Physiological Response of Different Heat-tolerant Watermelon Seedlings to High Temperature Stress
In order to explore the effects of high temperature stress on different heat-tolerant watermelon inbred lines,heat-sensitive(D27)and heat-tolerant(K53)watermelon seedlings were treated at 42 ℃ for 48 h,and their phe-notype,tissue structure,photosynthetic characteristics,antioxidant enzyme activities and osmotic regulators were measured and analyzed every 12 h.The results showed that the leaf thickness,fence tissue thickness,sponge tissue thickness and tissue compactness of heat-tolerant K53 were larger than those of heat-sensitive D27 after high temperature stress.The proportion of sponge tissue in the palisade tissue of D27 decreased more than that of K53.With the increase of high tem-perature stress time,the net photosynthetic rate(Pn),transpiration rate(Tr)and stomatal conductance(Gs)of the two inbred lines decreased,and the intercellular CO2 concentration(Ci)increased.And the change amplitude of D27 was greater than that of K53.Among the four photosynthetic pigment contents,the heat-tolerant type was higher than the heat-sensitive type under high temperature stress at different treatment times.The superoxide dismutase(SOD)and peroxidase(POD)of the two inbred lines increased first and then decreased with the increase of high temperature stress time,and the enzyme activity was the highest at 24 h,and the enzyme activity of K53 was significantly higher than that of D27.After high temperature stress,the relative conductivity of the two inbred lines increased,and the relative conductivity of K53 increased less than that of D27.The malondialdehyde(MDA)content of D27 was reduced;the MDA content of K53 decreased after an increase.With the increase of high temperature stress,the soluble protein content and pro-line content(Pro)of K53 were significantly higher than those of D27 at 24 h.In summary,the heat-tolerant type K53 had a stronger resistance to high temperature stress than the heat-sensitive type D27.
Citrullus lanatusHeat toleranceHigh temperature stressAnatomical structurePhysiological characteristics
万方数据
维普
