马尾松短枝腋芽休眠解除后形态与解剖学观察

Morphologic and Anatomic Observations of Pinus massoniana after Axillary Bud Dormancy Release

为系统了解马尾松短枝腋芽休眠解除后的发育进程,对马尾松1年生长枝顶端进行截顶处理并定期取样,采用形态观测和石蜡切片法,观察了短枝腋芽发育成枝的生长过程。结果表明:在马尾松1年生枝上着生的短枝上(针叶束内),有一枚肉质状腋芽,直径约为针叶宽度的1/5,并有完整的分生组织。截顶处理后,腋芽休眠解除,分生组织被激活,周缘分生组织不断分化形成新的鳞叶。初期,腋芽发育较为缓慢,经过12 d才能分化出新的鳞叶;随后鳞叶分化速度加快,腋芽的纵向生长速度开始超过径向,第24天已发育为非肉质状鳞叶包裹的饱满的腋芽,并在腋芽下部鳞叶的叶腋处分化出针叶原基;第32天左右,腋芽已发育完全,然后开始抽梢。短枝腋芽先分化出鳞叶,再由鳞叶叶腋分化出针叶的发育过程,与长枝顶芽的发育相似。

To understand the outgrowth processes of dormancy axillary buds on the dwarf branch of Pinus massoniana, apexes of one-year long branches were cut off in order to induce release of the axillary buds. The buds were regularly sampled after the treatments and observed with morphological measurement and paraffin section methods. There was a tiny axillary bud with complete meristem organizations and its diameter was only 1/5 of needle width. The meristems of bud were activated after removing apexes of long branches, while new cataphylls differentiated from the peripheral meristem constantly. In the beginning, development of axillary buds was slow and it would take 12 d to form the new cataphylls. And then, it was rapid with that the growth rate along vertical was higher than radial direction. After 24 d, the axillary bud developed to a big and fleshy bud wearing mature cataphylls, and needle primordia under axillary of cataphylls could be detected near the base of the buds during this period. Around 32 d later, outgrowth of branches were observed from the developed buds. It was obviously that the development of axillary buds on dwarf branches was similar to that of apex buds on the long branch in Pinus.