Abstract:

The experiments on leaf chlorophyll content of shading and high temperature of rice HS was carried out to verify that strong light, rather than high temperature, was the cause of leaf chlorosis (yellowing), and to confirm the shade rate of eliminating leaf chlorosis (yellowing). The results showed that: under the condition of natural light intensity, the leaf chlorophyll content of rice HS during the tillering stage dramatically decreased, resulting in chlorosis; however, when 3/4 or 2/4 of the natural light intensity (under the same temperature condition) was removed, the leaf chlorophyll content showed little change and no obvious leaf chlorosis was observed; when the natural light intensity was restored for those plants which were shaded for one month but did not show leaf chlorosis, the plants also started to show detectable leaf chlorosis, confirming that the leaf chlorosis was caused by strong light intensity. When more than 2/4 of the natural light intensity was removed, the leaf chlorosis and photooxidation of HS were not detectable. High temperatures (under medium and weaker light) do not cause significant changes in the chlorophyll content and leaf color of rice HS.

Key words: rice, chlorophyll, chlorosis, photooxidation, light intensity