Anatomy of stem cuttings in relation to adventitious rooting of some forest trees

【摘要】：正Some old forest trees are classified as difficult-to-root due to presence of lignifications in internal stem tissue(sclerenchyma tissues) forming a continuous layer that surrounds primary phloem and the vascular bundles. This has been shown in stem cuttings of Eucalyptus microtheca,Acacia Senegal and Sterculia setigera old trees.But in some other trees these tissues are absent or present as a broken layer hence;they are classified as easy rooting ones.This phenomenon has been shown by cuttings from young and old A.nilotica trees;young age's cuttings of Eucalyptus microtheca, Grewia tenax,and rejuvenated old trees A.Senegal,and Sterculia setigera young trees.Adventitious roots that appear in most cuttings with or without treatment with rooting hormones were found to be formed from tissues retaining capacity and stimulated to renewed division of cell in of primordia as was been shown by the transverse section of stem cuttings of E. microtheca.