Initiation and Development of Sex Reversal and Ovule Abortion Process of Pinus massoniana Polycone Strobilu

Zhao Yang
2018 International Journal of Agriculture and Biology  
To cite this paper: Yang, Z., C. Ting-qiao, W. Xiu-rong and Y. Xue-mei, 2018. Initiation and development of sex reversal and ovule abortion process of Pinus massoniana polycone strobilus. Int. J. Agric. Biol., Abstract This paper describes the morphological and microstructure of Pinus massoniana strobilus. The result revealed two distinct development processes of the polycone. The first process was seen during the strobilus differentiation stage of P. massoniana. It occurred from August and
more » ... from August and synchronized with the starting time of the normal microstrobili development to the end of December, with strings of reproductive primordia on the terminal buds. During this period, not only the visible microstrobili were shown, but also the megastrobilum, characterized bracts and ovuliferous scales appeared. Even strings of megastrobilum primordia grew at the base of the terminal buds. The second process was seen during the sex reversal of the development of the microstrobilus. The terminal buds differentiated and developed in the form of microstrobilus till mid-March next year. In the next 10 days or so, the microsporangia changed into bracts and ovuliferous scales of the megastrobilus basipetally. By the end of March, the microstrobili were entirely converted to megastrobili and the female "polycone" formed. Besides, ovule abortion was observed during the development of female gametophyte of the polycone. In mid-April, the number of free nuclei of ovules in the female gametophyte of polycone began to decrease and the center gradually became empty. At the beginning of May, the free nuclei of the normal ovules began to cellize, but the free nuclei of the aborted ovules in the polycone virtually disappeared and only the cavity was visible.
doi:10.17957/ijab/15.0539 fatcat:6wc764kavjaqrpha7vpybi5n6u