| 1. |
- Patel, Vinay, et al.
(författare)
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Development of vascular cambium in the leaf rachis of Kigelia Africana (Lam.) Benth
- 2010
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Ingår i: PRAJÑĀ - Journal of Pure and Applied Sciences. - Gujarat, India : Sardar Patel University. - 0975-2595. ; 18:1-4, s. 40-43
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Tidskriftsartikel (refereegranskat)abstract
- The structural changes during the vascular cambium development from procambium in the leaf rachis of Kigelia africana bearing leaflets of different developmental stages (young, mature and old rachis) were investigated. The different regions from the internodes of rachis bearing young, copper brown coloured leaves revealed the sequential stages of cambial development. Terminal region of the rachis showed developing procambium along with protoxylem and protopholem derivatives, middle regions exhibited the development of interfascicular cambium whereas basal region showed complete ring of vascular cambium with secondary phloem derivatives. Rachis bearing brownish coloured leaflets showed an active cambium with both secondary xylem and phloem derivatives indicating bidirectional cambial growth. Rachis with fully matured dark green leaflets was characterized by the presence of dormant cambium surrounded by mature xylem and phloem elements and occurrence of calcium oxalate crystals in the phloem parenchyma cells. The study also describes the pattern of vascular cambial development in the leaf rachis of Kigelia, a deciduous tree and it was compared with development of vascular cambium in the leaves of conifers and evergreen dicotyledons. Influence of leaf maturity on cambial activity and secondary xylem development is discussed.
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| 2. |
- Patel, Vinay R., et al.
(författare)
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Cambial activity, annual rhythm of xylem production in relation to phenology and climatic factors and lignification pattern during xylogenesis in drum-stick tree (Moringa oleifera)
- 2014
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Ingår i: Flora. - : Elsevier. - 0367-2530 .- 1618-0585. ; 209:10, s. 556-566
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Tidskriftsartikel (refereegranskat)abstract
- The interrelationship among seasonality of cambium, wood formation, cell size variation, lignification, tree phenology and climatic factors has been examined in Moringa oleifera, a tropical evergreen tree. The vascular cambium in Moringa is a storied with a distinct seasonal variation in its structure due to dimensional changes in rays. Though cambium remains active throughout the year it is sensitive to water availability. Peak cambial cell division and rate of xylem differentiation are influenced by average rainfall during the monsoon period. Cambial cell division reaches higher up in the tree trunk when it is supporting a high number of branches and leaves. Statistical analysis of cell size variation and climate factors revealed that xylem cell development is greatly influenced by rainfall and rarely by temperature. Lengths of fusiform initials and vessel elements are positively correlated. The pattern of lignification during xylogenesis shows that the vessels are the first element to develop lignified walls and ray cells are the last elements to become lignified. Fiber cell walls show more syringyl lignin, while the cell walls of other xylem elements are characterized by relatively more guaiacyl lignin units.
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| 3. |
- Sivan, Pramod, 1984-, et al.
(författare)
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Distribution of tension wood like gelatinous fibres in the roots of Acacia nilotica (Lam.) Willd
- 2014
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Ingår i: Planta. - : Springer. - 0032-0935 .- 1432-2048. ; 240:6, s. 1191-1202
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Tidskriftsartikel (refereegranskat)abstract
- The present study was aimed to investigate the anatomy of reaction xylem in the positively gravitropic roots of Acacia nilotica growing in compact and waterlogged soils. The roots collected from the two different sites showed occurrence of gelatinous fibres throughout xylem radii from a distance of 4 cm from the soil surface. The thickness of gelatinous layer (G-layer) increased in the root collected from the deeper soil. Further, the ultrastructural studies revealed a complete replacement of S2 and S3 layers in G-fibres nearer to root tip region as compared to the root portion close to upper part of the soil surface. In addition, these fibres demonstrated intense lignification in compound middle lamellae region of G-fibre walls. Moreover, the vessel density and their width increased considerably near the root tip region. The immunofluorescence analysis suggested that the β-1,4-galactans were prevalent in G-layer, whereas the xylan was restricted to only regions of lignified secondary wall. The similarities in distribution pattern and anatomical features of G-fibres in waterlogged and non-waterlogged roots suggest the occurrence of G-fibres as inherent characteristics in the roots of Acacia nilotica.
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