不同生长阶段水分胁迫对冬小麦生长发育和产量形成的影响

o investigate the influences of water stress at different growth stages on the growth and yields of winter wheat, field experiments have been conducted under a rainout shelter in the Guanzhong Plain of China during two seasons of 2012-2013 and 2013-2014. The changes of several eco-physical characteristics of wheat growth were measured and compared, including height, leaf area index (LAI), phenology, biomass, and yield. The whole life cycle of wheat was divided into five main stages (wintering, greening, jointing, heading, and grain filling). Water stress occurred at two continuous stages, while irrigations were applied at other stages, which resulted in four different levels of stress period (D1-D4). There were two irrigation levels of 40 mm (I1) and 80 mm (I2). There were a total of eight treatments that had three replicates and followed a split-plot experiment design. An extra rainfed treatment was arranged outside. The results showed that wheat growth could be obviously influence by water stress when water stress occurred before jointing since height, LAI and biomass all became lower. However, the influences on wheat growth and yield were not notable when water stress occurred after jointing stage. Water stress can shorten the life cycle wheat. The maximum advancing of maturation date could be nine days. For the same irrigation level, relative higher numbers of spikes and grains could be attained when there were water stresses at heading and gain-filling stages, but unit grain weight became lower. On the contrary, higher value of unit grain weight could be gotten when there were irrigations at heading and gain-filling stages, but the numbers of spikes and grains became lower. There was a clear interaction between the intensity and occurring stage of water stress. In general, the greening and filling stages were the critical periods for wheat crop consumption to guarantee a higher yield.