| Compared to diploid rice,autotetraploid rice has higher yield potential,and the grain filling characteristics directly influence rice yield and rice quality.The germination characteristic of seeds is an important agronomic character of crops.So it is very important to analysis the grain filling and germination characteristics in autotetraploid rice.In this study,the total nine rice lines,including 4 diploid rice(E23,E25,E232 and E285)and their autoteraploid rice(T43,T45,T432 and T485)and a neo-type tetraploid rice(H1),were used as the research material to study their sink-source relationship.The total four rice lines,includingT45,E25,T485 and E285,were applied to study the change of nonstructured carbohydrate content in different organs during grain filling stage and the response to different concentrations of glucose,mannitol,gibberellin,and abscisic acid treatment during germination process.The main results are as follows.1.The averaged length,width and area of top three leaves in autotetraploid rice were higher than those in diploid rice,and were increaed by 9.22%,4.41% and 11.17%,respectively.The total grain number were decreased by 41.10% and the seed set were declined in autotetraploid rice.The neo-type tetraploid rice had larger leaf width and area and higher seed set than autotetraploid rice,showing higher yield potential.2.With respect to the grain filling characteristic,it turned out that the different change of sucrose contents were detected during the 15-20 days period after pollination.The average of sucrose content of different organs in T485 were 3.12 and 3.29 times higher than those of E285,respectively,while T45 is 0.76 and 0.78 times of E25,respectively.The weight of thousand seeds of autoteraploid rice were higher than that of diploid rice and increased by 27.61% and 51.84%,respectively,indicating that the higher content of sucrose is helpful to improve the weight of thousand seeds during the late grain filling process in autoteraploid rice.3.The analysis on germination characteristics showed that the germination speed and rate in autotetraploid rice were lower than those in diploid rice.When the grain were shelled,the difference of germination speed and rate were not significant between atuotetraploid rice and diploid rice.Except GA,glucose,mannitol and ABA had negative effects on root and shoot growth.Glucose has the greatest influence on root growth,the average root length of the shelled seeds in the 3% glucose-treated group was 20.33% of that of control group.ABA had the greatest influence on shoot,the average shoot length of the shelled seeds in the 10 μmol/L ABA-treated group was 28.46% of that of control group.GA had strong negative effect on root growth,the average of root length of the shelled seeds in the 1.5 μmol/L and 10 μmol/L GA-treated group were 1.31% and 2.95% of that of control group,respectively.In 5 μmol/L ABA group,The root growth of T485 have a great advantage over E285,when their seeds were treated with 5 μmol/L ABA.Based on qRTPCR analysis,it was showed that the higher expression level of ABA8OX-2,OsGA2OX-1,OsGA2OX-2 and OsGA2OX-3 were detected during 24-36 h period in T485,compared to E285,implying the reason of high ABA resistance T485. |
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