| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 4554551 | Environmental and Experimental Botany | 2013 | 8 Pages |
In the present study, we investigated time course changes of water status including relative water content (RWC), leaf osmotic potential (ΨΠ), stomatal conductance (gs), proline (Pro), chlorophyll fluorescence (Fv/Fm) and total chlorophyll content in the Arabidopsis thaliana under PEG-induced drought stress after exogenous ABA treatment. To a better explanation for the role of ABA in the water status of A. thaliana to drought stress, wild-type (Columbia) and ABA-deficient mutant (aba2) of A. thaliana were used in the present study. Moreover, three weeks old Arabidopsis seedlings were applied exogenously with 50 μM ABA and exposed to drought stress induced by 40% PEG8000 (−0.73 MPa) for 6 h, 12 h and 24 h (hours). Our findings indicate that RWC of wild-type and aba2 started to decrease in the first 12 h and 6 h of PEG-induced drought stress, respectively. However, exogenous treatment of 50 μM ABA increased their RWC under drought stress. On the other hand, while ΨΠ of both genotypes started to decrease in the first 6 h of drought stress, these declines in ΨΠ were prevented by ABA treatment under stress throughout the experiment; it was more pronounced in aba2 at 24 h. While the highest increase in gs was obtained in aba2 after 24 h stress, ABA-induced highest decrease in gs was obtained in the same genotype during 12 h, as compared to PEG-treated group alone. On the other hand, Pro content increased in all treatment groups of ABA-deficient mutant aba2 at 12 h and 24 h. However, Pro content in ABA + PEG treated aba2 plants was higher than in PEG- and ABA-treated plants alone at the end of the 24 h. Drought stress decreased Fv/Fm and total chlorophyll contents of both genotypes while 50 μM ABA alleviated these reductions during drought stress, as compared to PEG stressed plants. On the other hand, 50 μM ABA treatment alone did not create any remarkable effect on Fv/Fm and total chlorophyll contents.These findings indicate that exogenous ABA showed an alleviative effect against damage of drought stress on relative water content, osmotic potential, stomatal conductance, proline, chlorophyll fluorescence and total chlorophyll content of both genotypes during 24 h of drought stress treatment.
Research highlights▶ ABA starts to prevent decrease in leaf osmotic potential in the first 6 h of drought stress. ▶ ABA enhances leaf relative water during 24 h of stress. ▶ ABA increased proline level of ABA-deficient mutant at 12–24 h of drought stress. ▶ ABA protected maximum quantum yield of PSII from drought-induced damage during 24 h. ▶ ABA decreases stomatal conductance of ABA deficient mutant only 6–12 h, not at 24 h.
