Physiological mechanisms of methyl jasmonate in apple rootstock M26's response to saline-alkali stress
To explore the response characteristics of apple rootstock to salt-alkaline stress following treatment with exogenous Methyl Jasmonate(MeJA),the apple rootstock M26 was used as the experimental material.Seven treatment groups were established,including CK1(control with normal watering),CK2(salt-alkaline stress:200 mmol·L-1 NaCl∶NaHCO3 in 1∶1 ratio),T1(salt-alkaline stress+0.05 μmol·L-1 MeJA),T2(salt-alkaline stress+0.5 μmol·L-1 MeJA),T3(salt-alkaline stress+5 μmol·L-1 MeJA),T4(salt-alkaline stress+50μmol·L-1 MeJA),and T5(salt-alkaline stress+500 μmol·L-1 MeJA).Phenotypic growth,photosynthetic pig-ments,and osmotic regulatory substance contents of the apple rootstock were observed and measured under each treatment.Correlation and principal component analyses were conducted.The results indicated that compared to CK2,MeJA treatments on seedling leaves did not significantly expand leaf edge yellowing.It led to increased levels of chlorophyll a(Chl a)content,chlorophyll b(Chl b)content,total chlorophyll(Chl a+b)content,net photo-synthetic rate(Pn),soluble sugars(SS)content,soluble proteins(SP)content,superoxide dismutase(SOD)activity,proline(Pro)content,peroxidase(POD)activity,and catalase(CAT)activity.Among these,T4 ex-hibited the highest increase,with an average range of 12.77％to 69.80％.MeJA treatment resulted in elevated leaf electrical conductivity(REC),superoxide anion(O2·-)content,and malondialdehyde(MDA)concentration com-pared to CK1.The increases in T1,T2,T3,and T5 ranged from 30.5％to 109.2％,with T4 showing the smallest increase at 18.72％to 45.02％.Correlation analysis revealed a highly significant positive correlation between Chl a and Chl b as well as Chl a+b content,and a highly significant negative correlation with MDA,O2·- content,and REC.A significant negative correlation was observed with SP and H2O2 content.Principal component analysis of 17 indicators showed that three principal components accounted for 95.25％of the cumulative variance.Based on the principal components,the comprehensive ranking of MeJA's alleviating effect on M26 seedling leaves under salt-al-kaline stress was T4＞T5＞T3＞T2＞T1.In conclusion,under 200 mmol·L-1 salt-alkaline stress,application of 50μmol·L-1 exogenous methyl jasmonate(MeJA)had the most effective regulatory impact on the physiological char-acteristics of apple rootstock M26.
apple rootstock M26methyl jasmonatesaline-alkali stressphysiological effects
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维普
