The Research On Cold Resistance Study Of Two Species Of Hydroponics Color Leaf Plants Under Artificial Low Temperature Stress

Photinia×fraseri and Euonymus japonicus Thunb.cv.' Aureo-marginatus' Nichols are resistance trim,easy cultivation,like strong light irradiationgreen,sleek,fresh and beautiful,it has high visual value and extensive landscape application prospect.In order to study the cold tolerance of the two color-leaved plants under hydroponic cultivation,the experiment was carried out under 50 days of low temperature stress and 10 days in an artificial climate box.The physiological characteristics such as external growth morphology,relative chlorophyll content,relative water content,fluorescence kinetic parameters,malondialdehyde content and root activity of these two species were analyzed and studied in this paper.The main results are as follows:(1)the external morphology of Photinia:There was no death in Photinia×fraseri,but death occurred on the 40th day in the extremely severe cold stress group of Euonymus japonicus Thunb.cv.'Aureo-marginatus' Nichols.The order of external growth morphology of Photinia×fraseri isTr(3?)>Tr(0?)>Tr(-3?)>Tr(-6?).The order of external growth morphology of of Euonymus japonicus Thunb.cv.'Aureo-marginatus' Nichols is Tr(3?)>Tr(0?)>Tr(-3?)>Tr(-6?).(2)relative chlorophyll content:The relative chlorophyll content of the treatment group of Photinia xfraseri is Tr(3 ?)<Tr(0 ?)<Tr(-3 ?)<Tr(-6 ?);The relative chlorophyll content of each low-temperature treatment group of Euonymus japonicus Thunb.cv.'Aureo-marginatus' Nichols is Tr(0?)<Tr(-3?)<Tr(3?)<Tr(-6?).(3)relative water content:the range of relative water content of each low temperature treatment group of Photinia xfraseri isTr(-3 ?)<Tr(0?)<Tr(3 ?)<Tr(-6?).The range of relative water content of poplar at low temperature of Euonymus japonicus Thunb.cv.'Aureo-marginatus' Nichols isTr(-3?)<Tr(0?)<Tr(3?)<Tr(-6?).(4)malondialdehyde content:the increasing range of MDA content of Photinia ×fraseri is in the order ofTr(0?)<Tr(-3?)<Tr(3?)<Tr(-6?),the MDA content of Euonymus japonicus Thunb.cv.' Aureo-marginatus' Nichols Tr(-3?)treatment group,decreased for the longest time,and the cold resistance was the strongest.The decreasing range of MDA content of Euonymus japonicus Thunb.cv.'Aureo-marginatus' Nichols is from small to large in the order of Tr(-3?)<Tr(0?)<Tr(3?)<Tr(-6?).Fluorescence kinetic parameters:FO value:The four gradient FO values of Photinia×fraseri from small to large in order of Tr(0?)<Tr(3?)<Tr(-3?)<Tr(-6?),and the light energy utilization ability of four temperature groups isTr(0?)>Tr(3?)>Tr(-3?)>Tr(-6?).The death rate appeared in the very severe cold stress group of Euonymus japonicus Thunb.cv.' Aureo-marginatus' Nichols.The order of the four gradient FO values wasTr(3 ?)<Tr(0?)<Tr(-3?)<Tr(-6?),and the light energy utilization ability of the four temperature groups wasTr(3?)>Tr(0?)>Tr(-3?)>Tr(-6?).Fv/Fm value:The decreasing range of Fv/Fm value of Photinia×fraseri from small to large is all ranked as follows:Tr(-3?)<Tr(3?)<Tr(0?)<Tr(-6?).The decreasing range of Fv/Fm value of Euonymus japonicus Thunb.cv.'Aureo-marginatus'Nichols was from small to large in order ofTr(3?)<Tr(-3?)<Tr(0?)<Tr(-6?).qP value:the decreasing range of qP value of Photinia×fraseri is from small to large in order ofTr(-3?)<Tr(0?)<Tr(3?)<Tr(-6?).The order of decreasing range of qP value of Euonymus japonicus Thunb.cv.'Aureo-marginatus' Nichols isTr(0?)<Tr(3?)<Tr(-3?)<Tr(-6?).ETR value:The ETR values of the four gradients of Photinia xfraseri are from large to small in order ofTr(-3?)<Tr(3?)<Tr(0?)<Tr(-6?),and the ETR values of the four gradients in Euonymus japonicus Thunb.cv.'Aureo-marginatus ' Nichols are decreased from small to large in order ofTr(0?)<Tr(-3?)<Tr(3?)<Tr(-6?).Fv'/Fm' value:The Fv'/Fm' value of Photinia×fraseri and Euonymus japonicus Thunb.cv.'Aureo-marginatus' Nichols are decreased from small to large in the order of Tr(-3?)<Tr(3?)<Tr(0?)<Tr(-6?).(6)Root activity:the decreasing range of root activity of Photinia xfraseri is from small to large in the order of Tr(-3?)<Tr(-6?)<Tr(0?)<Tr(3?).The order of decreasing range of root activity of Euonymus japonicus Thunb.cv.'Aureo-marginatus' Nichols from small to large isTr(3?)<Tr(0?)<Tr(-3?)<Tr(-6?).In general,under 50 days of low temperature stress,hydroponics Photinia×fraseri can withstand the low temperature of-6?,but the physiological activities decrease with the decrease of temperature,while the hydroponics Euonymus japonicus Thunb.cv.'Aureo-marginatus' Nichols can only bear the low temperature of-3?.Under 40 days of low temperature stress at-6?,the leaves fell off seriously,blacken,and upper root part shows death,but on the 8th day of the restoration experiment,the new buds begin to grow again,indicating that the plants of Euonymus japonicus Thunb.cv.' Aureo-marginatus ' Nichols are not completely dead.Its roots can also continue to maintain growth and development.