Influence of Short-term Application of Abscisic Acid in Nutrient Solution on Growth and Drought Tolerance of Tomato Seedlings

초록

This study was conducted to evaluate influence of short-term application of abscisic acid (ABA) in nutrientsolution on growth and drought tolerance of tomato seedlings. The treatments included four ABA concentrations(0.5, 1, 2, 3mg·L-1) and control (non-treatment) were applied to the nutrient solution in a hydroponic system. On the5th and 10th day after growing in the nutrient solution containing ABA, seedlings were transferred to -5 bars of PEG-8000 in a growth chamber to induce water stress. Except for stem diameter and fresh and dry weight of root, therewere no statistical differences in other growth parameters among control, 0.5 and 1mg·L-1 of ABA treatments. Seedlingsgrowths were strongly inhibited in nutrient solution containing 2 and 3mg·L−1 of ABA. The root growth such asfresh and dry weigh of root, total root surface area, and average root diameter was slightly enhanced in 1mg·L−1 ofABA treatment. The elevation of ABA concentrations in nutrient solution resulted in the decrease in transpirationrate and increase in stomatal diffusive resistance and leaf temperature of tomato seedlings. The initiations of seedlingwilting after treating in -5 bars of PEG were delayed from 10 hrs in control to 30 hrs in ABA applied treatments. Additionally, the high percentages of recovered seedlings were observed in 0.5 and 1mg·L−1 of ABAtreatments after re-irrigation. Therefore, short-term application of 1mg·L−1 of ABA in the nutrient solution stimulatedthe root growth and drought tolerance of tomato seedlings by delaying the start time of wilting point andenhancing the recovery after re-irrigation.

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