| Machine-transplanted rice seedlings in plate has many problems with seedling flexibility,seedling quality and greenup date in production.Suitable plant growth regulators could have beneficial effects on plant height,root system and physiological function;hence,the improviment in seedling quality and rooting ability may play a critical role in solving the above mentioned problems.In this experiment,three varieties,Quanliangyou-1,Quanliangyou-681 and Fenghuazhan,were used,and grown at Yangtze University Farm in 2016.Thirteen chemical control agents were set up in the rice seedling,the small seedlings and big seedlings by two processing periods.Field experiments were conducted based on the screening results of seedling quality,rooting ability,physiological characteristics of seedling,to study the effects of chemical regulation on the greenup date and grain yield of mechanical-transplanting rice.The results showed that:(1)B1(DA-6),C3(Indole butyric acid potassium+ NAA-K+6-BA),C4(Indole butyric acid potassium+ NAA-K+ triacontanol),C5(Indole butyric acid potassium+ NAA-K+1.8% sodium nitrophenolate 1000 times),C6(Indole butyric acid potassium+ NAA-K+DA-6)were selected in this study.These chemical reagents(plant growth regulators)improve the quality of the seedlings;(1)the application of these chemical reagents improved the plant height,leaf length,and the growth of longest root.These chemical reagents had signicifant effect on the seedling endogenous hormones.The growth of leaf and root was significant in the first three days after treatment,the following three days the growth was stagant,and their growth was recovery in the next three days.(2)the rooting ability was also improved,especially the increased number of adventitious roots,but the sustained effects of rooting among treatments were different.C6 treatment(Indole butyric acid potassium+ NAA-K+DA-6)had longer and stable sustanined effects compared with other treatments.(3)dry matter accumulation and dry weight per hundred of seedlings increased significantly.(4)the growth difference between inbred cultivars and hybrid cultivars was significant.The rooting ability,the rate of leaf appearance and leaf age in hybrid rice were greater than inbred after treatments.C6 treatment(Indole butyric acid potassium+ NAA-K+DA-6)had significant effects on the rooting ability among tested cultivars in terms of sustained effects,and B1(DA-6)had significant effects on the Seedling plumpness.(2)Chemical regulation treatmetns improved the physiological process(chlorophyll content and soluble sugar content,soluble protein)of seedlings.The performance of these physiological charactersitics had similar trend as agronomical traits above.The soluble protein content at 9 days after treatment returned to pre-treatment levels.The increase in the soluble protein content of tested cultivars betwen C4 and C6 treatments was significantly higher than other treatments.(3)Chemical regulation had benefical effects on the rooting ability of seedling,and shortened greenup date of seedlings.Machine-transplanted rice seedlings in plate after 7 days in the field experiments,the longest white root length,white root numbers and white root ratio of tested cultivars in the five chemical regulation treatments was stagnant,significantly increased and slightly increased,respectively.Souluble sugar content showed different pattern,stagnant,significant increase,decrese and restore.The longest white root length,white root numbers,white root ratio and soluble sugar of tested cultivars were significantly increased,and the rooting ability and greenup data was also improved in the C6 treatment.(4)Chemical regulation treatments increased the grain yield of mechanicaltransplanting rice.Among yield components,chemical treatments had siginificant effects on the panicle,followed by spikeletes per panicle and grain filling.The difference in yield components among tested cultivars was significant among different chemical regulation treatments.C6 treatment(Indole butyric acid potassium+ NAA-K+DA-6)significantly increased the grain yield of mechical-transplanting rice.According to the application date of chemical regulation treatments,small the contribution of chemical regulation in small seedlings was greater than big seedlings to grain yield. |
PDF Full Text Request