高温胁迫下不同烤烟品种的生理响应及耐热性综合评价OA

[Objective]The study aimed to investigates the physiological effects of high-temperature stress on different flue-cured tobacco cul-tivars and assesses their heat resistance performance.[Method]The study tested 5 tobacco cultivars(CB-1,Y121,Y116,NX212 and NC102)under 4 temperature treatments(25,35,40 and 45 ℃).Following treatment,measurements were taken for leaf relative water con-tent,photosynthetic fluorescence parameters,osmolytes content and antioxidant system activity.A comprehensive evaluation was then conduc-ted by combining the heat resistance coefficient with the results of principal component analysis(PCA).[Result]In terms of photosynthetic inhibition,compared with the 25 ℃ treatment(CK),CB-1 exhibited the greatest reductions in total chlorophyll content(63.37％)and net photosynthetic rate(92.77％)at 45 ℃,indicating its high sensitivity to high temperature.In contrast,Y121 showed the smallest decrease in chlorophyll content(25.51％),while Y116 maintained a relatively lower reduction in net photosynthetic rate(80.04％).Regarding physio-logical responses,compared with the 25 ℃ treatment(CK),NC102 exhibited the highest increase in ascorbate peroxidase activity(480.64％)under 45 ℃ stress,whereas Y116 showed the smallest increases in malondialdehyde content(39.01％)and superoxide dismutase ac-tivity(26.73％).Principal component analysis summarized the various physiological indicators into 5 key principal components responsive to high temperature,with membership function further analyzing the weight values of each component.The results indicated that,the comprehen-sive heat tolerance ranking at 45 ℃:Y116＞Y121＞NX212＞CB-1＞NC102.[Conclusion]Tobacco Y116 demonstrated better heat tolerance at 45 ℃ relative to other cultivars.