| Cucumber cultivation has a long history,is a worldwide vegetable.But the cucumber on water demand is high,drought stress(drought stress)has a tremendous impact on the sustainable development of cucumber industry,high transport costs in different regions,thus cultivating drought resistant cucumber varieties,scientific water management is one of the most economical and effective measures,found that the mechanism of resistance to drought stress in the previous research of plants in and the content of the secondary metabolites and related enzyme activity may reflect the host resistance level to a certain extent,but the research on this aspect of fresh cucumber is seldom reported,so it is of great significance,and can provide the basis for further research on resistance of cucumber.In this study,the effects of drought stress on the content of secondary metabolites and the activities of related enzymes in Cucumber(Southern China)and Mount Huangshan(16)were studied.The main changes of the secondary metabolites of Cucumber Seedlings under different drought stress and related enzyme activities,the accumulation of metabolic substances and analysis of related enzymes of cucumber next time of drought stress,defense response and drought resistance mechanism of stress and the same under drought conditions,the difference of different types of cucumber varieties of secondary metabolites and related enzyme activity the reasons for the existence and difference analysis.The results of this study show that cucumber Zhongnong No.16(North China)the drought resistance of cucumber is superior to the old Mount Huangshan(Southern China)drought resistance,Mount Huangshan old cucumber(Southern China type)changes of secondary metabolism of seedlings and their related enzymes is generally greater than Zhongnong No.16(North China)cucumber,the effects of drought stress on more sensitive.Drought stress can directly affect the secondary metabolites and related enzymes in Cucumber seedlings.After drought stress of two kinds of cucumber leaves PAL,POD,PPO activity had increased in different degrees,which leaves Mount Huangshan old cucumber seedlings in PPO activity compared with control growth than other large,respectively which were 4.15 times and 5 times.Both mild drought stress or severe drought stress,two kinds of three kinds of secondary metabolism related enzymes activity in cucumber leaves reached the peak at 4D and before,even if the latter due to the damage of membrane structure and decrease the activities of these three enzymes were higher than that of the control,and this confirms that drought stress can directly affect the secondary metabolism enzyme activity of cucumber leaves.Because of the difference of material,the content of lignin,Dan Ning,total phenolics and flavonoids in the leaves of Mount Huangshan old cucumber seedlings was less than that of the middle peasants 16 before the drought stress.After drought stress,the contents of lignin,tannin and total phenolics in leaves of two kinds of cucumber seedlings were increased in different degrees,and the increase rate was the same,no more than 2 times of the control.Both mild drought stress or severe drought stress,two kinds of cucumber leaves in three kinds of secondary metabolites content reached the peak at 4D and before,even if the latter due to the damage of membrane structure and decrease the content of the three substances,will be higher than that of the control,and increase material content of most treatments were greater than the old Mount Huangshan cucumber Zhongnong No.16,and this proved that drought stress can directly affect the leaves of Cucumber Seedlings in the content of secondary metabolites.Change the content of flavonoids and other different,then increased in were first decreased the content of flavonoids in leaves of Cucumber Seedlings under two kinds of drought stress,both mild drought stress or severe drought stress,two kinds of flavonoid content in cucumber leaves reached the lowest value at 4D and before.Whether it is Mount Huangshan or old cucumber Zhongnong No.16,the content of flavonoids in leaves of seedlings under stress in mild drought is always less than the control,while the two kinds of flavonoid content in leaves of Cucumber Seedlings under severe drought stress when 10 d started higher than that of the control.Three kinds of enzyme activity enhanced expression contributes to secondary metabolism,changes of PAL,POD,PPO activity and lignin,tannin,total phenol content is consistent,these have confirmed that drought stress can directly affect the secondary metabolites and related enzymes in Cucumber seedlings.Whether it is Mount Huangshan old cucumber(Southern China type)or Zhongnong 16(Hua Beixing),most of the variation of secondary metabolism related enzymes and metabolites are the same,the decline in the degree of material under severe drought stress than under mild drought stress decreased the degree,the two are not a linear relationship. |
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