Effect of High Temperature on Leaf Physiological Changes as Chlorophyll composition and Photosynthesis Rate of Rice

Abstract

High temperature impairs rice grain yield and quality. To understand the effect of high temperature on leaf physiological activity and grain filling, two cultivars of rice that Dongan and Ilpum were exposed to high temperature during ripening stage. Grain filling rate, perfect grain ratio and grain weight of high temperature (27℃±4℃) treated both rice cultivars were decreased than those of control temperature (22℃±4℃) treated. The reduction rates of grain filling ratio, perfect grain ratio and grain weight of high temperature treated to control treated rice were higher in Ilpum than Dongan. Chlorophyll contents of rice leaves under high temperature at early ripening stage were higher than those of control temperature, but those were slowly decreased with no difference between temperature treatment since at mid ripening stage. Although chlorophyll a/b ratio under high temperature was decreased from heading to 15 days after heading, that was gradually increased since 15 days after heading. Protein concentrations of rice leaves for ripening stage was a similar pattern with chlorophyll changes. The rate of photosynthesis at 14 days after heading under high temperature was higher than those of control temperature, but there was no difference at those of 7 and 34 days after heading between two temperature treatment. Free sugars under high temperature treated leaves were lower than control temperature. Consequently, these results exhibit that high temperature accelerate leaf physiological activity as chlorophyll synthesis and photosynthesis rate unlike the deterioration of grain filling.

Combined and single effects of elevated CO2 and temperatures on rice bakanae disease under controlled conditions in phytotrons

“…The highest carbohydrate content was determined when infected plants were grown at medium temperatures and elevated CO 2 . Total carbohydrates have been reported to increase in rice under elevated CO 2 conditions, but they might also decrease in rice when high temperature is applied (Shon et al, 2015;Uprety et al, 2007). This study has shown that the increase in carbohydrates oc- expressed in a resistant rice cultivar (Selenio), inoculated with F. fujikuroi, which apparently showed no symptoms of infection (Matić et al, 2016).…”

Climatic constraints to yield and yield components of temperate japonica rice

“…The present results suggest that the anticipated global warming will adversely affect temperate japonica rice production in South Korea and highlight the need for new cultivars with the high‐temperature tolerance in the ripening stage. Recently, some progress has been achieved with the screening and breeding of the temperate japonica rice with high‐temperature tolerance during the ripening stage: Donganbyeo for mid‐late cultivar (Shon et al., 2015) and Jungmo1024 for early cultivar (Jeung et al., 2016). However, heat‐induced sterility should also gain attention since it can be intensified by not only increased temperature but also elevated CO 2 concentration, which increases panicle (canopy) temperature by reducing the transpiration rate (Matsui et al., 1997).…”