Effects Of Ethephon On Chlorophyll Metabolic Pathway Of Zoysia Japonica Under Low Temperature Stress

A study was conducted on the effect of ethephon on chlorophyll metabolism pathway under low temperature stress of Zoysia japonica with Zoysia japonica as experimental material,through physiological index detection,chlorophyll metabolism related enzyme activity and gene expression analysis,explore the ethephon in low temperature stress influence Zoysia japonica chlorophyll metabolism of the key enzymes and genes.It was found that spraying ethephon with suitable concentration range could relieve stress injury and reduce chlorophyll loss during low temperature stress.Some key regulatory genes can provide target genes and research basis for subsequent research on the use of biotechnology to regulate the chlorophyll content of Zoysia japonica.The specific research results are as follows:(1)Spraying 100 mg / L to 200 mg / L of Ethephon on Japanese Zoysia japonica can significantly increase the growth density and chlorophyll content of Japanese Zoysia japonica under low temperature stress,and can also significantly improve the leaf complex during the low temperature recovery process.The effect of green has important practical value for prolonging the green period of Zoysia japonica and improving the quality of ping view.(2)52 days after spraying Ethephon at room temperature,the conductivity of Zoysia japonica decreased,indicating that spraying Ethephon at room temperature did not cause stress damage to Zoysia japonica and by enhancing the stability of the leaf cell membrane,it was conducive to coping with stress The low temperature treatment leads to a significant decrease in chlorophyll content and relative water content,and the electrical conductivity rises significantly.Ethephon treatment can reduce the loss of chlorophyll under low temperature conditions,reduce the decline in relative water content and theincrease in conductivity.It can alleviate the low temperature damage of Japanese Zoysia.(3)52 days after spraying ethephon at room temperature,the Zoysia plants accumulated a large amount of soluble protein,while the soluble sugar content decreased.Low temperature treatment reduced the soluble protein and soluble sugar content of Japanese Zoysia grass and promoted a significant increase in proline content.The main osmo-regulatory substance accumulated by Zoysia japonica in response to low-temperature stress is proline.Ethephon treatment can regulate cell osmotic potential and reduce low-temperature damage by increasing the content of proline,soluble sugar and soluble protein in Zoysia japonica.(4)Low temperature treatment regulates and affects the chlorophyll content of Zoysia japonica at two levels of protein and gene expression.Under low temperature stress,the chlorophyll synthesis rate decreases and the degradation rate rises,which ultimately leads to a decrease in chlorophyll content.Specifically,the chlorophyll synthesis precursor enzyme ALAD Decreased activity and chlorophyll synthesis genes such as ZjALAD,ZjHEMD,ZjURO-D2,ZjCPOX,ZjMg CH1,ZjMg CH3,ZjCHLM,ZjNADPH1,ZjNADPH2 gene expression levels are down-regulated;chlorophyll degradation pathway-related enzymes MDcase and RCCR activity are increased,and up-regulation of ZjRCCR gene expression levels results in chlorophyll Accelerated degradation: Ethephon treatment inhibits the rise of chlorophyll degradation pathway related genes,inhibits the enzyme activity of MDcase and RCCR,reduces the degradation rate of chlorophyll,and alleviates the loss of chlorophyll under low temperature conditions.(5)Chlorophyll b has the function of absorbing and transmitting light energy,and in addition to absorbing and transmitting light energy,chlorophyll a helps the conversion of light energy,promotes effective photosynthetic efficiency,increases the accumulation of organic matter,and improves the cold resistance of plants.The value of chlorophyll a / b of Zoysia japonica significantly decreased,mainly due to the increased expression of the ZjOs CAO gene,which accelerated the synthesis of chlorophyll b,and the decrease in the expression of the ZjNYC1 gene inhibited the conversion of chlorophyll b to chlorophyll a.Ethylene can increase the value of chlorophyll a / b of Zoysia japonica under low temperature conditions,mainly because the expression of ZjOs CAO gene significantly decreases,inhibiting the synthesis of chlorophyll b.The increase in the expression of ZjNYC1 gene accelerates the conversion of chlorophyll b to chlorophyll a.