Abstract
In order to make clear the cause of growth reterdation of Ladino clover induced by high temperature during the summer, the influences of high temperature on dry matter and leaf production of the plant were studied. The plants were grown under controlled environmental conditions with temperatures of 15°C, 20°C, 25°C and 30°C for 31 days after cutting. The total amount of dry matter production at the high temperature (30°C) was less than that at the lower temperatures (below 25°C). The expansions of leaf area in early period of regrowth were more rapid at the higher temperatures than at the lower temperatures, but those in middle and later period were more rapid at the lower temperatures than at high temperatures. The increasing rate of living leaf number decreased remarkably with advancement of the regrowth period at the higher temperatures (especially 30°C). The remarkable depletion of increasing rate of living leaf number at the higher temperatures was caused by both the decrease of emergences and life spans of leaves. From these results, it may be concluded that the depletion of dry matter productivity at the high temperature (30°C) is caused by the decrease of lear area affected by the decrease of emergances and life spans of leaves.
