Studies on the Formation of Microspores and Development of Male Gametophyte in Acer yanjuechi (Aceraceae)

Abstract

Acer yanjuechi is on the extremely endangered situation. This paper studied the formation of microspores and development of male gametophyte in Acer yanjuechi by using paraffin method to find the cause. The results are as follows: there are two kinds of flowers in Acer yanjuechi, bisexual flower and male flower. The stamens of male flowers could dehisce, but bisexual ones could not. Four pollen sacs make up one anther. The anther wall is of ground form. The endothercium develops fibular thickenings, and the tapetum is of the glandular type. The cytokinesis of the microspore mother cells in meiosis is of the simultaneous type. The microspore tetrads is of tetrahedral, and pollen grains are two-celled when mature. In the whole development of anthers, pollen abortions appear constantly and make pollens shriveled and embolic. The reasons are following: the callose dissolve ahead of time, nucleus microspore adhere to each other, anthers become vacuolating, and so on, which maybe one of the causes of being in danger of Acer yanjuechi. Pollen viability was detected initially, ranging from 36.98% to 60.54%, and the average is 45.97%. This article laid the foundation of anatomical data about Acer yanjuechi in the formation of microspores and development of male gametophyte.