Comparative analysis of ultrastructural and metabolic changes in the transmitting tissue of  Ananas comosus (L.) Merr. after various pollinations.

Abstract

The study of enzyme activity during pollen development can provide an idea of the role of different enzymes in pollen tube growth and elucidate certain basic patterns and mechanisms of plant growth.The tissue-specific peroxidases in the style transmitting tissue may play a direct role in regulating pollen tube growth. Coordination between pollen and pistil is essential for successful pollination in flowering plants. A.comosus (pineapple) in Bromeliaceae prevents self-fertilization rates due to gametophytic self-incompatibility. The stigma of two commercial cultivars of Ananas was pollinated with its pollen and also pollen from other cultivar. Cross-pollinated stigma showed higher peroxidase activity compared to self-pollinated and open pollinated pistil of the flower. In peroxidase localization reddish color appeared on the stigma of cross-pollinated pistil.TEM analysis showed ultrastructural and metabolic changes in the transmitting cells of styles in Ananas after various pollinations. The cells in the transmitting tissue of Ananas is rich in cytoplasm and numerous large rough endoplasmic reticulum, large vacuole, golgi vesicles and prominent nucleus in cross-pollinated pistil.