Melatonin improves the germination rate of cotton seeds under drought stress by opening pores in the seed coat
Melatonin improves the germination rate of cotton seeds under drought stress by opening pores in the seed coat
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DOI：
10.7717/peerj.9450
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发表时间：
2020-07-06
期刊：
影响因子：
2.7
通讯作者：
Liu, Liantao
中科院分区：
文献类型：
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作者：
Bai, Yandan;Xiao, Shuang;Liu, Liantao
棉花（Gossypium hirsutum L.）棉花种子受到干旱胁迫的影响，但干旱胁迫下影响种子萌发的生理机制以及褪黑激素（MT）对棉花种子萌发的影响尚不清楚。因此，我们研究了外源MT对干旱胁迫下棉花抗氧化能力和表皮微结构的影响。结果表明，干旱胁迫使种皮吸水能力降低，显著抑制棉花种子的萌发和生长。干旱胁迫导致活性氧（ROS）、丙二醛（MDA）和植物生长调节物质（如，脯氨酸、可溶性蛋白质和可溶性糖）;它还降低了抗氧化酶和α-淀粉酶的活性。干旱胁迫抑制赤霉素（GA（3））合成，增加脱落酸（阿坝）含量，严重影响种子萌发。而MT（100 μ M）浸种对棉花种皮气孔的数量和开放度有正调节作用。外源MT处理提高了种子的发芽率、发芽势、胚根长度和鲜重，并提高了超氧化物歧化酶（SOD）、过氧化物酶（POD）和α-淀粉酶的活性。此外，MT还通过降低干旱胁迫下H2 O2、O2-和MDA的含量，提高了有机渗透物质的含量。进一步的分析表明，MT浸种通过影响阿坝和GA 3含量来缓解干旱胁迫。我们的研究结果表明，MT在保护棉花种子免受干旱胁迫方面具有积极的作用。
The germination of cotton (Gossypium hirsutum L.) seeds is affected by drought stress; however, little is known about the physiological mechanism affecting germination and the effect of melatonin (MT) on cotton seed germination under drought stress. Therefore, we studied the effects of exogenous MT on the antioxidant capacity and epidermal microstructure of cotton under drought stress. The results demonstrated a retarded water absorption capacity of testa under drought stress, significantly inhibiting germination and growth in cotton seeds. Drought stress led to the accumulation of reactive oxygen species (ROS), malondialdehyde (MDA), and osmoregulatory substances (e.g., proline, soluble protein, and soluble sugars); it also decreased the activity of antioxidant enzymes and alpha-amylase. Drought stress inhibited gibberellin acid (GA(3)) synthesis and increased abscisic acid (ABA) content, seriously affecting seed germination. However, seeds pre-soaked with MT (100 mu M) showed a positive regulation in the number and opening of stomata in cotton testa. The exogenous application of MT increased the germination rate, germination potential, radical length, and fresh weight, as well as the activities of superoxide dismutase (SOD), peroxidase (POD), and alpha-amylase. In addition, MT application increased the contents of organic osmotic substances by decreasing the hydrogen peroxide (H2O2), superoxide anion (O-2(-)), and MDA levels under drought stress. Further analysis demonstrated that seeds pre-soaked with MT alleviated drought stress by affecting the ABA and GA(3) contents. Our findings show that MT plays a positive role in protecting cotton seeds from drought stress.