水氮耦合对燕麦光合特性的影响

为了解水氮耦合对燕麦旗叶光合特性的影响,揭示不同水分条件下的氮肥效应,探明适宜燕麦生长的最佳水氮条件。以燕科1号为供试材料,在防雨棚内肥水控制的条件下,研究燕麦在不同水氮条件下净光合速率(Pn)、胞间CO2摩尔分数(Ci)、气孔导度(Gs)、蒸腾速率(Tr)及水分利用效率(WUE)的变化规律。结果表明,在供水欠缺的W1、W2条件下,适量的施氮可以提高水分胁迫下植物的渗透调节能力和抗旱性,达到增加Pn、Ci、Gs、Tr及WUE的目的;在供水较充足的W3条件下,施氮可明显提高燕麦各光合生理指标,而且与施氮135kg.hm-2(N3)耦合,可充分发挥水氮互作优势,为最佳水氮耦合模式,但当施氮量达180kg.hm-2时,各光合生理指标有下降趋势,水氮互作优势减弱。可见,水、氮水平以及水氮互作效应在一定程度上决定燕麦的光合生产能力。水、氮两因素及其互作效应对Pn、Tr、Gs、Ci、WUE的影响均达到显著或极显著水平。

Effects of Water Nitrogen Coupling on Photosynthetic Characteristics of Oat

In order to realize effects of water nitrogen coupling on photosynthetic characteristics of oat and reveal nitrogen fertilizer effects under different water nitrogen treatment, and elucidate the feasible combination of water and nitrogen for better growth of oat.With Yanke 1 as experimental material, photosynthetic rate(Pn), transpiration rate(Tr), intercellular CO₂ concentration(Ci), stomatal conductance(Gs) and wate use efficiency (WUE) of oat were studied under the controlled conditions.The results showed that under water stress conditions of W1 and W2, a moderate amount of nitrogen could improve osmotic adjustment ability and drought resistance of oat, and result in enhancing Pn, Ci, Gs, Tr and WUE.Under the W3 conditions, nitrogen application could improve the photosynthetic physiological indexes obviously, giving full play to water and nitrogen interactions advantage under the condition of 135 kg·hm^-2 nitrogen application, which was the best combination of water nitrogen interaction management model.Applying 180 kg·hm^-2 nitrogen resulted in negative effect of water nitrogen coupling.Variance analysis showed that there was significant or very significant interaction between irrigation regime and amounts of nitrogen application.