栝楼不定根尖分化不定芽过程中的细胞组织学研究

将栝楼（Trichosanthes kirilowii)长约0.5-1cm不定根尖（连同原外植体茎段或根段一起,或不连）培养在MS附加6－BA5mg/L的培养基上光照培养15d,可在根尖分化出大量不定芽。不定根尖培养过程中每隔2－3d取材,用FAA固定液固定1次,通过石蜡切片观察,将栝楼的不定根尖端分化不定芽的细胞组织学变化分为4个时期。1．启动期（0-3d),根尖分生组织细胞、中柱鞘细胞起动分裂。2“根茎转变区”原形成层形成期（4－6d0。起动细胞分裂后形成2－3层体积小、核大、质浓、近似扁平形的细胞层,组成“杯形”的“根茎转变区”原形成层。3．“根茎转变区”形成期（7－10d)。原形成层不同部位加速分裂使根尖膨大成半球形、球形或梭形,并在膨大区进行维管组织的转变。4．芽分化形成期（11－15d)。原形成层在不同部位向外形成“突起”即分生细胞团,每个“突起”发育为1个芽原基。作者还讨论了栝楼与其它植物根芽产生的异同。

Cyto-Histological Studies on the Adventitious Buds Differentiating from Adventitious Roots Tips of Trichosanthes kirilowii

About 0.5-1 cm long adventitious root tips (with their plantlets or without) of Trichosanthes kirilowii were cultured on MS with BA 5 mg/L for 15 days, they produced numerous adventitious buds. By the paraffin-cut section method, the anatomy of adventitious buds formation was studied and the buds differentiation can be divided into four phases: (1) Initiation phase (0-3 days). Root meristematic cells and pericyclic cells first divided. (2) "The zone of transition from root to shoot " precambium formation phase (4-6 days). The initiation cells divided and formed two or three near flat layers of cells with smaller volumes, bigger necleuses, and denser cytoplasmises. They connected and formed precambium of the transition zone from root to shoot. (3) "The transition zone from root to shoot"formation phase (7-10 days). The precambium cells continualy divided at different place from the tip and made the root apex to expend, and formed half ball or a ball or shuttle in shape. In the meanwhile, root vascular tissues were transforming to shoot vascular tissues within the expanded district. (4) Buds formation phase (11-15 days). The precambium produced many hemishery protuberances at different region and each protuberance produced a bud primordia. In addition, the author compared the differences of root buds production between Trichosanthes krilowii and other plants.