Cumparsion between Anthers of two Rice (Oryza sativa L.) Cultivars with Tolerance to High Temperatures at Flowering or Susceptibility

Abstract

Anthers of rice cultivar, cv. Nipponbare, which showed floret fertility even when the temperature at flowering was high (tolerant) and cv. Hinohikari, which showed floret sterility at high temperatures (susceptible) were compared. The anther of Nipponbare had better developed cavities for dehiscence and thicker locule walls than Hinohikari. The well-developed cavities enable easy rupture of the septa in response to swelling of the pollen grains. The thick locule walls promote the swelling of pollen grains by retaining water in the locules. Since the swelling of pollen grains is the driving force to open the theca and the septum rupture is an indispensable process for the theca dehiscence, the well-developed cavities and the thick locule walls may be responsible for the tolerance to high temperatures in Nipponbare.