施肥对小麦旗叶光合特性的影响研究

Effect of fertilization on photosynthetic characteristics of wheat flag leaf

用LI-6400观测氮磷钾用量对小麦旗叶光合特性日变化的影响,试验设4个处理,分别为高氮低磷高钾(N4P2K2)、无氮无磷高钾(N1P1K2)、无氮高磷无钾(N1P3K1)和高氮高磷无钾(N4P3K1),试验结果表明:N4P2K2处理对小麦旗叶光合作用有利;而由于N4P3K1处理缺少钾元素且氮磷过量,小麦旗叶光合速率(Pn)较低;N1P1K2和N1P3K1处理下光合作用较弱。对同种处理下不同时期小麦旗叶光合速率日变化的比较,N1P3K1处理在3个生育时期的旗叶光合速率差别较大,N4P2K2与N1P1K2处理在各生育期光合作用的差别表现居中,N4P3K1处理各时期的旗叶光合速率差别最小。N1P1K2处理小麦成熟期的光合速率仍然保持较高水平,钾肥在小麦成熟期影响较大。

Daily variations in net photosynthetic rate of wheat flag leaf under different N, P and K rates were observed by LI-6400. Four treatments - high N （300 kg-hm-2） and K （75 kg.hm-2） with low P （32.5 kg＇hm-2） （N4P2K2）, high K without N and P （N1P1K2）, high P （65 kg＇hm-2） without N and K （N1P3K1） and high N and P without K （N4P3K1） were used in the experiment. The results revealed differences among daily variations in net photosynthetic rate （P,） of wheat flag leaf under different fertilization treatments. N4P2K2 treatment significantly promoted wheat flag leafP,. However, N4P3K1 treatment did not significantly promote wheat flag leafPn. Photosynthesis was generally weak in N1P1K,2 and N1P3K1 treatments. Daily variations in flag leafP, under the same treatment but at grain filling, milky and mature stages were also compared. Difference in Pn among three main growth stages was highest under NIP3K1 treatment and lowest under N4P3K1 treatment, it was medium under N4P2K2 and N1P1K2 treatments. Pn was relatively high under N1P1K2 treatment at mature stage. This suggested that K fertilizer influenced daily variations in photo- synthetic characteristics of wheat flag leaf at mature stage.