共查询到5条相似文献,搜索用时 0 毫秒
1.
Na Zhang Bing Zhao Hai‐Jun Zhang Sarah Weeda Chen Yang Zi‐Cai Yang Shuxin Ren Yang‐Dong Guo 《Journal of pineal research》2013,54(1):15-23
Abstract: A comprehensive investigation was carried out to determine the changes that occurred in water‐stressed cucumber (Cucumis sativus L.) in response to melatonin treatment. We examined the potential roles of melatonin during seed germination and root generation and measured its effect on reactive oxygen species (ROS) levels, antioxidant enzyme activities, and photosynthesis. Melatonin alleviated polyethylene glycol induced inhibition of seed germination, with 100 μm melatonin‐treated seeds showing the greatest germination rate. Melatonin stimulated root generation and vitality and increased the root:shoot ratio; therefore, melatonin may have an effect on strengthening cucumber roots. Melatonin treatment significantly reduced chlorophyll degradation. Seedlings treated with 100 μm melatonin clearly showed a higher photosynthetic rate, thus reversing the effect of water stress. Furthermore, the ultrastructure of chloroplasts in water‐stressed cucumber leaves was maintained after melatonin treatment. The antioxidant levels and activities of the ROS scavenging enzymes, i.e., superoxide dismutase, peroxidase, and catalase, were also increased by melatonin. These results suggest that the adverse effects of water stress can be minimized by the application of melatonin. 相似文献
2.
Melatonin applied to cucumber (Cucumis sativus L.) seeds improves germination during chilling stress
Magorzata M. Posmyk M. Baabusta M. Wieczorek E. Sliwinska K. M. Janas 《Journal of pineal research》2009,46(2):214-223
Abstract: The relationship between germination and melatonin applied during osmo- and hydropriming was studied in cucumber seeds. The proportion of nuclei with different DNA contents, the mean ploidy and the (2C + 4C = 8C)/2C ratio in unprimed and primed, dry and imbibed at 10°C seeds were established by flow cytometry. Thiobarbituric acid reactive substances and protein oxidation were also estimated. Melatonin and indole-3-acetic acid (IAA) concentrations in the seeds were determined using high-performance liquid chromatography with electrochemical detection. Being sensitive to chilling stress, seeds that germinated well (99%) at 25°C showed only 30% germination at 15°C, and almost no germination (4%) at 10°C. Hydropriming in water improved seed germination to 50–60% at 15°C and the addition of melatonin (25–100 m ) also increased the rate of germination. Osmopriming in polyethylene glycol increased germination at 15°C to 78%, and 98% when combined with 50 m melatonin. Osmoprimed seeds germinated even at 10°C and reached 43%, and 83% when 50 m melatonin was applied. None of the treatments induced DNA synthesis, although during the first 24 hr of imbibition at 10°C the mean ploidy and the (2C + 4C = 8C)/2C ratio increased, which is indicative of the advanced Phase II of germination. Hydro- and osmopriming slightly decreased IAA content in the seeds in most of the cases; only hydropriming with 100 and 500 m melatonin increased it. Melatonin protected membrane structure against peroxidation during chilling, but excessive melatonin levels in cucumber seeds (∼4 μg/g fresh weight) provoked oxidative changes in proteins. There is still lack of information explained clearly the role of melatonin in plant physiology. This molecule acts multidirectionally and usually is alliged to other compounds. 相似文献
3.
Glutathione‐dependent induction of local and systemic defense against oxidative stress by exogenous melatonin in cucumber (Cucumis sativus L.) 下载免费PDF全文
Hao Li Jie He Xiaozhen Yang Xin Li Dan Luo Chunhua Wei Jianxiang Ma Yong Zhang Jianqiang Yang Xian Zhang 《Journal of pineal research》2016,60(2):206-216
Melatonin is involved in defending against oxidative stress caused by various environmental stresses in plants. In this study, the roles of exogenous melatonin in regulating local and systemic defense against photooxidative stress in cucumber (Cucumis sativus) and the involvement of redox signaling were examined. Foliar or rhizospheric treatment with melatonin enhanced tolerance to photooxidative stress in both melatonin‐treated leaves and untreated systemic leaves. Increased melatonin levels are capable of increasing glutathione (reduced glutathione [GSH]) redox status. Application of H2O2 and GSH also induced tolerance to photooxidative stress, while inhibition of H2O2 accumulation and GSH synthesis compromised melatonin‐induced local and systemic tolerance to photooxidative stress. H2O2 treatment increased the GSH/oxidized glutathione (GSSG) ratio, while inhibition of H2O2 accumulation prevented a melatonin‐induced increase in the GSH/GSSG ratio. Additionally, inhibition of GSH synthesis blocked H2O2‐induced photooxidative stress tolerance, whereas scavenging or inhibition of H2O2 production attenuated but did not abolish GSH‐induced tolerance to photooxidative stress. These results strongly suggest that exogenous melatonin is capable of inducing both local and systemic defense against photooxidative stress and melatonin‐enhanced GSH/GSSG ratio in a H2O2‐dependent manner is critical in the induction of tolerance. 相似文献
4.
Melatonin is involved in multiple plant developmental processes and various stress responses. To explore the roles of melatonin played as well as its association with abscisic acid (ABA) in a process of drought priming‐induced cold tolerance (DPICT), a wild‐type barley and its ABA‐deficient mutant Az34 counterpart were selected for comparison, in which the effects of melatonin application (either foliarly or rhizospherically) and/or drought priming on the cold tolerance of both types of barleys were systematically investigated. It was demonstrated that the early drought priming induced an increase of endogenous melatonin production, which is not ABA dependent. In addition, exogenously applied melatonin resulted in higher ABA concentration in the drought‐primed plants than in the nonprimed plants when exposed to cold stress, indicating that ABA responded in a drought‐dependent manner. The interplay of melatonin and ABA leads to plants maintaining better water status. Drought priming‐induced melatonin accumulation enhanced the antioxidant capacity in both chloroplasts and mitochondria, which sustained the photosynthetic electron transport in photosynthetic apparatus of the plants under cold stress. These results suggest that the exogenous melatonin application enhances the DPICT by modulating subcellular antioxidant systems and ABA levels in barley. 相似文献
5.
Feedback suppression of meal‐induced glucagon‐like peptide‐1 (GLP‐1) secretion mediated through elevations in intact GLP‐1 caused by dipeptidyl peptidase‐4 inhibition: a randomized,prospective comparison of sitagliptin and vildagliptin treatment 下载免费PDF全文
Oleg Baranov MD Melanie Kahle Dipl. troph. Carolyn F. Deacon PhD Jens J. Holst MD PhD Michael A. Nauck MD 《Diabetes, obesity & metabolism》2016,18(11):1100-1109