Compared growth of seedlings of five Sudanian woody species grown in rhizotronsOriginal Title (non-English) Croissance comparee des plantules de cinq especes ligneuses soudaniennes elevees en rhizotron [French]

摘要

In addition to biophysical constraints, insufficient scientific knowledge of the ecology of seminal regeneration of several Sudanian woody species hinders favourable implementation of cultivation techniques adapted to early stages of forestry regeneration. The objective of this study is to follow the development of seedlings of five woody species of Sudanian natural forests : Terminalia avicennioides Guill. et Perr., Piliostigma thonningii (Schumach. & Thonn.) Milne-Redh., Isoberlinia doka Caib et Stapf, Afzelia africana Sm. et Detarium microcarpum Guill. et Perr. The study was carried out on seedlings grown in rhizotons on two soil profile types. The results show that all species, apart from A. africana, have cryptogeal germination. At an early stage seedlings allocate the resource preferably in the roots, causing swelling of the top root due to the accumulation of reserves. It also results in early rooting. Rate of depth-rooting depends on the species and soil types. D. microcarpum have the strongest rate of rooting and T. avicennioides the weakest. The top-rooting of seedlings of T. avicennioides and A. africana is negatively affected by soil compaction. Cryptogeal germination and early development of the root system make it possible for seedlings to better support drought, fire and browsing. The stems of seedlings have rhythmic growth due to a rhythmic functioning of the terminal buds.