Histological and Biochemical Analysis of Pollen-pistil Interaction in Mandarins

摘要

Reproductive biology of many citrus species is characterized by parthenocarpic process and pollen-pistil incompatibility. These processes are related with seedlessness that is a very important characteristic in the evaluation of fruits for fresh market. However, seeds are commonly found when a seedless cultivar is not grown in isolated blocks due to the cross pollination between sexually compatible cultivar occurs. In order to decipher pollen-pistil interaction, changes in unpollinated and pollinated pistils, pollen tube behaviour and TGase activity in the style in controlled pollination were investigated. The results showed that during flowering time drastic changes in the gynoecium occurred. Several changes regarding shape and secretory activity of stylar canal cells, from the stigma toward the ovary, were observed. In the different combinations dissimilar behaviour of growing pollen tube was observed, according to the different degree of compatibility among the genotypes. TGase activity appeared strongly involved in pollen tube growth inhibition.