Temperature inside the Flower of Rice Plants

Abstract

The temperature inside the rice flower was measured at different air temperatures in flooded condition on fine days, in glass house rooms of phytotron, growth cabinets, screenhouse, and fields at the International Rice Research Institute, Philippines and Regional Rice Research Station, Punjab Agricultural University, Kapurthala, India. The temperature inside the flower was slightly higher than that of the ambient air at temperatures below approximately 30°C (Fig. 1). While above approximately 30°C, the flower temperature becomes lower than that of the ambient air, and it decreases with the rise in air temperature. The difference in temperature outside and inside the flower reaches approximately 2°C at an ambient temperature of 40°C. This result indicates that (1) the same mechanism as that which controls body temperature operates in rice flowers as well as in the leaves of other plant species, and (2) the level of transpiration in rice flowers is the same as that in the leaves of other plants. Air humidity affected the temperature of the rice flower (Table 3). Nevertheless, the data presented in Fig. 1 provides a measure of rough estimation for the temperature of rice flowers from ambient air temperature, in flooded fields on fine days. This estimation will be useful in such studies as high-temperature induced sterility at anthesis, in which flower temperature is the problem. © 1981, CROP SCIENCE SOCIETY OF JAPAN. All rights reserved.