Rasaei Seyedeh Safoura, Sarmast Mostafa K, Ghaleh Zahra Rezaei, Zarei Hossein, Savchenko Tatyana
Department of Horticultural Science and Landscape Engineering, Faculty of Plant Production, Gorgan University of Agricultural Sciences and Natural Resources (GUASNR), Gorgan, 49138-43464 Golestan Iran.
Institute of Basic Biological Problems, Pushchino Scientific Center for Biological Research, Russian Academy of Sciences, Pushchino, Russia.
Physiol Mol Biol Plants. 2025 Feb;31(2):329-342. doi: 10.1007/s12298-025-01559-5. Epub 2025 Feb 22.
Drought is a natural disaster that exerts considerable adverse impacts on the agricultural sector. This study aimed to investigate the cytokinin-mediated carbohydrate accumulation in the aerial parts of the plant and the roots in four-month-old drought-stressed tall fescue ( Schreb.) plants. To achieve this, exogenous treatments containing 50 mM of the synthetic cytokinin 6-Benzylaminopurine (6-BA) were applied prior to the onset of drought stress and every seven days during the 14-day drought stress period. These plants were subjected to varying levels of soil water holding capacity (WHC): 25 ± 5% (severe stress), 50 ± 5% (moderate stress), and 100 ± 5% (control). A range of morpho-physiological, biochemical, and molecular responses were evaluated. Our data suggest that the reduction of starch and the accumulation of water-soluble carbohydrates (WSCs) induced by severe drought stress were mitigated (reduced by half) in the roots and shoots of plants treated with 6-BA under similar drought conditions. This treatment may support plants by promoting the normal storage of energy reserves, thereby enhancing their resilience during subsequent periods of water scarcity. Furthermore, the application of 6-BA facilitates the regulation of carbohydrate accumulation, proline content, and enzymatic activity. 6-BA functions by downregulating the expression of cytokinin oxidase/dehydrogenase genes, particularly and 3, and by upregulating the gene. This mechanism inhibits the degradation of cytokinins and promotes root growth under conditions of severe drought stress. 6-BA reduced expression during moderate drought stress compared to the corresponding control, indicating that cytokinins can alter auxin transport mechanisms and help plants prioritize growth processes under water scarcity. The application of 6-BA not only serves as an effective sink for enhancing starch accumulation in leaves but also inhibits the expression of the chlorophyll degradation gene (), thereby preventing chlorophyll degradation. This dual action aids plants in sustaining their growth and development during episodes of short-term drought stress.
The online version contains supplementary material available at 10.1007/s12298-025-01559-5.
干旱是一种对农业部门产生重大不利影响的自然灾害。本研究旨在调查细胞分裂素介导的碳水化合物在四个月大的干旱胁迫高羊茅（Festuca arundinacea Schreb.）植株地上部分和根系中的积累情况。为此，在干旱胁迫开始前以及14天干旱胁迫期内每隔七天施加含有50 mM合成细胞分裂素6-苄基腺嘌呤（6-BA）的外源处理。这些植株经受不同水平的土壤持水量（WHC）：25±5%（重度胁迫）、50±5%（中度胁迫）和100±5%（对照）。评估了一系列形态生理、生化和分子反应。我们的数据表明，在类似干旱条件下，用6-BA处理的植株的根和地上部分中，严重干旱胁迫诱导的淀粉减少和水溶性碳水化合物（WSC）积累得到缓解（减少一半）。这种处理可能通过促进能量储备的正常储存来支持植株，从而增强它们在随后缺水时期的恢复力。此外，6-BA的施用有助于调节碳水化合物积累、脯氨酸含量和酶活性。6-BA通过下调细胞分裂素氧化酶/脱氢酶基因（特别是CKX1和CKX3）的表达以及上调ARR1基因的表达来发挥作用。这种机制在严重干旱胁迫条件下抑制细胞分裂素的降解并促进根系生长。与相应对照相比，6-BA在中度干旱胁迫期间降低了PIN2的表达，表明细胞分裂素可以改变生长素运输机制并帮助植株在缺水情况下优先进行生长过程。6-BA的施用不仅作为增强叶片中淀粉积累的有效库，还抑制叶绿素降解基因（SGR）的表达，从而防止叶绿素降解。这种双重作用有助于植株在短期干旱胁迫期间维持其生长和发育。
在线版本包含可在10.1007/s12298-025-01559-5获取的补充材料。
