatanus L. II. Possible regulation by a vectorial fieid of auxin waves

    Directory of Open Access Journals (Sweden)

    Jacek A. Adamczyk

    2014-02-01

    Full Text Available The acropetal effects of auxin on elongation of axillary buds and on modulation of the wave-like pattern of basipetal efflux of natural auxin to agar from Acer pseudoplatanus L. shoots were studied. When synthetic IAA was applied to cut surfaces of one of two branches the elongation growth of buds situated on the opposite branch was retarded, suggesting regulation independent of the direct action of the molecules of the applied IAA. Oscillations in basipetal transport of natural auxin along the stem segments were observed corroborating the results of other authors using different tree species. Apical application of synthetic IAA for 1 hour to the lateral branch caused a phase shift of the wave-like pattern of basipetal efflux of natural auxin, when the stem segment above the treated branch was sectioned. The same effect was observed evoked by the laterally growing branch which is interpreted as an effect of natural auxin produced by the actively growing shoot. These modulations could be propagated acropetally at a rate excluding direct action of auxin molecules at the sites of measurement. The results seem to corroborate the hypothesis suggesting that auxin is involved in acropetal regulation of shoot apex growth through its effect upon modulation of the vectorial field which arises when the auxin-waves translocate in cambium.

  16. Lebensspuren holzzerstörender Organismen an fossilen Hölzern aus dem Tertiär der Insel Lesbos, Griechenland

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    H. Süss

    2001-01-01

    Full Text Available Lebensspuren (Schadbilder holzzerstörender Organismen an fossilen Holzresten aus dem Untermiozän von Lesbos (Griechenland werden beschrieben. Von pflanzlichen Holzzerstörern konnten Bakterien, imperfekte Pilze, Weiß- und Braunfäulepilze und in das Holz eingewachsene Wurzeln nachgewiesen werden. Von tierischen Holzzerstörern wurden Termitenfraß, durch Pflanzensauger (Homopteren verursachtes Wundgewebe, Larvenfraß der Kambium-Minierfliege Palaeophytobia (Agromyzidae, Diptera und Fraßgänge mit Koprolithen verschiedener Käferarten (Anobiiden? und Milben (Acari gefunden. Außerdem werden durch Kristallisationsvorgänge im Holz verursachte kugelförmige Gebilde beschrieben. Traces of wood destroying organisms on fossil wood from the Lower Miocene of Lesbos (Greece are described. Among nonanimal wood destroyers evidence is presented of bacteria, Fungi imperfecti, whiterot and brownrot fungus and penetrating roots. Animal wood destroyers include termite feeding traces, wound tissues produced by plant suckers (Homoptera, larval feeding traces of the cambium miner Palaeophytobia (Agromyzidae, Diptera and feeding channels, with coprolites, of several beetle species (Anobiidae? and Mites (Acari. In addition globe-like structures produced in the wood through crystallization processes are described. doi:10.1002/mmng.20010040105

  17. Changes of Soluble Protein, Peroxidase Activity and Distribution During Regeneration After Girdling in Eucommia ulmoides

    Institute of Scientific and Technical Information of China (English)

    HOUHong-Wei; Kalima-N'KomaMWANGE; WANGYa-Qing; CUIKe-Ming

    2004-01-01

    Peroxidases are known to play important roles in plant wound healing. Biochemical analysisand histochemical localization techniques were used to assess changes and distribution of peroxidases inthe recovering bark after girdling in Eucommia ulmoides Oliv. Between 4 and 21 days after girdling (DAG),peroxidases activity in the girdled trees significantly increased by 30-40 times over that in ungirdled trees.During the whole bark recovery process (from 0 to 63 DAG), the peroxidase signal was not found in thetissue regions subjected to intense cell division activity (regenerating cambial zone and phellogen). However,high peroxidase activity was detected in the callus, cortex-like, mature phloem and xylem. Interestingly, itwas shown that, in maturing xylem and phloem cells, there was respectively an inward and outwardperoxidase activity gradient on both sides of the cambium zone. An isoelectric-focusing electrophoresis ofthe extracted protein displayed two isozyme bands of peroxidase: POD Ⅰ and POD Ⅱ. POD Ⅰ was onlydetected in the xylem fraction and could play a role in xylem differentiation. POD Ⅱ was only identified inthe recovering bark portion and could be more engaged in bark regeneration process. A relationshipbetween IAA and peroxidase is also discussed.

  18. Bio-ecology of Taxus Baccata l. in Kakheti

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    Tamar Nadiradze

    2013-01-01

    Full Text Available The article discusses the bio-ecology of Taxus baccata L. in Kakheti (eastern Georgia, particularly in Tsinandali Park. Yew (Taxus baccata L. preserved in Tsinandali Park (Telavi region, Georgia was chosen as an object for long-lasting observation over plant vegetation. Vegetation of 47 new specimens were studied during the period 2001-2010. It was observed the buds opening, the vegetation finishing, the cambium active periods beginning and finishing, the sprout stiffen process, the rate and time of growth. The period between 2001 and 2004 is distinguished by the relatively intensive growth of yew samples. In 2004-2010 growth period was shortened. It is suggested, that shortening often growth period in yew specimen is related to the deficit of water in soil due to frequent drought and snowless winters in Telavi region in the last decade.Observation conducted on the peculiarities of cambial growth confirms that yew has strong ability of frost-resistance. We consider that the bio-ecological studies of yew tree, as an endangered species, and its implementation in decorative gardening will contribute to its conservation

  19. Impact of the 2013-2015 weather variability on seasonal growth dynamics and daily stem-size changes of three coexisting broadleaved tree species

    Science.gov (United States)

    van der Maaten, Ernst; Pape, Jonas; van der Maaten Theunissen, Marieke; Scharnweber, Tobias; Smiljanic, Marko; Wilmking, Martin

    2016-04-01

    Dendrometers are measurement devices that continuously monitor stem-size changes of trees without invasive sampling of the cambium. Dendrometers record both irreversible tree growth as well as reversible signals of stem water storage and depletion, making them important tools for studying tree water status, tree physiology and short-term growth responses of trees to weather fluctuations. In this study, a three-year dendrometer dataset (2013-2015) is used to study seasonal growth dynamics and daily stem-size changes of three coexisting broadleaved tree species (common hornbeam (Carpinus betulus L.), European beech (Fagus sylvatica L.), and pedunculate oak (Quercus robur L.)), growing in an unmanaged forest in northeastern Germany. Seasonal growth patterns (i.e. growth onset, cessation and duration) are analyzed in relation to environmental conditions, and forest meteorological factors driving daily stem-size changes are identified. Following dry conditions in 2014, especially the growth of beech was reduced. Oak was less affected, and displayed a distinct early growth onset for all study years.

  20. Regulation of phytohormones on root primordium initiation and adventitious root formation in the etiolated shoots of Paeonia suffruticosa 'Yinfen Jinlin'

    Institute of Scientific and Technical Information of China (English)

    Zeng Duan-xiang; Yin Wei-lun; Zhao Xiao-qing; Wang Hua-fang

    2006-01-01

    Tree peony is well known and sought after for its large, colorful flowers. Its propagation is via vegetative methods. Mechnisms of the adventitious rooting and the regulation of rooting processes are the principles and techniques of plant propagation and improvement. Microstmctures and fluctuations of phytohormones in the adventitious rooting were studied with the etiolated softwood shoots of Paeonia suffruticosa 'Yinfen Jinlin'. There are no pre-primordia in the shoots of the cultivar. Adventitious roots are produced in five stages: shoot selection, primordium initiation, primordium growth, conducting tissue differentiation and root protrusion. Primordia initiated in the cortex. The contents of the endogenous hormones, IAA, ABA and GA, were 5.842, 0.873 and 1.043to GA, CTK and ABA clearly increased at the stage of primordium initiation, while they showed low levels at the stages of primordium growth. The ratios were restored at the shoot levels at the stage of root protrusion. IBA provoked primordia initiation in the cortex, the vascular cambium, the pith and even in the callus induced on the base of shoots. IAA levels in the treated shoots increased gradually to its highest level (three times of control) at the stage of conducting tissue differentiation. The ratios of IAA to GA, CTK and ABA clearly decreased at the stage of primordium initiation. The ratio of IAA to ABA is regulated at 10:1.

  1. THE STUDY OF GROWTH RING OF TREES AT NATIONAL PARK OF SIBERUT IN MENTAWAI ISLANDS

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    Mansyurdin,

    2016-03-01

    Full Text Available Growth ring trees are formed by activity of the cambium which is influenced by the changing seasons. In the tropical are not all of trees species produce the growth ring, because the season of tropics is more uniform throughout the year and does not show sharp distinction between the periods of high rainfall and period of low rainfall. This study has concentred on several tree forest areas in Siberut National Park, Mentawai Islands. Samples were ollected by using borer on the main stem on the height of 130 cm. To see or not to see growing circle with to be checked macroscopically and microscopically. The macroscopic examination was done polished core by several grades of sandpaper in the transverse surface Tree species which have growth ring continued to microscopic observation with making slice anatomy. Based on 46 species of trees were examined, and 6 species were with found a growth ring in the number of cell mixture early wood and late wood from these species.

  2. The translation elongation factor eEF-1Bβ1 is involved in cell wall biosynthesis and plant development in Arabidopsis thaliana.

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    Zakir Hossain

    Full Text Available The eukaryotic translation elongation factor eEF-1Bβ1 (EF1Bβ is a guanine nucleotide exchange factor that plays an important role in translation elongation. In this study, we show that the EF1Bβ protein is localized in the plasma membrane and cytoplasm, and that the transcripts should be expressed in most tissue types in seedlings. Sectioning of the inflorescence stem revealed that EF1Bβ predominantly localizes to the xylem vessels and in the interfascicular cambium. EF1Bβ gene silencing in efβ caused a dwarf phenotype with 38% and 20% reduction in total lignin and crystalline cellulose, respectively. This loss-of-function mutant also had a lower S/G lignin monomer ratio relative to wild type plants, but no changes were detected in a gain-of-function mutant transformed with the EF1Bβ gene. Histochemical analysis showed a reduced vascular apparatus, including smaller xylem vessels in the inflorescence stem of the loss-of-function mutant. Over-expression of EF1Bβ in an eli1 mutant background restored a WT phenotype and abolished ectopic lignin deposition as well as cell expansion defects in the mutant. Taken together, these data strongly suggest a role for EF1Bβ in plant development and cell wall formation in Arabidopsis.

  3. Comparative histochemical localization of secondary metabolites in seed-raised and in vitro propagated plants of Excoecaria agallocha Linn. (Euphorbiaceae), the milky mangrove tree of historical significance.

    Science.gov (United States)

    Satyan, R S; Aveek, N; Eganathan, P; Parida, A

    2010-10-01

    Mangroves synthesize novel secondary chemicals that are poorly understood. Among the euphorbiaceous mangrove species, Excoecaria agallocha Linn. produces novel terpenoids and alkaloids of medicinal importance. We conducted a comparative tissue level histochemical study of E. agallocha L. to determine whether in vitro propagation alters the content of phytochemicals within the plant parts. Transverse sections of the root, stem and leaves of seed-raised saplings and in vitro propagated plants stained with 10% vanillin-perchloric acid revealed accumulation of terpenoids in the cork cambium. Alkaloids were localized using Dragendorf's reagent in the cortex of the root sections as brown layers. Methylene blue staining revealed that seed-raised plants possessed more lignified cells, distinct latex ducts and ellipsoidal guard cells compared to the plants propagated in vitro, which revealed abnormal, circular guard cells. The phytochemical content of E. agallocha propagated by the in vitro method was comparable to the seed-raised plants. Phytochemical studies of the species of E. agallocha propagated in vitro would confirm whether the species could be used for its medicinal compounds. PMID:19701827

  4. In vitro rhizogenesis: histoanatomy of Cedrela odorata (Meliaceae) microcuttings.

    Science.gov (United States)

    Millán-Orozco, Liliana; Corredoira, Elena; San José, Maria del Carmen

    2011-03-01

    Cedrela odorata (Meliaceae) is considered as one of the most valuable forest tree in the tropics. Clonal propagation of this species provide an alternative method to propagate superior genotypes, being the production of good quality adventitious roots one of the most important steps in micropropagation techniques. The sequence of anatomical changes that takes place during the formation of adventitious roots in shoots of Cedrela odorata cultured in vitro is described in this study. Eigth-week-old shoots, from multiplication cultures, were rooted in Murashige and Skoog's medium (1962) with half-strength macronutrients and with 0 or 1 mg/l indole-3-butyric acid (IBA). Between 12 and 24h after the start of rooting, some cambium, phloem and interfascicular parenchyma cells became dense cytoplasm, nuclei with prominent nucleoli and the first cell divisions were observed, especially in shoots treated with auxin (dedifferentiation phase). After 3-4 days, the number of dedifferentiated cells and mitotic divisions increased considerably, and the formation of groups of some 30-40 meristematic cells (meristemoids) was observed (induction phase). The first primordial roots developed from the 4th-5th day. The vascular tissues of these primordia connected to those of the explant, and roots began to emerge from the base by day 6. Development of the primordial roots was similar in the control shoots and shoots treated with 1 mg/l IBA, although there were more roots per explant in the latter. PMID:21513204

  5. Cavitation and water fluxes driven by ice water potential in Juglans regia during freeze-thaw cycles.

    Science.gov (United States)

    Charra-Vaskou, Katline; Badel, Eric; Charrier, Guillaume; Ponomarenko, Alexandre; Bonhomme, Marc; Foucat, Loïc; Mayr, Stefan; Améglio, Thierry

    2016-02-01

    Freeze-thaw cycles induce major hydraulic changes due to liquid-to-ice transition within tree stems. The very low water potential at the ice-liquid interface is crucial as it may cause lysis of living cells as well as water fluxes and embolism in sap conduits, which impacts whole tree-water relations. We investigated water fluxes induced by ice formation during freeze-thaw cycles in Juglans regia L. stems using four non-invasive and complementary approaches: a microdendrometer, magnetic resonance imaging, X-ray microtomography, and ultrasonic acoustic emissions analysis. When the temperature dropped, ice nucleation occurred, probably in the cambium or pith areas, inducing high water potential gradients within the stem. The water was therefore redistributed within the stem toward the ice front. We could thus observe dehydration of the bark's living cells leading to drastic shrinkage of this tissue, as well as high tension within wood conduits reaching the cavitation threshold in sap vessels. Ultrasonic emissions, which were strictly emitted only during freezing, indicated cavitation events (i.e. bubble formation) following ice formation in the xylem sap. However, embolism formation (i.e. bubble expansion) in stems was observed only on thawing via X-ray microtomography for the first time on the same sample. Ultrasonic emissions were detected during freezing and were not directly related to embolism formation. These results provide new insights into the complex process and dynamics of water movements and ice formation during freeze-thaw cycles in tree stems.

  6. CAFFEINE AND P -ANISALDEHYDE FROM THE FRUITS OF ENTEROLOBIUM SAMAN PRAIN

    Directory of Open Access Journals (Sweden)

    Mohammad Kaisarul Islam et al.

    2012-01-01

    Full Text Available Fruits of the plant were air dried for several days and cut into small pieces, which were subjected to oven dried for 24 hours at 45-50°C to effect further chopping. Cold methanol extract of fruits were subjected to acid-base treatment to separate the alkaloids. The treated extract was subjected to column chromatography to isolate the pure compound. The xanthine alkaloid, 1, 3, 7-trimethyl-1H-purine-2, 6 (3H, 7H-dione, caffeine (compound 1 and also p-anisaldehyde (compound 2 were isolated from the column fraction of this ‘alkaloid containing residue’ by elution with ethyl acetate/10% methanol and ethyl acetate/50-100% methanol, respectively. The isolated pure compounds were identified by extensive spectral (1H-NMR, 13C-NMR, DEPT, HMBC, HSQC, Mass data analysis. Greshoff isolated an alkaloid, pithecolobin from the bark, which is saponin like in its action. Wehmer stated that the seeds also contain pithecolobin. In the Philippines, a decoction of the inner bark (fresh cambium and the fresh leaves of this tree is used in diarrhea. All these above mentioned study lead us to work on it.

  7. Evaluation of cambial electrical resistance for the appraisal of tree vitality on reclaimed coal lands

    Energy Technology Data Exchange (ETDEWEB)

    Keith Plamping; Martin Haigh; Michael J. Cullis; Rhian E. Jenkins [Earthwatch Europe, Oxford (United Kingdom)

    2009-03-15

    Cambium electrical resistance (CER) is explored as a rapid-assessment method of measuring of forest vitality and disease damage. A five year study in a 10-year-old mixed plantation of Alder (Alnus glutinosa, L.) and Oak (Quercus petraea (Mattuschka) Liebl.) created for the reclamation of surface-coal mined land in South Wales found a negative correlation between CER and tree maturity and no correlation between CER and fertiliser treatment levels. However, it detected strong significant correlations between CER and both a tree vitality index and diameter breast height (DBH) after five years. In fact, CER shows very strong and significant negative correlations with DBH recorded in 2007 and 2002, while tree vitality correlates more strongly with DBH than CER. Partial correlation of the data finds that when these data are controlled for the effect of DBH-the correlation between CER and vitality is no longer significant, while partial correlations between vitality and DBH in both 2002 and 2007-controlled for CER-remain highly significant. The conclusion is that while CER may act as a useful measure and predictor of tree vitality-DBH is better.

  8. Successive cambia: a developmental oddity or an adaptive structure?

    Directory of Open Access Journals (Sweden)

    Elisabeth M R Robert

    Full Text Available BACKGROUND: Secondary growth by successive cambia is a rare phenomenon in woody plant species. Only few plant species, within different phylogenetic clades, have secondary growth by more than one vascular cambium. Often, these successive cambia are organised concentrically. In the mangrove genus Avicennia however, the successive cambia seem to have a more complex organisation. This study aimed (i at understanding the development of successive cambia by giving a three-dimensional description of the hydraulic architecture of Avicennia and (ii at unveiling the possible adaptive nature of growth by successive cambia through a study of the ecological distribution of plant species with concentric internal phloem. RESULTS: Avicennia had a complex network of non-cylindrical wood patches, the complexity of which increased with more stressful ecological conditions. As internal phloem has been suggested to play a role in water storage and embolism repair, the spatial organisation of Avicennia wood could provide advantages in the ecologically stressful conditions species of this mangrove genus are growing in. Furthermore, we could observe that 84.9% of the woody shrub and tree species with concentric internal phloem occurred in either dry or saline environments strengthening the hypothesis that successive cambia provide the necessary advantages for survival in harsh environmental conditions. CONCLUSIONS: Successive cambia are an ecologically important characteristic, which seems strongly related with water-limited environments.

  9. Coexistence and Competition between Tomicus yunnanensis and T. minor (Coleoptera: Scolytinae in Yunnan Pine

    Directory of Open Access Journals (Sweden)

    Rong Chun Lu

    2012-01-01

    Full Text Available Competition and cooperation between bark beetles, Tomicus yunnanensis Kirkendall and Faccoli and Tomicus minor (Hartig (Coleoptera: Scolytinae were examined when they coexisted together in living Yunnan pine trees (Pinus yunnanensis Franchet in Yunnan province in Southwest China. T. yunnanensis bark beetles were observed to initiate dispersal from pine shoots to trunks in November, while the majority of T. minor begins to transfer in December. T. yunnanensis mainly attacks the top and middle parts of the trunk, whereas T. minor mainly resides in the lower and middle parts of the trunk. The patterns of attack densities of these two species were similar, but with T. yunnanensis colonizing the upper section of the trunk and T. minor the lower trunk. The highest attack density of T. Yunnanensis was 297 egg galleries/m2, and the highest attack density of T. minor was 305 egg galleries/m2. Although there was significant overlap for the same bark areas, the two species generally colonize different areas of the tree, which reduces the intensity of competition for the relatively thin layer of phloem-cambium tissues where the beetles feed and reside.

  10. Did the late spring frost in 2007 and 2011 affect tree-ring width and earlywood vessel size in Pedunculate oak ( Quercus robur) in northern Poland?

    Science.gov (United States)

    Puchałka, Radosław; Koprowski, Marcin; Przybylak, Julia; Przybylak, Rajmund; Dąbrowski, Henryk P.

    2016-08-01

    Trees are sensitive to extreme weather and environmental conditions. This sensitivity is visible in tree-ring widths and cell structure. In our study, we hypothesized that the sudden frost noted at the beginning of May in both 2007 and 2011 affected cambial activity and, consequently, the number and size of vessels in the tree rings. It was decided to test this hypothesis after damage to leaves was observed. The applied response function model did not show any significant relationships between spring temperature and growth. However, this method uses average values for long periods and sometimes misses the short-term effects. This is why we decided to study each ring separately, comparing them with rings unaffected by the late frost. Our study showed that the short-term effect of sudden frost in late spring did not affect tree rings and selected cell parameters. The most likely reasons for this are (i) cambial activity producing the earlywood vessels before the occurrence of the observed leaf damage, (ii) the forest micro-climate protecting the trees from the harsh frost and (iii) the temperature decline being too short-lived an event to affect the oaks. On the other hand, the visible damage may be occasional and not affect cambium activity and tree vitality at all. We conclude that oak is well-adapted to this phenomenon.

  11. Effect of auxin on xylem tracheids differentiation in decapitated stems of Pinus silvestris L. and its interaction with some vitamins and growth regulators

    Directory of Open Access Journals (Sweden)

    T. J. Wodzicki

    2015-05-01

    Full Text Available The effects of several vitamins and substances known as important agents in regulation of cell metabolism upon secondary xylem differentiation were studied in interaction with auxin (IAA as applied in lanoline to decapitated stems of 5-year-old Pinus silvestris trees in early and late-summer. Tested substances were: gibberellic acid, kinetin, nicotinic acid, thiamine, pyridoxine, calcium panthotenate, choline chloride, riboflavin, inositol, ascorbic acid, vitamin, A (alcohol, vitamin A (ester, saponin. None of the effects of these substances appeared significant enough to indicate the involvement in the seasonal variation of the response of cambium or differentiating tracheids to auxin. However, several effects, especially those of inositol, vitamin A and pyridoxine upon cambial xylem production and further stages of tracheid differentiation were observed. Auxin (IAA affected cambial activity and subsequent differentiation of tracheids during the earliest stages of cell ontogenesis. At these stages auxin treatment induced quantitative expression of the developmental processes involving radial growth and secondary wall formation by tracheids. In this respect, auxin did not affect cells advanced in differentiation, however, it proved to be an essential factor in the completion of the full cycle of tracheid ontogenesis.

  12. Cavitation and water fluxes driven by ice water potential in Juglans regia during freeze-thaw cycles.

    Science.gov (United States)

    Charra-Vaskou, Katline; Badel, Eric; Charrier, Guillaume; Ponomarenko, Alexandre; Bonhomme, Marc; Foucat, Loïc; Mayr, Stefan; Améglio, Thierry

    2016-02-01

    Freeze-thaw cycles induce major hydraulic changes due to liquid-to-ice transition within tree stems. The very low water potential at the ice-liquid interface is crucial as it may cause lysis of living cells as well as water fluxes and embolism in sap conduits, which impacts whole tree-water relations. We investigated water fluxes induced by ice formation during freeze-thaw cycles in Juglans regia L. stems using four non-invasive and complementary approaches: a microdendrometer, magnetic resonance imaging, X-ray microtomography, and ultrasonic acoustic emissions analysis. When the temperature dropped, ice nucleation occurred, probably in the cambium or pith areas, inducing high water potential gradients within the stem. The water was therefore redistributed within the stem toward the ice front. We could thus observe dehydration of the bark's living cells leading to drastic shrinkage of this tissue, as well as high tension within wood conduits reaching the cavitation threshold in sap vessels. Ultrasonic emissions, which were strictly emitted only during freezing, indicated cavitation events (i.e. bubble formation) following ice formation in the xylem sap. However, embolism formation (i.e. bubble expansion) in stems was observed only on thawing via X-ray microtomography for the first time on the same sample. Ultrasonic emissions were detected during freezing and were not directly related to embolism formation. These results provide new insights into the complex process and dynamics of water movements and ice formation during freeze-thaw cycles in tree stems. PMID:26585223

  13. Experimental evidence for heat plume-induced cavitation and xylem deformation as a mechanism of rapid post-fire tree mortality.

    Science.gov (United States)

    West, Adam G; Nel, Jacques A; Bond, William J; Midgley, Jeremy J

    2016-08-01

    Recent work suggests that hydraulic mechanisms, rather than cambium necrosis, may account for rapid post-fire tree mortality. We experimentally tested for xylem cavitation, as a result of exposure to high-vapour-deficit (D) heat plumes, and permanent xylem deformation, as a result of thermal softening of lignin, in two tree species differing in fire tolerance. We measured percentage loss of conductance (PLC) in distal branches that had been exposed to high-D heat plumes or immersed in hot water baths (high temperature, but not D). Results were compared with predictions from a parameterized hydraulic model. Physical damage to the xylem was examined microscopically. Both species suffered c. 80% PLC when exposed to a 100°C plume. However, at 70°C, the fire-sensitive Kiggelaria africana suffered lower PLC (49%) than the fire-resistant Eucalytpus cladocalyx (80%). Model simulations suggested that differences in PLC between species were a result of greater hydraulic segmentation in E. cladocalyx. Kiggelaria africana suffered considerable PLC (59%), as a result of heat-induced xylem deformation, in the water bath treatments, but E. cladocalyx did not. We suggest that a suite of 'pyrohydraulic' traits, including hydraulic segmentation and heat sensitivity of the xylem, may help to explain why some tree species experience rapid post-fire mortality after low-intensity fires and others do not. PMID:27152877

  14. The site of water stress governs the pattern of ABA synthesis and transport in peanut

    Science.gov (United States)

    Hu, Bo; Cao, Jiajia; Ge, Kui; Li, Ling

    2016-01-01

    Abscisic acid (ABA) is one of the most important phytohormones involved in stress responses in plants. However, knowledge of the effect on ABA distribution and transport of water stress at different sites on the plant is limited. In this study, water stress imposed on peanut leaves or roots by treatment with PEG 6000 is termed “leaf stress” or “root stress”, respectively. Immunoenzyme localization technolony was first used to detect ABA distribution in peanut. Under root stress, ABA biosynthesis and distribution level were all more pronounced in root than in leaf. However, ABA transport and the ability to induce stomatal closure were still better in leaf than in root during root stress; However, ABA biosynthesis initially increased in leaf, then rapidly accumulated in the vascular cambium of leaves and induced stomatal closure under leaf stress; ABA produced in root tissues was also transported to leaf tissues to maintain stomatal closure. The vascular system was involved in the coordination and integration of this complex regulatory mechanism for ABA signal accumulation. Water stress subject to root or leaf results in different of ABA biosynthesis and transport ability that trigger stoma close in peanut. PMID:27694957

  15. Expression pattern conferred by a glutamic acid-rich protein gene promoter in field-grown transgenic cassava (Manihot esculenta Crantz).

    Science.gov (United States)

    Beltrán, J; Prías, M; Al-Babili, S; Ladino, Y; López, D; Beyer, P; Chavarriaga, P; Tohme, J

    2010-05-01

    A major constraint for incorporating new traits into cassava using biotechnology is the limited list of known/tested promoters that encourage the expression of transgenes in the cassava's starchy roots. Based on a previous report on the glutamic-acid-rich protein Pt2L4, indicating a preferential expression in roots, we cloned the corresponding gene including promoter sequence. A promoter fragment (CP2; 731 bp) was evaluated for its potential to regulate the expression of the reporter gene GUSPlus in transgenic cassava plants grown in the field. Intense GUS staining was observed in storage roots and vascular stem tissues; less intense staining in leaves; and none in the pith. Consistent with determined mRNA levels of the GUSPlus gene, fluorometric analyses revealed equal activities in root pulp and stems, but 3.5 times less in leaves. In a second approach, the activity of a longer promoter fragment (CP1) including an intrinsic intron was evaluated in carrot plants. CP1 exhibited a pronounced tissue preference, conferring high expression in the secondary phloem and vascular cambium of roots, but six times lower expression levels in leaf vascular tissues. Thus, CP1 and CP2 may be useful tools to improve nutritional and agronomical traits of cassava by genetic engineering. To date, this is the first study presenting field data on the specificity and potential of promoters for transgenic cassava.

  16. Anatomical structure of african violet (Saintpaulia ionantha L. vitro- and exvitroplantlets

    Directory of Open Access Journals (Sweden)

    Adriana PETRUŞ-VANCEA

    2010-11-01

    Full Text Available In this article we study the histo-anatomical structure of vegetative organs of African violet (Saintpaulia ionantha L. vitro- and exvitroplantlets in comparison with similar aspects at the same organs of the greenhouse plants (control lot. The phytoinoculs vitroculture period was 120 days, the ex vitro acclimatization for the exvitroplantlets needed 30 days, and the greenhouse cultivar was 2 years old. Finally, we found that only rootlets of the vitroplantlets had a primary structure because at stemlets level has been identified the cambium presence still the vitroculture period. The cortical parenchyma cells at vitro- and exvitroplantlets was larger and less compact in comparison with those of control lot. Also, in the vitroplantlet rootles and stemlets the report cortex:central cylinder was much higher and vascular bundle was very poorly represented that at exvitroplantlets, but especially in comparison with these aspects in the plants grown in natural conditions. The spongy parenchyma at leaflets from in vitro culture was composed of fewer cell layers which was larger and less compact in comparison with those of exvitroplantlet leaf homologous layers and with the same layers from the leaf of greenhouse plants. At in vitro leaflets the peryphloemic protective mechanical tissue was at an early forming stage. However, we consider these differences as being due to the plants normal ontogenetic development.

  17. A simple shoot multiplication procedure using internode explants, and its application for particle bombardment and Agrobacterium-mediated transformation in watercress.

    Science.gov (United States)

    Ogita, Shinjiro; Usui, Miki; Shibutani, Nanae; Kato, Yasuo

    2009-07-01

    A shoot multiplication system derived from internode explants was investigated with the aim of improving genetic characteristics of watercress (Nasturtium officinale R. Br.). Internodes of ca. 1 cm excised from in vitro stock shoot culture were placed on half-strength Murashige and Skoog (MS) medium supplemented with 3 muM 2,4-dichlorophenoxyacetic acid as a pre-treatment. Laser scanning microscopy indicated clearly that the first sign of meristematic cell division could be seen after 1-2 days of pre-culture, and meristematic tissues multiplied along the vascular cambium of the internode segment during 7 days of culture. Multiple shoots could be obtained from more than 90% of the pre-treated explants when they were subsequently transferred to MS medium supplemented with 1 muM thidiazuron for 3 weeks. These findings indicate that pre-treatment of the internodes for 7 days promoted their capacity for organogenesis. Using this pre-treatment, frequent generation of transgenic watercress plants was achieved by adapting particle bombardment and Agrobacterium-mediated transformation techniques with a construct expressing a synthetic green florescent protein gene.

  18. Effect of auxin (iaa upon the proteolytic system in differentiating secondary xylem of pine (Pinus sylvestris L.

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    Krzysztof J. Rakowski

    2014-02-01

    Full Text Available Effects of decapitation and IAA on proteolytic activity were studied in main stem of 4-7 year-old Pinus sylvestris trees. Proteolytic activity in the extract from differentiating secondary xylem was found to be totally reduced in decapitated 2-3 year-old segments of the main stem after a few weeks. Simultaneous application of IAA in lanolin paste prevented this reduction. Proteolytic activity reduced totally after decapitation was restored within 2 days when auxin was applied. Analogous responses to decapitated and auxin application were observed in respect to cambial activity and protein level. The latter effects were not correlated in time with the effects upon the activity of proteases. The differences were especially visible when phloem continuity between the decapited stem segment and the rest of the tree crown was broken by ring-barking. The results suggest dependence of a proteolytic system on the shoot apical control. In this epigenetic system of control the role of auxin seems to be directly associated with the seasonal meristematic activity of the cambium, which was observed in earlier studies.

  19. Genome-wide characterization and expression profiling of the AUXIN RESPONSE FACTOR (ARF gene family in Eucalyptus grandis.

    Directory of Open Access Journals (Sweden)

    Hong Yu

    Full Text Available Auxin is a central hormone involved in a wide range of developmental processes including the specification of vascular stem cells. Auxin Response Factors (ARF are important actors of the auxin signalling pathway, regulating the transcription of auxin-responsive genes through direct binding to their promoters. The recent availability of the Eucalyptus grandis genome sequence allowed us to examine the characteristics and evolutionary history of this gene family in a woody plant of high economic importance. With 17 members, the E. grandis ARF gene family is slightly contracted, as compared to those of most angiosperms studied hitherto, lacking traces of duplication events. In silico analysis of alternative transcripts and gene truncation suggested that these two mechanisms were preeminent in shaping the functional diversity of the ARF family in Eucalyptus. Comparative phylogenetic analyses with genomes of other taxonomic lineages revealed the presence of a new ARF clade found preferentially in woody and/or perennial plants. High-throughput expression profiling among different organs and tissues and in response to environmental cues highlighted genes expressed in vascular cambium and/or developing xylem, responding dynamically to various environmental stimuli. Finally, this study allowed identification of three ARF candidates potentially involved in the auxin-regulated transcriptional program underlying wood formation.

  20. Climatic control of tracheid production of black spruce in dense mesic stands of eastern Canada.

    Science.gov (United States)

    Dufour, Boris; Morin, Hubert

    2013-02-01

    Inferences on climate change effects are reliable only if they are based on a causal relationship rather than simple statistical predictive capacity. To assess for causal links between climate and mature black spruce (Picea mariana (Mills.) BSP) radial growth, we combined the use of wood anatomy, cambium phenology, climate and soil measurements (air temperature and humidity, precipitations, soil temperature and water content, photosynthetically active radiation), and a model selection approach proceeding backwards from a full model. Results show that the number of tracheids is responsible for 88% of the variation in ring width whereas mean tracheid diameter accounts for the remaining 12%. The number of tracheids produced depends on factors related to photosynthesis during tracheid production, i.e., daily light intensity and maximum temperature between the day of initiation and the day of cessation of tracheid production, plus soil temperature during August of the previous year which is an important period for determining the number of new needles produced. It is also important to consider duration of the period for tracheid production. These results imply that short-term climate change should increase black spruce radial growth. They also suggest that the typical use of post-growth ring width sampling individually linked to air temperature and precipitations is not sufficient to infer climate change effects accurately on radial growth where there is no strong single climatic limitation but multiple limitations instead. PMID:23355635

  1. Xylogenesis in black spruce: does soil temperature matter?

    Science.gov (United States)

    Lupi, Carlo; Morin, Hubert; Deslauriers, Annie; Rossi, Sergio

    2012-01-01

    In boreal ecosystems, an increase in soil temperature can stimulate plant growth. However, cambium phenology in trees was better explained by air than soil temperature, which suggested that soil temperature is not the main limiting factor affecting xylogenesis. Since soil temperature and snowmelt are correlated to air temperature, the question whether soil temperature directly limits xylogenesis in the stem will remain unresolved without experiments disentangling air and soil temperatures. This study investigated the effects of an increase of 4 °C in soil temperature and a consequent 1-week earlier snowmelt on growth of black spruce [Picea mariana (Mill.) BSP] in the boreal forest of Quebec, Canada. The soil of two natural stands at different altitudes was warmed up with heating cables during 2008-2010 and cambial phenology and xylem production were monitored weekly from April to October. The results showed no significant effect of the treatment on the phenological phases of cell enlargement and wall thickening and lignification. The number of cells produced in the xylem also did not differ between control and heated trees. These findings allowed the hypothesis of a direct influence of soil temperature on stem growth to be rejected and supported the evidence that, in the short term, air temperature is the main limiting factor for xylogenesis in trees of these environments. PMID:22210529

  2. Translocated signals regulating root meristem activity in lupins (Lupinus albus and L. angustifolius)

    International Nuclear Information System (INIS)

    Pluripotent stem cells in flowering plants occur at the root and shoot apices, at the cambium of shoot organs and the root pericycle. These meristematic cells provide sites for cell division and postembryonic organ differentiation. Their activity responds to environmental and endogenous cues that determine rate and direction of growth, developmental pattern and change in organ function. Recent analysis of gene expression in the shoot apical meristem (SAM) of Arabidopsis has revealed close cell/cell interactions and an exchange of signals between differentiating cell types. However, it is clear that the long distance translocation channels of vascular plants, phloem and xylem, also provide regulatory signals that influence the course of events in the SAM, such as the transition from vegetative to floral development. These channels serve as pathways for translocation of assimilates providing the vascular link between 'sources' and 'sinks' on the plant. Similarly, the below ground meristems responsible for root growth, lateral root initiation and branching as well as the initiation of nodules on legumes receive translocated shoot-derived 'signals' as well as assimilates in phloem. Physiological studies have established that such signals are integral components of meristem activity but their nature has not been clearly established. (author)

  3. Investigating the Role of Extensin Proteins in Poplar Biomass Recalcitrance

    Energy Technology Data Exchange (ETDEWEB)

    Fleming, Margaret Brigham; Decker, Stephen R.; Bedinger, Patricia A.

    2016-04-13

    The biological conversion of cellulosic biomass to biofuel is hindered by cell wall recalcitrance, which can limit the ability of cellulases to access and break down cellulose. The purpose of this study was to investigate whether hydroxyproline-rich cell wall proteins (extensins) are present in poplar stem biomass, and whether these proteins may contribute to recalcitrance. Three classical extensin genes were identified in Populus trichocarpa through bioinformatic analysis of poplar genome sequences, with the following proposed names: PtEXTENSIN1 (Potri.001G019700); PtEXTENSIN2 (Potri.001G020100); PtEXTENSIN3 (Potri.018G050100). Tissue print immunoblots localized the extensin proteins in poplar stems to regions near the vascular cambium. Different thermochemical pretreatments reduced but did not eliminate hydroxyproline (Hyp, a proxy for extensins) from the biomass. Protease treatment of liquid hot water-pretreated poplar biomass reduced Hyp content by a further 16% and increased subsequent glucose yield by 20%. These data suggest that extensins may contribute to recalcitrance in pretreated poplar biomass, and that incorporating protease treatment into pretreatment protocols could result in a small but significant increase in the yield of fermentable glucose.

  4. 银杏垂乳个体发生及系统学意义%Ontogenesis and Systematics Implications of Ginkgo biloba Chichi

    Institute of Scientific and Technical Information of China (English)

    邢世岩; 张倩; 付兆军; 刘莉娟; 刘晓静; 辛红; 吴岐奎

    2013-01-01

    垂乳银杏是银杏家族中的一特异种质,银杏垂乳分根生、干生和枝生垂乳.中国现有垂乳银杏348株,分布在19个省(市),日本有43株.垂乳银杏与性别无关,但以300年以上古树居多.银杏垂乳呈圆锥状,外皮粗糙,并且垂直向下生长.这些垂乳生长到地面时可以产生根系和叶片.垂乳在树体上可以单一出现,也可以几个聚生.垂乳的顶部没有顶端分生组织,只出现形成层、次生木质部和韧皮部.从距垂乳顶端1cm处纵断面显示它的管胞具有许多取向,从距其顶端7 cm处取的断面显示,管胞接近正常的形成层取向.银杏垂乳发生机制通常有生长素说、愈伤或不定芽说、环境诱变说、病变或衰老说、子叶芽说.银杏垂乳也许对该物种的生长、发育及营养繁殖、野生性及长寿命具有重要的生态学和系统学意义.%Chichied ginkgo is a distinctive germplasm in ginkgo family.Ginkgo biloba chichi is divided into rooted chichi,stemmed chichi and branched chichi.There are 348 chichied ginkgo trees in China distributed in 19 provinces,and there are 43 plants in Japan.Chichied ginkgoes have no relations with gender but the most of chichied ginkgoes are older than 300 years.Chichi is coniform shaped with rough bark and grows vertically downward.These chichies can produce roots and leaves when they have grown down to the ground.Chichi on the tree can be a single appearance or a few aggregate.The tip of chichi has no apical meristem and only has cambium,secondary xylem and phloem.The median longitudinal sections exhibited various orientations of the tracheids at 1 cm from the tip of chichi.However,the sections revealed that tracheid orientation changed from being very variable in the centre to a more normal orientation as the cambium's at 7 cm from the tip.There are many theories on the chichi occurrence mechanisms,including Auxin theory,callus or adventitious bud theory,environmental mutagenesis theory

  5. Estudios evolutivos-del desarrollo en tallos fósiles de Corystospermaceae (Corystospermales, Spermatopsida Evolutionary developmental studies in fossil stems of Corystospermaceae

    Directory of Open Access Journals (Sweden)

    Josefina Bodnar

    2012-06-01

    in gondwanic Triassic paleofloras. This group accounts for an excellent case study because their stems are preserved permineralized, showing cellular and histological details, and it is possible to examine their whole ontogeny in a single individual since the cells of the secondary xylem and phloem are produced in successive layers retaining permanently their position. In the ontogenetic studies of pteridosperms, regulating mechanisms of development must be discerned comparing with ontogenies of comparable living plants. This extrapolation is possible since it is known that regulating processes of secondary growth are homologous in all lygnophytes. Most of corystosperm axes present a dissected secondary vascular cylinder, and tissues with unusual development and position, which is caused by four classes of cambial deviations: 1- differential activity throughout the stem circumference; 2- remnant activity; 3- inverse or centripetal cambium; and 4 - successive inverse and/or normal cambia (poyxyly. The origin of these cambium deviations is intimately linked to heterotopic events, including neoheterotopy and homeosis. By comparison with living plant studies, it is theorized that homeotic genes implied with these events could be those related to the beginning of cambial activity, cell differentiation, and vascular bundle arrangement.

  6. 沙棘微扦插不定根发生的形态解剖学研究%Morphological and anatomical features during the formation of adventitious roots of sea buckthorn by micro-cuttage multiplication

    Institute of Scientific and Technical Information of China (English)

    姚景瀚; 李伟

    2013-01-01

    利用石蜡切片法对沙棘微扦插不定根的发生进行形态解剖学研究.结果表明:沙棘属于诱导型生根,观察到其不定根原基起源于2个区域,一部分根原基起源于维管形成层细胞,另一部分起源于韧皮部薄壁细胞区域.沙棘不定根原基继续发育时,一部分沿射线向外生长,另一部分向外生长的同时会与茎段的髓连接起来,这种现象在其他树种中尚未发现.沙棘插穗不定根的发生整体上可分为4个阶段:1)维管形成层细胞和韧皮部薄壁细胞分裂出一些排列紧密、细胞质浓、具有分生组织特点的薄壁细胞团;2)新形成的薄壁细胞团不断分裂并且脱分化,形成具有很强分生能力的不定根原基发端细胞;3)根原基发端细胞继续分裂,沿着射线向远离轴心的方向伸展,从而形成根原基;4)根原基穿过韧皮射线和皮层,向外继续朝皮孔方向发展,最终从皮孔伸出形成不定根,不定根伸出皮孔前内部维管系统发育完善并与茎部维管系统相连接.%Morphological and anatomical features were observed during the formation of adventitious roots of sea buckthorn by micro-cuttage multiplication with paraffin method. The results showed that adventitious root primordium originated from two areas ( one was cell of vascular cambium, and the other was cell from cortex parenchyma) was inductive root formation type. When the adventitious root of sea buckthorn continued to grow, this phenomenon that one of its part extended out in ray direction and the other part would connect with the marrow of stem while it was stretching out remained undiscovered in other species. In general, formation of adventitious root of sea buckthorn can be divided into four stages: 1 ) The cells of cortex parenchyma and vascular cambium divided into parenchyma cell groups which contained the characteristics of meristem, stood in a line and bore dense cytoplasm concentration. 2 ) Newly formed parenchyma

  7. 不同浓度外源IAA 处理对杉木茎部基因表达的影响%Cloning and expression analysis of differentially expressed genes in Chinese fir stems treated by different concentrations of exogenous IAA

    Institute of Scientific and Technical Information of China (English)

    杨立伟; 施季森

    2012-01-01

    为了揭示吲哚-3-乙酸(Indole-3-acetic acid,IAA)参与杉木木材发育调控的遗传机制,文章分别以0、3mg.IAA/g.lanolin 处理不同阶段的杉木截顶茎秆作为驱动方(Driver)和测试方(Tester),利用抑制消减杂交技术(Suppression substractive hybridization,SSH),对其中差异表达的目的基因进行了分离和克隆.共获得332 个Unigenes,其潜在的功能分别涉及到细胞组织和生物合成、发育进程调控、电子传递、逆境应答以及信号传导等方面;进一步地表达鉴定发现ClHIRA、ClPGY1 和ClARF4 等集中于茎部近轴区域表达的基因,能够积极地响应外源IAA 刺激的维管形成层分裂和管胞分化活动;而ClSMP1、ClTCTP1 和ClTRN2 等集中于茎部远轴区域表达的基因,则在转录水平上对外源IAA 的处理水平及近轴次生维管的发育变化表现出负相关的关系.这一结果表明特异性定位的发育基因对木材形成组织中内源IAA 水平变化的差异性识别和响应很可能是生长素参与林木维管形成层次生发育调节的重要分子机制.%To reveal the potential genetic mechanisms of indole-3-acetic acid (IAA) that regulate Chinese fir wood formation, cloned the differentially expressed genes via suppress subtractive hybridization (SSH) using the truncated stems treated by 0 and 3 mg IAA/g lanolin as the driver and tester, respectively. A total of 332 unigenes that were involved in cell organization and biosynthesis, developmental processes control, election transport, stress response, and signal transduction. To further test the results from SSH, we selected those unigenes, whose putative encoding proteins showed significantly homologous with HIRA, PGY1, SMP1, TCT, TRN2, and ARF4, and analyzed their expressed specificity in the wood formative tissues and their response to the secondary developmental changes of vascular cambium stimulated by 0, 1, and 3 mg.IAA/g.lanolin treatment. The results showed that CIHIRA, CIPGY

  8. IMPACTS, PATTERNS, INFLUENCING FACTORS AND POLICIES OF FUELWOOD EXTRACTION IN WAY KAMBAS NATIONAL PARK, INDONESIA

    Directory of Open Access Journals (Sweden)

    Ari Rakatama

    2016-04-01

    Full Text Available Uncontrolled fuelwood extraction from conservation forest of Way Kambas National Park (WKNP could threaten the existing forest. This paper studies the way to tackle the forest degradation in WKNP, with less negative impacts to the local people. Study was conducted by analysing existing data and maps of WKNP in terms of forest degradation, forest inventories, current policies, survey on how fuelwood is extracted, observation on fuelwood gatherers, fuelwood demand, and identification of further policy options. Results show that the most significant factors influencing the fuelwood extraction activity in WKNP are land ownership, followed by the distance to forest area, income level, the number of household members and age of household head. In the field, the fuelwood utilization is allowed by WKNP Authority, although it is formally forbidden.It was stated that fuelwood extraction in the area should be less than 2.89 ton/ha/year to maintain its sustainability, based on the mean WNKP forest tree annual increment. The fact shows that fuelwood extraction in WKNP reduces of forest biomass stock (1.06 tons/ha/year and decreases species diversity index (from 3.05 to 2.45, species evenness index (from 1.06 to 0.91 and old-young tree ratio (from 1.29 to 1. Ecosystem quality reduction is mainly caused by destructive techniques in extracting fuelwood such as slashing, scratching cambium, and cutting trees. Therefore, recommended policy includes legalizing fuelwood extraction with restrictions, providing alternative fuelwood and other biomass energy resources outside WKNP, conducting preventive (establishing checkpoints and increasing patrols and pre-emptive (educating and campaigning efforts, collaborating with other stakeholders, and empowering local economy.

  9. Morpho-anatomical and growth alterations induced by arsenic in Cajanus cajan (L.) DC (Fabaceae).

    Science.gov (United States)

    Pita-Barbosa, Alice; Gonçalves, Elton Carvalho; Azevedo, Aristéa Alves

    2015-08-01

    Arsenic (As) is a toxic element to most organisms. Studies investigating anatomic alterations due to As exposure in plants are scarce but of utmost importance to the establishment of environmental biomonitoring techniques. So, this study aimed to investigate the effects of As on the development and initial root growth in Cajanus cajan (Fabaceae), characterize and quantify the possible damages, evaluate genotoxic effects, and identify structural markers to be used in environmental bioindication. Plants were exposed hydroponically to 0.5, 1.0, 1.5, and 2.0 mg As L(-1), as sodium arsenate. Growth parameters were measured, and in the end of the exposure, root samples were analyzed for qualitative and quantitative anatomical alterations. Arsenic genotoxicity was evaluated through analysis of the mitotic index in the root apex. Compared to the control, As-treated seedlings showed an altered architecture, with significantly decreased root length (due to the lower mitotic index in the apical meristem and reduced elongation of parenchyma cells) with darkened color, and abnormal development of the root cap. A significant increase in vascular cylinder/root diameter ratio was also detected, due to the reduction of the cellular spaces in the cortex. The secondary xylem vessel elements were reduced in diameter and had sinuous walls. The severest damage was visible in the ramification zone, where uncommon division planes of phellogen and cambium cells and disintegration of the parenchyma cells adjacent to lateral roots were observed. The high sensibility of C. cajan to As was confirmed, since it caused severe damages in root growth and anatomy. The main structural markers for As toxicity were the altered root architecture, with the reduction of the elongation zone and increase of ramification zone length, and the root primordia retained within the cortex. Our results show a new approach about As toxicity and indicate that C. cajan is a promising species to be used for

  10. Stereo and scanning electron microscopy of in-shell Brazil nut (Bertholletia excelsa H.B.K.): part two-surface sound nut fungi spoilage susceptibility.

    Science.gov (United States)

    Scussel, Vildes M; Manfio, Daniel; Savi, Geovana D; Moecke, Elisa H S

    2014-11-01

    This work reports the in-shell Brazil nut spoilage susceptible morpho-histological characteristics and fungi infection (shell, edible part, and brown skin) through stereo and scanning electron microscopies (SEM). The following characteristics related to shell (a) morphology-that allow fungi and insects' entrance to inner nut, and (b) histology-that allow humidity absorption, improving environment conditions for living organisms development, were identified. (a.1) locule in testae-the nut navel, which is a cavity formed during nut detaching from pods (located at 1.0 to 2.0/4th of the shell B&C nut faces linkage). It allows the nut brown skin (between shell and edible part) first contact to the external environment, through the (a.2) nut channel-the locule prolongation path, which has the water/nutrients cambium function for their transport and distribution to the inner seed (while still on the tree/pod). Both, locule followed by the channel, are the main natural entrance of living organisms (fungi and insects), including moisture to the inner seed structures. In addition, the (a.3) nut shell surface-which has a crinkled and uneven surface morphology-allows water absorption, thus adding to the deterioration processes too. The main shell histological characteristic, which also allows water absorption (thus improving environment conditions for fungi proliferation), is the (b.1) cell wall porosity-the multilayered wall and porous rich cells that compose the shell faces double tissue layers and the (b.2) soft tissue-the mix of tissues 2 faces corner/linkage. This work also shows in details the SEM nut spoilage susceptible features highly fungi infected with hyphae and reproductive structures distribution.

  11. Histological examination of horse chestnut infection by Pseudomonas syringae pv. aesculi and non-destructive heat treatment to stop disease progression.

    Science.gov (United States)

    de Keijzer, Jeroen; van den Broek, Lambertus A M; Ketelaar, Tijs; van Lammeren, André A M

    2012-01-01

    Since its emergence in Northwest Europe as a pathogen that infects trunks and branches of Aesculus spp. (the horse chestnuts) approximately one decade ago, Pseudomonas syringae pv. aesculi has rapidly established itself as major threat to these trees. Infected trees exhibit extensive necrosis of phloem and cambium, which can ultimately lead to dieback. The events after host entry leading to extensive necrosis are not well documented. In this work, the histopathology of this interaction is investigated and heat-treatment is explored as method to eradicate bacteria associated with established infections. The early wound-repair responses of A. hippocastanum, both in absence and presence of P. s. pv. aesculi, included cell wall lignification by a distinct layer of phloem and cortex parenchyma cells. The same cells also deposited suberin lamellae later on, suggesting this layer functions in compartmentalizing healthy from disrupted tissues. However, monitoring bacterial ingress, its construction appeared inadequate to constrain pathogen spread. Microscopic evaluation of bacterial dispersal in situ using immunolabelling and GFP-tagging of P. s. pv. aesculi, revealed two discriminative types of bacterial colonization. The forefront of lesions was found to contain densely packed bacteria, while necrotic areas housed bacterial aggregates with scattered individuals embedded in an extracellular matrix of bacterial origin containing alginate. The endophytic localization and ability of P. s. pv aesculi to create a protective matrix render it poorly accessible for control agents. To circumvent this, a method based on selective bacterial lethality at 39 °C was conceived and successfully tested on A. hippocastanum saplings, providing proof of concept for controlling this disease by heat-treatment. This may be applicable for curing other tree cankers, caused by related phytopathogens. PMID:22808044

  12. The poplar basic helix-loop-helix transcription factor BEE3 – Like gene affects biomass production by enhancing proliferation of xylem cells in poplar

    Energy Technology Data Exchange (ETDEWEB)

    Noh, Seol Ah, E-mail: s6022029@korea.ac.kr; Choi, Young-Im, E-mail: yichoi99@forest.go.kr; Cho, Jin-Seong, E-mail: jinsung3932@gmail.com; Lee, Hyoshin, E-mail: hslee@forest.go.kr

    2015-06-19

    Brassinosteroids (BRs) play important roles in many aspects of plant growth and development, including regulation of vascular cambium activities and cell elongation. BR-induced BEE3 (brassinosteroid enhanced expression 3) is required for a proper BR response. Here, we identified a poplar (Populus alba × Populus glandulosa) BEE3-like gene, PagBEE3L, encoding a putative basic helix-loop-helix (bHLH)-type transcription factor. Expression of PagBEE3L was induced by brassinolide (BL). Transcripts of PagBEE3L were mainly detected in stems, with the internode having a low level of transcription and the node having a relatively higher level. The function of the PagBEE3L gene was investigated through phenotypic analyses with PagBEE3L-overexpressing (ox) transgenic lines. This work particularly focused on a potential role of PagBEE3L in stem growth and development of polar. The PagBEE3L-ox poplar showed thicker and longer stems than wild-type plants. The xylem cells from the stems of PagBEE3L-ox plants revealed remarkably enhanced proliferation, resulting in an earlier thickening growth than wild-type plants. Therefore, this work suggests that xylem development of poplar is accelerated in PagBEE3L-ox plants and PagBEE3L plays a role in stem growth by increasing the proliferation of xylem cells to promote the initial thickening growth of poplar stems. - Highlights: • We identify the BEE3-like gene form hybrid poplar (Populus alba × Populus glandulosa). • We examine effects of overexpression of PagBEE3L on growth in poplar. • We found that 35S:BEE3L transgenic plants showed more rapid growth than wild-type plants. • BEE3L protein plays an important role in the development of plant stem.

  13. Stereo and scanning electron microscopy of in-shell Brazil nut (Bertholletia excelsa H.B.K.): part two-surface sound nut fungi spoilage susceptibility.

    Science.gov (United States)

    Scussel, Vildes M; Manfio, Daniel; Savi, Geovana D; Moecke, Elisa H S

    2014-11-01

    This work reports the in-shell Brazil nut spoilage susceptible morpho-histological characteristics and fungi infection (shell, edible part, and brown skin) through stereo and scanning electron microscopies (SEM). The following characteristics related to shell (a) morphology-that allow fungi and insects' entrance to inner nut, and (b) histology-that allow humidity absorption, improving environment conditions for living organisms development, were identified. (a.1) locule in testae-the nut navel, which is a cavity formed during nut detaching from pods (located at 1.0 to 2.0/4th of the shell B&C nut faces linkage). It allows the nut brown skin (between shell and edible part) first contact to the external environment, through the (a.2) nut channel-the locule prolongation path, which has the water/nutrients cambium function for their transport and distribution to the inner seed (while still on the tree/pod). Both, locule followed by the channel, are the main natural entrance of living organisms (fungi and insects), including moisture to the inner seed structures. In addition, the (a.3) nut shell surface-which has a crinkled and uneven surface morphology-allows water absorption, thus adding to the deterioration processes too. The main shell histological characteristic, which also allows water absorption (thus improving environment conditions for fungi proliferation), is the (b.1) cell wall porosity-the multilayered wall and porous rich cells that compose the shell faces double tissue layers and the (b.2) soft tissue-the mix of tissues 2 faces corner/linkage. This work also shows in details the SEM nut spoilage susceptible features highly fungi infected with hyphae and reproductive structures distribution. PMID:25318846

  14. Analyses of GA20ox- and GID1-over-expressing aspen suggest that gibberellins play two distinct roles in wood formation.

    Science.gov (United States)

    Mauriat, Mélanie; Moritz, Thomas

    2009-06-01

    Gibberellins (GAs) are involved in many aspects of plant development, including shoot growth, flowering and wood formation. Increased levels of bioactive GAs are known to induce xylogenesis and xylem fiber elongation in aspen. However, there is currently little information on the response pathway(s) that mediate GA effects on wood formation. Here we characterize an important element of the GA pathway in hybrid aspen: the GA receptor, GID1. Four orthologs of GID1 were identified in Populus tremula x P. tremuloides (PttGID1.1-1.4). These were functional when expressed in Arabidopsis thaliana, and appear to present a degree of sub-functionalization in hybrid aspen. PttGID1.1 and PttGID1.3 were over-expressed in independent lines of hybrid aspen using either the 35S promoter or a xylem-specific promoter (LMX5). The 35S:PttGID1 over-expressors shared several phenotypic traits previously described in 35S:AtGA20ox1 over-expressors, including rapid growth, increased elongation, and increased xylogenesis. However, their xylem fibers were not elongated, unlike those of 35S:AtGA20ox1 plants. Similar differences in the xylem fiber phenotype were observed when PttGID1.1, PttGID1.3 or AtGA20ox1 were expressed under the control of the LMX5 promoter, suggesting either that PttGID1.1 and PttGID1.3 play no role in fiber elongation or that GA homeostasis is strongly controlled when GA signaling is altered. Our data suggest that GAs are required in two distinct wood-formation processes that have tissue-specific signaling pathways: xylogenesis, as mediated by GA signaling in the cambium, and fiber elongation in the developing xylem.

  15. Variation in the radial patterns of sap flux density in pubescent oak (Quercus pubescens) and its implications for tree and stand transpiration measurements.

    Science.gov (United States)

    Poyatos, Rafael; Cermák, Jan; Llorens, Pilar

    2007-04-01

    Radial variation in sap flux density across the sapwood was assessed by the heat field deformation method in several trees of Quercus pubescens Wild., a ring-porous species. Sapwood depths were delimited by identifying the point of zero flow in radial patterns of sap flow, yielding tree sapwood areas that were 1.5-2 times larger than assumed based on visual examinations of wood cores. The patterns of sap flow varied both among trees and diurnally. Rates of sap flow were higher close to the cambium, although there was a significant contribution from the inner sapwood, which was greater (up to 60% of total flow) during the early morning and late in the day. Accordingly, the normalized difference between outer and inner sapwood flow was stable during the middle of the day, but showed a general decline in the afternoon. The distribution of sap flux density across the sapwood allowed us to derive correction coefficients for single-point heat dissipation sap flow measurements. We used daytime-averaged coefficients that depended on the particular shape of the radial profile and ranged between 0.45 and 1.28. Stand transpiration calculated using the new method of estimating sapwood areas and the radial correction coefficients was similar to (Year 2003), or about 25% higher than (Year 2004), previous uncorrected values, and was 20-30% of reference evapotranspiration. We demonstrated how inaccuracies in determining sapwood depths and mean sap flux density across the sapwood of ring-porous species could affect tree and stand transpiration estimates.

  16. Intrusive growth of primary and secondary phloem fibres in hemp stem determines fibre-bundle formation and structure.

    Science.gov (United States)

    Snegireva, Anastasia; Chernova, Tatyana; Ageeva, Marina; Lev-Yadun, Simcha; Gorshkova, Tatyana

    2015-01-01

    Plant fibres-cells with important mechanical functions and a widely used raw material-are usually identified in microscopic sections only after reaching a significant length or after developing a thickened cell wall. We characterized the early developmental stages of hemp (Cannabis sativa) stem phloem fibres, both primary (originating from the procambium) and secondary (originating in the cambium), when they still had only a primary cell wall. We gave a major emphasis to the role of intrusive elongation, the specific type of plant cell growth by which fibres commonly attain large cell length. We could identify primary phloem fibres at a distance of only 1.2-1.5 mm from the shoot apical meristem when they grew symplastically with the surrounding tissues. Half a millimeter further downwards along the stem, fibres began their intrusive elongation, which led to a sharp increase in fibre numbers visible within the stem cross-sections. The intrusive elongation of primary phloem fibres was completed within the several distal centimetres of the growing stem, before the onset of their secondary cell wall formation. The formation of secondary phloem fibres started long after the beginning of secondary xylem formation. Our data indicate that only a small portion of the fusiform cambial initials (<10 %) give rise directly or via their derivatives to secondary phloem fibres. The key determinant of final bundle structure, both for primary and secondary phloem fibres, is intrusive growth. Through bi-directional elongation, fibres join other fibres initiated individually in other stem levels, thus forming the bundles. Our results provide the specific developmental basis for further biochemical and molecular-genetic studies of phloem fibre development in hemp, but may be applied to many other species. PMID:26019229

  17. Pharmacognostical and phytochemical studies on roots of Bombax ceiba Linn.

    Directory of Open Access Journals (Sweden)

    Pankaj H. Chaudhary

    2014-12-01

    Full Text Available Context: Bombax ceiba Linn. (Bombacaceae is a well-known plant for its antihypertensive, antioxidant, antidiabetic, aphrodisiac and uterine tonicity properties. Aims: To study pharmacognostical, physicochemical and phytochemically the roots of this plant. Methods: Pharmacognostical study included the macroscopic characters like size, color, surface characteristics, texture, fracture characteristics and odor of the roots. The intact root as well as powdered drug were studied under a microscope to analyze the cellular characteristics of the drug. Physicochemical parameter like extractive values, loss on drying (LOD, total ash, water-soluble and acid insoluble ash, foaming index and hemolytic index of Bombax ceiba root powder were determined as per WHO guidelines. Preliminary phytochemical screening and qualitative chemical examination studies have been carried out for the various phytoconstituents. HPTLC have also carried out using cyclohexane: diethyl ether: ethyl acetate as mobile phase. Results: Chemical evaluation and TLC studies shown presence of alkaloids, glycosides, flavonoids, steroids, saponins and tannins. The microscopic characters have shown presence of cork, cambium, xylem vessels, stone cells, starch grains, calcium oxalate crystals and phloem fibers. Microscopy analysis of the powder included the cork cells, fibers, calcium oxalate crystals and vessel. The presence of steroids was confirmed in HPTLC fingerprinting studies. Conclusions: Pharmacognostical and preliminary phytochemical screening of Bombax ceiba roots will be useful in order to authenticate, standardize and avoid any adulteration in the raw material. The diagnostic microscopic characters and physicochemical data will be helpful in the development of a monograph. The chromatographic fingerprinting profile can be used to standardize extracts and formulations containing Bombax ceiba roots.

  18. Histological examination of horse chestnut infection by Pseudomonas syringae pv. aesculi and non-destructive heat treatment to stop disease progression.

    Directory of Open Access Journals (Sweden)

    Jeroen de Keijzer

    Full Text Available Since its emergence in Northwest Europe as a pathogen that infects trunks and branches of Aesculus spp. (the horse chestnuts approximately one decade ago, Pseudomonas syringae pv. aesculi has rapidly established itself as major threat to these trees. Infected trees exhibit extensive necrosis of phloem and cambium, which can ultimately lead to dieback. The events after host entry leading to extensive necrosis are not well documented. In this work, the histopathology of this interaction is investigated and heat-treatment is explored as method to eradicate bacteria associated with established infections. The early wound-repair responses of A. hippocastanum, both in absence and presence of P. s. pv. aesculi, included cell wall lignification by a distinct layer of phloem and cortex parenchyma cells. The same cells also deposited suberin lamellae later on, suggesting this layer functions in compartmentalizing healthy from disrupted tissues. However, monitoring bacterial ingress, its construction appeared inadequate to constrain pathogen spread. Microscopic evaluation of bacterial dispersal in situ using immunolabelling and GFP-tagging of P. s. pv. aesculi, revealed two discriminative types of bacterial colonization. The forefront of lesions was found to contain densely packed bacteria, while necrotic areas housed bacterial aggregates with scattered individuals embedded in an extracellular matrix of bacterial origin containing alginate. The endophytic localization and ability of P. s. pv aesculi to create a protective matrix render it poorly accessible for control agents. To circumvent this, a method based on selective bacterial lethality at 39 °C was conceived and successfully tested on A. hippocastanum saplings, providing proof of concept for controlling this disease by heat-treatment. This may be applicable for curing other tree cankers, caused by related phytopathogens.

  19. Wood chemical composition in species of Cactaceae: the relationship between lignification and stem morphology.

    Directory of Open Access Journals (Sweden)

    Jorge Reyes-Rivera

    Full Text Available In Cactaceae, wood anatomy is related to stem morphology in terms of the conferred support. In species of cacti with dimorphic wood, a unique process occurs in which the cambium stops producing wide-band tracheids (WBTs and produces fibers; this is associated with the aging of individuals and increases in size. Stem support and lignification have only been studied in fibrous tree-like species, and studies in species with WBTs or dimorphic wood are lacking. In this study, we approach this process with a chemical focus, emphasizing the role of wood lignification. We hypothesized that the degree of wood lignification in Cactaceae increases with height of the species and that its chemical composition varies with wood anatomy. To test this, we studied the chemical composition (cellulose, hemicellulose, and lignin content in 13 species (2 WBTs wood, 3 dimorphic, and 8 fibrous with contrasting growth forms. We also analyzed lignification in dimorphic and fibrous species to determine the chemical features of WBTs and fibers and their relationship with stem support. The lignin contents were characterized by Fourier transform infrared spectroscopy and high performance liquid chromatography. We found that 11 species have a higher percentage (>35% of lignin in their wood than other angiosperms or gymnosperms. The lignin chemical composition in fibrous species is similar to that of other dicots, but it is markedly heterogeneous in non-fibrous species where WBTs are abundant. The lignification in WBTs is associated with the resistance to high water pressure within cells rather than the contribution to mechanical support. Dimorphic wood species are usually richer in syringyl lignin, and tree-like species with lignified rays have more guaiacyl lignin. The results suggest that wood anatomy and lignin distribution play an important role in the chemical composition of wood, and further research is needed at the cellular level.

  20. Tropical dendrochemistry: A novel approach for reconstructing seasonally-resolved growth rates from ringless tropical trees

    Science.gov (United States)

    Poussart, P. M.; Myneni, S. C.

    2005-12-01

    Although tropical forests play an active role in the global carbon cycle and are host to a variety of pristine paleoclimate archives, they remain poorly characterized as compared to other ecosystems on the planet. In particular, dating and reconstructing the growth rate history of tropical trees remains a challenge and continues to delay research efforts towards understanding tropical forest dynamics. Traditional dendrochronological techniques have found limited applications in the tropics because temperature seasonality is often too small to initiate the production of visible annual growth rings. Dendrometers, cambium scarring methods and sub-annual records of oxygen and carbon isotopes from tree cellulose may be used to estimate growth rate histories when growth rings are absent. However, dendrometer records rarely extend beyond the past couple of decades and the generation of seasonally-resolved isotopic records remains labour intensive, currently prohibiting the level of record replication necessary for statistical analysis. Here, we present evidence that Ca may also be used as a proxy for dating and reconstructing growth rates of trees lacking visible growth rings. Using the Brookhaven National Lab Synchrotron, we recover a radial record of cyclic variations in Ca from a Miliusa velutina tree from northern Thailand. We determine that the Ca cycles are seasonal based on a comparison between radiocarbon age estimates and a trace element age model, which agree within 2 years over the period of 1955 to 2000. The amplitude of the Ca annual cycle is significantly correlated with growth rate estimates, which are also correlated to the amount of dry season rainfall. The measurements at the Synchrotron are fast, non-destructive and require little sample preparation. Application of this technique in the tropics holds the potential to resolve longstanding questions about tropical forest dynamics and interannual to decadal changes in the carbon cycle.

  1. Seasonal Variation of Carbon Metabolism in the Cambial Zone of Eucalyptus grandis.

    Science.gov (United States)

    Budzinski, Ilara G F; Moon, David H; Lindén, Pernilla; Moritz, Thomas; Labate, Carlos A

    2016-01-01

    Eucalyptus species are the most widely hardwood planted in the world. It is one of the successful examples of commercial forestry plantation in Brazil and other tropical and subtropical countries. The tree is valued for its rapid growth, adaptability and wood quality. Wood formation is the result of cumulative annual activity of the vascular cambium. This cambial activity is generally related to the alternation of cold and warm, and/or dry and rainy seasons. Efforts have focused on analysis of cambial zone in response to seasonal variations in trees from temperate zones. However, little is known about the molecular changes triggered by seasonal variations in trees from tropical countries. In this work we attempted to establish a global view of seasonal alterations in the cambial zone of Eucalyptus grandis Hill ex Maiden, emphasizing changes occurring in the carbon metabolism. Using transcripts, proteomics and metabolomics we analyzed the tissues harvested in summer-wet and winter-dry seasons. Based on proteomics analysis, 70 proteins that changed in abundance were successfully identified. Transcripts for some of these proteins were analyzed and similar expression patterns were observed. We identified 19 metabolites differentially abundant. Our results suggest a differential reconfiguration of carbon partioning in E. grandis cambial zone. During summer, pyruvate is primarily metabolized via ethanolic fermentation, possibly to regenerate NAD(+) for glycolytic ATP production and cellular maintenance. However, in winter there seems to be a metabolic change and we found that some sugars were highly abundant. Our results revealed a dynamic change in E. grandis cambial zone due to seasonality and highlight the importance of glycolysis and ethanolic fermentation for energy generation and maintenance in Eucalyptus, a fast growing tree. PMID:27446160

  2. Why Be a Shrub? A Basic Model and Hypotheses for the Adaptive Values of a Common Growth Form.

    Science.gov (United States)

    Götmark, Frank; Götmark, Elin; Jensen, Anna M

    2016-01-01

    Shrubs are multi-stemmed short woody plants, more widespread than trees, important in many ecosystems, neglected in ecology compared to herbs and trees, but currently in focus due to their global expansion. We present a novel model based on scaling relationships and four hypotheses to explain the adaptive significance of shrubs, including a review of the literature with a test of one hypothesis. Our model describes advantages for a small shrub compared to a small tree with the same above-ground woody volume, based on larger cross-sectional stem area, larger area of photosynthetic tissue in bark and stem, larger vascular cambium area, larger epidermis (bark) area, and larger area for sprouting, and faster production of twigs and canopy. These components form our Hypothesis 1 that predicts higher growth rate for a small shrub than a small tree. This prediction was supported by available relevant empirical studies (14 publications). Further, a shrub will produce seeds faster than a tree (Hypothesis 2), multiple stems in shrubs insure future survival and growth if one or more stems die (Hypothesis 3), and three structural traits of short shrub stems improve survival compared to tall tree stems (Hypothesis 4)-all hypotheses have some empirical support. Multi-stemmed trees may be distinguished from shrubs by more upright stems, reducing bending moment. Improved understanding of shrubs can clarify their recent expansion on savannas, grasslands, and alpine heaths. More experiments and other empirical studies, followed by more elaborate models, are needed to understand why the shrub growth form is successful in many habitats. PMID:27507981

  3. Cavitation and water fluxes driven by ice water potential in Juglans regia during freeze–thaw cycles

    Science.gov (United States)

    Charra-Vaskou, Katline; Badel, Eric; Charrier, Guillaume; Ponomarenko, Alexandre; Bonhomme, Marc; Foucat, Loïc; Mayr, Stefan; Améglio, Thierry

    2016-01-01

    Freeze–thaw cycles induce major hydraulic changes due to liquid-to-ice transition within tree stems. The very low water potential at the ice–liquid interface is crucial as it may cause lysis of living cells as well as water fluxes and embolism in sap conduits, which impacts whole tree–water relations. We investigated water fluxes induced by ice formation during freeze–thaw cycles in Juglans regia L. stems using four non-invasive and complementary approaches: a microdendrometer, magnetic resonance imaging, X-ray microtomography, and ultrasonic acoustic emissions analysis. When the temperature dropped, ice nucleation occurred, probably in the cambium or pith areas, inducing high water potential gradients within the stem. The water was therefore redistributed within the stem toward the ice front. We could thus observe dehydration of the bark’s living cells leading to drastic shrinkage of this tissue, as well as high tension within wood conduits reaching the cavitation threshold in sap vessels. Ultrasonic emissions, which were strictly emitted only during freezing, indicated cavitation events (i.e. bubble formation) following ice formation in the xylem sap. However, embolism formation (i.e. bubble expansion) in stems was observed only on thawing via X-ray microtomography for the first time on the same sample. Ultrasonic emissions were detected during freezing and were not directly related to embolism formation. These results provide new insights into the complex process and dynamics of water movements and ice formation during freeze–thaw cycles in tree stems. PMID:26585223

  4. Chimpanzee isotopic ecology: a closed canopy C3 template for hominin dietary reconstruction.

    Science.gov (United States)

    Carlson, Bryce A; Kingston, John D

    2014-11-01

    The most significant hominin adaptations, including features used to distinguish and/or classify taxa, are critically tied to the dietary environment. Stable isotopic analyses of tooth enamel from hominin fossils have provided intriguing evidence for significant C4/CAM (crassulacean acid metabolism) resource consumption in a number of Plio-Pleistocene hominin taxa. Relating isotopic tooth signatures to specific dietary items or proportions of C3 versus C4/CAM plants, however, remains difficult as there is an ongoing need to document and quantify isotopic variability in modern ecosystems. This study investigates the ecological variables responsible for carbon isotopic discrimination and variability within the C3-dominated dietary niche of a closed canopy East African hominoid, Pan troglodytes, from Ngogo, Kibale National Park, Uganda. δ(13)C values among C3 resources utilized by Ngogo chimpanzees were highly variable, ranging over 13‰. Infrequent foraging on papyrus (the only C4 plant consumed by chimpanzees at the site) further extended this isotopic range. Variation was ultimately most attributable to mode of photosynthesis (C3 versus C4), food type, and elevation, which together accounted for approximately 78% of the total sample variation. Among C3 food types, bulk carbon values ranged from -24.2‰ to -31.1‰ with intra-plant variability up to 12.1‰. Pith and sapling leaves were statistically more (13)C depleted than pulp, seeds, flowers, cambium, roots, leaf buds, and leaves from mature trees. The effect of elevation on carbon variation was highly significant and equivalent to an approximately 1‰ increase in δ(13)C for every 150 m of elevation gain, likely reflecting habitat variability associated with topography. These results indicate significant δ(13)C variation attributable to food type and elevation among C3 resources and provide important data for hominin dietary interpretations based on carbon isotopic analyses. PMID:24993419

  5. Ectopic expression of a cytochrome P450 monooxygenase gene PtCYP714A3 from Populus trichocarpa reduces shoot growth and improves tolerance to salt stress in transgenic rice.

    Science.gov (United States)

    Wang, Cuiting; Yang, Yang; Wang, Haihai; Ran, Xiaojuan; Li, Bei; Zhang, Jiantao; Zhang, Hongxia

    2016-09-01

    In Arabidopsis thaliana and Oryza sativa, the cytochrome P450 (CYP) 714 protein family represents a unique group of CYP monooxygenase, which functions as a shoot-specific regulator in plant development through gibberellin deactivation. Here, we report the functional characterizations of PtCYP714A3, an OsCYP714D1/Eui homologue from Populus trichocarpa. PtCYP714A3 was ubiquitously expressed with the highest transcript level in cambium-phloem tissues, and was greatly induced by salt and osmotic stress in poplar. Subcellular localization analyses indicated that PtCYP714A3-YFP fusion protein was targeted to endoplasmic reticulum (ER). Expression of PtCYP714A3 in the rice eui mutant could rescue its excessive-shoot-growth phenotype. Ectopic expression of PtCYP714A3 in rice led to semi-dwarfed phenotype with promoted tillering and reduced seed size. Transgenic lines which showed significant expression of PtCYP714A3 also accumulated lower GA level than did the wild-type (WT) plants. The expression of some GA biosynthesis genes was significantly suppressed in these transgenic plants. Furthermore, transgenic rice plants exhibited enhanced tolerance to salt and maintained more Na(+) in both shoot and root tissues under salinity stress. All these results not only suggest a crucial role of PtCYP714A3 in shoot responses to salt toxicity in rice, but also provide a molecular basis for genetic engineering of salt-tolerant crops. PMID:26970512

  6. The effect of slope exposition on the growth dynamics of Larix gmelinii in permafrost conditions of Central Siberia. I. Differences in tree radial dynamics growth in the north- and south-facing slopes

    Directory of Open Access Journals (Sweden)

    А. V. Benkova

    2015-08-01

    Full Text Available This paper is devoted to revealing the distinctive characteristics of radial growth of larch trees (Larix gmelinii (Rupr. Rupr. growing in permafrost contrast conditions of the north and south facing slopes (Central Siberia, 64°19´23˝ N, 100°13´28˝ E. Even-aged larch stems regenerated after strong fire in 1899 in opposite north and south facing slopes of the hills situated on the banks of Kulingdakan stream were under study. Two sample sites at the middle part of the slopes were established. 23 model trees in the north facing slope and 13 ones in the south-facing slope were selected for dendrochronological analysis. From each tree, disks at 1.3 m height of the stems were taken. Tree ring widths were measured, comparative analysis of dynamics of radial growth in the slopes was made. In order to separate time intervals, characterized by distinctive climate impact on radial increment, sliding response functions were calculated and analyzed. Daily solar radiation for both sample sites was calculated. The results showed that solar radiation in the north-facing slope is 20 % less than that in south-facing slope. Solar radiation regime promotes intensive thickening of moss-lichen cover, so that its thickness to 2009 was nearly two times thicker than in south-facing slope. Both factors affected the worth thermal soil growth conditions in the north facing slope. The latter was responsible for narrower ring widths formation in the stems and governed higher sensitivity of the trees to air temperature in the periods of cambium reactivation, start and intensive growth.

  7. The poplar basic helix-loop-helix transcription factor BEE3 – Like gene affects biomass production by enhancing proliferation of xylem cells in poplar

    International Nuclear Information System (INIS)

    Brassinosteroids (BRs) play important roles in many aspects of plant growth and development, including regulation of vascular cambium activities and cell elongation. BR-induced BEE3 (brassinosteroid enhanced expression 3) is required for a proper BR response. Here, we identified a poplar (Populus alba × Populus glandulosa) BEE3-like gene, PagBEE3L, encoding a putative basic helix-loop-helix (bHLH)-type transcription factor. Expression of PagBEE3L was induced by brassinolide (BL). Transcripts of PagBEE3L were mainly detected in stems, with the internode having a low level of transcription and the node having a relatively higher level. The function of the PagBEE3L gene was investigated through phenotypic analyses with PagBEE3L-overexpressing (ox) transgenic lines. This work particularly focused on a potential role of PagBEE3L in stem growth and development of polar. The PagBEE3L-ox poplar showed thicker and longer stems than wild-type plants. The xylem cells from the stems of PagBEE3L-ox plants revealed remarkably enhanced proliferation, resulting in an earlier thickening growth than wild-type plants. Therefore, this work suggests that xylem development of poplar is accelerated in PagBEE3L-ox plants and PagBEE3L plays a role in stem growth by increasing the proliferation of xylem cells to promote the initial thickening growth of poplar stems. - Highlights: • We identify the BEE3-like gene form hybrid poplar (Populus alba × Populus glandulosa). • We examine effects of overexpression of PagBEE3L on growth in poplar. • We found that 35S:BEE3L transgenic plants showed more rapid growth than wild-type plants. • BEE3L protein plays an important role in the development of plant stem

  8. Two cassava promoters related to vascular expression and storage root formation.

    Science.gov (United States)

    Zhang, Peng; Bohl-Zenger, Susanne; Puonti-Kaerlas, Johanna; Potrykus, Ingo; Gruissem, Wilhelm

    2003-12-01

    Cassava ( Manihot esculenta Crantz) storage roots, organs accumulating large amounts of starch, develop from primary roots via secondary growth. The availability of promoters related to storage-root formation is a prerequisite for engineering root traits in cassava. Two cDNAs, c15 and c54, were identified from a storage-root cDNA library of cassava MCol1505 via differential screening. The transcripts of c15 and c54 were detected in storage roots but not in leaves by Northern analysis. Homology analysis of the deduced amino acid sequences showed that C15 is likely to be related to cytochrome P450 proteins, which are involved in the oxidative degradation of various compounds, while C54 may be related to Pt2L4, a cassava glutamic acid-rich protein. The promoter regions of c15 and c54 were isolated from the corresponding clones in a cassava genomic library. A 1,465-bp promoter fragment ( p15/1.5) of c15 and a 1,081-bp promoter region ( p54/1.0) of c54 were translationally fused to the uidA reporter gene, and introduced into cassava and Arabidopsis thaliana (L.) Heynh. The expression patterns of p15/1.5::uidA and p54/1.0::uidA in transgenic plants showed that both promoters are predominantly active in phloem, cambium and xylem vessels of vascular tissues from leaves, stems, and root systems. More importantly, strong beta-glucuronidase activity was also detected in the starch-rich parenchyma cells of transgenic storage roots. Our results demonstrate that the two promoters are related to vascular expression and secondary growth of storage roots in cassava.

  9. Why Be a Shrub? A Basic Model and Hypotheses for the Adaptive Values of a Common Growth Form

    Science.gov (United States)

    Götmark, Frank; Götmark, Elin; Jensen, Anna M.

    2016-01-01

    Shrubs are multi-stemmed short woody plants, more widespread than trees, important in many ecosystems, neglected in ecology compared to herbs and trees, but currently in focus due to their global expansion. We present a novel model based on scaling relationships and four hypotheses to explain the adaptive significance of shrubs, including a review of the literature with a test of one hypothesis. Our model describes advantages for a small shrub compared to a small tree with the same above-ground woody volume, based on larger cross-sectional stem area, larger area of photosynthetic tissue in bark and stem, larger vascular cambium area, larger epidermis (bark) area, and larger area for sprouting, and faster production of twigs and canopy. These components form our Hypothesis 1 that predicts higher growth rate for a small shrub than a small tree. This prediction was supported by available relevant empirical studies (14 publications). Further, a shrub will produce seeds faster than a tree (Hypothesis 2), multiple stems in shrubs insure future survival and growth if one or more stems die (Hypothesis 3), and three structural traits of short shrub stems improve survival compared to tall tree stems (Hypothesis 4)—all hypotheses have some empirical support. Multi-stemmed trees may be distinguished from shrubs by more upright stems, reducing bending moment. Improved understanding of shrubs can clarify their recent expansion on savannas, grasslands, and alpine heaths. More experiments and other empirical studies, followed by more elaborate models, are needed to understand why the shrub growth form is successful in many habitats. PMID:27507981

  10. The impact of an increasing elephant population on the woody vegetation in southern Sabi Sand Wildtuin, South Africa

    Directory of Open Access Journals (Sweden)

    Kay Hiscocks

    1999-02-01

    Full Text Available In 1961, a fence was erected between privately owned Sabi Sand Wildtuin (SSW and the Kruger National Park (KNP, which largely prevented elephants entering the SSW. In 1993, the fence was removed. This lead to a rapid influx of elephants into the SSW during the winter months, most of which move back into the KNP during the wet summer season. In 1993, the SSW elephant population was 1/1045 ha but increased to 1/305.8 ha in 1996. It more than doubled to 1/146 ha in 1998. This study was undertaken on the property Kingston, in southern SSW, to assess the impact of elephants on woody vegetation and determine why they show seasonal dietary preferences for specific tree parts. Vegetation utilisation was recorded on a five kilometer transect of vehicle track in 1996 and repeated in 1998. From the transect, species density was calculated for those trees impacted on. Trees that had been newly bark stripped were recorded in 1996 and 1998. Cambium samples were collected in summer and winter from eight tree species. Field observations of elephants impacting on woody vegetation augmented the data base. Transect analysis showed a strong correlation between tree utilisation and density. The most visual damage was of Combretum apiculatum, Acacia burkei, Pterocarpus rotundifolius and Grewia species. Tree damage increased by 73 from 1996 to 1998. Significantly higher levels of nitrogen, sodium and magnesium were found in the species most regularly bark stripped. Bull elephants were responsible for 94 of the trees seen uprooted. The results suggested that SSW can sustain the present elephant population, but further influx at the present rate of increase, will have a negative impact on the reserve.

  11. Anatomical Features of the Scots Pine Stem Phloem After Forest FireAnatomical Features of the Scots Pine Stem Phloem After Forest Fire

    Directory of Open Access Journals (Sweden)

    V. V. Stasova

    2015-02-01

    Full Text Available The aim of this work was to study changes in anatomical structure of phloem tissue in pine (Pinus sylvestris L. stems influenced by creeping forest fires of various rates. The experiments were carried out in the Lower Angara river region of the Angara provenance, Krasnoyarsk Krai, Central Siberia. The trees with green crowns and different fire damaged butts were chosen as models. Control (undamaged trees were taken from stands adjacent to experimental plots. The changes of inner bark thickness, number of phloem annual layers between cambium and periderm and number of cells in conductive phloem were found in the stem side opposite to fire scars. The structure fluctuations of phloem tissue were detected: disturbances of sieve cell arrangement, phloem ray enlargements, resin canal overgrowth and formation of great resin ducts. The lignin accumulation was observed in inner bark and a large amount of callusing was detected between conductive and nonconductive phloem. Over the course of time, repairing of tissues occurred and the normal inner bark structure and chemistry (without lignin were restored. The creeping fire of low intensity caused the maximal changes of phloem quantitative characteristics in trees with bark charring and these tendencies were stored after eight years. After creeping fire of high intensity the tendency for phloem thickening in trees with one fire scar and to thinning in strongly damaged trees were revealed. Also tendencies to decrease of the number of phloem annual layers, number of sieve cells in conductive phloem and ray frequency with increasing of stem injury degree were observed, besides axial parenchyma percentage trended to increase. Eight years after fire these tendencies were often not visible.

  12. Hypoxia and hypercarbia in endophagous insects: Larval position in the plant gas exchange network is key.

    Science.gov (United States)

    Pincebourde, Sylvain; Casas, Jérôme

    2016-01-01

    Gas composition is an important component of any micro-environment. Insects, as the vast majority of living organisms, depend on O2 and CO2 concentrations in the air they breathe. Low O2 (hypoxia), and high CO2 (hypercarbia) levels can have a dramatic effect. For phytophagous insects that live within plant tissues (endophagous lifestyle), gas is exchanged between ambient air and the atmosphere within the insect habitat. The insect larva contributes to the modification of this environment by expiring CO2. Yet, knowledge on the gas exchange network in endophagous insects remains sparse. Our study identified mechanisms that modulate gas composition in the habitat of endophagous insects. Our aim was to show that the mere position of the insect larva within plant tissues could be used as a proxy for estimating risk of occurrence of hypoxia and hypercarbia, despite the widely diverse life history traits of these organisms. We developed a conceptual framework for a gas diffusion network determining gas composition in endophagous insect habitats. We applied this framework to mines, galls and insect tunnels (borers) by integrating the numerous obstacles along O2 and CO2 pathways. The nature and the direction of gas transfers depended on the physical structure of the insect habitat, the photosynthesis activity as well as stomatal behavior in plant tissues. We identified the insect larva position within the gas diffusion network as a predictor of risk exposure to hypoxia and hypercarbia. We ranked endophagous insect habitats in terms of risk of exposure to hypoxia and/or hypercarbia, from the more to the less risky as cambium mines>borer tunnels≫galls>bark mines>mines in aquatic plants>upper and lower surface mines. Furthermore, we showed that the photosynthetically active tissues likely assimilate larval CO2 produced. In addition, temperature of the microhabitat and atmospheric CO2 alter gas composition in the insect habitat. We predict that (i) hypoxia indirectly favors

  13. Anatomy of Leaves from 6 Types of Suaeda in Tarim Basin%塔里木盆地碱蓬属6种植物叶的解剖学研究

    Institute of Scientific and Technical Information of China (English)

    杨赵平; 贾露

    2011-01-01

    We used olefin section to study anatomy of the leaves from 6 types of Suaeda from Tarim Basin of Xinjiang , it showed that there were different adaptive structures in the trees for salty environment where these leaves of the trees lived: (1) Three species of Suaeda, Suaeda stellatiflora, S.prostrata and S.kosinskyi having extruding growth of outer flank on epidermic cells, while that of it in S.arcuata, Suaeda rigida and S.altissima were not significantly extruding; (2) The mesophyll in the leaves of 6 species of trees were with a ring palisade shape, and there differentiated a layer of storage tissue with rare or no chloroplast for water in epidermic tissue of S.prostrate, S.kosinsky and S.arcuata; ( 3 ) The cells in palisade tissue of S.rigida were small and with more layers of cells, and that of S.kosinsky were not well-differentiated but turn into many storage tissues; (4 ) The main vein of S.rigid and 5.altissima were differentiated into a layer of cambium, but not found in other 4 species.%采用石蜡切片法观察了塔里木盆地的碱蓬属6种植物的解剖结构,表明碱蓬属6种植物具不同的适应盐生生境的结构特征:(1)星花碱蓬、平卧碱蓬与肥叶碱蓬表皮细胞外侧壁常外凸生长,五蕊碱蓬、硬枝碱蓬与高碱蓬外凸生长不明显;(2)碱蓬属6种植物叶肉为环栅型,特别的是平卧碱蓬、肥叶碱蓬与五蕊碱蓬表皮下分化出了一层不含或含极少叶绿肥体的贮藏组织;(3)硬枝碱蓬栅栏组织细胞的形态小、细胞的层数较多,而肥叶碱蓬叶肉栅栏不发达,分化出了大量的贮藏组织;(4)硬枝碱蓬与高碱蓬的主脉维管束内分化出了1层形成层而另外4种没有形成层.

  14. Missing Rings in Pinus halepensis - The Missing Link to Relate the Tree-Ring Record to Extreme Climatic Events.

    Science.gov (United States)

    Novak, Klemen; de Luis, Martin; Saz, Miguel A; Longares, Luis A; Serrano-Notivoli, Roberto; Raventós, Josep; Čufar, Katarina; Gričar, Jožica; Di Filippo, Alfredo; Piovesan, Gianluca; Rathgeber, Cyrille B K; Papadopoulos, Andreas; Smith, Kevin T

    2016-01-01

    Climate predictions for the Mediterranean Basin include increased temperatures, decreased precipitation, and increased frequency of extreme climatic events (ECE). These conditions are associated with decreased tree growth and increased vulnerability to pests and diseases. The anatomy of tree rings responds to these environmental conditions. Quantitatively, the width of a tree ring is largely determined by the rate and duration of cell division by the vascular cambium. In the Mediterranean climate, this division may occur throughout almost the entire year. Alternatively, cell division may cease during relatively cool and dry winters, only to resume in the same calendar year with milder temperatures and increased availability of water. Under particularly adverse conditions, no xylem may be produced in parts of the stem, resulting in a missing ring (MR). A dendrochronological network of Pinus halepensis was used to determine the relationship of MR to ECE. The network consisted of 113 sites, 1,509 trees, 2,593 cores, and 225,428 tree rings throughout the distribution range of the species. A total of 4,150 MR were identified. Binomial logistic regression analysis determined that MR frequency increased with increased cambial age. Spatial analysis indicated that the geographic areas of south-eastern Spain and northern Algeria contained the greatest frequency of MR. Dendroclimatic regression analysis indicated a non-linear relationship of MR to total monthly precipitation and mean temperature. MR are strongly associated with the combination of monthly mean temperature from previous October till current February and total precipitation from previous September till current May. They are likely to occur with total precipitation lower than 50 mm and temperatures higher than 5°C. This conclusion is global and can be applied to every site across the distribution area. Rather than simply being a complication for dendrochronology, MR formation is a fundamental response of trees

  15. Hypoxia and hypercarbia in endophagous insects: Larval position in the plant gas exchange network is key.

    Science.gov (United States)

    Pincebourde, Sylvain; Casas, Jérôme

    2016-01-01

    Gas composition is an important component of any micro-environment. Insects, as the vast majority of living organisms, depend on O2 and CO2 concentrations in the air they breathe. Low O2 (hypoxia), and high CO2 (hypercarbia) levels can have a dramatic effect. For phytophagous insects that live within plant tissues (endophagous lifestyle), gas is exchanged between ambient air and the atmosphere within the insect habitat. The insect larva contributes to the modification of this environment by expiring CO2. Yet, knowledge on the gas exchange network in endophagous insects remains sparse. Our study identified mechanisms that modulate gas composition in the habitat of endophagous insects. Our aim was to show that the mere position of the insect larva within plant tissues could be used as a proxy for estimating risk of occurrence of hypoxia and hypercarbia, despite the widely diverse life history traits of these organisms. We developed a conceptual framework for a gas diffusion network determining gas composition in endophagous insect habitats. We applied this framework to mines, galls and insect tunnels (borers) by integrating the numerous obstacles along O2 and CO2 pathways. The nature and the direction of gas transfers depended on the physical structure of the insect habitat, the photosynthesis activity as well as stomatal behavior in plant tissues. We identified the insect larva position within the gas diffusion network as a predictor of risk exposure to hypoxia and hypercarbia. We ranked endophagous insect habitats in terms of risk of exposure to hypoxia and/or hypercarbia, from the more to the less risky as cambium mines>borer tunnels≫galls>bark mines>mines in aquatic plants>upper and lower surface mines. Furthermore, we showed that the photosynthetically active tissues likely assimilate larval CO2 produced. In addition, temperature of the microhabitat and atmospheric CO2 alter gas composition in the insect habitat. We predict that (i) hypoxia indirectly favors

  16. Multi-decadal carbon and water relations of African tropical humid forests: a tree-ring stable isotope analysis

    Science.gov (United States)

    Hufkens, Koen; Helle, Gerd; Beeckman, Hans; de Haulleville, Thales; Kearsley, Elizabeth; Boeckx, Pascal

    2013-04-01

    Little is known about the temporal dynamics of the carbon sequestering capacity and dynamics of African tropical humid forest ecosystems in response to various environmental drivers. This lack of knowledge is mainly due to the absence of ecosystem scale flux measurements of gas exchange. However, tree growth often displays itself as alternating pattern of visible rings due to the seasonally varying growth speed of the vascular cambium. Consequently, analysis of tree growth through tree-ring analysis provides us with insights into past responses of the carbon sequestering capacity of key species to abrupt ecosystem disturbances and, while slower, a changing climate. Not only does the width and density of growth rings reflect annual growth but their isotopic composition of 13C/12C and 18O/16O isotopes also reveal the environmental conditions in which the trees were growing. In particular, stable isotope ratios in tree-rings of carbon are influenced by fractionation through carboxylation during photosynthesis and changes in leaf stomatal conductance. Similarly, fractionation of oxygen isotopes of soil water occurs at the leaf level through evapo-transipiration. As a consequence, 18O/16O (δ18O) values in wood cores will reflect both the signal of the source water as well as that of for example summer humidity. Therefore, both C and O stable isotopes might not only be valuable as proxy data for past climatic conditions but they also serve as an important tool in understanding carbon and water relations within a tropical forest ecosystems. To this end we correlate long term climate records (1961 - present) with tree ring measurement of incremental growth and high resolution analysis of tree-core stable isotope composition(δ13C , δ18O) at a tropical humid forests in the DR Congo. The Yangambi Man And Biosphere (MAB) reserve is located in the north-eastern part of DR Congo, with a distinct tropical rainforest climate. In addition to the tree-core data records and

  17. Distribution of ABA and AhNCED1 in Peanut Leaves of Different Drought Resistant Cultivars Subjected to Drought Stress%不同花生品种响应干旱胁迫后叶片内ABA与AhNCED1的分布

    Institute of Scientific and Technical Information of China (English)

    胡博; 肖素妮; 吕滟; 李玲

    2012-01-01

    以粤油7号和汕优523两个不同抗旱性品种为材料,研究响应干旱胁迫后叶片ABA(abscisic acid,脱落酸)和AhNCED1 (Arachis hypogaea nine-cis-epoxycarotenoid dioxygenase)的分布以及含量变化.结果表明,两种花生品种响应干旱胁迫后叶片的维管组织中ABA分布增强且含量增加,AhNCED1蛋白分布也增强;且在水分胁迫初期粤油7号花生AhNCED1蛋白分布强于汕优523,其体内ABA分布水平也高于汕优523;经ABA生物合成抑制剂Naproxen处理后,两种花生叶片ABA分布减弱,但粤油7号叶片维管组织中ABA分布水平仍高于汕优523.结果表明维管组织是干旱胁迫下花生叶片中ABA和AhNCED1分布的主要区域,且粤油7号花生抗旱性强可能与其体内AhNCED1和ABA的分布量较高有关.%In this study, the changes of ABA distribution and ABA content in leaf of two species of the peanut (Yueyou 7 and Shanyou 523) were researched through the immunoenzyme localization and ELISA methods. The results showed that the ABA distribution and ABA content in peanut leaf were increased after drought stress. The synthesis of ABA and AhNCED1 in the leaves of Yueyou 7 appeared more quickly than that in the susceptible cultivar (Shanyou 523). Furthermore, AhNCEDl transcript and protein in Yueyou 7 were induced more than that in Shanyou 523, coinciding with higher ABA accumulation. After treated with Naproxen, ABA distribution were lower than that treated with PEG. These results showed that the vascular cambium is the main region of leaf in peanut response to drought stress, and the higher drought-resistant of Yueyou 7 peanut may be relate to the more distribution of ABA and AhNCEDl in leaf.

  18. A comparison of the hydraulic efficiency of a palm species (Iriartea deltoidea) with other wood types.

    Science.gov (United States)

    Renninger, Heidi J; McCulloh, Katherine A; Phillips, Nathan

    2013-02-01

    Palms are an important component of tropical ecosystems, living alongside dicotyledonous trees, even though they have a very different growth pattern and vascular system. As monocots, vessels in palms are located within vascular bundles and, without a vascular cambium that many dicotyledonous trees possess, palms cannot add additional vessels to their vascular system as they get older and taller. This means that hydraulic architecture in palms is more predetermined, which may require a highly efficient hydraulic system. This preset nature, along with the decoupling of hydraulic and mechanical functioning to different cell types, may allow palms to have a more efficient hydraulic system than dicotyledonous trees. Therefore, this study seeks to determine the efficiency of the hydraulic system in the palm Iriartea deltoidea (Ruiz & Pav.) and compare this efficiency with other tree forms. We measured cross-sectional areas of roots, stems and fronds as well as leaf areas of I. deltoidea saplings. Likewise, cross-sections were made and vessel diameters and frequencies measured. This allowed for the calculation of theoretical specific conductivity (K(S,calc)), theoretical leaf-specific conductivity (K(L,calc)), and vessel diameter and vessel number ratios between distal and proximal locations in the palms. Iriartea deltoidea palms were found to have the largest, least frequent vessels that diverged most from the square packing limit (maximum number of vessels that fit into a given area) compared with other major tree forms, and they therefore invested the least space and carbon into water transport structures. Likewise, conduits tapered by ∼1/3 between ranks (root, bole and petiole), which represents an efficient ratio with regard to the trade-offs between safety and efficiency of the conducting system. Conduits also exhibited a high conservation of the sum of the conduit radii cubed (Σr(3)) across ranks, thereby approximating Murray's law patterning. Therefore, our

  19. Hõimlane verejõe tagant: Saami muinaslood tootempõhjapõdrast. II

    Directory of Open Access Journals (Sweden)

    Enn Ernits

    1997-01-01

    Full Text Available In the second part of the research is treated the most important event of the adult life of Meandash - getting married. Marriage between a man and an animal is based on totemistic conceptions. The stories of Meandash finding a wife and marrying her can be divided into two or three Subgenres. Of the first, the author knows only three versions, of the second twelve versions, but of the third - unless it is a forage or a combination of occasions - only one.The first subgenre is characterized by marrying a wife from beyond the river of blood, the second by a threesome of suitors (a raven, a seal and a reindeer, and the third by the bride observing how the food is prepared, which is forbidden. In the first subgenre, the totemistic and shamanlike way of thought is reflected, in which a reindeer man marries a mortal. The river of blood is in the Lapp conceptions the border separating the human and the mythical reindeer world. It is a border between the world of life and death, companions and ancestors. This border can only be crossed by a shaman, who turns into an otter (compare "Kalevala" XVI: 369-372, or uses incantations to make the river dry. In the latter case he uses alder cambium which is analogous to blood. In these stories is represented the motif of a house built of reindeer bones (Compare "Kalevala«, XXI: 159-162. Thus the house of the mythical reindeer is the reindeer himself. Here is expressed the microcosm of the Lapps and the traditions connected with the skeleton. The threshold of the reindeer's house were neckbones. It seems that the semantics of the neck has not been awarded proper attention in the Finno-Ugric religion history. The purposes of telling stories of getting married were 1 passing on information about the ancestors of the tribe and 2 separating the moral from the immoral for didactic purposes.Subgenres of the second kind express the way the reindeer people were imagined to be and to emphasize the benefits of originating

  20. 紫色甘薯色素分布的多样性%Diversity of Pigment Distribution in Purple Sweet Potato

    Institute of Scientific and Technical Information of China (English)

    时晓东; 刘良勇; 李云萍; 傅玉凡; 高峰

    2011-01-01

    采用色价法对紫色甘薯和普通白心甘薯共14个品种(品系)的色素含量和分布进行了检测和比较.结果表明:在不同的紫色甘薯品种(品系)中,色素的分布存在明显的差异;同一品种不同器官的色素含量也不相同,块根是紫色甘薯色素积累的主要器官;色素在块根内呈不均匀分布,表现为薯皮、初生形成层和木质部薄壁组织的色素含量不同,木质部薄壁组织内存在白色斑点.紫色甘薯色素在品种(品系)间分布的多样性为开展品种鉴定和遗传育种提供了丰富的种质资源,在器官和组织上分布的多样性为探讨色素合成与调控的细胞和分子机制奠定了试材基础.%The distribution of the purple pigment in 14 strains between purple-fleshed and white-fleshed sweetpotato was investigated in this paper.The result showed that there were significant differences on pigment distribution in strains and organs.The storage root of purple-fleshed sweetpotato is the predominant organ accumulating pigment.The uneven distribution of pigment was detected in storage root, including the difference among the contents of pigment in peel, primary cambium layer and xylem parenchyma which appeared white spots.The difference of the contents of pigment also observed from morphology apex to morphology base in the trailing part of purple-fleshed sweet potato.The diversity of purple-fleshed sweet potato pigment distribution in different strains laid a technical foundation for carrying on the variety identification and genetic breeding.Moreover, the diversity of pigment distribution in different organs and tissues provided the materials for the investigation of pigment biosynthesis and the mechanism of manipulation.

  1. 激素和防腐剂对树木损伤修复技术研究%Studies Technology on both Hormone and Antiseptic Renovating Trees Injury

    Institute of Scientific and Technical Information of China (English)

    王晓英; 冯殿齐; 王玉山; 赵进红; 陶娟; 高尚坤

    2012-01-01

    对5种树种的树干伤及形成层情况下,设置5个伤口涂补处理:1.空白,2.防腐剂,3.6-BA(5ppm)+防腐剂,4.IAA(15ppm)+防腐剂,5.6-BA(5ppm)+IAA(15ppm)+防腐剂。结果表明,防腐剂一纯松烟墨汁可以有效防止病原微生物侵染伤口和树体腐朽。涂补激素和防腐剂处理3、4、5与只涂补防腐剂处理2相比,添加激素涂补明显加速了伤口愈合,而处理3、4、5之间未见显著差异。激素并口墨汁溶液可以作为新型树木伤口液体涂料,具有一定的开发价值。%In the cambium injury of trunk of 5 tree species, the experiment seted up five wounds smearing treatments: 1. Blank, 2. Antiseptic, 3. 6--BA (5 ppm) and antiseptic, 4. IAA (15 ppm) and antiseptic, 5. 6--BA (5 ppm), IAA (15 ppm) and antiseptic. The results showed that the antiseptic--pure SongYan ink could effectively prevent the pathogenic microbes from infecting the wound and tree trunk decayed. Compare smearing hormone and antiseptic treatments 3, 4, 5 with only smea- ring antiseptic treatment 2, adding hormone significantly accelerated the wound healing, and there were no significantly differ- ences between 3, 4, and 5 treatments. Hormone and ink solution can be used as a new tree would liquid coating products, and it has some of the development value.

  2. Missing Rings in Pinus halepensis – The Missing Link to Relate the Tree-Ring Record to Extreme Climatic Events

    Science.gov (United States)

    Novak, Klemen; de Luis, Martin; Saz, Miguel A.; Longares, Luis A.; Serrano-Notivoli, Roberto; Raventós, Josep; Čufar, Katarina; Gričar, Jožica; Di Filippo, Alfredo; Piovesan, Gianluca; Rathgeber, Cyrille B. K.; Papadopoulos, Andreas; Smith, Kevin T.

    2016-01-01

    Climate predictions for the Mediterranean Basin include increased temperatures, decreased precipitation, and increased frequency of extreme climatic events (ECE). These conditions are associated with decreased tree growth and increased vulnerability to pests and diseases. The anatomy of tree rings responds to these environmental conditions. Quantitatively, the width of a tree ring is largely determined by the rate and duration of cell division by the vascular cambium. In the Mediterranean climate, this division may occur throughout almost the entire year. Alternatively, cell division may cease during relatively cool and dry winters, only to resume in the same calendar year with milder temperatures and increased availability of water. Under particularly adverse conditions, no xylem may be produced in parts of the stem, resulting in a missing ring (MR). A dendrochronological network of Pinus halepensis was used to determine the relationship of MR to ECE. The network consisted of 113 sites, 1,509 trees, 2,593 cores, and 225,428 tree rings throughout the distribution range of the species. A total of 4,150 MR were identified. Binomial logistic regression analysis determined that MR frequency increased with increased cambial age. Spatial analysis indicated that the geographic areas of south-eastern Spain and northern Algeria contained the greatest frequency of MR. Dendroclimatic regression analysis indicated a non-linear relationship of MR to total monthly precipitation and mean temperature. MR are strongly associated with the combination of monthly mean temperature from previous October till current February and total precipitation from previous September till current May. They are likely to occur with total precipitation lower than 50 mm and temperatures higher than 5°C. This conclusion is global and can be applied to every site across the distribution area. Rather than simply being a complication for dendrochronology, MR formation is a fundamental response of trees

  3. Missing Rings in Pinus halepensis - The Missing Link to Relate the Tree-Ring Record to Extreme Climatic Events.

    Science.gov (United States)

    Novak, Klemen; de Luis, Martin; Saz, Miguel A; Longares, Luis A; Serrano-Notivoli, Roberto; Raventós, Josep; Čufar, Katarina; Gričar, Jožica; Di Filippo, Alfredo; Piovesan, Gianluca; Rathgeber, Cyrille B K; Papadopoulos, Andreas; Smith, Kevin T

    2016-01-01

    Climate predictions for the Mediterranean Basin include increased temperatures, decreased precipitation, and increased frequency of extreme climatic events (ECE). These conditions are associated with decreased tree growth and increased vulnerability to pests and diseases. The anatomy of tree rings responds to these environmental conditions. Quantitatively, the width of a tree ring is largely determined by the rate and duration of cell division by the vascular cambium. In the Mediterranean climate, this division may occur throughout almost the entire year. Alternatively, cell division may cease during relatively cool and dry winters, only to resume in the same calendar year with milder temperatures and increased availability of water. Under particularly adverse conditions, no xylem may be produced in parts of the stem, resulting in a missing ring (MR). A dendrochronological network of Pinus halepensis was used to determine the relationship of MR to ECE. The network consisted of 113 sites, 1,509 trees, 2,593 cores, and 225,428 tree rings throughout the distribution range of the species. A total of 4,150 MR were identified. Binomial logistic regression analysis determined that MR frequency increased with increased cambial age. Spatial analysis indicated that the geographic areas of south-eastern Spain and northern Algeria contained the greatest frequency of MR. Dendroclimatic regression analysis indicated a non-linear relationship of MR to total monthly precipitation and mean temperature. MR are strongly associated with the combination of monthly mean temperature from previous October till current February and total precipitation from previous September till current May. They are likely to occur with total precipitation lower than 50 mm and temperatures higher than 5°C. This conclusion is global and can be applied to every site across the distribution area. Rather than simply being a complication for dendrochronology, MR formation is a fundamental response of trees

  4. Missing rings in Pinus halepensis – the missing link to relate the tree-ring record to extreme climatic events

    Directory of Open Access Journals (Sweden)

    Klemen eNovak

    2016-05-01

    Full Text Available Climate predictions for the Mediterranean Basin include increased temperatures, decreased precipitation, and increased frequency of extreme climatic events (ECE. These conditions are associated with decreased growth of trees and their increased vulnerability to pests and diseases. The anatomy of tree rings is responsive to these environmental conditions. Quantitatively, the width of a tree ring is largely determined by the rate and duration of cell division by the vascular cambium. In the Mediterranean climate, cambial cell division may occur throughout almost the entire year. Alternatively, cell division may stop during relatively cool and dry winters, only to resume in the same year with milder temperatures and increased availability of water. Under particularly adverse conditions, no xylem may be produced in parts of the stem, resulting in a missing ring (MR, which can link tree-ring anatomy to the occurrence of extreme events. A dendrochronological network of Pinus halepensis, a widespread tree species in the Mediterranean basin, was used to determine the relationship of MR to ECE. The network consisted of 113 sites throughout its distribution range. Binomial logistic regression analysis of 2595 MR series determined that MR increased in frequency with increased cambial age. Spatial analysis indicated that the geographic areas of southeastern Spain and northern Algeria contained the greatest frequency of MR. Further regression analysis indicated that the relationship of MR to total monthly precipitation and mean temperature was non-linear. In this first determination of climatic influences on MR, the formation of MR was most strongly associated with the combination of monthly mean temperature above 10°C from previous October till current February and total precipitation below 50 mm from previous September till current May. This conclusion is global and can be applied to every site across the distribution area. Rather than simply being a

  5. 毛白杨PtCDD基因5'片段的原核表达及功能分析%Prokaryotic Expression and Functional Analysis of 5'-Fragment of PtCDD Gene from Populus tomentosa

    Institute of Scientific and Technical Information of China (English)

    曹秀利; 杜娟; 王敏杰; 赵树堂; 卢孟柱

    2008-01-01

    The development of secondary vascular system in woody plants is a complex process including cambial cell differentiation,cell expansion,secondary wall formation and final programmed cell death (PCD).In order to validate the role of a Ca2+ -dependent DNage,found in the differentiating xylem,in the PCD process,it is necessary to express its gene of PtCDD and purify the product in a large quantity in order to raise antibody for further immuno-localization analysis.In this study,the 5'fragment of 637 bp was amplified by PCR from the Populus tomentosa cambium cDNA gene with primers designed according to the PtCDD gene sequence published in GenBank,and the fragment was ligated into the vector PET-30b(+) to construct the prokaryotic expression vector for PtCDD gene.The expressed PtCDD-(HIS)6 fusion protein was purified and the function was analyzed.The results showed that the PtCDD fragment could be successfully expressed in the Escherichia coli cells and the fusion protein exhibited the DNase activity.This achievement provided a solution to the problem that the entire protein could not be expressed in E.coli probably due to its strong digestion activity on DNAs,so that a convenient method of the antibody preparation became available to further investigate the role of PtCDD in PCD.%根据GenBank中毛白杨钙离子依赖型脱氧核糖核酸酶(PtCDD)基因序列,以毛白杨形成层区域的cDNA为模板,经PCR扩增出该基因上游637 bp的cDNA片段.将该片段与PET-30b(+)载体连接,构建杨树PtCDD基因片段原核表达载体并进行表达研究,获得大量的PtCDD-(HIS)6 融合蛋白.并进一步对该蛋白进行纯化和功能检测.结果表明:PtCDD基因片段能够在大肠杆菌体内表达出具有DNase功能的蛋白,克服了因表达全酶可能强烈降解DNA所带来的不能最终获得表达产物的问题,为今后PtCDD蛋白的抗体制备以及进一步研究奠定了基础.

  6. Tracheid production phenology of Picea mariana and its relationship with climatic fluctuations and bud development using multivariate analysis.

    Science.gov (United States)

    Dufour, Boris; Morin, Hubert

    2010-07-01

    Research on cambium phenology in trees and its limiting factors in natural conditions is still at an early stage of development, restricting our capacity to precisely evaluate the effect of growing season length and climate fluctuations on tracheid production. The first objective of this paper was to describe cambial tracheid production phenology of black spruce (Picea mariana (Mills.) BSP). Repeated tree ring sampling was performed from 2002 to 2006 on four sites (48 degrees 13.78' N, 71 degrees 15.18' W; 48 degrees 51.92' N, 70 degrees 20.57' W; 49 degrees 43.92' N, 71 degrees 56.88' W; and 50 degrees 41.78' N, 72 degrees 11.03' W) representative of closed black spruce forest in Quebec, Canada. The timing of cambial initiation and cambial cessation in black spruce differs from year to year, the first occurring on 4 June on average, whereas the second occurs on 15 August. During a single year, these events do not vary significantly in space within the study area. The duration of cambial tracheid production does not vary significantly in either time or space. The second objective of this study was to identify the climatic factors that explain variations in initiation and cessation. Air temperature and humidity, soil temperature and water content, rain precipitations, snow cover as well as photosynthetically active radiation were monitored at each studied site. These were then used to create sets of candidate regressors to explain timing of phenological events. Timing of cambial initiation is primarily dependent on mean temperature between mid-March and initiation itself. Vapor pressure during this period is also important but in a negative way. A significant effect of the previous year's August soil and air temperature conditions suggests a link with spring bud activity resumption, an interpretation that is supported by an analysis significantly linking measured timing of bud break to cambial initiation. Cessation of cambial tracheid production is influenced by

  7. Enraizamento de estacas de Ginkgo biloba tratadas com ácido indolbutírico e ácido bórico Rooting of Ginkgo biloba cuttings treated with indolbutyric and boric acids

    Directory of Open Access Journals (Sweden)

    Janice Valmorbida

    2008-04-01

    Full Text Available Objetivou-se neste trabalho estudar o efeito do ácido indolbutírico (AIB e do ácido bórico (B no enraizamento de estacas de Ginkgo biloba. Em estacas com duas folhas, medindo 15 cm de comprimento foram provocadas duas lesões na base de aproximadamente 2 cm, expondo o câmbio e procedeu-se à imersão por 10 segundos no tratamento correspondente, AIB (0, 1000, 2000 e 3000 mg L-1 na ausência ou presença de B (0 e 150 mg L-1. Em seguida foram colocadas para enraizar em bandejas de polipropileno contendo areia lavada. O delineamento foi em blocos casualizados num fatorial 4X2, com seis repetições. Foram avaliadas porcentagem de estacas enraizadas, estacas não enraizadas e mortas, diâmetro e comprimento das raízes, aos 70 dias do tratamento. Os dados foram submetidos à análise de variância sendo previamente testados para normalidade pelo Teste de Shapiro-Wilk. As médias foram comparadas pelo Teste de Tukey. Os tratamentos com 2000 mg L-1 de AIB foram superiores à ausência de AIB (80,55% vs. 55,56%, respectivamente, não diferindo dos demais tratamentos. A utilização de B não afetou a taxa de enraizamento, de estacas não enraizadas e mortas, não havendo interação entre a concentração de AIB e a utilização ou não de B. O diâmetro e o comprimento das raízes não foram afetados pela utilização de AIB e B.The aim of the work was to study the effect of indolbutyric (IBA and boric (B acids to root Ginkgo biloba cuttings. At the base of cuttings, with two leaves and 15 cm of length, were made two lesions with 2 cm to expose the cambium. Cuttings were treated for a period of 10 seconds with four concentrations of IBA (0, 1000, 2000 and 3000 mg L-1 combined with two concentration of B (0 and 150 mg L-1. After that, cuttings were taken in polypropylene trays filled with washed sand. The experimental design was of randomized blocks in the factorial arrangement (4x2, with six replications. After 70 days, evaluations were done

  8. Morphology and Physiological Responses of Chenopodium album L.under Salt Stress%盐胁迫下藜的形态结构与生理响应

    Institute of Scientific and Technical Information of China (English)

    吕秀云; 油天钰; 赵娟; 陈莎莎; 兰海燕

    2012-01-01

    本文采用石蜡切片、扫描电镜和体视显微镜对藜进行了形态结构观察和多种生理指标检测,研究在盐胁迫下藜的结构和生理变化.结果表明:在花期,藜的株高和茎粗显著降低,叶未产生明显肉质化.高盐(300mmol·L-1)胁迫下,叶维管束的导管数量及形成层层数增加,茎的维管束密度增加,根木质化程度增强,大导管密度显著降低.叶下表面的盐囊泡较上表面多,叶和茎细胞中均含有簇状结晶.随着盐浓度的升高,叶片中含水量降低,相对电导率升高,丙二醛(MDA)含量无显著变化,叶绿素含量在苗后期先升高后降低,在花期,其含量随盐浓度升高而降低.300mmol·L-1盐胁迫下,苗后期的可溶性糖、脯氨酸及甜菜碱含量显著增加;至花期,脯氨酸及甜菜碱含量显著高于对照.以上结果初步显示,高浓度盐胁迫对花期的藜形态结构及部分生理指标均比苗期产生显著影响,但300mmol·L1盐胁迫下藜仍能完成其生活史.%The present study investigated the morphology and physiological changes in Chenopodium album under salt stress by observation of paraffin sections, scanning electron microscope and stereo microscope. The results showed that the plant height and stem diameter decreased significantly at flowering stage, while the leaf succulence was not evident. Under high salt (300 mmol-L"') stress, the number of vascular vessle and layer of cambium in leaf increased, and the vascular bundle density in stem also increased, the Hgnified degree of root enhanced, the density of large vessle in root reduced significantly. The salt bladders on the abaxial surface were more than those on adaxial surface, and some clusters of crystallization were observed in cells of leaf and stem. With the increase of salt concentration, water content decreased; the relative electric conductance increased, while MDA content showed no difference. The content of chlorophyll increased first and then

  9. Tumores em certos híbridos do gênero nicotiana

    Directory of Open Access Journals (Sweden)

    F. G. Brieger

    1942-01-01

    genes reported in interspecific crosses involving N, longiflora (Brieger, 3 and Crepis tectorum (Hollingshead, 8. Since the hybrids with N. glauca are completely sterile, it cannot be decided whether the genes reported are only modifiers or are actually causing the tumour formation and the other abnormalities. 2 A histological study was made about the origin of stem tumours. The first sign is the activation of cells of the tissues between epidermies and collenchyma. Some cells adjoining other which are dead or dying start to grow and later on to divide, in the manner typical for cells under the action of traumatic hormons (cf. Brieger, 2. Later on the whole region is activated and the cortex layers degenerate. At this stage large tumours may be formed, but as yet without connection with the xylem (fig. 15. Later on the cambium and the secundary medulary rays participate in the irregular development (fig. 13 which finally reaches the medulla. Finally the central cylindre is forced open and the tumours connected with it (fig. 14. Thus tumours formation on the stem is endogeneous and starts from mature cells, not from meristematic cells. 3 Finally an observation is reported, without an attempt to explain it. In the earliest phases of tumours formation in the stem and in cells not participating it, intracellular bodies are observed (fig. 17 with a colourless membrane and on alveolar and highly refractive content. These bodies resemble somewhat cells of fungus such as Chytridiales, but, as already said, their nature is obscure.

  10. Leaf Blade Comparative Anatomy between the Female and the Male of Populus euphratica Oliv.%胡杨雌雄株叶片的比较解剖学研究

    Institute of Scientific and Technical Information of China (English)

    杨赵平; 刘琴; 李志军

    2011-01-01

    应用石蜡切片法对胡杨(Populus euphratica Oliv.)雌、雄株叶片进行比较解剖研究,结果表明:(1)胡杨雌、雄株叶片都由表皮、叶肉与叶脉构成,表皮由2层细胞构成复表皮;上、下表皮内均分化出了2~3层栅栏组织细胞,栅栏组织之间有少量海绵组织细胞;主脉维管束通常1个,由木质部、韧皮部、少量形成层及类似禾本科植物的维管束鞘所构成.(2)胡杨雌株叶片的表皮细胞厚度、角质层厚度、叶片厚度、栅栏组织厚度、主脉维管束高度及木质部高度都明显大雄株.(3)雌雄株叶片上、下表皮气孔的数目、栅栏组织在叶肉中的百分比、主脉维管束木质部所占的百分比存在一定差异,但是方差分析结果表明其差异不显著.(4)胡杨叶片的解剖结构具有旱生植物叶片的典型特点,但其雌株叶片旱生结构特点更明显,可能与雌雄株生殖功能相关.%The anatomical characteristics of females and males from Populus euphratica Oliv. were studied by paraffin section. The results are as follows:(1) All the female and the male leaves are composed of leaf epidermis,mesophyll and vein. Leaf epidermis is multi-epidermis usually composed of 2 layer cells. Near by adaxial and abaxial hypodermis, there are 2~ 3 layer palisade tissue cells. Between palisade tissue cells,there are a few sponge tissue cells. The number of vascular bundle in main vein is usually single,and they are composed of xylem, phloem, a little cambium and vascular bundle sheath that are similar to Poaceae’.(2)The female thickness of epidermal cells and horny layer,the thickness of mesophyll and palisade tissue,and the height of vascular bundle and xylem are obviously bigger than male’. (3)The female stomata numbers in epidermis,the percentage of palisade tissue in mesophyll and the precentage of xylem in main vein vascular bundle are a little different from the male,but the results of analysis of correlation and

  11. Ontogênese de caneluras em pedúnculo de flores de laranjeira doce infectados pelo vírus da tristeza dos citros estirpe "Capão Bonito"

    Directory of Open Access Journals (Sweden)

    Francisco André Ossamu Tanaka

    2009-12-01

    interrupted by the invading abnormal phloem proliferation, which produces undifferentiated cells with thin cell wall. The irregular activity of the vascular cambium continues followed by the complete degeneration of the xylem complemented by the appearance of dense phenolic deposits. Finally, there is the complete collapse of the xylem in the invaded region, and the corresponding space is occupied by the phloem mass which correspond to the stem pitting.

  12. Dendrochemistry Application as a Tool for Biomonitoring Environmental Pollution of Mining Areas%年轮化学示踪技术及在重现矿区重金属污染历史中的应用

    Institute of Scientific and Technical Information of China (English)

    雷梅; 郭立新; 张山岭

    2011-01-01

    The trees, naturally growing in the mining areas, can uptake heavy metals from air, soil, and irrigation water. The pathways of heavy metals entering the trees might be roots, barks, and leaves. After entering the trees, heavy metals will deposit in the tree-rings during cambium development. The long-term fluctuations of element contents in tree rings can be analysed by the laser ablation system coupled to an inductively coupled plasma mass spectrometer. Therefore, the pollution processes of mining areas can be recorded by the variation of heavy metal concentrations in the tree-rings, and the influential ratios of different pollution routes can be semi-quantitatively determined. Cases of applications of dendrochemistry in biomonitofing of air, water and soil pollution were reviewed in this article. Based on the point pollution characteristics of mining areas, the possibility of applying dendrochemistry for pollution monitoring was discussed. Aiming to improve the accuracy of research of atmospheric and soil pollution in mining areas by dendrochemistry, different influential factors of heavy metal concentrations in tree rings, such as tree species, selective uptake of elements by trees, climate variation and nutrient providing, were reviewed. Geostatistics, stable isotope tracer, and synchrotron radiation X-ray fluorescence can improve the accuracy of dendrochemistry for environmental pollution recording. Atmospheric dispersion model predicting ground-level concentrations from a point source of metal emissions, such as smelters, can be calibrated on tree rings in order to reconstruet the spatial and temporal Pb-contamination pattern. Dating of the historical record has been achieved using isotopic analysis, for example 210Pb and 137Cs. With the development of analytical techniques of heavy metals in tree rings, dendrochemistry will play a more important role in pollution monitoring in mining areas. This review highlights the strong potential for dendrochemistry to

  13. Alterações anatômicas foliares em plantas de Brachiaria subquadripara submetidas à aplicação de herbicidas Anatomic leaf changes in Brachiaria subquadripara submitted to herbicide application

    Directory of Open Access Journals (Sweden)

    N.V. Costa

    2012-06-01

    of the anatomic quantitative characteristics of the central vein and intervein regions of the leaf blade, as well as of the stem region: adaxial and abaxial epidermis %, endoderm %, vascular bundle %, aerenchyma lacunas %, parenchyma and leafthickness %, epidermal stem %, and vascular cambium and stem diameter %. The herbicides diquat and imazapyr promoted the largest number of changes in the quantitative anatomic characters of the midrib and intervein regions of the leaf and stem regions of the plants. However, with the exception of diquat, the herbicides were effective in controlling the B. subquadripara plants. All the herbicides allowed plant re-growth.

  14. Analysis of 4,664 high-quality sequence-finished poplar full-length cDNA clones and their utility for the discovery of genes responding to insect feeding

    Directory of Open Access Journals (Sweden)

    Douglas Carl J

    2008-01-01

    Full Text Available Abstract Background The genus Populus includes poplars, aspens and cottonwoods, which will be collectively referred to as poplars hereafter unless otherwise specified. Poplars are the dominant tree species in many forest ecosystems in the Northern Hemisphere and are of substantial economic value in plantation forestry. Poplar has been established as a model system for genomics studies of growth, development, and adaptation of woody perennial plants including secondary xylem formation, dormancy, adaptation to local environments, and biotic interactions. Results As part of the poplar genome sequencing project and the development of genomic resources for poplar, we have generated a full-length (FL-cDNA collection using the biotinylated CAP trapper method. We constructed four FLcDNA libraries using RNA from xylem, phloem and cambium, and green shoot tips and leaves from the P. trichocarpa Nisqually-1 genotype, as well as insect-attacked leaves of the P. trichocarpa × P. deltoides hybrid. Following careful selection of candidate cDNA clones, we used a combined strategy of paired end reads and primer walking to generate a set of 4,664 high-accuracy, sequence-verified FLcDNAs, which clustered into 3,990 putative unique genes. Mapping FLcDNAs to the poplar genome sequence combined with BLAST comparisons to previously predicted protein coding sequences in the poplar genome identified 39 FLcDNAs that likely localize to gaps in the current genome sequence assembly. Another 173 FLcDNAs mapped to the genome sequence but were not included among the previously predicted genes in the poplar genome. Comparative sequence analysis against Arabidopsis thaliana and other species in the non-redundant database of GenBank revealed that 11.5% of the poplar FLcDNAs display no significant sequence similarity to other plant proteins. By mapping the poplar FLcDNAs against transcriptome data previously obtained with a 15.5 K cDNA microarray, we identified 153 FLcDNA clones

  15. 瘤胃微生物对苜蓿茎降解特性及超微结构的影响%Effects of Rumen Microorganisms on Degradation Characteristics and Ultrastructure of Alfalfa Stem

    Institute of Scientific and Technical Information of China (English)

    徐俊; 侯玉洁; 赵国琦; 霍永久; 邬彩霞

    2014-01-01

    This study was conducted to investigate the effects of rumen microorganisms on degradation charac-teristics and ultrastructure of alfalfa stem. Alfalfa stems with similar growth profile and plant height were har-vested at early flowering to carried out a degradation rate experiment using nylon bags, at the same time, the second internode was longitudinally cut to six equal parts for samples which were incubated for 6 , 12 , 24 , 48 and 72 h in the rumen, repectively. The changes of ultrastructure of alfalfa stem were observed under scanning and transmission electron microscopes. The results showed as follows:1 ) dry matter and neutral detergent fi-ber were mostly degraded within 24 h of fermentation in rumen, and only a small part of neutral detergent fiber was degraded after 48 h. 2) The non-lignified epidermis, collencyma, chlorenchyma, cambium and primary xylem parenchyma were all quickly degraded, and completely degraded within 24 h of fermentation in rumen, but the lignified secondary xylem fiber and vessels remained undegraded. 3) Encapsulated cocci and irregularly shaped bacteria were the majorities of fiber digesters, and the degradation regularity was various with different structure of tissues. In conclusion, alfalfa stem can be rapidly degraded under the effects of rumen microorgan-isms, but the rate and content of degradation are related to the structure and composition of alfalfa stem, in ad-dition, the highly lignified structures are difficult to be degraded in the rumen. Therefore, reducing the content of lignification composition is an effective method to improve degradation rate of alfalfa stem.%本试验旨在研究瘤胃微生物对苜蓿茎降解特性及超微结构的影响。选用长势和株高相近的初花期苜蓿茎进行尼龙袋降解率试验,并截取第2节茎均分为6份,在瘤胃中分别降解6、12、24、48和72 h,利用扫描电镜和透射电镜观察其超微结构变化。结果表明:1)苜蓿茎干物质和中性洗

  16. Anatomia e desenvolvimento ontogenético de Coffea arabica L. var. typica Cramer Anatomy and ontogenetical development of Coffea arabica L. var. typica Cramer

    Directory of Open Access Journals (Sweden)

    D. M. Dedecca

    1957-01-01

    secondary growth, formed from a vascular cambium which makes its first appearance in a region localized approximately 5 cm from the root apex. Phellogen arises first in the pericycle and later in phloem and gives origin to a relatively thin periderm; this protective layer replaces the epidermis that is gradually killed and sloughs away. Lateral roots originate from pericyclic cells situated at the protoxylem outer edges. The origin of all stem tissues, as well as those of the leaves, can be traced back to a dome-shaped shoot apex, which measure 220-360 microns in diameter and 48-120 microns in its major height; this shoot apex interpreted under the terms of Schmidt's theory shows to possess a tunica composed of two or three cell layers, and a corpus, represented by a central core of irregularly arranged cells. Differentiation of meristematic tissue initiates at the distance of 800-900 microns from the shoot apex, but the complete primary tissue differentiation is only achieved in a region situated 2.5 cm from the shoot apex. Stem cross sections at this level exhibit the following tissue zones: epidermis, angular collenchyma, cortical parenchyma, pericycle, primary phloem, primary xylem and pith. No distinct endodermis is visible. The vascular cambium, firstly visible in a region distant 2.5 cm from the shoot apex, originates from procambial cells localized between the xylem and phloem, being at the beginning only fascicular; the cells of the primary rays undergo cambiform meristematic activity, and interfascicular cambium is thereby formed between the vascular bundles. Following a centripetal differentiation the cambial derivatives give rise to a continuous band of secondary xylem and secondary phloem. Older stem cross sections present a periderm which is about 70 microns thick. Cork cambium arises from the innermost cells of cortex and produces cork externally and phelloderm internally. Petiole presents a tricyclic structure, exhibiting three vascular bundles, the major

  17. Quimeras periclinais diplóldes-tetraplóides surgidas em forma de variações somáticas em Citrus

    Directory of Open Access Journals (Sweden)

    H. B. Frost

    1944-01-01

    hybrid mandarin (King x Dancy. From the variantbranch several progeny trees were grown in comparison with others derived irom the normal part of the tree. The results of extensive investigation indicate that the budded progeny of the variant branch includes at least two types of chimeral constitution : one is 2n-4n-4n respectively for its first, second, and third germ layers, and the other is 2n-4n-2n for the same layers. On the assumption that three germ layers exist in Citrus, it was demonstrated that the first germ layer forms the epidermis, the second one all leaf tissues (with the exception of the epidermis, the microsporocytes and at least part of the cortex of young vegetative shoots, and the third one forms the procambium, cambium, and the pith of the stem. Determination of chromosome number in root tips of cuttings of these two chimeras, demonstrated that these roots, at least when they derive from a callus, have their origin in the third germ layer. Comparison of stomata of mature leaves of different plants indicates that size differences, even if they are of statistical significance, are not always due to differences in chromosome number in the epidermis. The progeny trees of these chimeras differ considerably in growth habit, the one with a diploid third germ layer being approximately normal (erect, the other with a tetraploid third layer being low and broad. This fact suggests that the third layer plays a considerable role in determining the growth habit of the trees. Both chimeras are rather unfruitful, which is typical for Citrus tetraploids.

  18. Enraizamento de estacas, crescimento e respostas anatômicas de mudas clonais de cacaueiro ao ácido indol-3-butírico Stem cutting rooting, growth and anatomical responses of cacao tree clonal changes to the indole-3-butyric acid

    Directory of Open Access Journals (Sweden)

    Alberto José dos Santos Júnior

    2008-12-01

    -53, PS-1319 and CA-1.4 were evaluated. The IBA was applied in the base of stem cuttings, as an inert talc, in mixture concentrations of 2, 4, 6 and 8 g kg-1 together with the control, without IBA. The evaluation of the growth of roots, stem and leaves of the four clones were accomplished by 160 days after the cutting (DAC for all the IBA concentrations. However, the anatomical studies of the several plant organs were also made to the 160 DAC, but only for the concentration of 4g kg-1 IBA and the control. The clone CA-1.4 presented increment in the root dry biomass (RDB with the increase of the IBA concentrations, while for the other clones there were decreases of RDB starting from the 4 g kg-1 IBA. The same fact was observed for the stem and leaf dry biomass, except for CCN-10 that did not answer to the increment of the concentrations of IBA. There was an increase of the total leaf area for the clones CP-53 e PS-1319 with the increment of the IBA (concentration up to 4 g kg-1, while the leaves number only increased for the clones CA-1.4 and CP-53, concentrations up to 8 and 4 g kg-1 IBA, respectively. There was a decrease in the number of dead cuttings for the clones CA-1.4 and CCN-10 (up 8 g kg-1 of IBA and for the CP-53 (up to 4 g kg-1 of IBA. The best IBA concentrations for the branch cutting rooting of the cacao clones CP-53, PS-1319 and CCN-10 were of 4, 4 and 6 g kg-1 respectively, while for the clone CA-1.4 was the one of 8 g kg-1; the increase of the IBA concentration promoted anatomical changes in the plant organs of all the clones, influencing the activity of the vascular cambium in the stem and inducing the formation of a larger number of adventitious roots in the stem cuttings.

  19. 北亚热带生长期温度对马尾松径向生长的影响%Effects of air temperature in growth season on Masson pine(Pinus massoniana)radial growth in north subtropical region of China

    Institute of Scientific and Technical Information of China (English)

    封晓辉; 程瑞梅; 肖文发; 王瑞丽; 王晓荣; 高宝庆

    2011-01-01

    Longer growth season has been confirmed due to the elevated temperature in recent decades. Though the changes in the duration of growth season could affect tree productivity, it ’s unclear how the growth season with different initiating temperature affects the radial growth of tree. In order to investigate the effects of growth season’ s variability in temperature to the radial growth of Masson pine (Pinus massoniana) and search for the sensitive temperature to the growth, old Masson pine stands in Hanzhong, the northwest margin of north subtropical region, were chosen as test objects, with their tree ring width index chronology from 1945 to 2009 measured by dendrochronology method. The air temperatures on the first day, last day, and in the whole growth season as well as the active accumulative temperature during growth season were determined based on the daily mean temperature of Hanzhong, and the relationships between the temperatures and chronology were analyzed. The results showed that the growth season with initiating temperature 6. 0 ℃ -7. 5 ℃ had negative effects on the tree ring width index chronology, with 6. 0 ℃ being most significant. 10. 5 ℃ on the last day had significant positive effects on tree ring growth. 10. 0 ℃ and 10. 5 ℃ in growth season were significantly positively correlated with the tree ring growth, and the active accumulative temperature during growth season was also significantly positively correlated with the growth. These sensitive temperatures were respectively corresponding to the onset of photosynthesis, needle emergence in spring, and shutting down of cambium activity in autumn. Our study suggested that elevated temperature led to the changes in phenophase, and thereby, affected the radial growth of P. massoniana in Hanzhong.%近几十年由于温度升高导致的植物生长期的延长已经得到了证实,虽然生长期的长短变化会引起树木生产力变化,但不同起始温度的生长期对树木径

  20. PMRP Expression Characteristics and Analysisof the Function inArabidopsis%拟南芥PMRP的表达特性及功能分析

    Institute of Scientific and Technical Information of China (English)

    张昊; 由诗东; 高静; 张海丽; 李生辉; 邢继红; 王凤茹; 董金皋

    2014-01-01

    leaves, the growth time of rosette leaves was longer, the more expression of PMRPwas tested (the relative expression ofPMRP in the 1st, 2nd, 3rd and 4th pairs of the rosette leaves were 1 650, 1 113, 734, and 507, respectively) , then the sepals floral tissues (PMRP relative expression quantity is about 937),PMRP had distribution in the stem, root and seed , but the relative expression amount was less than 270. The relative expression level ofPMRP in stamens was the lowest (about 64), far below the expression quantity ofPMRP in sepals (937). The expression level ofPMRP gene was increased with the increase of growth time, the relative expression ofPMRP were 154 and 222, respectively, in 8 and 21 d roots, and 200 and 264, respectively, in 8 and 21 d stems. The rosette leaves were emerged from the branches, stalk lodging susceptible, vascular had no obvious cambium and the xylem and phloem arranged in disorder, the filaments became shorter in floral organs, the number of pod decreased, and the fertility reduced.[Conclusion]The START domain is extremely conservative in function.PMRP was expressed in different organs ofA. thaliana, with the extension of time, the expression level ofPMRP was also increased. The level ofPMRP in the flower stamens was the lowest, oncePMRPwas over-expressed inArabidopsis floral organs, stamens dysplasia, resulting in reduced fertility.PMRP had important function in regulating the origination of leaves, the vascular differentiation and development of floral organs.%分析拟南芥中功能未知基因PMRP(putative membrane related protein)的表达特性;明确PMRP在调控拟南芥生长发育过程中的作用。利用生物信息学方法,寻找拟南芥中与PMRP含相同结构域的基因,并绘制进化树;利用Real-time PCR技术分析PMRP在生长8和21 d的拟南芥根、茎中的相对表达量,比较生长21 d的拟南芥第1、2、3、4对莲座叶及茎生叶中PMRP的表达情况,分析花器官的萼片、花瓣和