| In order to studied the variation of non-structure carbohydrates in six different wheat varieties’ leaves(L) and roots(R) under drought stress. Six wheat varieties were cultivated under hydroponic condition in this experiment. Meanwhile,there were two treatments and a contrast treatment:the control treatment(CK,normal solution management conditions),15% PEG,20% PEG At the same time, For studying the effect of 0.5mmol?L-1 glucose on the drought resistance of wheat seedlings and on the wheat yield under water stress. Jinmai 47(JM47)and Zhengmai 9023(ZM9023) were cultivated under artificial climate chamber and field condition from 2013 to 2014.The main research results were as follows:1、The result displayed contents of non-structure carbohydrates including total soluble sugar, glucose, fructose, sucrose were decreasing with drought stress time extended, while Starch and fructan were on the contrary. Rewatering after previous drought stress made non-structure carbohydrates contents in leaves and roots approximated that of CK.The larger the drought sensitive coefficient was, the smaller the non-structure carbohydrates content’s change rate was. Drought sensitive coefficient had negative correlation with non-structure carbohydrates contents’ change rate. Correlation between change rate of soluble total sugar, fructose, starch and fructan and drought sensitive coefficient was significant. Dry matter weight was decrease under drought stress. Under both 15%PEG and 20%PEG,the drought sensitivity of six wheat varieties from high to low is Jinmai 47(JM47)、Aikang 58(AK58)、Zhoumai 22(ZM22)、Luohan 6 Hao(LH6)、Zhengmai 9023(ZM9023) and Xinong 979(XN979).2、Under water stress, the dry matter weight and plant height of wheat and root length were decreasing with increasing of the exogenous glucose concentration.However, when the concentration of glucose is higher than 0.5mmol?L-1, The change rate is on the contray.Result suggested suggesting that 0.5mmol?L-1glucose is the best option.3、 Under water stress, chlorophyll content of the wheat seedlings was decreased significantly and reached significant level compared with control, the wheat seedlings chlorophyll content can be effectively increased by glucose, but less than control levels; compared with the control, the chlorophyll content of wheat seedlings increased significantly after the adding glucose in nutrient solution under normal conditions, achieving significant level;In wheat seedlings water stress significantly lowerred the activity of SOD and POD, promoted the content of malondialdehyde to rise, adding 0.5 mmol?L-1 glucose in nutrient solution, the activity of SOD and POD was improved, the accumulation of malondialdehyde was suppressed, but CAT activity change rule is not obvious.In addition, soluble protein, ammonia nitrogen, nitrate nitrogen accumulation were suppressed under water stress;however,Adding glucose solution promoted the three products in wheat seedling accumulation. Activity of NR and GS which is key enzymes of nitrogen metabolic pathways is higher in strong drought resistance varieties than weak drought resistance varieties.Water stress reduced the activity of NR and GS, glucose can obviously promote the increase of NR and GS activity, change rate of two enzymes was the same to their productsincluding ammonia nitrogen and nitrate respectively. Research results in field showed: SPAD values increased after decreased trend with the growth period of wheat leaf, water stress reduced SPAD value. However, the SPAD value increased after spraying exogenous glucose, and reached significant level compared with the water stress. the SPAD value increased after adding glucose under water stress and reached significant level compared with the control, The result is in accordance with change rule of the chlorophyll content of wheat seedlings in artificial climate chamber.Results of wheat yield and the three elements of yield showed that the drought condition resulted in the decrease of the wheat acres ear number, grain number per spike, 1000 grain weight and yield. the wheat acres ear number, grain number per spike, 1000 grain weight and yield increased after glucose the processing, and significant, but still less than the control level.After adding glucose under normal conditions, several indexes have increased, but only the grain and yield reached significant level comparing with the normal conditions.As a result, glucose advantageous key enzyme activity increase of wheat nitrogen metabolism and the accumulation of related products. |
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