A Morphological and Histological Characterization of Male Flower in Chestnut (<em>Castanea</em>) Cultivar 'Yanshanzaofeng'

Abstract

Chinese chestnut (Castanea mollissima Blume.) is a widely distributed fruit tree and well known for its ecological and economic value. In order to evaluate obstacles to male reproductive in the C. mollissima, a morphological and histological characterization of male flower of chestnut cultivar 'Yanshanzaofeng' were examined by paraffin section technique and scanning electron microscopy. The results showed that male catkins with floral primordia were formed in the buds of one-year olds shoots in later April. Later, a protoderm, ground meristem and a procambium had differentiated in young anthers. Each young anther soon developed to four microsporangia. The anther wall layers developed completely by mid-May and consisted of one-cell-layered epidermis, one-cell-layered endothecium, two or three middle layers and one-cell-layered tapetum. The tapetum was of glandular type. Microspore mother cells underwent meiosis through simultaneous cytokinesis in later May and gave rise to tetrads of microspores, which were tetrahedrally arranged. Mature pollens contained two cells with three germ pores. Anthers were dehiscent and pollen grains shed by early June. Based our results, we did not find the abnormal male flower in the C. molissma cv 'yanshanzaofeng', indicating that male gametes were fertile and thus was considered as pollenizers.