黄花杓兰的花芽发育

对黄花杓兰（Cypripedium flavum P.F.Hunt et Summerh.）成年植株做了一个生长季的研究，提出了一年芽、二年芽和多年休眠芽的概念。指出由芽形成到植株开花需两年时间，其具体发育路线是：第一年6－7月份，根状茎顶端二年芽基部外侧有两个新的小芽产生，即“一年芽”，至9－10月份发育出7－9片幼叶，然后随气温下降停止生长；第2年4月份复苏，即为“二年芽”，二年芽在本生长季内发育成混合芽，但一般情况下只有一个充分发育，另一个未能充分发育并且一般将来也不再有发育的机会，被称为“多年休眠芽”；第3年5月份充分发育的二年芽长出地面，形成植株，迅速开花、结果，至9月底植株枯萎。本文还讨论了黄花杓兰发育过程与环境的关系。

Differentiation of Flower Bud of Cypripedium flavum

Cypripedium flavum P. F. Hunt et Summerh.is an alpine perennial herb growing in Northwest Yunnan,China.The study on differentiation of its flower bud has been carried out.The results show that the process from bud formation to completion of floral organs differentiation lasts two years,and dormant buds can be subdivided into one year buds,two year buds and perennial dormant buds by their different developmental phases.From early June to July of the first year,two one year buds emerge from the lateral base of the two year bud and differentiate 7 to 9 spires before October and lay dormant in winter.In the next year,they (called 'two year buds' now) start to grow in late April,and differentiate floral organs in summer.During this period,two new one year buds develop.After this,usually only one of the two year buds continue growing.The other one lay dormant and usually do not develop again.It is called 'perennial dormant bud'.At the end of second growth season,an entire mix bud which contains spires,sepals,petals,stamina and pistils occours.In the third year,it's growth commences as the weather become warmer in late spring.The plants flower in May and fruit in June,and wither from September to October.The developmental process of the buds shows an adaptive mode in alpine regions.