Effects of exogenous melatonin on growth and physiology of garden chrysanthemum under drought stress
[Objective]The study aimed at exploring the alleviation effect of exogenous melatonin(MT)on garden chrysanthemum under drought stress and screening its suitable concentration,providing reference for planting garden chrysanthemum in arid and semi-arid areas.[Method]With the garden chrysanthemum Xuanqiu ninghong as the test material and the 20%PEG as a drought stress penetrant,the different concen-trations of MT(50,100,150,200 μmol/L)were sprayed on the leaves to study the its effects on the growth and physiological indexes of chrysanthemum seedlings under drought stress.[Result]Under the drought stress conditions,the exogenously spraying of 100 μmol/L MT could effectively alleviate the damage caused by drought stress to the garden chrysanthemum seedlings.Compared with the PEG treatment,the chlorophyll content and relative water content of the leaves increased by 37.4%and 69.1%,respectively,and the relative conductivity(REC)and malonaldehyde content(MDA)decreased by 55.7%and 42.8%,re-spectively.Hydrogen peroxide(H2O2)increased by 75.0%,and proline(Pro)by 60.6%.The activities of superoxide dismutase(SOD),peroxidase(POD),catalase(CAT)were 1.9,2,and 3.2 times of PEG treat-ment.The results of the Principal Component Analysis showed that exogenous MT mainly had a great influ-ence on the chlorophyll content and relative water content of leaves,and on the fresh weight of shoots of gar-den chrysanthemum.[Conclusion]This study showed that the exogenously spraying of 100 μmol/L MT could effectively alleviate the damage to the garden chrysanthemum Xuanqiu ninghong caused by drought stress,improving the drought tolerance of the cutting seedlings.
garden chrysanthemumexogenous melatoninPEG drought stressphysiological index
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