Study On Physiological And Biochemical Of Water Stress By Crops (Wheat-Maize)

Based on the study of wheat and maize, through different water control to observe wheat, maize, ecological indicators, physiological and biochemical parameters, morphology index, water use efficiency and crop using water law etc., the conclusion can be drawn as follows:(1) At winter turning green-the jointing and maize seedlings-jointing stage, water stress inhibits the growth of plant height, leaf area expansion and dry matter accumulation, inhibition consistent with the stress level; After rewatering there are different compensation effect at maize seedling and jointing stage of water stress, seedling water stress compensation effect is more obvious, pre-stress during and after the maize has been higher than the growth rate is basically in control, the end of fertility control has been little difference; maize jointing on sensitive to water stress, but the compensation effect after rewatering weak. Maize seedling to heading maturity greater consumption of water the faster processing of leaf area increase; tasseling medium-to-date with the filling of the leaf area decreases with increasing water consumption, water consumption through out the growing period and the daily growth of leaf area is the second related;(2) Different times and levels of water stress on photosynthetic performance of crops will have different impacts. Different times, levels and durations of water stress on photosynthetic performance of maize has different impacts. Seedling and jointing of water stress inhibits photosynthesis, in which photosynthesis on stomatal conductance, transpiration rate and degree of inhibition and the stress level, stress took a positive correlation. Jointing stage of the photosynthetic suppression is more obvious; effects of water stress experienced, the different stress times, coercion, maize photosynthetic performance of compensation with different results. Seedling stress after rewatering leaf net photosynthetic rate, transpiration rate showed two peaks changes occur midday depression. From the net photosynthetic rate, transpiration rate and stomatal conductance of relations, the stomata is an important factor affecting the size photosynthesis;(3) In the mild water stress, rate of decline in maize leaves little drop of chlorophyll. In moderate and severe water stress, chlorophyll content reduces larger; there is high content of chlorophyll at maize filling stage under severe stress;(4) Under water stress, crop leaf proline (Pro) a lot of accumulation, the more severe stress, the greater the accumulation. After rewatering, the content of Pro decreased. With water stress degree increasing, SOD activity increased and then decline, mild and moderate water stress higher than the control treatment, while treatment of severe lower than the control. SOD activity after rehydration and processing the same trend, but the gap between each treatment was not obvious.POD and SOD activity in different under water stress, POD activity showed a linear increase of POD activity undone after the water is lower than the control, no significant difference with the control (P<0.05). Water stress conditions, often occurring membrane lipid peroxidation, MDA at significantly increased under water stress, reflects the extent of damage to objects, the MDA content after rehydration highest in the treatment of severe, but mild and moderate treatment of MDA content slightly lower than controls, indicating severe damage on crop heavy, not easy to restore;(5) Drought inhibits root growth, with the reduction of soil moisture, root length reduces, total biomass decreases. By the histologic observation that catheter diameter hole reduces with water stress increasing, which is conducive to root under water stress conditions in a small amount of soil moisture slow consumption, in order to improving water use efficiency and increasing crop yields;(6) Root tips under different water stress distribution of the masses of polysaccharide results show that: with the severity of water stress, root tip increased polysaccharide, polysaccharide in the epidermal cells distributed mainly in free form, and in the root cap cells are mainly starch granules forms of distribution, with the accumulation of polysaccharide in turn increase the absorption capacity of roots, oxidation and reduction ability, increased root adaptation to drought.