硝酸银与脱落酸相配合影响菜心离体培养之植株再生方式的组织学研究

HISTOLOGICAL STUDIES OF PLANT REGENERATION MODES OF BRASSICA PARACHINENSIS BY AFFECTING AgNO_3 AND ABA

菜心带子叶的子叶柄在培养基中是否添加ＡｇＮＯ３与ＡＢＡ可导致两种不同的植株再生方式：添加ＡｇＮＯ３与ＡＢＡ时由外植体直接出芽，而不加ＡｇＮＯ３与ＡＢＡ则植株再生经过愈伤组织阶段再分化成芽。培养１—３ｄ，子叶柄切口端之皮层及维管束的薄壁细胞开始启动，细胞迅速分裂而形成分生细胞团和少量愈伤组织。第４天，在不含ＡｇＮＯ３与ＡＢＡ的培养基上，分生细胞团则形成根原基进而发育成根；或者去分化形成愈伤组织。在这种条件下，只有少数芽原基可由培养１５ｄ后的愈伤组织再分化产生．在含ＡｇＮＯ３与ＡＢＡ的培养基上，分生细胞旺盛增殖而形成大量分生细胞团，并由这种分生细胞团直接形成大量的芽原基．１０ｄ左右即可产生为数众多的丛生不定芽．ＡｇＮＯ３与ＡＢＡ相配合抑制了不定根及愈伤组织的形成和生长，促进大量增生的分生细胞团直接分化为不定芽的芽原基．

Histological studies revealed that there were two different regeneration modes when cotyledon petioles of Brassica parachinensis as the explants were cultured in the medium with or without AgNO3 and ABA. In mode Ⅰ,in medium with AgNO3 and ABA,shoots regenerated directly from the cut end of cotyledon petioles and did not pass through callus stage. After 4 days of inoculation, the vascular parenchyma cells at the cut end of the explant initiated to active division and became meristem centre and then adventitious buds were regenerated. In mode Ⅱ,in medium without AgNO3 and ABA, vascular parenchyma cells at the cut end initiated to division and gave rise to form root meristem or/and callus from which shoots and roots were subsequently regenerated. So the two modes of plant regeneration resulted in whether the medium contained AgNO3 and ABA or not.