| Buckwheat is an important coarsecrop in China with prominent nutrition and healthcare functions,but its low yield and difficulty in hulling limit the development of industry.In this study,thin shell buckwheat varieties Guimiku(M18),and Guimiku 55(M55)were selected as materials to explore the key enzyme activities involving in carbon and nitrogen metabolism,including sucrose synthase(SS),starch synthase(SSS),adenosine diphosphate glucose focal phosphorylase(AGP),diphosphate ribulose carboxylase/oxygenase(Rubisco),nitrate reductase(NR),glutamate oxaloacetate transaminase(GOT),glutamate pyruvate transaminase(GPT)and glutamine synthase(GS),as well as the main agronomic and yield traits,as compared to the female parent Xiaomiqiao(XMQ).The prospective results will provide scientific reference for the improvement of yield and breeding of hybrid thin-shell buckwheat.The main results are as follows:(1)The relative chlorophyll content and net photosynthetic rate in leaves of M18and M55 were not significantly different from CK at 10d after emergence,but were significantly higher than CK at 20d.The leaf area of M18 and M55 was significantly higher than CK at 10d and 20d after emergence.These results indicated that some achievements had been made in improving the photosynthetic capacity of thin-shell Tartary buckwheat.(2)Compared to CK.the average activities of Rubisco and SSS in M18 and M55leaves at seedling stage were higher,whereas the activity of AGP was slightly higher and the activity of SS was significantly higher at 20d.In addition,the contents of sucrose,glucose and starch were higher than CK at seedling stage.The average Rubisco activity of M18,M55 in top leaves and the second top leaves was higher than that of CK during grain filling;while the average SSS activity of different organs was higher,whereas the average activity of AGP in the second top leaves was higher,and the activity of AGP was significantly higher in grains at 25d and 30d after grain filling.Although SS activity in the top leaf of M18 and M55 was not significantly different from CK,that in the second top leaves and grains at late grain filling stage were significantly higher than CK.(3)The NR activity of M18 and M55 leaves at seedling stage was significantly higher than that of CK,however,the activities of GS,GOT and GPT were not significantly improved.During grain filling,the NR activity in the top leaves of M18and M55 was significantly higher than that of CK,while that in the stems and grains was significantly higher than that of CK at late grain filling stage.However,the NR activity of the second top leaves was significantly lower than that of CK.Compared to CK,the activity of GS,GOT,GPT and the nitrogen contens in different organs in most tested periods were not increased.However,the amounts of nitrogen in individual plants of M18 and M55 were significantly increased,compared to CK.(4)During grain filling,compared to CK,the height of M18 and M55 plants were lower and the number of main stem nodes were higher,but the number of branches were similar.However,the number of seeds per plant,the yield per plant and yield were significantly higher than CK.The grain number per plant of M18 and M55reached 412 and 426,the yield per plant reached 6.24g and 6.44g,and the yield reached 1.249t/hm~2 and 1.289t/hm~2,respectively.In conclusion,the photosynthetic capacity of thin-shell tartary buckwheat was significantly improved,and the enzyme activities related to starch synthesis were enhanced,which promoted the synthesis and accumulation of carbohydrates and increased the grain yield.The increase of NR activity at seedling stage and grain filling stage contributed to the absorbong of nitrogen in plant,but the enzyme activities related to nitrogen assimilation and amino acid synthesis were not significantly enhanced.It was speculated that this might be resulted in the relative shortage of nitrogen supply and the increase of sink capacity in thin-shell Tartary buckwheat. |
PDF Full Text Request