Abstract
Recently, rice growth and production have been influenced by climatic change worldwide. In particular, under low solar radiation and cloudy weather, rice plants show abnormal physiological responses. In this experiment, plants of the rice cultivar Samgwangbyeo grown 40% and 70% shading and natural conditions at the primordium initiation stage (PI) for 30 days and the booting stage for 10 days up to heading were compared. After shading treatments, culm lengths were significnatly longer than that in natural condition plots, and panicle lengths were shorter in the 40% and 70% shading treatment plots compared to control plots. After heading, the production of dry matter treated at the PI stage was significantly lower than that at the booting stage. SPAD values of the leaf color and N concentration of leaves treated with shading were greater than those under natural conditions. In the shading treatment, the lodging index at 20 days after heading was significantly higher than that in natural condition. For yield components, number of panicles, spikelet number per panicle, and ripened grain ratio significantly decreased with shading treatment; thus, rice yield decreased significantly. For rice quality, the protein content of the head rice treated with shading was significantly higher than that in the control plot, but the amylose content of rice treated with shading was signifiantly lower than that in rice in control plots.
벼의 일조부족에 대한 생리적 반응을 조사하기 위하여 유수형성기와 수잉기에 각각 40%, 70% 차광처리를 출수직전까지 처리한 결과를 요약하면 다음과 같다. 1. 유수형성기와 수잉기에 차광처리후 출수기 간장은 차광처리가 유의하게 길어졌고, 수장은 유의하게 감소하였다. 2. 출수 후 건물생산량은 무처리에 비하여 차광 처리구에서 현저하게 감소하였으며 유수형성기 처리가 수잉기 처리에 비하여 유의한 감소를 보였고, 40% 차광처리보다 70% 차광처리에서 현저하게 감소하였다. 3. 차광처리구의 출수 후 잎의 엽색도와 질소 함량은 무처리에 비하여 유수형성기와 수잉기 처리 모두 차광 처리 정도가 높을수록 높아졌다. 4. 출수 후 20일에 벼 식물체 도복지수는 차광처리가 현저히 높아졌으며, 유수형성기 처리구가 수잉기 처리보다 유의하게 높아졌다. 5. 차광처리는 수량구성요소 중에서 이삭수와 이삭당 영화수를 감소시켰으며, 등숙률과 천립중을 감소시킴으로서 수량을 유의하게 감소시켰다. 6. 차광처리는 쌀의 단백질 함량을 높였으며 아밀로스 함량은 감소폭이 크지 않았다.
