Botany Department, Faculty of Science, Cairo University, Giza 12613, Egypt.
Plant Physiol Biochem. 2013 Oct;71:173-83. doi: 10.1016/j.plaphy.2013.07.007. Epub 2013 Jul 26.
Seed germination and growth of seedlings are critical phases of plant life that are adversely affected by various environmental cues. Water availability is one of the main factors that limit the productivity of many crops. This study was conducted to assess the changes in the sensitivity of chickpea seedlings to osmotic stress by prior treatment of chickpea seeds with a low concentration (50 ppm) of ellagic acid. Ellagic acid was isolated and purified from Padina boryana Thivy by chromatographic techniques. After ellagic acid treatment, seeds were germinated for 10 days under different osmotic potentials (0, -0.2, -0.4, -0.6 and -0.8 MPa) of polyethylene glycol (PEG) solutions. Ellagic acid treatment accelerated the germination and seedling growth of chickpea under osmotic stress conditions. Consistent with the accelerated growth, ellagic acid-treated seedlings also showed a significant increase in the total antioxidant capacity (FRAP) as well as an increase in the compatible solutes (proline and glycine betaine) content. Additionally, treated seedlings revealed lower lipid peroxidation levels (MDA), electrolyte leakage (EL) and H2O2. Flavonoid and reduced glutathione (GSH) content, and the activity of antioxidant enzymes [catalase (CAT), peroxidase (POX), superoxide dismutase (SOD), glutathione reductase (GR)] and enzymes of the shikimic acid pathway [phenylalanine ammonia lyase (PAL) and chalcone synthase (CHS)] all showed a remarkable increase with ellagic acid pretreatment compared to untreated seedlings especially under mild osmotic stress values (-0.2 and -0.4 MPa). These results suggested that treatment with ellagic acid could confer an increased tolerance of chickpea seedlings to osmotic stress, through reducing levels of H2O2 and increasing antioxidant capacity.
种子萌发和幼苗生长是植物生命的关键阶段，会受到各种环境信号的不利影响。水分供应是限制许多作物生产力的主要因素之一。本研究旨在评估先用低浓度（50ppm）鞣花酸处理鹰嘴豆种子，是否会改变鹰嘴豆幼苗对渗透胁迫的敏感性。鞣花酸是通过色谱技术从 P. boryana Thivy 中分离和纯化得到的。用鞣花酸处理后，种子在不同的渗透势（0、-0.2、-0.4、-0.6 和-0.8MPa）的聚乙二醇（PEG）溶液中发芽 10 天。鞣花酸处理加速了渗透胁迫条件下鹰嘴豆的萌发和幼苗生长。与加速生长一致，鞣花酸处理的幼苗也表现出总抗氧化能力（FRAP）显著增加，以及相容性溶质（脯氨酸和甘氨酸甜菜碱）含量增加。此外，处理过的幼苗显示出较低的脂质过氧化水平（MDA）、电解质泄漏（EL）和 H2O2。类黄酮和还原型谷胱甘肽（GSH）含量以及抗氧化酶[过氧化氢酶（CAT）、过氧化物酶（POX）、超氧化物歧化酶（SOD）、谷胱甘肽还原酶（GR）]和莽草酸途径的酶[苯丙氨酸解氨酶（PAL）和查尔酮合酶（CHS）]的活性均显著增加与未经处理的幼苗相比，尤其是在轻度渗透胁迫值（-0.2 和-0.4MPa）下，用鞣花酸预处理后。这些结果表明，鞣花酸处理可以通过降低 H2O2 水平和增加抗氧化能力，赋予鹰嘴豆幼苗对渗透胁迫的更高耐受性。
