Anther and pollen grain development in Bartlett cultivar and the effect of temperature on pollen grain germination of Bartlett, Natanzi and Dargazi cultivars in pear (Pyrus communis L.)

European pear (Pyrus communis L.) belonged to Rosaceae family and Maleae subfamily. To expand our knowledge about this species, the developmental stages of anthers and pollen grains of the Bartlett cultivar were investigated with common histological methods such as fixation in FAA, dehydration, embedding in paraffin, sectioning with a microtome, and hematoxylin-eosin staining. The findings showed that the anthers are bitheca and tetrasporangiate. The developmental pattern of the anther wall follows the basic type. Cytokinesis of microspores is simultaneous, and the arrangement of microspores is tetrahedral. The tapetum is of glandular type with a single layer, and the tapetal cells are binucleate. Mature pollen grains are two-celled, tricolpate, and exine sculpturing is striate. The anthesis of the anther is introse and takes place through longitudinal slits, and the pollen grains are released as monad. To investigate the effect of temperature on the germination of pollen grains, three cultivars Bartlett, Natanzi and Dargazi were used. An increase in temperature accelerates the germination rate of pollen grains in all three cultivars. At ۵°C, the germination percentage was generally lower in all cultivars. In all three cultivars, pollen grain germination was zero at both ۰ and ۱ hour. As time passed, particularly at ۲ and ۴ hours, the percentage of germination increased significantly. However, after ۴ hours, the germination rate in all three cultivars showed only a slight increase. Pollen grains at ۵°C exhibited lower germination compared to other temperatures. These results indicate that ۵°C is not a suitable temperature for pollen germination in these cultivars, while ۲۵°C appears to be the optimal germination temperature for all cultivars.

کلیدواژه ها:

Anther ، Development ، Germination ، Pollen grain ، Pear (Pyrus communis L.) ، بساک ، تکوین ، جوانه زنی ، دانه گرده ، گلابی (Pyrus communis L.)