Damage and compensatory effects of winter drought on winter wheat

Field experiments were carried out to investigate the damage and compensatory effects of winter drought on winter wheat. The results of the study show that, after winter drought, the growth and development of winter wheat, display obviously dual effects of damage and compensatory. The productive tiller percentage increases while spike number per hectare reduces. Plant height does not change significantly, but internode under ear becomes shorter. Tillering before winter grows stouter. The first leaf of spring is larger but the flag leaf is much smaller. The stomata density of flag leaf increases while the stomata area reduces. Epidermal cells are decrescent, and the cell wall becomes more undulant. The ring number of mesophyll cells of flag leaf is reduced to 2-4, and there are rarely cells have ring number above 10. The number of chloroplasts of the mesophyll decreased and some of the chloroplasts leave the cell wall, free in the cytoplasm. The growing period becomes shorter, the periods of flagging stage, flowering stage and maturity stage come 4-7 days in advance, the filling stage shorten 5-7 days than CK. Winter drought decreases photosynthetic rate of flag leaves. Kernels per ear, 1000 grain weight, ear length and yield all become less. The inspiration effect in a short time after rewater cannot compensate the damage of winter drought.