Study On The Florescence Biology Of Carya Illinoinensis

Carya illinoinensis is a monoecious cross-pollination tree,the female and male flowersmaturing in the different times is a widespread phenomenon,therefore its yield and quality arerather low.To grasp flowering phenology characteristics and mechanisms of floral buddifferentiation,and then thus providing scientific theory for varieties configuration and enhanceyield and quality of Carya illinoinensis,in this study,we used four kinds of Carya illinoinensis(Mahan, Pawnee, ZhongShan25and Jinhua) as experimental materials,and observed theircharacteristics of the flowering period,besides that,we analysed the processes of floral buddifferentiation of Mahan through anatomical observation and physiological and biochemicaldetermination. The main results are as follows:1The florescence of four varieties was focused on April to mid-May,the best pollinationperiod of female flowers and the pollen dispersal period of male flowers were both short and just3~5days. The highest male-female ratio was up to26:1.According to flowering dates of maleand female of four varieties, We could get that Mahan, Jinhua and Zhongshan25wereprotogynous, but Pawnee was protandrous. So Pawnee was a pollinated plant for Mahan, Jinhua andZhongshan25, furthermore, it was the best pollinated tree.2The process of male bud differentiation of Mahan can be divided into five periods: maleinflorescence differentiation, male flower primordium differentiation, appearance of bractprimordium, appearance of stamen primordium, and anther differentiation.3The process of female bud differentiation lasted about ten months, it contained criticalperiod of morphological differentiation,female inflorescence differentiation, appearance ofpedicel primordium and female flower primordium, appearing of bract primordium, appearanceof calyx primordium and pistil primordium, appearance of immature embryo, and mature periodof female flower.4Assaying some physiological indexes in branches and leaves of Mahan during the periodof floral bud differentiation, we get to know that these physiological indexes produce an effect onfloral bud differentiation. The conclusion as follow:(1) The accumulation of soluble sugar,soluble starch and soluble protein was benefit tofloral bud differentiation.(2) SOD has no significant effect on floral bud differentiation, while increase of PODactivity could promote stamen and female flower primordium differentiation.(3) Four kinds of endogenous hormones had different effects on floral bud differentiation. Amongthem, lower content of IAA and higher content of ZR played significant role in promoting floral buddifferentiation. However, it is beneficial to start the system of floral buddifferentiation, when the contentof GA was higher. In addition, higher content of ABA was conducive to male flower primordiumdifferentiation, stamen primordium differentiation was promoted, when contents of GA and ABA werelower, and ratios of ABA/GA and ZR/GA were higher.