不同水氮水平对全立架露地栽培伽师瓜光合特性与水分利用效率的影响

探讨不同水氮水平对全立架露地栽培伽师瓜膨果初期挂果叶片光合特性及水分利用效率日变化的影响,以期为全立架露地栽培伽师瓜的合理水氮管理提供依据。田间试验于2012年在新疆全立架栽培伽师瓜主产县岳普湖县进行,灌水定额3个水平为:5250、6750、8250m3·hm-2;施氮量3个水平为:0、225、375kg·hm-2;灌溉方式为沟灌。结果表明:全立架露地栽培伽师瓜膨果初期挂果叶片净光合速率日变化及气孔导度日变化均呈双峰曲线型,不同水氮水平下净光合速率的峰值分别出现在11:00-13:00和17:00左右,光合"午休"出现在15:00左右。6750、8250m3·hm-2的灌水量提高叶片净光合速率、气孔导度和蒸腾速率的效果明显,且具有较低的气孔限制值,但8250m3·hm-2高灌水量的瞬时水分利用效率低于6750m3·hm-2灌水量6.7%;适宜的灌水量下,225、375kg·hm-2的施氮量可提高叶片的净光合速率和瞬时水分利用效率,且程度相近。适宜喀什地区全立架露地栽培伽师瓜膨果初期挂果叶片进行光合作用的水氮组合为施氮素225kg·hm-2、灌水6750m3·hm-2,其在获得较高净光合速率的同时,也有助于水分利用效率的保持。

Photosynthetic Characteristics and Water Use Efficiency of Trellis-Cultivated Melon Grown under Different Irrigation and Nitrogen Levels

Leaf photosynthetic characteristics and water use efficiency of trellis-culture melon(Cucumis melo var. saccharinus Naud)were researched during early stage of fruit rapid-growth under different nitrogen(N)and irrigation(I) levels. Field experiment was conducted in 2012 at main trellis-culture melon producing areas. Irrigation treatments were applied at the rates of 5 250,6 750 and 8 250 m3 ·ha-1 . The N treatments were 0,225 and 375 kg·ha-1 . Water was applied to the field with conventional furrow irrigation. The results showed that daily changes of Pn and Gs of trellis-culture melon leaf presented a bimodal curve,peak value appeared at 11:00-13:00 and 17:00,midday depression appeared at 15:00. Irrigation quantity (6 750,8 250 m3 ·ha-1 ) improved the Pn,Gs and evaporation of the melon leaf,and obtained lower Ls. The Pn and WUE increased significantly at the application amount of nitrogen at 225,375 kg·ha-1 ,and no significant difference between 225 kg·ha-1 and 375 kg·ha-1 . The optimum combination of irrigation and nitrogen were nitrogen 225 kg·ha-1 ,irrigation water 6 750 m3 ·ha-1.