Cytological Observation Of Male Sterile In Prunus Mahaleb L. And Karyotype Analysis Of Prunus Pseudocerasus L.

Both Prunus mahaleb L. and Prunus pseudocerasus L. belong to Cerasus Subgenus Prunus, Rosaceae. In order to make better use of these two kinds of germ plasm resources, we performed karyotype analysis on P. pseudocerasus and cytological research on male sterile lines of P. mahaleb. The experiment used the flower bud of P. mahaleb male sterile and fertile plants as experimental materials. The development of microspore and gametophyte were studied by using the method of routine paraffin section. We also used scanning electron microscope to observe the anther and pollen. The objectives of the study were to analysis the procedure of pollen development in P. mahaleb male sterility line, and to explore the reason that caused it. Through performed squash slide root tip, shoot tip and flower bud of P. pseudocerasus, we could obtain the chromosome distribution graph and analyze it. At last, we could get the results of karyotype analysis of P. pseudocerasus and explore the most suitable experimental materials and methods to analyze the karyotype of P. pseudocerasus. The results showed that:(1) There were no differences between the sterile plants and the fertile plants in the period of the pollen mother cell; it meant that all the pollen mother cells could form the normal tetrad, and then the tapetal cell of the sterile plants expanded and squeezed to the central of anther chamber.(2) After tetrad stage, the tapetal cells of the sterile plant could stick to the microspore, which will disappear with tapetum because the material and space needed for microspore’s growth were not enough.(3) There was another type of male sterility. The male sterility can develop pollen grains. After tetrad stage, the microspore vacuolization occurred, which caused pollen grain’s inclusions disappear. Because pollen grains lost its activity, abnormal phenomena appeared.(4) Scanning electron microscopy showed that the anther and the pollen of sterile plant displayed the shape of a mummify state, but the anther of fertile plant had four obvious cavities and the pollen aperture was clearly visible.(5) P. pseudocerasus was used for tissue culture and rapid propagation, then we could get adventitious root which was the most suitable materials of this P. pseudocerasus karyotype analysis experiment. By using the treatments of colchicines treatment, carnot fixation, hypotonic, acidoysis, hypotonic, enzymatic hydrolysis, staining and tabletting, we could get the best spilt phase. We found that P. pseudocerasus was tetraploid type, chromosome number was 2n = 4x = 32.