水氮耦合对黍稷光合特性及产量的影响

目前，水和肥已成为旱地农业发展的主要限制性因素。在干旱半干旱地区，研究水肥耦合对作物的光合特性及产量的影响，可以为旱作区农作物的高产、稳产提供一定的理论指导。以‘5283黄’和‘晋黍5号’两个黍稷品种为材料，通过盆栽试验，在黍稷全生育期设3个水分水平和3个氮素水平，研究水氮耦舍对黍稷光合特性及产量的影响。结果表明：在灌水量相同的条件下，适量施氮均使黍稷叶绿素含量、PSⅡ的潜在活性（Fv／F0）、可变荧光与最大荧光之比（Fv／Fm）、净光合速率（Pn）和蒸腾速率（Tr）升高，提高了叶片进行光合作用的能力；不同处理的Pn、气孔导度（Gs）、Fv／F0和Fv／Fm随着生育期的推进先升高后降低，表现为低一高一低的变化趋势，拔节期达最大值；叶绿素含量、Tr、胞间CO2浓度（Ci）均随生育期的推进逐渐增大，抽穗期达最大值。重度水分胁迫下各处理受害程度显著高于其他水分处理，不施氮条件下的各处理受害程度大于其他施氮处理，且‘晋黍5号’对水分和氮素较为敏感。在重度水分胁迫（W1）和中度水分胁迫（W2）条件下，施用氮肥能明显缓解干旱胁迫带来的不利影响，同时在养分缺乏的地区，适量增加灌水量均可以明显改善黍稷叶片的光合能力，延缓叶片衰老，有利于作物维持较大的光合面积和较长的光合作用时间，改善籽粒特性和增加穗粒数，提高产量。

Effect of Irrigation and Nitrogen Supply on Photosynthetic Characters and Yield of Broomcorn Millet

Water and fertilizer has become the main restrictive factors of dryland agriculture development at present. In the arid and semi-arid area, the study about irrigation and nitrogen supply on photosynthetic characters and yield of crops can provide some theoretical guidance for high yield, stable yield in dryland crop. The effects of irrigation and nitrogen application on photosynthetic characters and yield of broomcom millet was studied in a pot experiment. ＇5283 huang＇ and ＇Jinshu 5＇ two varieties of proso were experimental materials. Two factors including 3 irrigation levels and 3 nitrogen fertilizer levels were set up. The results indicated that, chlorophyll content, Fv/Fo, Fv/Fm, photosynthetic rate and transpiration rate increased with increasing nitrogen supply at equivalent moisture. The capacity of the leaves for photosynthesis was enhanced. In different treatments, photosynthetic rate, Gs concentration, Fv/Fo and Fv/Fm increased first then decreased with the growth period increased, changing trends were low-high-low, jointing stage was reached to the maximum value. Chlorophyll content, transpiration rate, stomatal conductance increased with the growth period increased, heading stage was reached to the maximum value. Degree of victim about the treatments under severe moisture stress was significantly higher than the other moisture treatments. Degree of victim about the treatments that had no nitrogen fertilizer were significantly higher the other amount of nitrogen, and ＇Jinshu 5＇ were more sensitive to water and nitrogen. Under severe water stress and moderate water stress, adverse the nitrogen fertilizer supply could ease drought stress. At the same time, adverse the amount of water could improve photosynthesis of leaves of proso, delay leaf senescence, conducive to crop to maintain photosynthesis in photosynthetic larger area and longer time in areas where lack of nutrients, it could also improved kernel characteristics and increase grain number and increased oroduction.