亏缺灌溉下小麦水分利用效率与光合产物积累运转的相关研究

Relationship of Water Use Efficiency with Photoassimilate Accumulation and Transport in Wheat under Deficit Irrigation

在大田栽培条件下,以小麦旱地品种晋麦47和西峰20、水旱兼用型品种石家庄8号和水地品种4185为材料,分别进行0水(T0)、一水(T1)和二水灌溉(T2)处理(每次灌水量60 mm),研究了光合速率、叶面积指数、干物质积累与分配、根系分布、耗水量、产量因子与水分利用效率(WUE)的关系。结果表明,在拔节前不灌溉,拔节到开花期亏缺灌溉,促进干物质积累和深根发育。随着灌溉水的增加,耗水量显著增加,产量和WUE与耗水量呈二次曲线关系。T0处理显著减少了干物质积累和成穗数,产量、经济系数(HI)和WUE最低。T1和T2产量的提高主要是增加了穗数和穗粒数。灌浆期水分亏缺降低了光合速率(Pn)和气孔导度(Gs),加速了功能叶片的衰老,但诱导了花前储存碳库的再转运,显著提高了HI和产量。因此,在拔节和开花期亏缺灌溉促进根系生长,提高了土壤水分的利用效率。而产量和产量WUE的提高主要是由于增加了灌浆期叶片的Pn和光合功能持续期,促进花前储存碳库的再转运,显著提高了HI。

Deficit irrigation in winter wheat （ Triticum aestivum L. ） has been practiced in the areas with limited irrigation water resources. The objectives of this study were to （i） investigate the effect of different deficit irrigations on yield and water use efficiency （WUE） ; and （ii） understand the physiological mechanisms of drought resistance, water saving and high yield under deficit irrigation in wheat. A field experiment was conducted using four wheat （Jinmai 47 and Xifeng 20 in dryland, Shijiazhuang 8 and 4185 in dry-wet land） with the treatments of rainfed （T0）, watering once at jointing （T1） and watering twice at jointing and anthesis （T2）. The amount of irrigation is 60 mm each time. The physiological parameters measured included net photosynthetic rate （ Pn ）, stomatal conductance （ Gs ）, leaf area index, dry matter accumulation and partitioning, root distribution, yield components and water consumption, as well as the corelation between WUE and yield components. Non-irrigation before jointing and deficit irrigation from jointing to anthesis could significantly improve dry matter production and deep root development, and significantly save irrigation water. Both grain yield and WUE were conically related with water consumption. Non-irrigation significantly decreased dry matter accumulation and number of spikes. Low available soil water from booting to late grain filling resulted in the lowest biomass, grain yield, harvest index and WUE in TO treatment. The increased yield in T1 and T2 was mainly contributed by the increased number of spikes, and seeds per spike. The increased WUE was mainly contributed by increased HI. Water stress during grain filling reduced Pn and Gs, and accelerated photosynthetic leaf senescence. However, the water stress during grain filling induced remobilization of pre-anthesis carbon reserves to grains, significantly contributing the increased grain yield and HI. It is concluded that deficit irrigation between jointing and anthesis can change the root spread and develop deep root system, and significantly increase soil water use efficiency. Increasing both photosynthesis and photosynthetic duration, as well as increasing the remobilization of pre-anthesis carbon reserves and HI must increase wheat yield and WUE.