Effects Of Drought Stress On Soybean Nutrients Absorption,Yield And Related Enzyme

Soybean is main source of vegetable protein and oil of human,water is a key factor limiting the soybean yield. With the demand growth for soybean in recent years, learning the characteristics of soybean water requirement,enriching the regular of soybean water requirement in growth stages, provide a scientific basis for science irrigation and improving utilization of water.This experiment was conducted from 2013 to 2014 with sand culture. The irrigation was conducted in a glass shed. The varieties of experiment included HN44 and HN65. Drought stress was conducted in the different growth stages, to research theeffects of drought stress on soybean nutrients absorption, yield and related enzyme. The results showed that:Compared with the control, drought stress treatment inhibited the N P K elements absorption and accumulation of soybean plants. In the 5% PEG drought stress treatment, the accumulation of nitrogen and phosphorus of soybean seeds was mostly affected by drought stress at R5. The HN44 seeds accumulation of nitrogen and phosphorus decreased 37.26%, 42.43%, HN65 decreased 37.24%, 39.84%. In the 10% PEG drought stress treatment, the accumulation of nitrogen and phosphorus of soybean seeds was mostly affected by drought stress at V3. The HN44 seeds accumulation of nitrogen and phosphorus decreased 43.15%, 61.12%, HN65 decreased 49.5%, 67.57%. The potassium accumulation of soybean seeds was mostly affected by drought stress at R5. Compared with the non-drought tolerant variety HN 65 the drought-tolerant variety HN 44 was less affected by drought. The soybean N P K accumulation concentration was lower in the high concentration of 10% PEG drought stress than low concentration of 5% PEG drought stress.The regular of SOD and POD activity of soybean leaves in the different drought stages was basically the same, the trend has a transient increase and then significant reduction, and the stronger the degree of drought stress the influence was more obvious. The regular of MDA and Pro content of soybean leaves in the different drought stages were basically the same,showed a significant upward trend after drought stress, the stronger the degree of drought stress the influence was more obvious. Compared with the non-drought tolerant variety HN 65 the drought-tolerant variety HN 44 was less affected by drought. Comparing the three periods of drought stress, the SOD, POD activity and MDA content of soybean leave were mostly affected by drought stress at V3,Pro content of soybean leave was mostly affected by drought stress at R5.Compared with the control, the soybean plant soluble sugar content in the drought stress treatment increased at V3,decreased at R2 and R5. Compared with the low concentration of drought stress high concentration of drought stress was affected more significantly. The soluble protein content of soybean leaves after drought stress treatment at V3 and R5, low concentration of drought stress has a transient increase then a significant reduction,high concentration of drought stress decreased significantly. The soluble protein content decreased significantly after drought stress treatment at R2,the stronger the degree of drought stress the influence was more obvious. The regular of soybean leaves chlorophyll content in the different drought stages was basically the same, during drought stress chlorophyll content was significantly lower than the control, the high concentration of drought stress affected the chlorophyll content significantly. Compared with the non-drought tolerant variety HN 65 the drought-tolerant variety HN 44 was less affected by drought. Comparing the three periods of drought stress,the soybean leave soluble protein content was mostly affected by drought stress at V3,the two treatments of HN44 decreased 42.86% and 57.14%, HN65 decreased 65.38% and 76.92%. The soybean leaves chlorophyll content was mostly affected by drought stress at R5,the two treatments of HN44 decreased 52.77%and 65.51%, HN65 decreased 59.61% and 72.47%.Compared with the control, the dry matter accumulation of soybean plant was inhibited by drought stress treatment, the inhibitory aggravation increased with the drought stress concentration increasing; the dry matter accumulation of soybean was mostly affected by drought stress at V3. The soybean yield was significant decreased by drought stress, mainly expressed in the reduction of seed weight of per plant and effective number of pods, the soybean yield was mostly affected by drought stress at R5. The two treatments soybean yield of HN44 decreased 18.29% and 24.24%, HN65 decreased 19.74% and 42.46%. Compared with the non-drought tolerant variety HN 65 the drought-tolerant variety HN 44 was less affected by drought. From the view of two varieties, the soybean yield was lower in the 10% PEG drought stress treatment than the 5% PEG drought stress treatment.