Abstract:

Five kinds of experimental bamboo (Phyllostachys violascens) plants representing different flower bud differentiation stages were selected based on whole bamboo growth vigour, leaf colour and size, and farmers's cultivation experiences. Collected bamboo samples marked in the field which are supposed to have flower would be identified by later field observation, analysis and determination of bamboo rhizome and leaf in different flower bud differentiation stages on the dynamic change of 5 kinds of endogenous phytohormones of iPA、Zr、ABA、IAA and GA₃,flower bud differentiation of P. violascens could be divided into 3 stages, I.e. flower-bud induction, flower-bud initiation, and flower-bud development. CTK promoting P. violascens flower bud differentiation was iPA, rather than Zr. GA₃ was acted as a promoter during its physiological and biochemical differentiation stage, but a inhibitor during its flower-bud development stage. ABA role was the same as GA₃, but IAA is different with ABA and GA₃, IAA was behaviored as a promoter during all the flower bud differentiation stage. The start-up of bamboo physiological and biochemical differentiation was trigged by change of ratio of iPA to ABA and iPA to GA₃, I.e. bamboo flower induction was initiated once their ratio value reached a certain level. iPA/ABA role was much bigger than iPA/GA₃ in regulation and control of flower bud differentiation. Ratio value of 5 kinds of phyto-hormones was ranged from 1.2 to 11.3, particularly iPA was peaked at 11.3 during bamboo bud induction stage. High content hormones was produced inside bamboo leaves, not from production and transportation of rhizome and root; bamboo leaves were supposed as the sensor of receiving flowering signal to trig flowering procedure which played important role in bamboo flowering, but bamboo rhizome was not such a organ as bamboo leaves, therefore it did not play role in bamboo flowering.

Key words: Phyllostachys violascens, endogenous hormone, flower bud differentiation, regulation mechanism