| Soybean is an important use of grain and oil crops in China. Greatly improving soybean yield and production capacity, it is main measures to make up for shortages domestically, to achieve soybean self-sufficiency, to protect national food security. Moreover move abscission of flowers and pods is one of the main obstacle factors in affecting the yield and production capacity of soybean. Therefore, researching mechanism of abscission in flowers and pods,finding solutions matters, has great significance for improved yield and production capacity in soybean. With the problem in production of soybean is high abscission rate of soybean flowers and pods, through comparative studies, research to regulation effects and mechanism of flowers and pods abscission by foliage sprayed two classes of plant growth regulators, to provide new trains of thought for cultivation of high yielding, high efficiency and cultivated engineering in soybean.DTA-6（diethyl aminoethyl hexanoate, Growth Promoter） and S3307（uniconazole,Growth Inhibition）, three semi-determinate soybean varieties of Suinong 28（SN28）, Kenfeng 16（KF16）,and Hefeng 50（HF50） were used as material. The research was cultivated by means of small region culture in field, mainly selected the optimal concentration in 2012. Different concentrations of DTA-6(0, 15 mg·L-1, 30 mg·L-1, 60 mg·L-1, 120 mg·L-1) and S3307(0, 25mg·L-1, 50 mg·L-1, 75 mg·L-1, 100 mg·L-1) ware foliage sprayed at R1 stage, water was CK, by researching flowers and pods of abscission and yield to select the optimal concentration of two classes. The experiment in 2013 basic on selected optimal concentration of DTA-6(60 mg·L-1),S3307(50 mg·L-1) and Water（CK）, preliminary experiment in 2012, further discuss and research from rate of flowers and pods abscission, carbohydrate metabolism, endogenous hormones, key abscisic enzymes and GmAC gene expression. The study from morphology-physiology-molecular level system to reveal the mechanism of flowers and pods abscission in soybean, break through the similar study of former studies are usually limited within either one aspect, the study is more system and farther.Conclusion:1. The regulating of DTA-6 and S3307 on flowers and pods abscission, yield and yield component factors.（1） DTA-6 and S3307 could significantly regulate flowers and pods abscission（P<0.05）;DTA-6 60 mg·L-1 was decreased abscission rate of soybean flowers and pods 7.16%-9.52% ±CK, increased yield 9.70%-17.41% ± CK; S3307 50 mg·L-1 was decreased abscission rate of soybean flowers and pods-6.71-9.74% ±CK, increased yield 7.26%-14.68% ±CK.（2） DTA-6 and S3307 increased pods per plant, the DTA-6 is better（16.32%±CK） than the S3307 in three varieties. On the whole, S3307 decreased seeds per pod（1.58%±CK）; DTA-6decreased seeds per pod（1.68%±CK）. 100-seed weight relatively stable, treatments and CK were not significantly.（3）In the mass yield DTA-6>S3307>CK in 2012, yield S3307>DTA-6>CK in 2013. DTA-6and S3307 could regulate flowers and pods abscission, promote yield（12.34%）.2. The regulating differences of DTA-6 and S3307 between normal and abscission of flowers and pods: DTA-6 and S3307 treatment decreased MDA activity, improved SOD, POD,AC and PG activity in normal pods. With the pod improving, each treatments MDA, SOD, POD,soluble sugar and soluble protein in abscission pods was significantly greater than normal pods,AC and PG in abscission pods was significantly lower than normal pods. Compared with normal pods at every treatment, physiological index of abscission pods were show that plasma membrane peroxidation was enhanced, balance of protective enzyme system was broken,reduced protein synthesis rates was greater than increased protein degradation rates, certain tissues was degradation, soluble material were increased; related abscission enzymes activity reduced.3. The difference in DTA-6, S3307 and CK on physiological indexes:（1） DTA-6 and S3307 increased GA3, decreased ABA; and increased GA3/ABA rate in leaves, pod shell and seeds.（2） The relative expression of abscission cellulase gene（GmAC）, was decreased（51.00%）by DTA-6 in KF16, and was decreased（47.32%） by S3307. GmAC was regulated by DTA-6 and S3307 result in inhibiting effect in soybean.（3） DTA-6 and S3307 enhanced protective enzymes function in normal and abscission of soybean pod shell; decreased MDA content; increased SOD, POD activity in normal pods,DTA-6 and S3307 decreased AC and PG activity at pod-filling early stage in SN28 and KF16,but at pod-filling late stage in HF50,compared with effectiveness S3307 was better than DTA-6;MDA, SOD, POD activity（content） of abscission pod were different in different time and variety,were not found discipline; indexes of oxygen free radical metabolism in abscission pod were higher than in normal pods, and has different trend curve.（4） DTA-6 and S3307 decreased Inv of leaf in days after spraying 7d; decreased Inv of flowers, buds and young pods in days after spraying 21d; increased Inv of pod husks in days after spraying 42 d. Inv of grains in days after spraying 35 d decreased by DTA-6;Inv of grains in days after spraying 42 d decreased by S3307. DTA-6 and S3307 improved Inv of flowers and pods to adapt to the different periods of the formation in flowers and pods, there were difference in DTA-6 and S3307 at time and value.（5） DTA-6 and S3307 could significantly regulate sucrose, soluble sugar and starch content in flowers, buds, young pods, pod husks and grain in days after spraying 7d, the early and later period of the seeds formation in three varieties. S3307 promote the photosynthate in leaf, in the this aspect, S3307 was better than DTA-6. DTA-6 significantly increased starch, this DTA-6 was better than the S3307 in days after spraying 49-56 d, DTA-6 and S3307 promoted the photosynthate accumulation, in favour of improved source-sink relationship. |
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