Microsporogenesis and male gametophyte development in Prunus mahaleb Linn.

Microsporogenesis and male gametophyte development in Prunus mahaleb Linn. were assessed using a method combined of scanning electron microscopy (SEM) and paraffin sections. The results showed the following: (1) the anther underwent normal development and is tetrasporangiate. The tapetum was glandular; (2) cytokinesis occurred simultaneously with meiosis in the microspore mother cell, and the tetrads were tetrahedral; (3) after meiosis, microspores generated by microsporogenesis were more or less irregular in shape during the contraction period. As the microspore increased in size, mature three cell types pollen grains finally developed in the chambers; (4) mature pollen grains were observed by SEM. The shape of the pollen was nearly flat and triangular. There were three germinal furrows in the exine of the pollen with horizontal stripes. These findings provide a scientific basis for explaining the reproductive biological characteristics of the breeding resources of Prunus mahaleb, and microspore vacuolization is considered to be the main explanation for the low fruit set.