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Sample records for cambium

  1. Vascular Cambium Development

    Science.gov (United States)

    Nieminen, Kaisa; Blomster, Tiina; Helariutta, Ykä; Mähönen, Ari Pekka

    2015-01-01

    Secondary phloem and xylem tissues are produced through the activity of vascular cambium, the cylindrical secondary meristem which arises among the primary plant tissues. Most dicotyledonous species undergo secondary development, among them Arabidopsis. Despite its small size and herbaceous nature, Arabidopsis displays prominent secondary growth in several organs, including the root, hypocotyl and shoot. Together with the vast genetic resources and molecular research methods available for it, this has made Arabidopsis a versatile and accessible model organism for studying cambial development and wood formation. In this review, we discuss and compare the development and function of the vascular cambium in the Arabidopsis root, hypocotyl, and shoot. We describe the current understanding of the molecular regulation of vascular cambium and compare it to the function of primary meristems. We conclude with a look at the future prospects of cambium research, including opportunities provided by phenotyping and modelling approaches, complemented by studies of natural variation and comparative genetic studies in perennial and woody plant species. PMID:26078728

  2. WOX4 imparts auxin responsiveness to cambium cells in Arabidopsis.

    Science.gov (United States)

    Suer, Stefanie; Agusti, Javier; Sanchez, Pablo; Schwarz, Martina; Greb, Thomas

    2011-09-01

    Multipotent stem cell populations, the meristems, are fundamental for the indeterminate growth of plant bodies. One of these meristems, the cambium, is responsible for extended root and stem thickening. Strikingly, although the pivotal role of the plant hormone auxin in promoting cambium activity has been known for decades, the molecular basis of auxin responsiveness on the level of cambium cells has so far been elusive. Here, we reveal that auxin-dependent cambium stimulation requires the homeobox transcription factor WOX4. In Arabidopsis thaliana inflorescence stems, 1-N-naphthylphthalamic acid-induced auxin accumulation stimulates cambium activity in the wild type but not in wox4 mutants, although basal cambium activity is not abolished. This conclusion is confirmed by the analysis of cellular markers and genome-wide transcriptional profiling, which revealed only a small overlap between WOX4-dependent and cambium-specific genes. Furthermore, the receptor-like kinase PXY is required for a stable auxin-dependent increase in WOX4 mRNA abundance and the stimulation of cambium activity, suggesting a concerted role of PXY and WOX4 in auxin-dependent cambium stimulation. Thus, in spite of large anatomical differences, our findings uncover parallels between the regulation of lateral and apical plant meristems by demonstrating the requirement for a WOX family member for auxin-dependent regulation of lateral plant growth. PMID:21926336

  3. Molecular regulation of vascular cambium identity and activity

    OpenAIRE

    Kucukoglu, Melis

    2015-01-01

    In plants, secondary development and wood formation originates from the cell divisions within the vascular meristem, where the vascular stem cells are located. This thesis work presents my results on the molecular regulation of vascular cambium stem cell identity and activity. I have investigated the role of the receptor-like kinase PXC1 during vascular development in Arabidopsis thaliana. Mutant analysis revealed that in the absence of PXC1, plants display a pendant phenotype and reduced...

  4. MOL1 is required for cambium homeostasis in Arabidopsis.

    Science.gov (United States)

    Gursanscky, Nial Rau; Jouannet, Virginie; Grünwald, Karin; Sanchez, Pablo; Laaber-Schwarz, Martina; Greb, Thomas

    2016-05-01

    Plants maintain pools of pluripotent stem cells which allow them to constantly produce new tissues and organs. Stem cell homeostasis in shoot and root tips depends on negative regulation by ligand-receptor pairs of the CLE peptide and leucine-rich repeat receptor-like kinase (LRR-RLK) families. However, regulation of the cambium, the stem cell niche required for lateral growth of shoots and roots, is poorly characterized. Here we show that the LRR-RLK MOL1 is necessary for cambium homeostasis in Arabidopsis thaliana. By employing promoter reporter lines, we reveal that MOL1 is active in a domain that is distinct from the domain of the positively acting CLE41/PXY signaling module. In particular, we show that MOL1 acts in an opposing manner to the CLE41/PXY module and that changing the domain or level of MOL1 expression both result in disturbed cambium organization. Underlining discrete roles of MOL1 and PXY, both LRR-RLKs are not able to replace each other when their expression domains are interchanged. Furthermore, MOL1 but not PXY is able to rescue CLV1 deficiency in the shoot apical meristem. By identifying genes mis-expressed in mol1 mutants, we demonstrate that MOL1 represses genes associated with stress-related ethylene and jasmonic acid hormone signaling pathways which have known roles in coordinating lateral growth of the Arabidopsis stem. Our findings provide evidence that common regulatory mechanisms in different plant stem cell niches are adapted to specific niche anatomies and emphasize the importance of a complex spatial organization of intercellular signaling cascades for a strictly bidirectional tissue production. PMID:26991973

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

  10. 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

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

  13. Discontinuous lines on the radial face of wavy-grained xylem as a manifestation of morphogenic waves in the cambium

    Directory of Open Access Journals (Sweden)

    Beata Zagórska-Marek

    2014-02-01

    Full Text Available There appear in the wood of Entandrophragma, beside the basic interlocked grain, local minute undulations of grain the manifestation of which are checkered figures, either slanting or horizontal, on the radial face of boards. In reference to the model the slanting checkered figure is interpreted as the result of sudden appearance in the cambium of a wave of orientational tendency (morphogenetic wave of relatively short wavelengths and stabilized amplitude from the moment of its appearance, moving vertically. This wave induces undulations in the arrangement of cambial initials. The undulation pattern also moves, however, its rate is half that of the morphogenic wave rate. The amplitude of the undulations oscillates between a maximal value and null which means that in successive wood layers there is wavy grain alternating with straight grain. The horizontal checkered figure may be explained by a local shift of the prase by one half of the period of the morphogenic wave of relatively long wavelengths underlying the interlocked grain formation.

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

    Directory of Open Access Journals (Sweden)

    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.

  15. 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

    Directory of Open Access Journals (Sweden)

    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.

  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-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

  18. 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

  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-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

  1. Dicty_cDB: Contig-U15425-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available zed libr... 46 1.8 1 ( EX326935 ) GQ02826.B7_C09 GQ028 - Cambium / phloem scrappi...ng... 46 1.8 1 ( EX317135 ) GQ02811.B7_G13 GQ028 - Cambium / phloem scrapping... 46 1.8 1 ( EX317035 ) GQ028...11.B7_C08 GQ028 - Cambium / phloem scrapping... 46 1.8 1 ( DX511975 ) 762_1_14169231_5489_43582_012 Arachis

  2. 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

  3. Seasonal development of cambial activity in relation to xylem formation in Chinese fir.

    Science.gov (United States)

    Wu, Hongyang; Xu, Huimin; Li, Hanyin; Wei, Dongmei; Lin, Jinxing; Li, Xiaojuan

    2016-05-20

    The vascular cambium is a lateral meristem which can differentiate into secondary phloem and xylem. The secondary growth of woody plants resulting from vascular cambium activity has been a focus of considerable attention, but the quantitative relationships between cambial activity and secondary xylem formation have been little studied. Our analysis of cytological changes in the cambium of Chinese fir (Cunninghamia lanceolata), revealed a significant positive correlation between vascular cambium cell numbers and cambium zone width through the seasonal cycle. Cambium cell numbers and the cambium cell radial diameter were closely related to xylem formation. Immuno-labeling showed that de-esterified homogalacturonan and (1-4)-β-d-galactan epitopes were highly abundant in cell walls of dormant-stage cambium, whereas high methylesterified homogalacturonan was strongly labeled in the active stage. Raman spectroscopy detected significant changes in the chemical composition of cell walls during the active-dormant stage transition. More pectin and less monolignols occurred in radial cell walls than in tangential walls during the dormant stage, but no significant changes were found in other stages, indicating that pectin accumulation facilitates cell wall expansion, with cambium activity transition. Our quantitative analysis of the relationship between cambial activity and xylem formation, as well as the cell wall modification during the active stage provides useful information about cambial characteristics and xylogenesis. PMID:26986869

  4. 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

  5. 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

  6. 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

  7. 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

  8. 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

  9. 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

  10. 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-

  11. 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

  12. 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

  13. 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

  14. 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

  15. Cytokinin-dependent secondary growth determines root biomass in radish (Raphanus sativus L.)

    OpenAIRE

    Jang, Geupil; Lee, Jung-Hun; Rastogi, Khushboo; Park, Suhyoung; Oh, Sang-Hun; Lee, Ji-Young

    2015-01-01

    Highlight Comparative studies using Arabidopsis and radish (Raphanus sativus) found that cytokinin-mediated regulatory programmes in the cambium are important for the radial growth of radish roots and its variations.

  16. 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

  17. 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.

  18. 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

  19. 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.

  20. 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

  1. 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-

  2. 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

  3. 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 )

  4. 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

  5. hca: an Arabidopsis mutant exhibiting unusual cambial activity and altered vascular patterning

    Czech Academy of Sciences Publication Activity Database

    Pineau, C.; Amandine, F.; Ranocha, P.; Jauneau, A.; Turner, S.; Lemonnier, G.; Renou, J.P.; Tarkowski, Petr; Sandberg, G.; Jouanin, L.; Sundberg, B.; Boudet, A.M.; Goffner, D.; Pichon, M.

    2005-01-01

    Roč. 44, č. 2 (2005), s. 271-289. ISSN 0960-7412 Institutional research plan: CEZ:AV0Z50380511 Keywords : Arabidopsis thaliana * cambium * secondary xylem Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 6.969, year: 2005

  6. 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

  7. 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.

  8. 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.

  9. 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

  10. 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...

  11. 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...

  12. 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...

  13. 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 ...

  14. WUSCHEL-related Homeobox genes in Populus tomentosa: diversified expression patterns and a functional similarity in adventitious root formation

    OpenAIRE

    Liu, Bobin; Wang, Lin; Zhang, Jin; Li, Jianbo; Zheng, Huanquan; Chen, Jun; Lu, Mengzhu

    2014-01-01

    Background WUSCHEL (WUS)-related homeobox (WOX) protein family members play important roles in the maintenance and proliferation of the stem cell niche in the shoot apical meristem (SAM), root apical meristem (RAM), and cambium (CAM). Although the roles of some WOXs in meristematic cell regulation have been well studied in annual plants such as Arabidopsis and rice, the expression and function of WOX members in woody plant poplars has not been systematically investigated. Here, we present the...

  15. Transcriptome Characteristics and Six Alternative Expressed Genes Positively Correlated with the Phase Transition of Annual Cambial Activities in Chinese Fir (Cunninghamia lanceolata (Lamb.) Hook)

    OpenAIRE

    Wang, Zhanjun; Chen, Jinhui; Liu, Weidong; Luo, Zhanshou; Wang, Pengkai; Zhang, Yanjuan; Zheng, Renhua; Shi, Jisen

    2013-01-01

    Background The molecular mechanisms that govern cambial activity in angiosperms are well established, but little is known about these molecular mechanisms in gymnosperms. Chinese fir (Cunninghamia lanceolata (Lamb.) Hook), a diploid (2n  = 2x  = 22) gymnosperm, is one of the most important industrial and commercial timber species in China. Here, we performed transcriptome sequencing to identify the repertoire of genes expressed in cambium tissue of Chinese fir. Methodology/Principal Findings ...

  16. 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...

  17. 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...

  18. Cell wall thickening in developing tension wood of artificially bent poplar trees

    OpenAIRE

    Abedini, Raoufeh; Clair, Bruno; Kambiz POURTAHMASI; Laurans, Françoise; Arnould, Olivier

    2015-01-01

    Trees can control their shape and resist gravity thanks to their ability to produce wood under tensile stress. This stress is known to be produced during the maturation of wood fibres but the mechanism of its generation remains unclear. This study focuses on the formation of the secondary wall in tension wood produced in artificially tilted poplar saplings. Thickness of secondary wall layer (SL) and gelatinous layer (GL) were measured from cambium to mature wood in several trees sampled at di...

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

    OpenAIRE

    Keijzer, de, Ander; Broek, van den, W.; Ketelaar, T.; Lammeren, van, R.J.A.

    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 inv...

  20. 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...

  1. 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...

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

    OpenAIRE

    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 bio...

  3. 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.

  4. Cytokinin-dependent secondary growth determines root biomass in radish (Raphanus sativus L.).

    Science.gov (United States)

    Jang, Geupil; Lee, Jung-Hun; Rastogi, Khushboo; Park, Suhyoung; Oh, Sang-Hun; Lee, Ji-Young

    2015-08-01

    The root serves as an essential organ in plant growth by taking up nutrients and water from the soil and supporting the rest of the plant body. Some plant species utilize roots as storage organs. Sweet potatoes (Ipomoea batatas), cassava (Manihot esculenta), and radish (Raphanus sativus), for example, are important root crops. However, how their root growth is regulated remains unknown. In this study, we characterized the relationship between cambium and radial root growth in radish. Through a comparative analysis with Arabidopsis root expression data, we identified putative cambium-enriched transcription factors in radish and analysed their expression in representative inbred lines featuring distinctive radial growth. We found that cell proliferation activities in the cambium positively correlated with radial growth and final yields of radish roots. Expression analysis of candidate transcription factor genes revealed that some genes are differentially expressed between inbred lines and that the difference is due to the distinct cytokinin response. Taken together, we have demonstrated for the first time, to the best of our knowledge, that cytokinin-dependent radial growth plays a key role in the yields of root crops. PMID:25979997

  5. Stem Anatomy of Country Bean

    Directory of Open Access Journals (Sweden)

    M. Touhidul Islam

    2003-01-01

    Full Text Available Anatomical investigation has been made on the stem of country bean (Lablab purpureus (L. Sweet at different stages of growth following the standard paraffin method of microtechnique. The epidermis is single layered with multicellular hairs and glandular trichomes. Beneath the epidermis there are 5-10 layers of cortical cells. The primary vascular tissue appears after the elongation of the first internode of the stem. The vascular bundles are collateral and arranged in a ring. There are two types of vascular bundles, large and small. There are one or more small vascular bundles in between two large bundles. The large vascular bundle contains xylem and phloem but small bundle may or may not contain both xylem and phloem. There are several poles of primary phloem outside the primary xylem. The pericycle is discontinuous. Two adjacent groups of sclerenchyma are connected by one or two layers of sclerenchymatous cells. The cambium initiates in the primary vascular bundle between xylem and phloem at the basal part of the stem of 4 days old plant. Gradually it extends towards the upper part. The cambium is at first confined to the fascicular region. Subsequently it extends into the interfascicular region forming a complete cambial ring. After the formation of the fascicular cambium it gives rise to the secondary xylem adaxially and secondary phloem abaxially. In the mature stem, most of the vessels are multiple, some are paired while the others are solitary. Most of the fibre cells in the phloem region are found in groups. The fibre cells are arranged in such a way that the structure looks like a pyramid. Tannin cells are present in the phloem region of younger and mature stem. The secretory cells devoid of tanniniferous contents have been observed in the secondary phloem region of the mature stem. The phellogen appears in the deeper cortex and produces periderm with lenticel. The periderm consists of 3-5 layers of cork cells abaxially and 2-3 layers

  6. Anatomy of Lignosus Bean (Dipogon lignosus III. Stem

    Directory of Open Access Journals (Sweden)

    S.M. Abdul Bari

    2001-01-01

    Full Text Available Anatomical investigation has been made on the stem of lignosus bean (Dipogon lignosus (L. Verde. at different stages of growth. The epidermis is single layered consisting of small and large cells. The epidermis bears multicellular hair and glandular trichomes. Beneath the epidermis there are 5-6 layers of cortical cells in the stem. The primary vascular tissue appears after the elongation of the first internode of the stem of lignosus bean. The internode between cotyledonary node and first leaf is considered as the first internode of the stem. The vascular bundles are collateral and arranged in a ring. The secretory cells devoid of tanniniferous contents have been observed in the phloem region of the younger stem but not in older ones. The cambium initiates in the primary vascular bundle between xylem and phloem at the basal part of the stem of 7 days old plant. The cambium is at first confined to the fascicular region. Subsequently it extends into the interfascicular region forming a complete cambial ring. After the formation of fascicular cambium it gives rise to secondary xylem adaxially and secondary phloem abaxially. Some vessel members are paired while the others are solitary. Most of the paired vessels are radially arranged. The paired vessel members are more in number in the mature stem compared to that of the younger stem. The parenchyma covers the major area of the secondary xylem. The sclerenchymatous band abaxial to all large and small vascular bundles is discontinuous. The pith resembles a typical dicotyledonous stem. The phellogen appears in the deeper cortex and gives rise to 4-5 layers of cork cells abaxially and 3-4 layers of phelloderm adaxially

  7. The Contribution of Carbon and Water in Modulating Wood Formation in Black Spruce Saplings.

    Science.gov (United States)

    Deslauriers, Annie; Huang, Jian-Guo; Balducci, Lorena; Beaulieu, Marilène; Rossi, Sergio

    2016-04-01

    Nonstructural carbohydrates (NSCs) play a crucial role in xylem formation and represent, with water, the main constraint to plant growth. We assessed the relationships between xylogenesis and NSCs in order to (1) verify the variance explained by NSCs and (2) determine the influence of intrinsic (tissue supplying carbon) and extrinsic (water availability and temperature) factors. During 2 years, wood formation was monitored in saplings of black spruce (Picea mariana) subjected to a dry period of about 1 month in June and exposed to different temperature treatments in a greenhouse. In parallel, NSC concentrations were determined by extracting the sugar compounds from two tissues (cambium and inner xylem), both potentially supplying carbon for wood formation. A mixed-effect model was used to assess and quantify the potential relationships. Total xylem cells, illustrating meristematic activity, were modeled as a function of water, sucrose, and d-pinitol (conditional r(2) of 0.79). Water availability was ranked as the most important factor explaining total xylem cell production, while the contribution of carbon was lower. Cambium stopped dividing under water deficit, probably to limit the number of cells remaining in differentiation without an adequate amount of water. By contrast, carbon factors were ranked as most important in explaining the variation in living cells (conditional r(2) of 0.49), highlighting the functional needs during xylem development, followed by the tissue supplying the NSCs (cambium) and water availability. This study precisely demonstrates the role of carbon and water in structural growth expressed as meristematic activity and tissue formation. PMID:26850274

  8. Dicty_cDB: Contig-U00877-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available y Aquilegia formo... 42 0.009 2 ( FE861057 ) CAFY959.rev CAFY Pichia stipitis oxygen limited... x... 38 0.009 4 ( FE861058 ) CAFY959.fwd CAFY Pichia stipitis oxygen limited x... 38 0.010 4 ( F...E860161 ) CAFY487.rev CAFY Pichia stipitis oxygen limited x... 38 0.014 4 ( EY347959 ) CAWZ16237.fwd CAWZ He...lobdella robusta Primary Lat... 42 0.015 3 ( FE860162 ) CAFY487.fwd CAFY Pichia stipitis oxygen limited...8 - Cambium / phloem scrappin... 34 1.5 2 ( FE860055 ) CAFY431.rev CAFY Pichia stipitis oxygen limited x...

  9. 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...

  10. 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.

  11. Pre-Cretaceous Agaricomycetes yet to be discovered: Reinvestigation of a putative Triassic bracket fungus from southern Germany

    Directory of Open Access Journals (Sweden)

    A. P. Kiecksee

    2012-08-01

    Full Text Available Agaricomycetes are major components of extant terrestrial ecosystems; however, their fruiting bodies are exceedingly rare as fossils. Reinvestigation of a peculiar fossil from Late Triassic sediments of southern Germany interpreted as a bracket fungus revealed that this fossil in fact represents a wood abnormality, resulting from injury to the cambium and subsequent callus growth in a Baieroxylon -like ginkgoalean wood. As a result, the fossil record of the Agaricomycetes does not yet pre-date the Early Cretaceous, suggesting a late diversification of basidiomycetes possessing large fruiting bodies. doi:10.1002/mmng.201200006

  12. Origin of ash in the Central Indian Ocean Basin and its implication for the volume estimate of the 74,000 year BP Youngest Toba eruption

    Digital Repository Service at National Institute of Oceanography (India)

    Pattan, J.N.; Pearce, N.J.G.; Banakar, V.K.; Parthiban, G.

    COMMUNICATIONS CURRENT SCIENCE, VOL. 83, NO. 7, 10 OCTOBER 2002 889 at the b ase of the vascular bundles as reported ea r lier 7 and this formed a cambium - like layer which later spread rapidly. Microscopy observations of development of ca l- lus... in the young shoot buds revealed that merist e moids were formed from xylem parenchyma as indi cated. The present communication shows effectiveness of using sprouted buds on the nodal explants of 8 ? 10 - year - old, mature bamboo for induction of somatic...

  13. 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.

  14. Determining the Composition of Lignins in Different Tissues of Silver Birch

    Science.gov (United States)

    Fagerstedt, Kurt V.; Saranpää, Pekka; Tapanila, Tarja; Immanen, Juha; Alonso Serra, Juan Antonio; Nieminen, Kaisa

    2015-01-01

    Quantitative and qualitative lignin analyses were carried out on material from the trunks of silver birch (Betula pendula Roth) trees. Two types of material were analyzed. First, whole birch trunk pieces were cryosectioned into cork cambium, non-conductive phloem, the cambial zone (conductive phloem, cambium and differentiating xylem), lignified xylem and the previous year’s xylem; material that would show differences in lignin amount and quality. Second, clonal material from one natural birch population was analyzed to show variations between individuals and between the lignin analysis methods. The different tissues showed marked differences in lignin amount and the syringyl:guaiacyl (S/G) ratio. In the non-conductive phloem tissue containing sclereids, the S/G ratio was very low, and typical for phloem fibers and in the newly-formed xylem, as well as in the previous year’s xylem, the ratio lay between five and seven, typical for broadleaf tree xylem. Clonal material consisting of 88 stems was used to calculate the S/G ratios from the thioacidolysis and CuO methods, which correlated positively with an R2 value of 0.43. Comparisons of the methods indicate clearly that the CuO method is a good alternative to study the monomeric composition and S/G ratio of wood lignins. PMID:27135322

  15. 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

  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. Characterization of PTM5 in aspen trees: a MADS-box gene expressed during woody vascular development.

    Science.gov (United States)

    Cseke, Leland J; Zheng, Jun; Podila, Gopi K

    2003-10-30

    The vascular component of trees possesses some of the most specialized processes active in the formation of roots, stems, and branches, and its wood component continues to be of primary importance to our daily lives. The molecular mechanisms of wood development, however, remain poorly understood with few well-characterized regulatory genes. We have identified a vascular tissue-specific MADS-box gene, Populus tremuloides MADS-box 5 (PTM5) that is expressed in differentiating primary and secondary xylem and phloem. Phylogenetic analysis has shown that PTM5 is a member of the SOC1/TM3 class of MADS-box genes. Temporal expression analysis of PTM5 in staged vascular cambium and other tissues indicated that PTM5 expression is seasonal and is limited to spring wood formation and rapidly expanding floral catkins. Spatial expression analysis using in situ hybridization revealed that PTM5 expression is localized within a few layers of differentiating vascular cambium and xylem tissues as well as the vascular bundles of expanding catkins. Since many MADS-box genes are known to act as transcription factors, these results suggest that the coordinated expression of PTM5 with other vascular developmental genes may be a hallmark of the complex events that lead to the formation of the woody plant body. PMID:14585498

  18. 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.

  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. Application of synchrotron radiation X-ray fluorescence analysis to decoding the history of environmental pollutions using tree bark and tree trunk bark pockets

    International Nuclear Information System (INIS)

    Distributions of trace elements in tree bark and tree trunk bark pockets were successfully determined by Synchrotron Radiation induced X-ray fluorescence (SR-XRF) analysis. The sample include outer and inner tree bark, tree trunk bark pockets, cambium, xylem. Two dimensional X-ray fluorescence analysis of Ca, K, Mn, Sr, Zn, Fe, Cu and Pb in these samples were made with a combination of monochromatic X-ray (14-16.5 keV) of 150 - 500 μm or ca.6 μm size and an excitation source and Si(Li)-solid state detector. From the results of the XRF imaging results, it was found that the intensity of the elements, such as Pb, Fe and Cu, in outer bark and bark pockets samples were higher than those in cambium and xylem. Moreover, trace element levels were quantitatively analyzed by inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled plasma atomic emission spectrometry (ICP-AES). The results were consistent with the element distribution measured by two dimensional X-ray fluorescence analysis. This study has demonstrated the advantages of the SR-XRF technique in environmental pollution analysis of minute biological tissue. The XANES analysis disclosed that Pb deposited in the bark existed as Pb2+ state. (author)

  1. 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

  2. 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

  3. 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

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

    Directory of Open Access Journals (Sweden)

    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.

  5. 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

  6. Laticifer systems in Mandevilla illustris and M. velutina apocynaceae

    Directory of Open Access Journals (Sweden)

    Beatriz Appezzato-Da-Gloria

    2014-02-01

    Full Text Available Two Apocynaceae species from savanna (Cerrado area of Sao Paulo State, Brazil were studied. In both Mandevilla species examined, the laticifer systems are of non-articulated branched type, characteristic of the family. In vegetative organs reported was the occurrence of a primary laticifer system of which the cells were differentiated in the embryo. However, additional laticifer cells were always produced during the growth of the shoot apex. A secondary laticiferous system produced by the cells of vascular cambium was identified in the tuberous root and in the stem. A proposed discussion on this apparently unique record in Apocynaceae was arisen to evaluate the main distinction between articulated and non-articulated laticifers.

  7. PHARMACOGNOSTIC EVALUATION OF CISSUS QUADRANGULARIS L. STEM

    Directory of Open Access Journals (Sweden)

    R. Anitha* and P. Suji

    2012-07-01

    Full Text Available Cissus quadrangularis L. (Vitaceae is a common perennial climber also called Asthisamhara meaning bone setter is prescribed both in Ayurveda as well as Unani systems for its medicinal use. Pharmacognostic evaluation of Cissus quadrangularis stem revealed a stomatal index of 151 with Stephanocytic stomata in the epidermal peeling. The anatomical section of the stem showed deposits of characteristic acicular or needle shaped calcium oxalate crystals, raphides and intrafasicular cambium. The histochemical studies showed the presence of alkaloids, tannins, phenols and suberin. The phytochemical analysis of aqueous, petroleum ether and dichloromethane extracts were positive for alkaloids, phenol, steroids, flavanoids in all the extracts. The presence of sclerides, fiber sclerides epidermal cells, phloem with companion cells, ray fibers with pits, raphides, acicular and sand crystals of calcium oxalate were evident in powder analysis. Under 365nm UV green fluorescent emission was observed in acetic acid and methanol treated stem powder.

  8. 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.

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

    Directory of Open Access Journals (Sweden)

    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.

  10. 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

  11. Spatial variations in xylem sap flux density in the trunk of orchard-grown, mature mango trees under changing soil water conditions.

    Science.gov (United States)

    Lu, Ping; Müller, Warren J.; Chacko, Elias K.

    2000-05-01

    Circumferential and radial variations in xylem sap flux density in trunks of 13-year-old mango (Mangifera indica L.) trees were investigated with Granier sap flow sensor probes under limiting and non-limiting soil water conditions. Under non-limiting soil water conditions, circumferential variation was substantial, but there was no apparent relationship between sap flux density and aspect (i.e., the radial position of the sensor probes on the trunk relative to the compass). Hourly sap flux densities over 24 hours at different aspects were highly pair-wise correlated. The relationships between different aspects were constant during well-watered periods but highly variable under changing soil water conditions. Sap flux density showed marked radial variation within the trunk and a substantial flux was observed at the center of the trunk. For each selected aspect on each tree, changes in sap flux densities over time at different depths were closely correlated, so flux at a particular depth could be extrapolated as a multiple of flux from 0 to 2 cm beneath the cambium. However, depth profiles of sap flux density differed between trees and even between aspects within a tree, and also varied in an unpredictable manner as soil water conditions changed. Nevertheless, over a period of non-limiting soil water conditions, depth profiles remained relatively constant. Based on the depth profiles obtained during these periods, a method is described for calculating total sap flow in a mango tree from sap flux density at 0-2 cm beneath the cambium. Total daily sap flows obtained were consistent with water use estimated from soil water balance. PMID:12651518

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

    Directory of Open Access Journals (Sweden)

    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.

  13. [Cloning and expression analysis of differentially expressed genes in Chinese fir stems treated by different concentrations of exogenous IAA].

    Science.gov (United States)

    Yang, Li-Wei; Shi, Ji-Sen

    2012-04-01

    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, electron 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 ClHIRA, ClPGY1, and ClARF4, which were specifically expressed in the adaxial zone of stem, were positively response to the activities of cell division and tracheid differentiation stimulated by exogenous IAA treatment. However, ClSMP1, ClTCTP1, and ClTRN2, which were mainly expressed in the abaxial zones of stems, showed negative correlation with the treated levels of exogenous IAA and activities of vascular cambium secondary development at the transcriptional level. This result showed that the differential response of developmental regulatory genes located in different vascular tissues to the level changes of edogenous IAA in stems is likely to be an important molecular mechanism of auxin regulating wood formation. PMID:22522165

  14. 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.

  15. 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

  16. 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

  17. 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

  18. 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

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    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

  19. Assessing variation in the radial profile of sap flux density in Pinus species and its effect on daily water use.

    Science.gov (United States)

    Ford, Chelcy R; McGuire, Mary Anne; Mitchell, Robert J; Teskey, Robert O

    2004-03-01

    We monitored sap flux density (v) diurnally in nine mature southeastern pine (Pinus spp.) trees with a thermal dissipation probe that spanned the sapwood radius. We found the expected pattern of high v near the cambium and decreasing v with depth toward the center of the tree; however, the pattern was not constant within a day or between trees. Radial profiles of trees were steeper earlier in the day and became less steep later in the day. As a result, time-dependent changes in the shape of the radial profile of v were sometimes correlated with daily changes in evaporative demand. As the radial profile became less steep, the inner xylem contributed relatively more to total tree sap flow than it did earlier in the day. We present a 3-parameter Gaussian function that can be used to describe the radial distribution of v in trees. Parameters in the function represent depth in the xylem from the cambium, maximum v, depth in the xylem where maximum v occurs, and the rate of radial change in v with radial depth (beta). Values of beta varied significantly between trees and with time, and were sometimes correlated with air vapor pressure deficit (D). We hypothesize that this occurred during periods of high transpiration when the water potential gradient became great enough to move water in the inner sapwood despite its probable high hydraulic resistance. We examined discrepancies among estimates of daily water use based on single-point, two-point and multi-point (i.e., every 20 mm in the sapwood) measurements. When radial distribution of v was not considered, a single-point measurement resulted in errors as large as 154% in the estimate of daily water use relative to the estimate obtained from a multi-point measurement. Measuring v at two close sample points (10 and 30 mm) did not improve the estimate; however, estimates derived from v measured at two distant sample points (10 and 70 mm) significantly improved the estimate of daily water use, although errors were as great

  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. 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.

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

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    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.

  3. 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

  4. Atmospheric inorganic contaminants and their distribution inside stem tissues of Fraxinus excelsior L.

    Science.gov (United States)

    Catinon, Mickaël; Ayrault, Sophie; Daudin, Laurent; Sevin, Laure; Asta, Juliette; Tissut, Michel; Ravanel, Patrick

    The elements present on and in 4-year-old stem of Fraxinus excelsior L. were analysed and estimated quantitatively. The superficial deposit on the bark is a complex mixture mainly composed of organic matter, mineral nutrients, clay and anthropogenic elements coming from the atmosphere. The elements present inside the stem tissues represent a total amount which is generally much higher than the superficial deposit. The distribution of elements such as Ca, K, Fe, Mn, Zn, Cu and Pb was shown by PIXE analysis in stem transversal cuttings, showing the presence of solid multimineral particles only inside the suber. A new strategy of mechanical tissues isolation on fresh stems was carried out in order to obtain high amounts of each tissue allowing an accurate ICP-MS analysis and estimation of >20 elements in each tissue. A concentration decreasing gradient was measured for each element from suber to wood and pith in good agreement with the PIXE results. In the dividing cells of the vascular cambium, elements concentrations were very high since the cell wall weight was minimal. When expressing the amounts of each element per bark area unit, the whole bark content was only twice the wood+pith content for the studied elements. All these results suggest that, in Fraxinus stems, the root uptake and xylem transport of elements are generally not intense enough to hide the atmospheric flux of mineral contaminants.

  5. Atmospheric inorganic contaminants and their distribution inside stem tissues of Fraxinus excelsior L

    International Nuclear Information System (INIS)

    The elements present on and in 4-year-old stem of Fraxinus excelsior L. were analysed and estimated quantitatively. The superficial deposit on the bark is a complex mixture mainly composed of organic matter, mineral nutrients, clay and anthropogenic elements coming from the atmosphere. The elements present inside the stem tissues represent a total amount which is generally much higher than the superficial deposit. The distribution of elements such as Ca, K, Fe, Mn, Zn, Cu and Pb was shown by PIXE analysis in stem transversal cuttings, showing the presence of solid multi mineral particles only inside the suber. A new strategy of mechanical tissues isolation on fresh stems was carried out in order to obtain high amounts of each tissue allowing an accurate ICP-MS analysis and estimation of ≥ 20 elements in each tissue. A concentration decreasing gradient was measured for each element from suber to wood and pith in good agreement with the PIXE results. In the dividing cells of the vascular cambium, elements concentrations were very high since the cell wall weight was minimal. When expressing the amounts of each element per bark area unit, the whole bark content was only twice the wood + pith content for the studied elements. All these results suggest that, in Fraxinus stems, the root uptake and xylem transport of elements are generally not intense enough to hide the atmospheric flux of mineral contaminants. (authors)

  6. Atmospheric inorganic contaminants and their distribution inside stem tissues of Fraxinus excelsior L

    Energy Technology Data Exchange (ETDEWEB)

    Catinon, M.; Asta, J.; Tissut, M.; Ravanel, P. [Univ Grenoble 1, LECA, Equipe Perturbat Environm and Xenobiot, UMR 5553, Grenoble (France); Ayrault, S. [CEA Saclay, DSM, Lab Sci Climat and Environm, CEA-CNRS-UVSQ, F-91191 Gif Sur Yvette (France); Daudin, L. [CEA Saclay, DSM, Lab Pierre Sue, CEA-CNRS, F-91191 Gif Sur Yvette (France); Sevin, L. [CNRS, Ctr Rech Petrog and Geochim, SARM, F-54501 Vandoeuvre Les Nancy (France)

    2008-07-01

    The elements present on and in 4-year-old stem of Fraxinus excelsior L. were analysed and estimated quantitatively. The superficial deposit on the bark is a complex mixture mainly composed of organic matter, mineral nutrients, clay and anthropogenic elements coming from the atmosphere. The elements present inside the stem tissues represent a total amount which is generally much higher than the superficial deposit. The distribution of elements such as Ca, K, Fe, Mn, Zn, Cu and Pb was shown by PIXE analysis in stem transversal cuttings, showing the presence of solid multi mineral particles only inside the suber. A new strategy of mechanical tissues isolation on fresh stems was carried out in order to obtain high amounts of each tissue allowing an accurate ICP-MS analysis and estimation of {>=} 20 elements in each tissue. A concentration decreasing gradient was measured for each element from suber to wood and pith in good agreement with the PIXE results. In the dividing cells of the vascular cambium, elements concentrations were very high since the cell wall weight was minimal. When expressing the amounts of each element per bark area unit, the whole bark content was only twice the wood + pith content for the studied elements. All these results suggest that, in Fraxinus stems, the root uptake and xylem transport of elements are generally not intense enough to hide the atmospheric flux of mineral contaminants. (authors)

  7. INTELLIGENCE, COGNITION AND LANGUAGE OF GREEN PLANTS

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    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.

  8. 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.

  9. Symplesiomorphies in the WUSCHEL clade suggest that the last common ancestor of seed plants contained at least four independent stem cell niches.

    Science.gov (United States)

    Nardmann, Judith; Werr, Wolfgang

    2013-09-01

    Evolutionary studies addressing plant architecture have uncovered several significant dichotomies between lower and higher land plant radiations, which are based on differences in meristem histology and function. Here, we assess the establishment of different stem cell niches during land plant evolution based on genes of the stem cell-promoting WUSCHEL (WUS) clade of the WOX (WUSCHEL-related homeobox) gene family. WOX gene orthology was addressed by phylogenetic analyses of full-length WOX protein sequences and cellular expression pattern studies indicate process homology. Gene amplifications in the WUS clade were present in the last common ancestor (LCA) of extant gymnosperms and angiosperms. Whereas the evolution of complex multicellular shoot and root meristems relates to members in the WUS/WOX5 sub-branch, the evolution of marginal and plate meristems or the vascular cambium is associated with gene duplications that gave rise to WOX3 and WOX4, respectively. A fourth WUS clade member, WOX2, was apparently recruited for apical cell fate specification during early embryogenesis. The evolution and functional interplay of WOX3 and WOX4 possibly promoted a novel mode of leaf development, and evolutionary adaptations in their activities have contributed to the great diversity in shape and architecture of leaves in seed plants. PMID:23721178

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

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    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.

  11. 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.

  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. 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.

  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. 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

  16. 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.

  17. Characterization of Feeding Injuries Caused by Ceresa nigripectus Remes Lenicov (Hemiptera: Membracidae) on Alfalfa Stems.

    Science.gov (United States)

    Grosso, T P; Mercado, M I; Ponessa, G I; Conci, L R; Virla, E G

    2016-04-01

    Piercing-sucking insects cause mechanical and physiological injury to plants. Ceresa nigripectus Remes Lenicov is a pest of alfalfa in subtropical regions of South America and a carrier of the ArAWB phytoplasma. The aim of this study was to determine the feeding habits of this treehopper and to describe the effects of the feeding injuries on stem vascular tissues in alfalfa. Adults and nymphs of C. nigripectus inserted their stylets repeatedly girdling the stem. One week after feeding, alfalfa stems exhibited numerous feeding canals with salivary deposits, most of which reached the phloem. Two weeks after feeding, cortex and phloem cells next to the salivary sheath collapsed, mature tracheal elements became sparse and appeared with an increased cross-section area, and phenolic compounds increased in cells and cell walls compared to undamaged plants. Three weeks after feeding, an annular callus, formed by abnormal cell division and hypertrophy of preexisting cortex and vascular cambium cells, appeared immediately above the stem girdle. Parenchyma cells from the outer layers of the callus differentiated to form secondary anomalous amphicribal bundles in the wound. The aerial parts above the stem girdle eventually withered and died. PMID:26830435

  18. Early steps of adventitious rooting: morphology, hormonal profiling and carbohydrate turnover in carnation stem cuttings.

    Science.gov (United States)

    Agulló-Antón, María Ángeles; Ferrández-Ayela, Almudena; Fernández-García, Nieves; Nicolás, Carlos; Albacete, Alfonso; Pérez-Alfocea, Francisco; Sánchez-Bravo, José; Pérez-Pérez, José Manuel; Acosta, Manuel

    2014-03-01

    The rooting of stem cuttings is a common vegetative propagation practice in many ornamental species. A detailed analysis of the morphological changes occurring in the basal region of cultivated carnation cuttings during the early stages of adventitious rooting was carried out and the physiological modifications induced by exogenous auxin application were studied. To this end, the endogenous concentrations of five major classes of plant hormones [auxin, cytokinin (CK), abscisic acid, salicylic acid (SA) and jasmonic acid] and the ethylene precursor 1-aminocyclopropane-1-carboxylic acid were analyzed at the base of stem cuttings and at different stages of adventitious root formation. We found that the stimulus triggering the initiation of adventitious root formation occurred during the first hours after their excision from the donor plant, due to the breakdown of the vascular continuum that induces auxin accumulation near the wounding. Although this stimulus was independent of exogenously applied auxin, it was observed that the auxin treatment accelerated cell division in the cambium and increased the sucrolytic activities at the base of the stem, both of which contributed to the establishment of the new root primordia at the stem base. Further, several genes involved in auxin transport were upregulated in the stem base either with or without auxin application, while endogenous CK and SA concentrations were specially affected by exogenous auxin application. Taken together our results indicate significant crosstalk between auxin levels, stress hormone homeostasis and sugar availability in the base of the stem cuttings in carnation during the initial steps of adventitious rooting. PMID:24117983

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

    Directory of Open Access Journals (Sweden)

    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

  20. 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

  1. 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.

  2. Structure and vascular tissue expression of duplicated TERMINAL EAR1-like paralogues in poplar.

    Science.gov (United States)

    Charon, Céline; Vivancos, Julien; Mazubert, Christelle; Paquet, Nicolas; Pilate, Gilles; Dron, Michel

    2010-02-01

    TERMINAL EAR1-like (TEL) genes encode putative RNA-binding proteins only found in land plants. Previous studies suggested that they may regulate tissue and organ initiation in Poaceae. Two TEL genes were identified in both Populus trichocarpa and the hybrid aspen Populus tremula x P. alba, named, respectively, PoptrTEL1-2 and PtaTEL1-2. The analysis of the organisation around the PoptrTEL genes in the P. trichocarpa genome and the estimation of the synonymous substitution rate for PtaTEL1-2 genes indicate that the paralogous link between these two Populus TEL genes probably results from the Salicoid large-scale gene-duplication event. Phylogenetic analyses confirmed their orthology link with the other TEL genes. The expression pattern of both PtaTEL genes appeared to be restricted to the mother cells of the plant body: leaf founder cells, leaf primordia, axillary buds and root differentiating tissues, as well as to mother cells of vascular tissues. Most interestingly, PtaTEL1-2 transcripts were found in differentiating cells of secondary xylem and phloem, but probably not in the cambium itself. Taken together, these results indicate specific expression of the TEL genes in differentiating cells controlling tissue and organ development in Populus (and other Angiosperm species). PMID:19943172

  3. 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.

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

    Directory of Open Access Journals (Sweden)

    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.

  5. 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.

  6. 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.

  7. 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. PMID:26456092

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

    Directory of Open Access Journals (Sweden)

    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.

  9. A brief history of the TDIF-PXY signalling module: balancing meristem identity and differentiation during vascular development.

    Science.gov (United States)

    Etchells, J Peter; Smit, Margot E; Gaudinier, Allison; Williams, Clara J; Brady, Siobhan M

    2016-01-01

    474 I. 474 II. 475 III. 475 IV. 477 V. 477 VI. 477 VII. 479 VIII. 481 482 References 482 SUMMARY: A significant proportion of terrestrial biomass is constituted of xylem cells that make up woody plant tissue. Xylem is required for water transport, and is present in the vascular tissue with a second conductive tissue, phloem, required primarily for nutrient transport. Both xylem and phloem are derived from cell divisions in vascular meristems known as the cambium and procambium. One major component that influences several aspects of plant vascular development, including cell division in the vascular meristem, vascular organization and differentiation of vascular cell types, is a signalling module characterized by a peptide ligand called TRACHEARY ELEMENT DIFFERENTIATION INHIBITORY FACTOR (TDIF) and its cognate receptor, PHLOEM INTERCALATED WITH XYLEM (PXY). In this review, we explore the literature that describes signalling components, phytohormones and transcription factors that interact with these two central factors, to control the varying outputs required in vascular tissues for normal organization and elaboration of plant vascular tissue. PMID:26414535

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

    Directory of Open Access Journals (Sweden)

    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.

  11. Using pheromones to protect heat-injured lodgepole pine from mountain pine beetle infestation. Forest Service research note

    Energy Technology Data Exchange (ETDEWEB)

    Amman, G.D.; Ryan, K.C.

    1994-01-01

    The bark beetle antiaggregative pheromones, verbenone and ipsdienol, were tested in protecting heat-injured lodgepole pine (Pinus contorta Dougl. ex Loud.) from mountain pine beetle (Dendroctonus ponderosae) infestation in the Sawtooth National Recreation Area in central Idaho. Peat moss was placed around 70 percent of the basal circumference of lodgepole pines. When the peat moss was ignited, it simulated the smoldering of natural duff, generating temperatures that killed the cambium. The four treatments tested were uninjured tree, heat-injured tree, heat-injured tree treated with verbenone, and heat-injured tree treated with verbenone plus ipsdienol. Treatments were replicated 20 times. Mountain pine beetles were attracted into treatment blocks by placing mountain pine beetle tree baits on metal posts 3 to 5 meters from treated trees. Fisher's Extract Test showed that treatment and beetle infestation were not independent (P < 0.015). Check treatments contained more unattacked and mass-attacked trees, whereas pheromone treatments contained more unsuccessfully attacked trees.

  12. 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

  13. 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

  14. 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.

  15. Verifying the geographic origin of mahogany (Swietenia macrophylla King) with DNA-fingerprints.

    Science.gov (United States)

    Degen, B; Ward, S E; Lemes, M R; Navarro, C; Cavers, S; Sebbenn, A M

    2013-01-01

    Illegal logging is one of the main causes of ongoing worldwide deforestation and needs to be eradicated. The trade in illegal timber and wood products creates market disadvantages for products from sustainable forestry. Although various measures have been established to counter illegal logging and the subsequent trade, there is a lack of practical mechanisms for identifying the origin of timber and wood products. In this study, six nuclear microsatellites were used to generate DNA fingerprints for a genetic reference database characterising the populations of origin of a large set of mahogany (Swietenia macrophylla King, Meliaceae) samples. For the database, leaves and/or cambium from 1971 mahogany trees sampled in 31 stands from Mexico to Bolivia were genotyped. A total of 145 different alleles were found, showing strong genetic differentiation (δ(Gregorious)=0.52, F(ST)=0.18, G(ST(Hedrick))=0.65) and clear correlation between genetic and spatial distances among stands (r=0.82, P<0.05). We used the genetic reference database and Bayesian assignment testing to determine the geographic origins of two sets of mahogany wood samples, based on their multilocus genotypes. In both cases the wood samples were assigned to the correct country of origin. We discuss the overall applicability of this methodology to tropical timber trading. PMID:22770645

  16. 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.

  17. 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)

  18. 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.

  19. 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

  20. 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

  1. 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.

  2. Using laser micro-dissection and qRT-PCR to analyze cell type-specific gene expression in Norway spruce phloem

    Directory of Open Access Journals (Sweden)

    Nina E. Nagy

    2014-04-01

    Full Text Available The tangentially oriented polyphenolic parenchyma (PP and radially organized ray parenchyma in the phloem are central in the defense of conifer stems against insects and pathogens. Laser micro-dissection enables examination of cell-specific defense responses. To examine induced defense responses in Norway spruce stems inoculated with the necrotrophic blue-stain fungus Ceratocystis polonica, RNA extracted from laser micro-dissected phloem parenchyma and vascular cambium was analyzed using real-time RT-PCR (qRT-PCR to profile transcript levels of selected resistance marker genes. The monitored transcripts included three pathogenesis-related proteins (class IV chitinase (CHI4, defensin (SPI1, peroxidase (PX3, two terpene synthesis related proteins (DXPS and LAS, one ethylene biosynthesis related protein (ACS, and a phenylalanine ammonia-lyase (PAL. Three days following inoculation, four genes (CHI4, PAL, PX3, SPI1 were differentially induced in individual cell and tissue types, both close to the inoculation site (5 mm above and, to a lesser degree, further away (10 mm above. These resistance marker genes were all highly induced in ray parenchyma, supporting the important role of the rays in spruce defense propagation. CHI4 and PAL were also induced in PP cells and in conducting secondary phloem tissues. Our data suggests that different cell types in the secondary phloem of Norway spruce have overlapping but not fully redundant roles in active host defense. Furthermore, the study demonstrates the usefulness of laser micro-dissection coupled with qRT-PCR to characterize gene expression in different cell types of conifer bark.

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

    Science.gov (United States)

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

    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 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. PMID:25880223

  4. 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.

  5. 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.

  6. 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

  7. Tissue-Specific Distribution of Ginsenosides in Different Aged Ginseng and Antioxidant Activity of Ginseng Leaf

    Directory of Open Access Journals (Sweden)

    Ying-Chun Zhang

    2014-10-01

    Full Text Available The aim of this study was to systematically evaluate the effect of the cultivation year on the quality of different ginseng tissues. Qualitative and quantitative analyses of ginsenosides were conducted using a UPLC-UV-MS method. Eight main ginsenosides in three tissues (leaf, rhizome and main root and four parts (periderm, phloem, cambium and xylem of ginseng aged from 1 to 13 years were determined using a UPLC-PDA method. Additionally, the antioxidant capacities of ginseng leaves were analyzed by the DPPH, ABTS and HRSA methods. It was found that the contents of ginsenosides increased with cultivation years, causing a sequential content change of ginsenosides in an organ-specific manner: leaf > rhizome > main root. The ratio between protopanaxatriol (PPT, Rg1, Re and RF and protopanaxadiol (PPD, Rb1, Rb2, RC and Rd in the main root remained stable (about 1.0, while it increased in leaf from 1.37 to 3.14 and decreased in the rhizome from 0.99 to 0.72. The amount of ginsenosides accumulated in the periderm was 45.48 mg/g, which was more than twice as high compared with the other three parts. Furthermore, the antioxidant activities of ginseng leaves were measured as Trolox equivalents, showing that antioxidant activity increased along with time of cultivation. The results show that the best harvest time for shizhu ginseng is the fifth year of cultivation, and the root and rhizome could be used together within seven planting years for their similar PPT/PPD level. Besides, the quality of the ginseng products would be enhanced with the periderm. The ginseng leaf is rich in ginsenosides and has potential application for its antioxidant capacity.

  8. 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

  9. 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.

  10. 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

  11. Study of translocation and distribution of 14C-labelled assimilates in young apple trees

    International Nuclear Information System (INIS)

    Translocation and distribution of 14C-labelled assimilates within one shoot and between two adjacent shoots were studied in one-year old apple trees of the variety Golden Delicious grafted on stock MM-106. The shoots were 45-50 cm long, with 24-27 fully shaped leaves and an actively growing top. Top dressing of the upper developed leaf with 14CO2 results in translocation of 14C-labelled assimilates to the growing tip, but on top dressing of the lower leaf they translocate to the root system. The basic portion of the 14C-labelled assimilates from the middle leaf moves downwards while the smaller portion-upwards. The assimilates move down the stem in a spiral which in all test trees is left (looking from the cambium side). On 14CO2 dressing of the entire shoot, the 14C-labelled assimilates do not translocate to the adjacent shoot but run down to the root system. This character of assimilates distribution was preserved also in the cases when one of the shoots had previously been treated with gibberellin (0.015 per cent), alar (0.4 per cent), bent downwards or pinched off. The absence of translocation of 14C-labelled assimilates to the adjacent shoot in the specified treatments, which change the uptaking activity of the growing centers, is explained with the ability of this shoot to be selfsufficient with respect to assimlates supply. Translocation of 14C-labelled assimilates to the shoot receiving no top dressing was induced by its defoliation (leaving the growing tip and a few young leaves). (M.Ts.)

  12. 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

  13. 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

  14. Enhanced resistance to soybean cyst nematode Heterodera glycines in transgenic soybean by silencing putative CLE receptors.

    Science.gov (United States)

    Guo, Xiaoli; Chronis, Demosthenis; De La Torre, Carola M; Smeda, John; Wang, Xiaohong; Mitchum, Melissa G

    2015-08-01

    CLE peptides are small extracellular proteins important in regulating plant meristematic activity through the CLE-receptor kinase-WOX signalling module. Stem cell pools in the SAM (shoot apical meristem), RAM (root apical meristem) and vascular cambium are controlled by CLE signalling pathways. Interestingly, plant-parasitic cyst nematodes secrete CLE-like effector proteins, which act as ligand mimics of plant CLE peptides and are required for successful parasitism. Recently, we demonstrated that Arabidopsis CLE receptors CLAVATA1 (CLV1), the CLAVATA2 (CLV2)/CORYNE (CRN) heterodimer receptor complex and RECEPTOR-LIKE PROTEIN KINASE 2 (RPK2), which transmit the CLV3 signal in the SAM, are required for perception of beet cyst nematode Heterodera schachtii CLEs. Reduction in nematode infection was observed in clv1, clv2, crn, rpk2 and combined double and triple mutants. In an effort to develop nematode resistance in an agriculturally important crop, orthologues of Arabidopsis receptors including CLV1, CLV2, CRN and RPK2 were identified from soybean, a host for the soybean cyst nematode Heterodera glycines. For each of the receptors, there are at least two paralogues in the soybean genome. Localization studies showed that most receptors are expressed in the root, but vary in their level of expression and spatial expression patterns. Expression in nematode-induced feeding cells was also confirmed. In vitro direct binding of the soybean receptors with the HgCLE peptide was analysed. Knock-down of the receptors in soybean hairy roots showed enhanced resistance to SCN. Our findings suggest that targeted disruption of nematode CLE signalling may be a potential means to engineer nematode resistance in crop plants. PMID:25581705

  15. 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.

  16. 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

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

    Directory of Open Access Journals (Sweden)

    Liliana Millán-Orozco

    2011-03-01

    Full Text Available 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 1mg/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 1mg/l IBA, although there were more roots per explant in the latter. Rev. Biol. Trop. 59 (1: 447-453. Epub 2011 March 01.

  18. 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.

  19. 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

  20. 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.

  1. 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

  2. Incorporation of the label from 14C-glucose into cell-wall components during the maturation of cryptomeria tracheids

    International Nuclear Information System (INIS)

    The differentiating tracheids of cryptomeria fed with 14C-glucose for two hours were fractionated successively from the cambium into the mature tracheids. After hydrolyzing each cell-wall fraction, the hydrolyzates were separated from Klason lignin and subjected to further separation by thin-layer chromatography. Then the radioactivity of each sugar and the Klason lignin in each fraction was measured. From this experiment, it is suggested that: (1) In the primary-wall formation stage, the incorporation of the label from 14C-glucose into cellulose is low, whereas the incorporation of the label into hemicelluloses and pectin, which are rich in arabinose and galactose, is high. Large parts of the hemicelluloses and pectin are supplied to the radial walls and contribute to the radial enlargement. (2) The incorporation of the label into cellulose still is low between the S1 deposit stage and the early S2 deposit stage, but the active incorporation takes place from the middle of the S2 deposit stage to the S3 deposit stage. (3) The incorporation of the label into xylan is high from the S1 deposit stage to the early part of the S2 deposit stage. In subsequent stages, it gradually declines, but at the S3 stage it becomes high again. (4) The incorporation of the label into mannan is relatively low at the S1 stage. During the S2 formation, it becomes high, although it temporarily declines at the end of the S2 deposit stage. It is highest in the S3 deposit stage. (author)

  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. 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

  5. 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

  6. 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

  7. 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.

  8. 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

  9. An apple rootstock overexpressing a peach CBF gene alters growth and flowering in the scion but does not impact cold hardiness or dormancy

    Science.gov (United States)

    Artlip, Timothy S; Wisniewski, Michael E; Arora, Rajeev; Norelli, John L

    2016-01-01

    The C-repeat binding factor (CBF) transcription factor is involved in responses to low temperature and water deficit in many plant species. Overexpression of CBF genes leads to enhanced freezing tolerance and growth inhibition in many species. The overexpression of a peach CBF (PpCBF1) gene in a transgenic line of own-rooted apple (Malus×domestica) M.26 rootstock (T166) trees was previously reported to have additional effects on the onset of dormancy and time of spring budbreak. In the current study, the commercial apple cultivar ‘Royal Gala’ (RG) was grafted onto either non-transgenic M.26 rootstocks (RG/M.26) or transgenic M.26 (T166) rootstocks (RG/T166) and field grown for 3 years. No PpCBF1 transcript was detected in the phloem or cambium of RG scions grafted on T166 rootstocks indicating that no graft transmission of transgene mRNA had occurred. In contrast to own-rooted T166 trees, no impact of PpCBF1 overexpression in T166 rootstocks was observed on the onset of dormancy, budbreak or non-acclimated leaf-cold hardiness in RG/T166 trees. Growth, however, as measured by stem caliper, current-year shoot extension and overall height, was reduced in RG/T166 trees compared with RG/M.26 trees. Although flowering was evident in both RG/T166 and RG/M.26 trees in the second season, the number of trees in flower, the number of shoots bearing flowers, and the number of flower clusters per shoot was significantly higher in RG/M.26 trees than RG/T166 trees in both the second and third year after planting. Elevated levels of RGL (DELLA) gene expression were observed in RG/T166 trees and T166 trees, which may play a role in the reduced growth observed in these tree types. A model is presented indicating how CBF overexpression in a rootstock might influence juvenility and flower abundance in a grafted scion. PMID:26981253

  10. 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

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    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

  11. Morfoanatomia da plântula de Campomanesia xanthocarpa O. Berg. (Myrtaceae Morphology and anatomy of Campomanesia xanthocarpa O. Berg. seedlings (Myrtaceae

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    Alessandra Mara Gogosz

    2010-09-01

    seedling is epigeous, phanerocotylar with simple, opposite paracotyledons and eophylls. In 7-day-old seedlings, cambium formation begins and, 30 days after root emergence, the seedlings show secondary growth. The paracotyledons and eophylls have similar anatomical and morphological characteristics. The hypocotyl is the main storage body, containing starch grains, especially in 7-day-old seedlings. Glands and secretory cells occur in most organs excluding the root. The epidermis of the paracotyledons, eophylls and hypocotyl has simple, unicellular trichomes. Idioblasts with crystals are common in the mesophyll.

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

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    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

  13. Analysis of 4,664 high-quality sequence-finished poplar full-length

    Energy Technology Data Exchange (ETDEWEB)

    Ralph, S. [University of British Columbia, Vancouver; Gunter, Lee E [ORNL; Tuskan, Gerald A [ORNL; Douglas, Carl [University of British Columbia, Vancouver; Holt, Robert A. [Genome Sciences Centre, Vancouver, BC, Canada; Jones, Steven [Genome Sciences Centre, Vancouver, BC, Canada; Marra, Marco [Genome Sciences Centre, Vancouver, BC, Canada; Bohlmann, J. [University of British Columbia, Vancouver

    2008-01-01

    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. 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 x 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 for genes that were differentially expressed in

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

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    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.

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

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    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.

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

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    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

  17. 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

  18. The role of phytochrome A and gibberellins in growth under long and short day conditions: Studies in hybrid aspen

    Energy Technology Data Exchange (ETDEWEB)

    Eriksson, M.E. [Swedish Univ. of Agricultural Sciences, Umeaa (Sweden). Dept. of Forest Genetics and Plant Physiology

    2000-07-01

    apical meristem and cambium, respectively. Also, these plants have altered wood properties showing more numerous (71 %) and longer (8%) fibres as compared to the control plants. GA levels were modulated by altering the expression of the multifunctional enzyme GA 20-oxidase. This enzyme was shown by the over-expression studies to be a limiting factor in the biosynthesis of GAs. This enzyme was also shown to be regulated at the transcriptional level, both by photoperiod and active GA{sub 4}. Our studies indicate that GA 20-oxidase is very likely to be one of the most important factors in the GA-regulation of growth and growth cessation. In conclusion, these studies have shed light on the early stages of growth cessation in deciduous trees, especially with respect to the role of phyA and GAs. It has also given new information on the importance of GAs in growth as such, with important implications for wood production.

  19. Tumores em certos híbridos do gênero nicotiana

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    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.

  20. 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

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    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.