外源褪黑素对盐胁迫下矮牵牛生长和生理特性的影响OA

In order to explore the effect of exogenous melatonin(MT)on alleviating inhibitory of salt stress to growth of Petunia hybrida,the pot experiment was carried out in laboratory.The seedlings of P.hybri-da'Mirage'were used as test materials.Five treatments were set as blank group(CK1),NaCl stress group(CK2:100 mmol·L-1 NaCl),MT groups including spraying 50 μmnol·L-1 MT(T1),100 μmol·L-1 MT(T2)and 200 μmol·L-1 MT(T3)based on 100 mmol·L-1 NaCl stress for 16 days.The effects of different concen-trations of MT on growth and physiological characteristics of P.hybrida under salt stress were studied.The re-sults showed that NaCl stress significantly reduced the plant height,stem diameter and root length of P.hybri-da seedlings.Spraying different concentrations of MT on leaves could improve the plant height,stem diameter,root length,leaf number,fresh weight and dry weight of P.hybrida seedlings under salt stress,enhanced the superoxide dismutase(SOD)activity,decreased the malondialdehyde(MDA)content,and increased the chlorophyll content in leaves.Among them,200 μmol·L-1 MT treatment had the best effect on alleviating NaCl stress.Correlation analysis showed that there were significantly positive correlations between SOD activity,chlorophyll content,plant height,leaf number,stem diameter,root length and fresh weight.In summary,ex-ogenous MT could alleviate the inhibitory effect of NaCl stress on growth of P.hybrida seedlings by increasing SOD activity,inhibiting MDA accumulation and increasing chlorophyll content.The results of this study could provide technical bases for landscaping and efficient cultivation of P.hybrida in soil salinization area.