牡丹花芽的形态发生及其生命周期的观察

牡丹花芽是一个混合芽。它的形成和分化是由腋芽原基开始,历时三个年周期大约25个月的发育结束其生命周期。在三年发育过程中,顺序形成腋芽原始体,花原基和种子及果实。在器管建造过程中可以区分为营养生长和生殖生长两个大的阶段。由叶原基产生结束到苞片原基开始产生为其质变的临界点。如果此时的营养条件和成花激素都是合适的。腋芽原基就会继续发育而成混合芽。否则,发育就终止在叶原基形成阶段,只能形成叶芽。任何一年的处在第二个年周期的混合芽都要产生子一代芽的原始体。子一代芽又在它的第二个周期中产生子二代芽的原始体,一代接一代,依次类推的发育下去。利用花芽形成的规律可以解决牡丹栽培上的一些实际问题。

STUDIES ON MORPHOGENESIS AND LIFE CYCLE OF THE FLOWER BUD OF TREE PEONY (PAEON IA SUFFRUTICOSA ANDR)

The flower bud of tree peony is a mixed bud. It formed and differentiated from the axillary primodia and developed completely until the third growing year.The axillary primodia formed in the first growing year and the flower primodia formed in the second growing year and then flowering, seeding and fruiting were in the third growing year. The life cycle of a flower bud was about 25 months long. The process of organogenesis could be divided into two stages, the vegetative and reproductive.The critical point between the vegetative growth and the reproductive growth was from the end of leaf bud formation to the beginning of bract primodium formation.The axillary primodia would continue developing to form mixed buds if the nutrition and florigen were available and suitable at that time. Otherwise, it would stop developing at the leaf primodium stage and only formed a leaf bud.Generally, the mixed bud in the second growing year stage could produce the new primodia that would develop to a new mixed bud in the following year.The new mixed bud would produce the primodia again in its second growing year and so on.The rule of flower bud formation of tree peony could be used to explain and resolve some practical problems in tree peony cultivation.