Weerasin Sonjaroon
Kasetsart University, Thailand
Title: Exposure brassinosteroid and brassinosteroid mimics continually improve photosynthesis in rice subject to heat stress
Biography
Biography: Weerasin Sonjaroon
Abstract
The Epibrassinolide (EBR) is a steroids plant growth regulator. The 7,8-dihydro-8α-20-hydroxyecdysone (DHECD) and 7,8-dihydro-5α,8α-20-hydroxyecdysone (αDHECD)-a brassinosteroid mimics which has a chemical structure similar to natural BRs and functions like a BR on the physiological responses of rice under heat stress. In this experiment, we continually applied
water, EBR, DHECD and αDHECD on rice leaves every other day for 4 times. Rice was exposed to two differences, the temperature in a greenhouse where the temperature was controlled at 30/26oC day/night (normal temperature) and 40/30oC day/night (high temperature) for 7days. The treatments consisted of: control plants; control plants treated with EBR, DEHCD and αDHECD; heatstressed control plants; heat-stressed plants treated with EBR, DEHCD and αDHECD foliar application at the reproductive growth stage. EBR, DHECD and αDHECD were effective in increasing the net photosynthetic rate, stomatal conductance, Intercellular CO2 concentration and transpiration rate at normal temperature. Under heat stress, EBR, DHECD and αDHECD steadily enhanced the net photosynthetic rate, stomatal conductance, Intercellular CO2 concentration and transpiration rate. The results indicated that the foliar application of EBR, DHECD and αDHECD continually during reproductive growth could enhance heat tolerance in rice by increasing photosynthetic performance under high temperature stress.