Effect of Salicylic Acid on Growth of Cucumber (Cucumis sativus L.) Seedlings under Drought Stress

Abstract

     The objective of the present work was to determine the effect of salicylic acid (SA, 0,25mM and 0.50mM) on growth of cucumber under drought stress imposed by PEG - 6000. Drought markedly reduced growth and development of seedlings, but exogenously applied SA significantly increased plant growth both in drought and non - drought conditions. The increased growth was found for plant height, leaf number, leaf area and leaf area index, shoot and root dry matter, and chlorophyll a and chlorophyll b content in drought stress applied with 0.25mM SA and 0,50mM SA+ PEG in comparison with those in drought conditions without SA application. In addition, exogenous application of SA lowered the increase in proline content and MDA, but the negative effect of drought on H₂O₂ content and Fv/Fm index was not significantly ameliorated. Applicaion of 0.5 mM SA showed a better effect than 0.25 mM SA.