Study On Photosynthetic Characteristics Of Six Greening Tree Species In The City Of Harbin

In order to comprehensively understand the eco-physiological characteristics of the greening trees, increase the diversity of the garden greening trees and their ecological function and provide the scientific basis for choosing the greening trees species in Harbin. In this study, we studied on the photosynthetic character of Acer ginnala Maxim., Betula platyphylla Suk., Tilia mandshurica Rupr, Tilia amurensis Rupr., Quercus mongolica Fisch.ex Turcz. and Phellodedron amurense Rupr. using the portable photosynthetic measuring system(Li-6400). We made a comparison on the differences of the physiological indexes such as the maximum net photosynthetic rate, respiration rate, transpiration rate, apparent quantum yield, light saturation point, light compensation point and etc. of the six species between the months and species. The result showed thatThe diurnal variation curves of the photosynthetic rate of the six species showed different in different months.The diurnal variation curves of the transpiration rate of the six species were the single peak on the whole, and the peak value appeared in 12:00～13:00. The diurnal variation of the transpiration was basically in step with the diurnal variation of the photosynthetic rate. The diurnal mean values of the transpiration rate of the six species were different in different months. The result showed that the diurnal mean values of the transpiration rate between the six species were remarkably different; the diurnal mean values of the transpiration rate of Acer ginnala Maxim., in the other months the diurnal mean values of the transpiration rate had no significant difference.The diurnal mean values of the transpiration rate of every species were different in four month.The environmental condition in the green house had significant influences on the physiological indexes of the six tree species. The highest values of the net photosynthetic rate of the six species in March and April were basically in step with the highest values of the illumination intensity and the peaks appeared at about 12:00. The highest values of the net photosynthetic rate of the six species in May and June were not quite in step with the highest values of the illumination intensity. The peaks of the net photosynthetic rate and photosynthetically active radiation of the six species respectively appeared at 9: 00 am and 12:00 am.The variation trend of the stomatal conductance and net photosynthetic rate were basically consistent.The differences of the maximum net photosynthetic rate between four months of Acer ginnala Maxim.There were differences in the diurnal assimilation amount of the carbon between the six green tree species and in the same species between four months.The differences of the light saturation point of Acer ginnala Maxim.The light compensation points between six species had no significant difference.The apparent quantum yield between six species and four months all had no significant difference.The interspecies variations of WUE (water use efficiency) were significantly, the WUE of Acer ginnala Maxim.To sum up the above arguments, according to the characters of high photosynthetic capacity and making good use of the glare of Acer ginnala Maxim, and Betula platyphylla Suk., the above species could be considered to be planted in the good illumination condition place. Considering the illumination intensity and moisture and combining with the climate condition of Harbin, Acer ginnala Maxim., Tilia mandshurica Rupr, and Quercus mongolica Fisch.ex Turcz. which could make good use of the moisture should be first considered when selecting the greening trees on the soil with low water content. However, the trees with high photosynthetic capacity could be properly first considered on the soil with high water content, such as Acer ginnala Maxim., Quercus mongolica Fisch.ex Turcz. and Tilia mandshurica Rupr..