STUDIES ON THE ABILITY OF PHOTOSYNTHESIS OF THE TREES FOR REVEGETATION AND THE FUNCTION OF URBAN GREEN SPACE FOR FIXING CARBON

1994年在不同土壤水分条件下，通过控制夏秋两季的浇水，测定了香果树的光合速率和蒸腾速率，1995年测定了香樟、香果树和青冈树的光合速率和蒸腾速率。另外，在丸龟市厚井海滨公园种植的香樟树的生长情况。(1)土壤水分状况与树体生长在夏季，即使土壤水分充足，帕森斯树体的光合速率也表现出中午下降的现象。这种中午萧条的原因似乎是高温。当叶温超过35 ℃时，光合速率开始下降。另一方面，蒸腾速率随叶温的升高而增大。结果表明，土壤水势与叶水势之间存在着密切的相关关系，随着土壤干旱的加剧，光合速率和蒸腾速率下降。随着叶水势的降低，香樟和香果树的光合速率和蒸腾速率也随之降低，但夏季高温对香樟和香果树的影响小于香果树。(2)1994年春季，对蓬莱海滨公园种植的香樟树的土壤条件和根系发育进行了调查。这个公园是在填海造地上，树木是大约20年前种植的。但是，泥土却被压得很密。1994年春季进行沙丘土壤改良，1995年冬季进行土壤状况和根系发育调查。结果表明，土壤改良对根系发育有明显的影响。

The photosynthetic rate and the transpiration rate of Pasania edulis trees were measured under verious soil water conditions by controling watering in summer and fall in 1994, and those of Cinnamomum camphora, Pasania edulis and Quercus glauca trees were measured in the same way in 1995. And, the growth of Cinnamomum camphora trees planted in Hourai Sea-side Park in Marugame-city.(1) The soil water conditions and the growth of the treesThe photosynthetic rate Pasania edulis trees showed the mid-day depression in summer even if the soil hold enough water. The reason of this mid-day depression was seemed high temperature. When the leaf temperature was over 35ﾟC,the photosynthetic rate became decrease. On the other hand, the transpiration rate increased by the leaf temperture. It found a close co-relationship between soil water potential and leaf water potential, and according to the soil drought, the photosynthetic rate and the transpiration rate decreased. The WUE (water use efficiency) showed lower in summer than in fall.The photosynthetic rate and the transpiration rate of the Cinnamomun camphora trees and the Pasania edulis trees also decreased according to the leaf water potential, but the inflence of high temperature in summer on these two species were less than on pasania edulis trees.(2) The growth of Cinnamomun camphor trees in Horai Sea-side ParkThe soil comditions and root development of the Cinnamomun camphora trees planted in Horai Sea-side Park were investigated in spring in 1994. This park was on the reclaimed land, and the trees were planted about 20 years ago. However, the soil was compacted very densely. So, the root systems of the trees were very poor.The soil improvement was dune in spring in 1994, and the investigations of the soil condition and the root development were carried out in winter in 1995. As the results, it was clear the effects of the soil improvement on the root development.