ABORTIVE POLLEN DEVELOPMENT IN RELATION TO EARLY TAPETAL DEGRADATION IN MALE STERILE MANGOSTEEN
Pollen development in the apomictic mangosteen (Garcinia mangostana L.) has not been exhaustively studied. The objective of this study was to establish the developmental sequence and to determine whether the bursting of the tetrads/ microspores at a time corresponding to microspore release was the factor that contributed to male sterility. Flower buds of various sizes were collected and investigated through combined anatomical observations, histochemical studies, and fluorescence microscopy. The developmental stages were categorized as follows; early pollen mother cell (eaPMC), late pollen mother cell (laPMC), tetrads (TD), early microspore (eaM) and late microspore (laM). Recent studies have shown that the tapetum was disintegrated at the laPMC stage resulting in a significant decrease in the number of tetrads. A scattered primexine wall was deposited around the tetrad. A few of the released microspores could be seen but they did not develop into functional pollen grains. In contrast, most tetrads could not be librated and were degraded. The FCR test revealed that the microspores were not viable. After Oil red O staining, lipid stores were detected in all parts of the anther. Accumulations of carbohydrate were rarely detected (PAS reaction) in the anther wall layers, tapetal cells, sporogenous derivatives and loculi. Male sterility is probably caused by the early degeneration of the tapetum combined with a disruption of the formation of tetrads/microspores. Further studies of the sub-cellular level using analysis by transmission electron microscopy (TEM) are still the subject of intensive research.
Nuanjunkong, N., Purintavaragul, C. and Meesawat, U. (2014). ABORTIVE POLLEN DEVELOPMENT IN RELATION TO EARLY TAPETAL DEGRADATION IN MALE STERILE MANGOSTEEN. Acta Hortic. 1024, 217-221
primexine, callose, pollen mother cell, FCR test, apomictic