The Anatomical Studies On The Process Of Sexual Reproduction Of Camellia Oleifera

The process of sexual reproduction has a great effect on plants cultivation and breeding. Using Camellia Oleifera'XL No.1' as material, we investigated the anthesis, the flower bud differentiation, the mega-and microsporogenesis and male-and female gametogenesis and the whole process of pollination and fertilization by field observation, pollination experiments, paraffin sectioning and fluorescence microscope observations. The main results were as follows:1. The developing process of the flower bud differentiation of Camellia Oleifera 'XL No.1'was devided into seven stages, no differentitation phase, the predifferentation phase, the initial differential phase, the sepaldifferential period, the petal differential period, the stamen differential period, the pistil differentialperiod and the formation stage of the ovary and anther. The floral bud of'XL No.1'began to differentiate in mid-May, and enterd the pistil and stamen primordium-differentiating stage at the beginning of July. The ovary and anther were differentiated until mid-August, and until mid-September the flower bud differentiation was completed.2. The microsporogenesis and the development of the male gametophyte of Camellia Oleifera'XL No1'was completely normal.'XL No.1'had four ventricles in each anther; The development of the anther wall belonged to basic type; glandular tapetum; The meiosis in the microspore mother cells belonged to a simultaneous type and the microspores were arranged in a tetrahedron shape in the tetrads; pollen matured seven to nine days before blooming; The ripened pollen was of 2-cell type, and it had three germination apertures.3. The gynoecium ovary of Camellia Oleifera 'XL No.1' had three carpels, three ventricles, and three to seven ovules in each ventricle; Each ovule was anatropous, tenuinucellate, and with 2 integuments. A dyad formed from the first meiotic divisionis of megaspore mother cell. One cell of the dyad degenerated, and the other cell of the dyad participated in the development of embryo sac. The reserved cell of the dyad completed the second meiotic division, and formed a embryo sac that had a single binuclear cell. The embryo sac developed into eight mature nucleus megaspore during the blooming day by two mitoses. The megaspore growth of Camellia Oleifera'XL No.1'belonged to Allium type.4. During growing process, the microspore occurrence along with male mate formation not only had a comparative stable homologous relation with macrospore occurrence and female mate formation, but also had relative steady connection with the shape and character of blooming bud and inflorescence. The inner development process could be speculated by observing the outer configuration of pistil and androecium.5. Camellia Oleifera'XL No.1' pollinated and fertilized normally. Only a small part of self pollen geminated in one hour after pollination, and the pollen geminated in six hour in large quantitiesn after pollination. The pollen tube elongated to the middle parts of style after thirty-six hours, entered ovary after sixty-four hours, reached into embryo sac after eighty-four hours, and double fertilization was finally finished after one hundred and eight hours.6. Preliminary field pollination experiments were conducted on Camellia Oleifera 'XL No.1', and the results showed that the fruit set percentage of self-pollination of 'XL No.1', interspecific hybridization'XL No.1'×C. octopetala were significantly different, and the fruit set percentage were 90.3% and 74.2% respectively. Also, comparing the growth speed of the pollen tube of them, self pollen tube extended to stylar base after sixty-four hours, but the interspecific cross pollen tube extended to stylar base after ninety-six hours. The growth speed of self pollen was one and a half times of the growth speed of interspecific cross pollen. The results showed that the fruit set percentage of self-pollination was higher than the fruit set percentage of the interspecific cross, and the growth speed of the pollen tube of self-pollination was faster than growth speed of the pollen tube of the interspecific cross.