| In this experiment,2-year-old scion-stock combinations of ‘Nagafu No.2 / M26 / Malus sieversii',‘Nagafu No.2 / M26' and ‘Nagafu No.2 / M.sieversii' were used as the materials.Spraying 800 mg L-1 ethephon(CEPA)and 2 ?L L-1 1-methylcyclopropene(1-MCP)as the treatment group,and water as the control group were used to study the effects of these two growth regulators on the flower bud differentiation and physiological metabolism of ‘Nagafu No.2' with different rootstock scion combinations.The main results are as follows:1.Spraying CEPA promoted the lengthened growth and thickening growth of new shoots in each group,and significantly increased the flowering rate,which was increased by 17.4% and 6.8% in ‘Nagafu No.2 / M26 / Malus sieversii' and ‘Nagafu No.2 / M26',respectively.Spraying 1-MCP promoted the lengthened growth of new shoots,whereas inhibited the thickening growth,and significantly reduced the flowering rate and flowering delay.The flowering rate of ‘Nagafu No.2 / M26 / Malus sieversii' and ‘Nagafu No.2 / M26' were reduced by 9.1% and 4.6%,respectively.The flowering rate of ‘Nagafu No.2 / M26' was higher than that of the interstock ‘Nagafu No.2 / M26 / Malus sieversii' and the vigorous stock ‘Nagafu No.2 / Malus sieversii'.Among them,the flowering rate of ‘Nagafu No.2 / M26' was the highest.2.After spraying CEPA,the accumulation of total soluble sugar,glucose,sucrose and fructose was significantly promoted in leaves and buds of each scion-stock combination.The total soluble sugar in ‘Nagafu No.2 / M26 / M.sieversii' and ‘Nagafu No.2 / M26' was increased by 10.5% and 23.7%,respectively.The content of fructose also was increased by 44.1% and 55.5%,respectively.After spraying 1-MCP,the accumulation of total sugar,glucose,fructose and sucrose was inhibited in leaves and flower buds.The total soluble sugar was decreased by14.9% and 27.6% in ‘Nagafu No.2 / M26 / M.sieversii' and ‘Nagafu No.2 / M26',while the content of fructose was increased by35.9% and 32.1%,respectively.3.CEPA significantly increased the activities of sucrose synthetase(SS),sucrose phosphate synthase(SPS),phosphofructokinase(PFK)and ?-amylase(?-AMY).The activity of SS in ‘Nagafu No.2 / M26 / M.sieversii' and ‘Nagafu No.2 / M26' was increased by 14.0% and 23.2%,respectively.The activity of PFK also was increased by 9.2% and 11.9%,respectively.The activity of said four enzymes was decreased by spraying 1-MCP.Among them,the SS activity of the ‘Nagafu No.2 / M26 / M.sieversii' and ‘Nagafu No.2 / M26' was decreased by 68.6% and 71.9%,respectively.The activity of PFK was decreased by 44.9% and 30.1%,respectively.4.After spraying CEPA,the synthesis of endogenous ZT and ABA in leaves and flowers was promoted,while the synthesis of IAA was inhibited.Spraying 1-MCP,promoting the synthesis of IAA in leaves and flower buds,inhibiting ABA synthesis.Furthermore,it promoted ZT synthesis in the earlier stage.5.After spraying CEPA,the expression levels of sugar synthesis genes SUS4 and SPS1 F,the ETH signal response factor ERF5,the IAA response factor ARF5,the CTK synthesis gene CRF4,and the ABA synthesis gene ABF3 were up-regulated.The flowering regulatory factor TFL1 was down-regulated,while the AP1 was up-regulated.After spraying 1-MCP,the expression levels of SUS4 and SPS1 F were up-regulated in leaves and flower buds,while the ERF5,ARF5,CRF4 and ABF3 were down-regulated.Furthermore,the contents of ZT and ABA were decreased significantly.The expression level of TFL1 was up-regulated,whereas AP1 was down-regulated. |
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