小麦和大麦吸收N、P、K的动力学参数及相互作用机制研究

试验表明，液培4周的小麦和大麦对N03＾－、NH／和K＾＋的吸收均符合Michaelis—Menten动力学方程．小麦对4种养分离子的吸收能力表现为K＾＋＞H2P04＾－＞N03＾－＞NH4＾＋，大麦对4种养分离子的吸收能力表现为NO3＾－＞K＾＋＞H2P04＾－＞NH4＾＋；对于NO3＾－离子，小麦和大麦的吸收能力基本相等，而对K＾＋、NH4＾＋，及H2P04＾－离子，小麦对它们的吸收能力明显地大于大麦，这可能与大麦抵抗低K＾＋、低H2P04＾－及低NH4＾＋的能力较强有关；相对于K＾＋存在而言，营养介质中NH4＾＋存在，有助于小麦对N03＾－的吸收；相对于NO3＾－存在而言，营养介质中H2PO4＾－存在有助于大麦对K＾＋的吸收。

Absorption Kinetics of N, P and K and Mechanism of Ion Mutual Effect in Wheat and Barley

Solution culture experiments are conducted to obtain the uptake kinetics of N, P and K in wheat and barley with different N, P and K concentration solution. Results showed that the absorption rate of wheat and barley on NO - 3, NH + 4, H 2PO - 4 and K + can be described by Michaelis Menten kinetics. The absorption ability of wheat for the four ions was K +>H 2PO - 4>NO - 3>NH + 4, but for barley, the absorption ability was NO - 3>K +>H 2PO - 4>NH + 4. There was the same absorption rate in wheat and barley for NO - 3 ion, but for K +, NH + 4 and H 2PO - 4, the absorption ability of wheat was larger than that of barley. This will be likely to have relation in which barley have better ability to strive against low K +, P and NH + 4. In solution medium, NH + 4 will redound to wheat absorption of NO - 3 as compared to K +, while H 2PO - 4 will redound to wheat absorption of K + as compared to NO - 3.