Institute of Plant Physiology and Genetics, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria.
Int J Mol Sci. 2024 Nov 12;25(22):12127. doi: 10.3390/ijms252212127.
Wheat can tolerate a mild water deficit, but prolonged drought causes a number of detrimental physiological changes resulting in a substantial decrease in productivity. The present study evaluates the potential of the natural plant growth regulator melatonin to alleviate the negative effects of moderate drought in two Bulgarian winter wheat cultivars at the early vegetative stage. Melatonin doses of 75 µM were root-supplemented 24 h before or after the stress period. The levels of several biometric parameters, osmolyte content and stress indicators as well as the expression of genes coding for key enzymes of the proline biosynthesis pathway were analyzed in leaves at the end of the drought stress and after two and four days of recovery. Applied alone, melatonin did not exert significant effects on most of the monitored parameters. Water deprivation negatively affected seedlings' fresh weight and water content and increased the stress markers and osmolyte levels. These were accompanied by a high accumulation of and transcripts coding for the enzymes Δ-pyrroline-5-carboxylate synthase and Δ-pyrroline-5-carboxylate reductase, respectively. The effect of melatonin in reducing drought stress was similar whether applied before or after exposure, though slightly more effective when used as a pre-treatment.
小麦能够耐受轻度水分亏缺，但长期干旱会导致许多不利的生理变化，从而导致产量大幅下降。本研究评估了天然植物生长调节剂褪黑素在两个保加利亚冬小麦品种的早期营养生长阶段缓解中度干旱胁迫的潜力。在胁迫期前 24 小时或后 24 小时，用 75 μM 的褪黑素对根系进行处理。在干旱胁迫结束后以及恢复 2 天和 4 天后，分析叶片中的几个生物计量参数、渗透物含量和应激指标以及编码脯氨酸生物合成途径关键酶的基因的表达。单独使用时，褪黑素对大多数监测参数没有显著影响。水分剥夺会降低幼苗的鲜重和含水量，并增加应激标志物和渗透物的水平。这伴随着酶 Δ-吡咯啉-5-羧酸合成酶和 Δ-吡咯啉-5-羧酸还原酶的编码 和 转录物的大量积累。褪黑素在减轻干旱胁迫方面的效果无论在暴露前还是暴露后应用都相似，但作为预处理时效果略好。
