Analysis of the growth in forage crops : II. Effects of high temperature on photosyntehsis, respiration, chemical composition and regrowth of Ladino clover.

[摘要] To understand the causal relationships of growth retardation of Ladino clover caused by high temperature during summer, studies on the influences of high temperature upon photosynthesis, respiration, chemical composition and regrowth of the plant were carried out. Obtained results are as follows : 1) During regrowing process storone and root of the plant play a role as storage orgran. The former plays a role as primary storage organ and the latter as secondary one. 2) The relationships mentioned above fit not only the case of carbohydrates reserves but also nitrogen compounds. 3) In lower temperature plots, plant uses to some extent carbohydrates and nitrogen compounds reserved in storage organ during the first half of regrowth, but reserves them again during the latter half of regrowth. On the other hand, in higher temperature plots, plant uses the greater part of them during the first half of regrowth, and the amount of reservation during the latter half of regrowth, and the amount of reservation during the latter half of regrowth is lesser than that of the lower temperature plots. 4) The reasons to make the regrowth of plant in higher temperature plots worse are as follows : (1) decrease of emergences of leaves (2) promotion of aging of leaf blades (3) reduction of photosynthetic capacity affected by reduction of leaf area expansion capacity (4) increasing of respiration affected by high temperature and reduction of photosynthesis / respiration ratio decrease the dry matter production (5) decrease of nitrogen compounds contained in storage organ with advancement of regrowth. 5) Conclusively, two causes bringing about growth retardation of Ladino clover grown under higher temperature were deduced. The one is increase of respiration affected by high tempreature, the other promotion of aging of leaf blades.

[学科分类] 农业科学（综合）