Regulation On Soybean Flower And Pod By Foliage Applying Plant Growth Regulators In Different Development Stages

The experiment was conducted in the test site for soybean of Heilongjiang BaYi Agricultural University(which lies in Lin Dian County) from 2009 to 2010 in the field.. Glycine max (L.) Merr.'Hefeng50(H50)''Ken Nong 4(K4)'were used as the experimental materials, and the test method was field test. The regulation effects of three plant growth regulators (PGRs) of 2,3,5-Triiodobenzoic acid(TIBA), uniconazole (S₃₃₀₇) and diethyl aminoethyl hexanoate(DTA-6) on the flower and pod in soybean were investigated by spraying in V3(Third-node stage), R1(Beginning bloom stage)and R3(Beginning pod stage)stages, respectively. The results showed that:1. The number of pods and flowers of soybean can be significantly increased by S₃₃₀₇ and DTA-6 spraying in V3 stage, and S₃₃₀₇ could effectively reduce the rate of abscission and increase the number of pods. The number of flower and mature pods could be significantly increased by S₃₃₀₇ and DTA-6 spraying in R1 stage, and DTA-6 could effectively prevent the abscission of pods and increase the number of mature pods. The number of the pod and the mature pod could be significantly increased by three plant growth regulators spraying in R3 stage, which could effectively prevent the abscission, and the effect of TIBA was the best.2. The cellulase and PG activities of soybean flowers and pods were decreased by spaying TIBA,S₃₃₀₇ and DTA in V3 stage;but the effect was not signigicant to flowers. PGRs decreased abscission cellulose and PG activity significantly by spaying in R1 stage,the regulation effect of DTA-6 was the best,S₃₃₀₇ was the second.PGRs decreased abscission cellulose and PG activity and abscission pod by spaying in R3 stage , the regulation effect of TIBA was the best,S₃₃₀₇ was the second.3. The comparison of spraying of the plant growth regulators at different stages showed that the plant height were promoted by DTA-6 treatment, and prevented by TIBA and S₃₃₀₇ treatments. The spraying of S₃₃₀₇ and DTA-6 at different stages had promoting effects on the dry weight of the leaf, petiole, stem and pod, which indicated that the plant growth regulators could increace the accumulation of dry matter, thereby increasing the yield. The dry weight of the leaf, stem and pod was prevented by spraying TIBA in V3 stage.4. Spraying of S₃₃₀₇ and DTA-6 at different stages increased the content of chlorophyll, the photosynthetic rate, transpiration rate, LAI and LAR,but the spraying of TIBA had prevented LAI and LAR. The significant effects were the S₃₃₀₇ and DTA-6 treatment in V3 stage. The significant effects was DTA-6 treatment, and then S₃₃₀₇ at R1 stage. The significant effects were TIBA and DTA-6 treatments in R3 stage.5. Spraying of S₃₃₀₇ had regulatory effect on C/N of soybean leaves, and TIBAå’ŒDTA-6 decreased C/N of soybean leaves. Spraying of plant growth regulators in R1 and R3 stages increased C/N of soybean leaves .Spraying S₃₃₀₇ and DTA-6 in V3 stages had promoting effect on the content of sucrose, soluble sugar, starch and total plant sugar in leaves, and TIBA decreased the content of sucrose and starch , DTA-6 decreased the content of starch .In R1 stage , spraying of plant growth regulators increased the content of sucrose, soluble sugar, starch and total plant sugar in leaves,and decreased the content of starch and activity of inverting enzymes. In R3 stage, spraying of plant growth regulators increased the content of carbohydrate metabolize indexs ,effectively decreased activity of inverting enzymes,increased the level of carbohydrate metabolize .It provided a large of Carbon metabolism assimilation to reduce the falling of pods.6. Spraying of plant growth regulators at different stages increased nitrate reductase activity, and increaced the content of soluble soybean protein, nitrate, free amino acids and plant nitrogen, which provided more supply of nitrogen metabolic rate in order to prevent the abscission of pods. 7. Spraying of S₃₃₀₇ and DTA-6 at different stages increased the yield and the harvest index of soybean, and reduced by spraying of TIBA at V3 stage. Spraying of S₃₃₀₇ significantly increased soybean yield at V3 stage, the spraying of DTA-6 significantly increased yield at R1 stage,and Spraying TIBA significantly increased yield at R3 stage. Spraying of S₃₃₀₇ and DTA-6 increased the quality of seed at V3 stage, but the spraying of TIBA has no effect. Spraying of S₃₃₀₇ and DTA-6 increasthe quality of seed at R1 stage, but the spraying of TIBA has no effect. Spraying of plant growth regulators at R3 stage increasthe quality of soybean seed, and the treatment of S₃₃₀₇ had no significant effect.8. In conclusion, the regulation effect of S₃₃₀₇ was the best by spraying in V3 stage; the regulation effect of DTA-6 was the best by spraying in R1 stage; the regulation effect of TIBA was the best by spraying in R3 stage.