Govindankutty, M.P.Vellaichamy, K.2014-06-242014-06-242007-02In: Coconut research and development, proceedings of the international symposium, 1st, CPCRI, Kasaragod. 27-31 Dec. 1976. Edited by N. M. Nayar. Wiley Eastern, New Delhi 1983 p-421-425http://hdl.handle.net/123456789/3228Anatomy of loots from healthy and diseased coconut palms was studied using aerial microtome and free-hand sections. Some externally healthy roots from apparently healthy, and obviously diseased trees (naturally infected) from an area of active disease spread showed poorly staining mechanical and vascular tissues. Walls of tracheal elements were thinner and disorganized. Tyloses occurred occasionally in metaxylem vessels. Several roots revealed degenerate phloem. Necrotic effects were shown by abnormally and deeply staining phloem with dense contents. Tissue degeneration was less pronounced in metaphtoem. Many healthy-looking roots from apparently healthy and diseased palms had fungal hyphae (?) in metaxylem. Sections of roots with external lesions of the burrowing nematode Radopholus similis revealed the presence of nematodes and their eggs in cortical burrows. Such burrows contained deeply staining cells encircled by abnormal sclerenchyma. Degenerative changes in conducting elements could derange the flow of nutrients and thereby contribute to root death due to starvation.enArticle