Study On Physiological And Biochemical Changes,and Indentification Of Tolerance Of Bitter Gourd Under Low Temperature And Poor Light Stress

In this study,more than 30 individual indexes of seed germination,seedling growth,physiological and biochemical characteristics,photosynthetic parameters and chlorophyll fluorescence parameters of bitter gourd were determined by comparing low temperature and low light resistance of eight different varieties of bitter gourd.Twenty-five optimal indicators for low temperature and low light resistance of bitter gourd were selected and 20 optimized indexes were used to sort the eight bitter melon varieties with low tolerance to low temperature and low light.Two low temperature and low light resistance were selected.Of the bitter gourd varieties,for the actual production of other low temperature and low light resistance of bitter gourd germplasm resources to provide the basis.1.The relative germination potential,relative germination rate,relative germination index,and relative radicle were determined by comparing the germination rate of 12 bitter melon varieties at low temperature(13?)and compared with the control(room temperature 25?)(P<0.05),and the relative germination index,relative germination index,relative radicle length and relative vigor index were significantly different among different cultivars(p<0.05).The results showed that the germination rate of different bitter melon varieties was significantly different Therefore,five indicators can be used as bitter gourd seed germination low temperature tolerance evaluation index.2.Taking the 12 bitter gourd varieties as test materials,the chilling injury index and the low temperature mortality statistics of bitter gourd seedlings were carried out under the temperature of 10?/5?,and the weak and low temperature of different bitter gourd were obtained.The results showed that the chilling injury index of each cultivar was different under different treatment time.3.Eight cold bitter melon varieties with different low temperature tolerance were used to screen low temperature,low light,low temperature and low light test.The growth of bitter gourd seedlings was inhibited under low temperature treatment(light intensity 300?mol·m-2·s-1,daytime temperature 12?/7 ?,humidity 75%),and the growth indexes were decreased in different degrees.Chlorophyll a and chlorophyll content of chlorophyll a and chlorophyll were decreased.The activities of SOD,POD,APX and MDA were increased.(P<0.05).4.The plant height of the bitter gourd seedlings increased and the other growth indexes decreased.The photosynthesis was blocked and the total chlorophyll content was decreased.The photosynthesis was inhibited by low light intensity(light intensity 60?mol·m-2·s-1,daytime temperature 25?/18?,humidity 75%Decreased activity,SOD activity decreased,POD,APX enzyme activity increased,MDA content increased.5.The growth indexes of different varieties of bitter gourd were significantly decreased under low temperature and low light(light intensity 60?mol·m-2 · s-1,daytime temperature 12?/7?,humidity 75%).,Stomatal conductance,qP decreased,intercellular CO2 concentration increased;SOD,APX,CAT activity were increased,MDA content increased significantly.6.The correlation between the measured value and the change value of the correlation index and the chilling injury index and mortality can be used as the basis for the identification of low temperature and low light resistance of bitter gourd.The results showed that plant height,stem diameter,leaf area,SOD,APX,ion permeability,proline,soluble sugar,soluble protein,?Ch1a/b,Ch1T,?Car,net photosynthetic rate Pn,intercellular C02 concentration Ci,,Fv/Fm,Fv'/Fm',qP,ETR were significantly negatively correlated with the index of cold injury and mortality.The dry weight,POD,CAT,MDA,Gs and NPQ were the same Index,and mortality were significantly positively correlated.7.The initial selection index system of 25 low temperature and low light resistance of bitter gourd was established.The effects of plant height,stem diameter,leaf area,SOD,APX,ion permeability,proline,soluble sugar,soluble protein,?Chla/b,Ch1T,ACar,net photosynthetic rate Pn,intercellular C02 concentration Ci,,Fv/Fm,Fv'/Fm',qP,ETR,? strain dry weight,POD,CAT,MDA,stomatal conductance Gs,NPQ.8.The optimal index system of low temperature and low light resistance of bitter gourd was established.The leaf area,SOD,CAT,APX,ion permeability,and leaf permeability of the bitter gourd leaves after 10 days of treatment were studied at daytime temperature of 12?/7?,light intensity of 60?mol·m-2 · s-1 and humidity of 75%Soluble protein,?Chla/b,ChlT,ACar,net photosynthetic rate Pn,stomatal conductance Gs,?F0,Fv'/Fm',qP,ETR,MDA,intercellular C02 concentration Ci,NPQ.9.The results showed that the low temperature and low light resistance of eight bitter gourd cultivars identified by comprehensive membership function were from silver to bitter gourd,black rose,Xiangyouyou 1,early jade 1,Sichuan research 1,super No.1,Super No.3,large long white bitter gourd.