土がかわくにつれてアカマツのマキツケ苗の水分関係はどうかわるか

概要

論文の詳細を見る
In Japan, in spite of abundant annual precipitation, irregularity in its distribution causes severe drying of soil in the summer. Seedlings of conifers, which has not yet developed sufficent root systems to utilize moisture from deep layers of soil in such cases, suffers from soil dryness on their first summer. Experimental studies were carried out on the response of such seedlings to soil dryness.With decreasing soil moisture, transpiration rate decreased gradually at first and then suddenly to a nearly constant rate which was supposed as the rate of cuticular transpiration. The sudden decrease began when water retaining power of the soil reached 8-9 atmospheres and the constant rate was attained when the water retaining power reached nearly 15 atmospheres, which is nearly equivalent to the permanent wilting percentage. Water content of seedlings did not decrease until the water retaining power of the soil exceeds 15 atmospheres, then decreased suddenly to the critical moisture content, and then died. The critical moisture content of the seedlings seemed to be about 100% of their dry weight. The seedlings which were more resistant to soil dryness had lower top-root ratios and higher absolute weight of their tops and roots.
一般社団法人日本森林学会の論文
1953-03-25