The mitigation effects of exogenous melatonin on salinity-induced stress in Malus hupehensis
The mitigation effects of exogenous melatonin on salinity-induced stress in Malus hupehensis
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DOI：
10.1111/j.1600-079x.2012.00999.x
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发表时间：
2012-10-01
影响因子：
10.3
通讯作者：
Ma, Fengwang
中科院分区：
文献类型：
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作者：
Li, Chao;Wang, Ping;Ma, Fengwang
为了研究褪黑素在抗旱性中的潜在作用，我们测试了长期外源施用褪黑素对汉服苹果（Malus domestica Borkh.）的影响。在干旱条件下，土壤中添加100m褪黑素可以缓解氧化应激，延缓叶片衰老。该分子显著降低了叶绿素降解，抑制了衰老相关基因12 （SAG12）和磷酸合氧酶（PAO）的上调。该处理还能缓解干旱胁迫对光合作用的抑制。我们还研究了光系统II （PSII）在黑暗和光照条件下的猝灭和光化学效率，发现褪黑素有助于在干旱条件下维持PSII更好的功能。褪黑素的加入也控制了过氧化氢的爆发，可能是通过直接清除和增强抗氧化酶的活性和抗坏血酸谷胱甘肽循环的能力。因此，了解褪黑素对耐旱性的影响，为将这种化合物用于农业用途提供了新的可能性。褪黑素是一种吲哚胺类分子，在植物体内介导多种生理过程。我们研究了它在调节苹果生长、离子稳态和氧化应激反应中的作用。在高盐度条件下。受胁迫植物生长减缓，净光合速率和叶绿素含量明显下降。然而，0.1 μ m褪黑素预处理显著缓解了这种生长抑制，使植物保持提高的光合能力。褪黑素的加入也减少了由盐度引起的氧化损伤，可能是通过直接清除H2O2或增强抗坏血酸过氧化物酶、过氧化氢酶和过氧化物酶等抗氧化酶的活性。我们还研究了褪黑激素是否可能控制盐胁迫下离子通道基因的表达。在这里，MdNHX1和MdAKT1在叶片中被大幅上调，这可能有助于维持离子稳态，从而提高外源褪黑激素暴露的植物的耐盐性。
To examine the potential roles of melatonin in drought tolerance, we tested the effects of its long-term exogenous application on Hanfu' apple (Malus domestica Borkh.). When 100m melatonin was added to soils under drought conditions, the resultant oxidative stress was eased and leaf senescence was delayed. This molecule significantly reduced chlorophyll degradation and suppressed the up-regulation of senescence-associated gene 12 (SAG12) and pheophorbide a oxygenase (PAO). Such treatment also alleviated the inhibition of photosynthesis brought on by drought stress. We also investigated quenching and the efficiency of Photosystem II (PSII) photochemistry under dark and light conditions and found that melatonin helped to maintain better function of PSII under drought. The addition of melatonin also controlled the burst of hydrogen peroxide, possibly through direct scavenging and by enhancing the activities of antioxidative enzymes and the capacity of the ascorbateglutathione cycle. Thus, understanding this effect of melatonin on drought tolerance introduces new possibilities to use this compound for agricultural purposes.As an indoleamine molecule, melatonin mediates many physiological processes in plants. We investigated its role in regulating growth, ion homeostasis, and the response to oxidative stress in Malus hupehensis Rehd. under high-salinity conditions. Stressed plants had reduced growth and a marked decline in their net photosynthetic rates and chlorophyll contents. However, pretreatment with 0.1 mu m melatonin significantly alleviated this growth inhibition and enabled plants to maintain an improved photosynthetic capacity. The addition of melatonin also lessened the amount of oxidative damage brought on by salinity, perhaps by directly scavenging H2O2 or enhancing the activities of antioxidative enzymes such as ascorbate peroxidase, catalase, and peroxidase. We also investigated whether melatonin might control the expression of ion-channel genes under salinity. Here, MdNHX1 and MdAKT1 were greatly up-regulated in the leaves, which possibly contributed to the maintenance of ion homeostasis and, thus, improved salinity resistance in plants exposed to exogenous melatonin.