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

1994年采用夏、秋两季控制浇水的方法测定了不同土壤水分条件下樟树的光合速率和蒸腾速率，1995年采用相同的方法测定了樟树、樟树和白桦树的光合速率和蒸腾速率。以及在丸江市胡来海滨公园种植的香樟树的生长情况。(1)土壤水分条件与树木生长的关系：即使土壤水分充足，夏季杜鹃花的光合速率也会出现中午的下降。午间低潮的原因似乎是高温。当叶温超过35℃时，光合速率开始下降。蒸腾速率随叶温升高而增加。结果表明，土壤水势与叶片水势呈密切相关，土壤干旱程度不同，光合速率和蒸腾速率降低。水分利用效率（WUE）夏季低于秋季。樟树和杜鹃的光合速率和蒸腾速率也随叶片水势的变化而降低，但夏季高温对这两种树种的影响小于杜鹃。1994年春，对滨海公园种植的樟树的土壤条件和根系发育情况进行了调查。这个公园在填海土地上，这些树是大约20年前种的。然而，土壤被压得很密。所以，这些树的根系非常贫瘠。1994年春季进行土壤改良，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的影响较为明显。

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.