Comparative analyses of anther development in natural populations indicate premature degradation of sporogenous tissue as a cause of male sterility in Gaultheria fragrantissima
Gaultheria fragrantissima Wall. (Ericaceae) is a gynodioecious species having both hermaphrodite and male sterile plants. In this study, we present a comparative analysis of the different stages of anther development in naturally occuring hermaphrodite and male sterile populations of G. fragrantissima found in Meghalaya, India. While hermaphrodite flowers had well developed anther lobes, the male sterile flowers formed a white unorganized mass of tissues with a tuft of hairy outgrowth at the tip of the stamens. Histological analyses of progressive anther development in both the lines indicate an abnormal development of the sporogenous tissue in the developing anthers in the male steril line. While anther development in the hermaphrodite line was of the dicotyledonous type, the anthers of male sterile line showed progressive degradation of the sporogenous tissues and wall layers. Pollen development was also disrupted in male sterile line resulting in distorted pollen due to the irregular projection of exine wall. Our results suggest that premature degradation of the sporogenous tissues during anther development determines male sterility in G. fragrantissima.