不同施氮量对6个黑杨新无性系光合特性的影响

Effects of Different Nitrogen Levels on the Photosynthesis Characteristics of Six New Clones of Populus deltoids

试验以6种新的无性系黑杨扦插苗为材料,以对照(0 g尿素/株)、低氮(3 g尿素/株)、中氮(6 g尿素/株)及高氮(9 g尿素/株)4个不同的氮水平处理各无性系扦插苗,测定各无性系苗木的Pn、Ci、Tr和Gs等光合参数,及光饱和点、光补偿点和最大光合速率等光响应曲线特征参数。结果显示,6种新无性系随着尿素施用量的增加,光合参数表现出不同的变化。光合参数的结果表明,3个无性系02-34-334、03-04-111和03-04-170对氮素利用率较高,在低氮水平下具有较高的光合能力,03-04-170是氮不敏感无性系,108则是喜氮的无性系。而综合光响应曲线的结果发现,在低氮条件下,02-34-334和03-04-111无性系在高光强下的适应能力要大于其他无性系。因此,这2个无性系适于在中国土壤氮贫瘠、光照强度大的西北地区推广。

The response of photosynthesis characteristics of Populus deltoids seedlings to different soil nitrogen levels is the important basis to select the clones with high nitrogen use efficiency.In this study,cuttings of six new clones were treated with four different nitrogen levels,i.e.CK（0 g urea per plant）,low level（3 g urea per plant）,medium level（6 g urea per plant）,and high level（9 g urea per plant）,and the photosynthetic parameters including net photosynthetic（Pn）,intercellular CO2 concentration（Ci）,transpiration rate（Tr）,and stomatal conductance（Gs）,as well as light saturation point（Ps）,light compensation point（Pc）,and maximum photosynthetic rate were measured under the greenhouse conditions.These six clones exhibited different changes in photosynthetic parameters with the increase of urea.The results of photosynthetic parameters showed that three clones,02-34-334,03-04-111,and 03-04-170,were the high-nitrogen-efficiency clones that had high photosynthetic ability under low nitrogen level,03-04-170 was a nitrogen insensitive clone,and 108 was a nitrogen-preferring clone.After integrating the photosynthetic parameters and characteristic parameters of light response curve,it was found that under low nitrogen condition,the cuttings of 02-34-334 and 03-04-111 exhibited higher adaptability than other clones.So these two clones would be suitable for poor soil and high light intensity,and can be extended in northern areas of China.