Influence Of Foliage Spray Of Phosphorous And Potassium On Grain Weight Of Winter Wheat And Response To Drought Stress

Grain weight is a part of the wheat yield components, affect the wheat yield significantly. In the process of transformation from the high to the super-high-yield wheat, the increase of grain weight is important. On wheat growth anaphase, gush out "three prevention" is essential for regulation, can prevent and control plant diseases and insect pests in wheat, dry-hot wind disasters, improve wheat grain weight. Potassium phosphate monobasic is wheat "one spray is three" essential constituent. The grain-filling stage spraying potassium phosphate monobasic can drastically improve the wheat grain weight. But what about the mechanism of potassium phosphate monobasic controls the grain grouting, and the potassium phosphate monobasic under different water conditions on wheat grain grouting control effect, are not obvious. Based on this, this study choose different spike type wheat varieties, the flowering period spraying suitable concentration of potassium phosphate monobasic, sodium dehydration phosphate, potassium chloride solution, the observation different grain of grain filling, simultaneous determination grain endogenous hormones, flag leaf antioxidant activity, seed and stem sheath, such as the change of the carbohydrate content of potassium phosphate monobasic as discussed regulation of physiological mechanism of the grain grouting; Drought conditions in simulation field potted experiment was carried out, the wheat grouting period for two kinds of soil water treatment(normal water and drought stress), flowering period spraying potassium phosphate monobasic, research the potassium phosphate monobasic under different water conditions affect the grain grouting. The results show that:(1) Two different varieties of grain of grain grouting with the same regularity, superior grain weight, initial filling rate and maximum grouting rate were significantly greater than the inferior grain, and the early grain-filling rates for superior grain is greater than the inferior grains, late more than strong performance for inferior grain. Spraying on the leaf of P, K elements for superior grain grouting had no significant effect, but can significantly promote the inferior grain of grouting. Play a role of time is not the same for each element, K element main role in the early, the grouting period can significantly improve the inferior grain weight and grain filling rate, biggest and average filling rate; And P element began to work since middle and later periods of the grouting, grouting is significantly influenced later days inferior grains weight and active grouting. Stem and sheath dry weight per plant after flowering showed a downward trend after increased first, and closely related to photosynthate transshipment and the grain-filling process. Spraying on the leaf of P, K elements significantly influence the change of stem and sheath dry weight per plant, K elements can significantly reduce the early stage of the grouting stem and sheath dry weight per plant, but later have no obvious change, reflecting the K elements to promote the early stage of the grouting transport of photosynthate to grain, but the impact in the late stem and sheath photosynthate to panicle transport sustainability; P of the early stage of the grouting stem and sheath have no obvious effect on photosynthate accumulation and transportation, but can slow down late plant stem and sheath dry weight decreased trend. Under different spraying on the leaf, the flag leaf net photosynthetic rate showed the same rule with stem and sheath dry weight per plant. Spraying on the leaf P, K elements for superior grain IAA, Z + ZR, ABA content in grain and ETH release rate had no significant effect; Spraying P to the inferior grain of endogenous hormone content and ETH release rate has no obvious effect, spraying K can significantly improve the inferior wheat grain, Z + ZR, ABA content and the ETH release rate was decreased obviously, but had no significant effect of IAA content. Spraying on the leaf P can significantly improve the wheat flag leaf during mid to later grain filling of SOD, POD, CAT enzyme activity, reduce MDA content, increase the flag leaf SPAD value, and delay the senescence of flag leaf; Spraying K, by contrast, promote the flag leaf senescence. Spraying on the leaf discernible influence on the grain weight and yield of two cultivars, but the ear number per unit area and grain number per panicle, do not have any observable effect. Foliar spraying P alone had no significant effect on grain weight and yield, spraying K can significantly increase grain weight and yield, the main reason is P and K role time in wheat grouting period is different, P role in late grouting and K role in the early, the grouting effect on grain weight and yield and K is greater. Under the interaction of P and K, potassium phosphate monobasic markedly improved the wheat grain weight, and increases wheat yield considerably.(2) Drought stress significantly reduced the grain filling rate, shorten the duration of grouting, and dramatically reduce the wheat grain weight. Under the condition of normal water, exogenous spraying potassium phosphate monobasic had no significant effect on superior grain filling, but dramatically improved inferior grain grouting, improve its grain weight. Under drought stress, exogenous spraying potassium phosphate monobasic significantly promote the superior and inferior grain grouting, and substantially increased grain weight. Drought stress significantly inhibited the stem and sheath of photosynthate transshipment to the grain, and exogenous potassium phosphate monobasic significantly promote the transport of photosynthate to grain, increase grain starch content, effectively ease the inhibitory effect of drought stress on wheat grain grouting, improved the wheat grain weight.