In: Phyton, 51 Fasc. 2 (2011), S. 289-297, with 2 figures

Key words: Cambium, procambium, metacambium, Terminalia catappa.

Summary

RAJPUT K. S. & RAO K. S. 2011. Development of vascular cambium in the petiole of Terminalia catappa L. (Combretaceae). – Phyton (Horn, Austria) 51 (2): 289–297, with 2 figures.

Structure and development of vascular cambium and pattern of secondary growth were studied histologically in the petiole of Terminalia catappa L. (Combretaceae). The petiole cambium is non-storied with vertically elongated fusiform and small isodiametric ray cambial cells. After the forma-tion of few protoxylem and protophloem elements from procambium, periclinal divisions in me-tacambium produced metaxylem and metaphloem. Compared with main shoot, the differentiation of interfascicular cambium and continuity between fascicular and interfascicular cambium was rather slow. The procambial strands became more prominent in the second leaf giving rise to elements of metaxylem and metaphloem. In the third leaf tangential continuity between metacambial cells became more prominent with inception of interfascicular cambium between the bundles. The cambium remained active until the leaf reached senescent stage. With the initiation of senescence in the leaves, the cambial zone gradually became narrow with 1–2 layers of cells. The radial seriation and tangential continuity of the cambial zone between secondary xylem and phloem was lost with the differentiation of all cambial cells when the leaves were fully senescent. The study revealed the continuation of primary growth into secondary growth in the petiole with no well-defined transition zone in between.