【摘要】 以当地青杨作对照,对临夏85杨光合速率、枝干承载叶面积及年干物质生产量进行测定分析,结果表明:⑴临夏85杨年平均光合速率较青杨低20%,5～7月差异较大,8～10月差异不明显。⑵杨树枝干横断面积与其承载叶面积呈线性相关。临夏85杨承载叶面积随枝干粗度的增大而增长的趋势远强于青杨,直径为6cm的枝干,其叶面积是青杨的1 336倍;同粗度枝干承载叶面积的最大比值为1 3867。⑶叶片年生产干物质量,临夏85杨为0 8244kg/m2,青杨为0 9945kg/m2,直径为6cm的枝干,年生产的干物质量,临夏85杨较青杨提高11 1%。叶面积的剧增是临夏85杨生长量高于青杨的主要原因。更多还原

【Abstract】 Using local P.cathayanaRehd as check, the authors determined the photosynthesis speed, the sustainable total area of the leaves on the branch and the photosynthesis dry product of a year of Populus× ’Linxia 85 ’.There are some determination results:(1) The average photosynthesis speed of a year of Populus× ’Linxia 85’ is 20% lower than P.cathayana.The differences of photosynthesis speed of the two breeds are obvious during 5～7 months and small during 8～10 months.(2) The section area of the branch and the sustainable total area of the leaves on the branch show the linear correlation.The trend of increase of the sustainable total leaves area on the branch with the increase of branch dry product of Populus × ’Linxia 85 ’is greatly than that of P.cathayana.The sustainable total area of the leaves on 6 cm diameter branch of Populus ×’ Linxia 85 ’is 1.336 times than that of P.cathayana.The maximum proportion of the sustainable total leaves area on the same size diameter branch is 1.386 7.(3) That the dry product of per square meter of the leaves of Populus× ’Linxia 85’ is 0.824 4 kg, P.cathayanais 0.994 5 kg.During a year, the dry product of leaves on the branch with 6 cm diameter of Populus× ’Linxia 85’ is 11.1% more than that of P.cathayana.So the great increase of leaves area is the main factor which lead to the growth volume of Populus× ’Linxia 85’ is more greatly than that of P.cathayana.更多还原