水稻小穗维管束发育与联结初探

STUDY ON THE CONSTRUCTION OF VASCULARNETWORK OF A SPIKELET IN RICE

对不同发育时期的籼型、粳型或其不育系与保持系代表品种的小穗解剖观察表明：小穗维管束由小穗梗中央大维管束和３～５条边围维管束经分支、连接，不断产生新的维管束进入相应的组织．一般颖片中１～２条，第１稃片１～３条，第２稃片１～４条，第２朵退化小花残余结构中０～３条，顶生可孕小花的外稃５条，内稃３条，浆片各２条，雄蕊各１条，雌蕊３条．小穗维管束经数次分枝交叉、合并，其结构可分为：花托维管束节、雄蕊维管束节和雌蕊维管束节．与不育系相比，保持系小穗尤其是各枝梗的顶小穗中维管束粗壮，筛管比例大，由此发育成的小穗维管束有利于开花结实．

Vascular networks in the spikelet of indica and Japonica subspecies were observed. The results were as follows, The network consisted of a large “VB” (VB i.e. vascular Bundle) in the centre and many small “VBs” (i.e. twigged VB) in a rachilla. Both they could develop branches, going through into the relative constructures of a spikelet respectively. There were 1or2 VB in a glume (2or4 VBs in two glumes), 1～3 VB in a lst lemma, 1～4 VB in a 2nd lemma, and 5VBs in the lemma, 3VBs in the pelea, 2VBs in a lodicule, 1 VB in a stamen and 3VBs in a pistil in the uppermost floret respectively. There were three varscular bundle nodes in the network. i.e. the receptacle vascular bundle node, the stament vascular bundle node and the pistil vascular bundle node in a spikelet. Compared with the male sterile lines, there were larger area of both vascular bundle and sieve tubes in the vascular bundle in the vertical sectional spikelet in the fertile lines, which was of great benefit to flowering and fruiting.