Study On The Physiological Response And Adaptability Of Cucumber Grafted Seedlings Under Heat And Drought Resistance

A study on physiological characteristics effects of cucumber grafted seedlings, such as growth, changes of membrane parameter, chlorophyll content,changes of infiltrative regulate substances and protect enzyme activity, under heat and drought stress was conducted. Furthermore, the physiological response and adaptability mechanism of heat and drought resistance of cucumber grafted seedlings were explored. And adaptability of heat and drought stress and superiority in different cucumber grafted vatieties were analyzed.The results were as follow:1.Under heat stress, grafting greatly accelerated cucunber seedling height, stem diameter, leaf area and weight,comparable root top ratio and seedling index, improved the heat resitance,which markedly declined relative electrical conductivity and MDA content, increased chlorophyll, soluble protein, Pro content and improved resistant-oxidation enzyme activities.2.Under drought stress, grafting patencily accelerated cucunber seedling overground growth, which were seedling height, stem diameter, leaf area and weight. It also boosted up root activity, chlorophyll, leaf water, soluble protein, Pro content and resistant-oxidation enzyme activities, when it declined relative electrical conductivity and MDA content, improved the drought resitance.3.Under heat and drought stress, grafting has prodigouss advantage in six cucunber varieties, which increased seedling height, stem diameter and weight, improved root top ratio and seedling index,meantime declined relative electrical conductivity and MDA content,boosted up root activity, chlorophyll, leaf water, soluble protein,Pro content and resistant-oxidation enzyme activities.4.Throughout the heat and drought stress experiment, the heat stress at 40℃/25℃(day and night temperature), and the drought stress 55%～65%(soil relative humidity)each manifested the best heat resistance and drought tolerance in the comprehensive index of cucumber grafted seedlings. Through the best compound to treat the tested cucumber varieties, the relative advantage of grafting were Jinyou 4, Lu Feng, and Yuzahuang 4.