不同基因型小麦对低氮胁迫的生物学响应

采用溶液培养的方法,研究了不同基因型春小麦(加春1、2、4号)根系对低氮胁迫的生物学响应、小麦苗期氮素吸收、分配的基因型差异以及与根系形态之间的相关关系,结果表明,⑴低氮胁迫下小麦的根重、根长、根条数、根系总吸收面积与活跃吸收面积、根系SOD及POD活性、根系活力均明显降低,但不同基因型间的差异明显。低氮胁迫下加春2号小麦根系具有较好的形态学与生理学性状,并向地上部分配了较大比例的氮素,地上部氮累积量占总氮量的百分率比其它两种基因型分别高7.6%和8.2%,氮的利用率也比其它两种基因型高8.0%和9.9%。加春2号比其它两个基因型更能适应低氮环境胁迫。⑵在低氮胁迫下,春小麦根重、根总长度、根系活力、根系总吸收面积及活性吸收面积与总吸氮量呈显著线性相关,而在高氮水平下无相关关系,表明在氮素胁迫条件下,根系形态对氮吸收率起重要作用。

The Biological Response of Different Genotypes Spring Wheat Root System to Low Nitrogen Stress

Three wheat varieties (Jiachun1,Jiachun2 and Jiachun4) were used in order to compare the genotypic variations in total N uptake, N partition between shoot and root and its relation to root morphological and physiological characters under low nitrogen stress with solution culture. The results showed that (1) Comparing with the control group, the spring wheat seedling under low nitrogen stress has small height and short root length. And numbers of root, the activity of SOD and POD of root, total root length, total absorbing area, root dry weight, and active absorbing area and root activity decreased drastically. Jiachun2 was most tolerant to low concentration of N in the genotypes; it partitioned a larger amount N to its shoot in comparison with the other varieties. The percentage of shoot N accumulation to total N accumulation was increased by7.6 % and 8.2%. The utilization efficiency of N also increased by 8.0 % and 9.9%. (2) Total N uptake was significantly and positively correlated to root dry weight, total root length, root activity, total uptake area and active uptake area under low nitrogen stress. This indicates that genotypes with large root systems are able to obtain more N from low N medium. When N is not a limiting factor for plant growth, root morphology becomes less important in N uptake.