Primary Research On The Characteristicof Dichogamy Of Carya Illinoinensis

The female and male flowers of Carya illinoinensis maturing in the different times in order to avoid pollinating the female flowers by itself, we study on the characteristic of dichogamy. In this study, we used two kinds of Carya illinoinensis(Mahan, Pawnee) as experimental materials, and observed their characteristics of the flowering period, besides that, we analysed the processes of floral bud differentiation through anatomical observation and scanning electron microscopy observation and physiological and biochemical determination to research the characteristics of the mechanism of dichogamy between Mahan and Pawnee, The main results are as follows:1 Male and female flowers bloom of the protandrous type Pawnee begin from April to mid-May, the pollen dispersal period of male flowers is earlier than the best pollination period of female flowers, male and female flowering can meet; Male and female flowers bloom of the protogyny type Mahan begin from mid-April to mid-May, the pollen dispersal period of male flowers is late than the best pollination period of female flowers, male and female flowering can not meet; The best pollination period of female flowers and the pollen dispersal period of male flowers are both the same,they both last for 3-5days. The pollen dispersal period of male flowers of Pawnee can meet the best pollination period of female flowers of Mahan, so Pawnee was a pollinated plant for Mahan. The dichogamy of Carya illinoinensis can be genetic stability though the observation of characteristics of the flowering period between 3 years.2 We analysed the processes of female floral bud differentiation through anatomical observation, we get the result that the process of female bud differentiation of protandrous type and protogyny type can be divided into five periods:the undifferentiated stage, the initial stage of flower bud differentiation, and the stage of formation and development of the inflorescence, of the female involucre,and of the pistil. The protogyny type Mahan is in advance of the protandrous type Pawnee in the processes of female floral bud differentiation, thus as the foundation of the female flowers early bloom.3 We use the electron microscope to scan the process of male flowers development, it contains critical period of morphological differentiation:the undifferentiated stage, the initial stage of flower bud differentiation, the stamen formation stage, the anther formation stage, the pollen formation stage. The protandrous type Pawnee is in advance of The protogyny type Mahan in the processes of male floral bud differentiation,thus as the foundation of the male flowers early bloom.4 Assaying some physiological indexes in maleinflorescence and female flowers of Mahan and Pawnee during the period of floral bud differentiation, we can know these physiological indexes produce an effect on the phenomenon that female and male flowers maturing in the different times. The conclusions following:(1)The accumulation of soluble sugar content is conducive to male flowers flowering process, the accumulation of soluble starch content is conducive to female flowers flowering process.(2)The soluble sugar content and the soluble starch content of male flowers in Mahan are more than in Pawnee, on the contrary, the soluble sugar content and the soluble starch conten of female flowers in Pawnee are more than in Mahan.(3)The accumulation of soluble sugars is in favor of the process of male flowering, accumulation of soluble starch is in favor of the process of female flowering.(4)During Carya illinoinensis male flower bud Physiological differeniiation stage, soluble protein content was downward after increased and reached a Peak.And during physiological differentiation of the female flower stage protein content was up ward trend.