2022 Volume 21 Issue 2 Pages 213-218
To elucidate the effects of brine fulvic acid on hydroponically grown leaf lettuce, the endogenous plant hormones indole-3-acetic acid (IAA), trans-zeatin (tZ), isopentenyl adenine (iP), gibberellin1 (GA1), gibberellin4 (GA4), and abscisic acid (ABA) were quantified. After 39 days of hydroponic cultivation, the above-ground weight of the plants was significantly increased in the brine fulvic acid treatment. The concentration of IAA was 7.3 times higher in the largest leaf in the brine fulvic acid treatment than in the control treatment. tZ concentration in the root zone tended to be higher in the base zone in the control treatment, whereas in the brine fulvic acid treatment, it tended to be higher at the apical zone. The iP concentration was higher in roots in the brine fulvic acid treatment. The GA1 concentration was lower in leaves than in roots, but was higher in roots in the brine fulvic acid treatment. The GA4 concentration was lower in both leaves and roots in the brine fulvic acid treatment. Overall, the GA1 concentrations were higher than GA4 concentrations in roots, with the C-13 hydroxylation pathway being dominant. The GA1 concentration was higher in the new leaves than in the largest and outer leaves in both the control and brine fulvic acid treatment, and it was about twice as high in the control treatment and about seven times as high in the fulvic acidic treatment. ABA concentrations were generally higher in leaves in the brine fulvic acid treatment. The highest value of 209 pmol・g–1 FW was noted in the outer leaves.
