Exogenous Application of Melatonin Induces Tolerance to Salt Stress by Improving the Photosynthetic Efficiency and Antioxidant Defense System of Maize Seedling

Journal of Plant Growth Regulation - Melatonin is a ubiquitous signaling plant hormone that plays a crucial role in regulating the growth and development of plants under stress conditions. Since a...     

Exogenous Melatonin Achieves Drought Tolerance by Improving Photosynthesis in Maize Seedlings Leaves

Russian Journal of Plant Physiology - The beneficial roles of melatonin in plants have been widely reported, but its effect on photosynthesis under drought stress is not clear. In the study,...     

Modulation of Exogenous Glutathione in Ultrastructure and Photosynthetic Performance Against Cd Stress in the Two Barley Genotypes Differing in Cd Tolerance

Greenhouse hydroponic experiments were conducted using Cd-sensitive (Dong 17) and tolerant (Weisuobuzhi) barley genotypes to evaluate genotypic differences in response of photosynthesis and ultrastructure to Cd toxicity in the presence of exogenous glutathione (GSH). Addition of 20 mg L(-1) GSH in 5 μM Cd culture medium (Cd?+?GSH) significantly alleviated Cd-induced growth inhibition and reduced Cd concentration in leaves and roots especially in the sensitive genotype Dong 17. Exogenous GSH greatly ameliorated Cd-induced damages on leaf/root ultrastructure, e.g., compared with Cd alone treatment, chloroplasts in plants treated with Cd?+?GSH become better or in relatively normal shape with well-structured thylakoid membranes and parallel pattern of lamellae and unfolded more starch grains but less osmiophilic plastoglobuli; nuclei of root cells were better formed and chromatin distributed more uniformly in both genotypes, and number of plastids and mitochondria cristae in Dong 17 resumed to control level. The examination of photosynthetic performance revealed GSH dramatically increased net photosynthetic rate (P(n)), stomatal conductance (G(s)), and transpiration rate (T(r)) in the both genotypes and strongly stimulated Cd-induced decrease in the maximal photochemical efficiency (F(v)/F(m)) especially in the sensitive genotype.     

Modulation of Exogenous Glutathione in Phytochelatins and Photosynthetic Performance Against Cd Stress in the Two Rice Genotypes Differing in Cd Tolerance

Greenhouse hydroponic experiments were conducted using Cd-sensitive (Xiushui63) and tolerant (Bing97252) rice genotypes to evaluate genotypic differences in response of photosynthesis and phytochelatins to Cd toxicity in the presence of exogenous glutathione (GSH). Plant height, chlorophyll content, net photosynthetic rate (Pn), and biomass decreased in 5 and 50 μM Cd treatments, and Cd-sensitive genotype showed more severe reduction than the tolerant one. Cadmium stress caused decrease in maximal photochemical efficiency of PSII (Fv/Fm) and effective PSII quantum yield [Y(II)] and increase in quantum yield of regulated energy dissipation [Y(NPQ)], with changes in Cd-sensitive genotype being more evident. Cadmium-induced phytochelatins (PCs), GSH, and cysteine accumulation was observed in roots of both genotypes, with markedly higher level in PCs and GSH on day 5 in Bing97252 compared with that measured in Xiushui63. Exogenous GSH significantly alleviated growth inhibition in Xiushui63 under 5 μM Cd and in both genotypes in 50 μM Cd. External GSH significantly increased chlorophyll content, Pn, Fv/Fm, and Y(II) of plants exposed to Cd, but decreased Y(NPQ) and the coefficient of non-photochemical quenching (qN). GSH addition significantly increased root GSH content in plants under Cd exposure (except day 5 of 50 μM Cd) and induced up-regulation in PCs of 5 μM-Cd-treated Bing97252 throughout the 15-day and Xiushui63 of 5-day exposure. The results suggest that genotypic difference in the tolerance to Cd stress was positively linked to the capacity in elevation of GSH and PCs, and that alleviation of Cd toxicity by GSH is related to significant improvement in chlorophyll content, photosynthetic performance, and root GSH levels.     

外源褪黑素对盐胁迫下紫花苜蓿幼苗抗氧化能力以及光合作用效率的影响

紫花苜蓿为多年生豆科优良牧草,土壤盐碱化是其产量的重要限制因素.该研究以'中苜1号'紫花苜蓿为材料,在盐胁迫浓度和褪黑素浓度筛选试验基础上,设置盐(150 mmol/L NaCl)和褪黑素(30、50、80 μmol/L)单独及复合处理,采用水培根灌褪黑素的方法,探究外源褪黑素对盐胁迫下紫花苜蓿幼苗生长特性、膜透性、渗...     

Ectopic Expression of Arabidopsis Glycosyltransferase UGT85A5 Enhances Salt Stress Tolerance in Tobacco

Abiotic stresses greatly influence plant growth and productivity. While glycosyltransferases are widely distributed in plant kingdom, their biological roles in response to abiotic stresses are largely unknown. In this study, a novel Arabidopsis glycosyltransferase gene UGT85A5 was identified as significantly induced by salt stress. Ectopic expression of UGT85A5 in tobacco enhanced the salt stress tolerance in the transgenic plants. There were higher seed germination rates, better plant growth and less chlorophyll loss in transgenic lines compared to wild type plants under salt stress. This enhanced tolerance of salt stress was correlated with increased accumulations of proline and soluble sugars, but with decreases in malondialdehyde accumulation and Na⁺/K⁺ ratio in UGT85A5-expressing tobacco. Furthermore, during salt stress, expression of several carbohydrate metabolism-related genes including those for sucrose synthase, sucrose-phosphate synthase, hexose transporter and a group2 LEA protein were obviously upregulated in UGT85A5-expressing transgenic plants compared with wild type controls. Thus, these findings suggest a specific protective role of this glycosyltransferase against salt stress and provide a genetic engineering strategy to improve salt tolerance of crops.     

Advances in Salt Tolerance of Some Major Fiber Crops Through Classical and Advanced Biotechnological Tools: A Review

Journal of Plant Growth Regulation - Plant biofibers are of great economic and commercial importance. Among various fiber producing crops, cotton (Gossypium hirsutum L.), hemp (Cannabis sativa L.),...     

Exogenous Melatonin Improves the Growth of Rice Seedlings by Regulating Redox Balance and Ion Homeostasis Under Salt Stress

This study evaluated the effects of foliar spraying melatonin (MT) on the growth of salt-stressed rice. Seedlings were treated with 50 and 100 mM of NaCl and different concentrations of MT (25, 50, 100, 200, 300, and 400 μM) for 14 days. Different concentrations of MT could promote plant growth significantly under salt stress, particularly at concentrations of 200, 300, and 400 μM. A concentration of 200 μM MT was considered as optimal and used in a subsequent experiment on biomass, water content, antioxidation, mineral nutrition, salt absorption, and distribution of salt-stressed rice seedlings. Results showed that MT’s promoting effect on plant growth under salt stress was evident with time, particularly under high salt stress. MT improved the activities of antioxidant enzymes, reduced membrane lipid peroxidation, alleviated cell injury in plant leaves, and increased N content and Si accumulation in the leaves and roots under salt stress, particularly under high salinity. This compound also inhibited Na uptake and upward transport, but it promoted or maintained the uptake and upward transport of K and Ca in salt-stressed rice. Thus, MT improved the ion homeostasis of K/Na and Ca/Na in plants, particularly in the leaves. Foliar spraying of MT alleviated salt stress on rice by promoting nutrient accumulation or translocation, improving ion homeostasis, which is evident in the leaves, and consequently enhancing its salt resistance. The antioxidative improvement caused by MT might also be related to the improved ion homeostasis.

     

The Arabidopsis AtAAE13.1 Gene Enhances Salt Stress Tolerance in Angiosperms and Gymnosperm Plant Cells

In Vitro Cellular & Developmental Biology - Plant - The Arabidopsis malonyl-CoA synthetase gene AAE13.1 (AtAAE13.1) plays important roles in cell metabolism, plant growth and development, and...     

低温胁迫下褪黑激素对烟草悬浮细胞精氨酸脱羧酶活性的影响

研究了褪黑激素对烟草(Nicotiana tabacum)悬浮细胞在低温胁迫下精氨酸脱羧酶活性及细胞生存率的影响.发现褪黑激素可以明显提高低温胁迫下烟草悬浮细胞精氨酸脱羧酶的活性,并明显提高细胞的生存率.表明褪黑激素可能在低温条件下通过调节植物细胞内多胺的合成而提高抵御冷害的能力.     

低温胁迫下褪黑激素对烟草悬浮细胞精氨酸脱羧酶活性的影响

研究了褪黑激素对烟草(Nicotiana tabacum)悬浮细胞在低温胁迫下精氨酸脱羧酶活性及细胞生存率的影响。发现褪黑激素可以明显提高低温胁迫下烟草悬浮细胞精氨酸脱羧酶的活性, 并明显提高细胞的生存率。表明褪黑激素可能在低温条件下通过调节植物细胞内多胺的合成而提高抵御冷害的能力。     

Fullerenol [60] Nano-cages for Protection of Crops Against Oxidative Stress: A Critical Review

Journal of Plant Growth Regulation - Fullerenols are carbon nanoparticles that have been declared as free radical sponges. There is a need to take a prudent path toward its applications in various...     

Chitinase Gene Expression in Response to Environmental Stresses in Arabidopsis thaliana: Chitinase Inhibitor Allosamidin Enhances Stress Tolerance

The expression levels of three chitinase genes in Arabidopsis thaliana, AtChiA (class III), AtChiB (class I), and AtChiV (class IV), were examined under various stress conditions by semi-quantitative RT-PCR. Under normal growth conditions, the AtChiB and AtChiV genes were expressed in most organs of Arabidopsis plants at all growth stages, whereas the AtChiA gene was not expressed at all. The class III AtChiA gene was expressed exclusively when the plants were exposed to environmental stresses, especially to salt and wound stresses. Treatment of Arabidopsis plants with allosamidin, which inhibits class III chitinases, did not affect the growth rate. Surprisingly, however, the plants treated with allosamidin were more tolerant of abiotic stresses (cold, freezing, heat, and strong light) than the control plants. It also appeared that allosamidin enhances AtChiA and AtChiB expression under heat and strong light stresses. Allosamidin is likely to enhance abiotic stress tolerance, probably through crosstalk between the two signaling pathways for biotic and abiotic stress responses.     

褪黑素对铅胁迫下虎舌红和朱砂根生理响应及DNA损伤的调控效应

铅胁迫是影响植物生长的主要非生物因素之一。以二年生虎舌红(Ardisia mamillata)和朱砂根(A. crenata)为实验材料, 探究外源褪黑素(MT)处理对不同浓度铅胁迫下2种植物生理响应及DNA损伤的调控效应。结果表明, 相同处理时间内, 随着铅胁迫浓度的升高, 虎舌红与朱砂根的3种抗氧化酶活性、脯氨酸(Pro)及可溶性蛋白(SP)含量均先升高后降低, 而丙二醛(MDA)含量先降低后升高, 根尖胼胝质含量持续升高, 根系DNA损伤加剧。施加适宜浓度的外源褪黑素(MT)后, 不同浓度铅胁迫下2种植物的抗氧化酶活性得到有效增强, 且均在100 µmol∙L^-1 MT处理时达到最大值, Pro和SP含量均显著升高, MDA含量则先显著降低而后缓慢升高, 根尖胼胝质含量持续增加, 根系DNA损伤得到改善; 随着MT浓度的持续升高, 其缓解作用逐渐减弱。相较于虎舌红, 朱砂根对铅胁迫的抗性更强, 生理响应更稳定。施加外源MT可有效缓解铅胁迫对虎舌红和朱砂根的毒害作用(缓解效果朱砂根>虎舌红), 增强二者对铅毒的耐受性, 其中100 µmol∙L^-1 MT处理下缓解效果最佳。研究揭示了虎舌红和朱砂根抗铅性的优劣及外源MT对铅毒的缓解效应, 为紫金牛属植物抗铅性研究提供理论参考。     

Combined Application of Arbuscular Mycorrhizal Fungi and Exogenous Melatonin Alleviates Drought Stress and Improves Plant Growth in Tobacco Seedlings

Journal of Plant Growth Regulation - Studies have shown that the application of arbuscular mycorrhizal (AM) fungi or exogenous melatonin (MT) can alleviate drought stress and improve plant growth,...     

A Sweetpotato Geranylgeranyl Pyrophosphate Synthase Gene,IbGGPS, Increases Carotenoid Content and Enhances Osmotic Stress Tolerance in Arabidopsis thaliana

Sweetpotato highly produces carotenoids in storage roots. In this study, a cDNA encoding geranylgeranyl phyrophosphate synthase (GGPS), named IbGGPS, was isolated from sweetpotato storage roots. Green fluorescent protein (GFP) was fused to the C-terminus of IbGGPS to obtain an IbGGPS-GFP fusion protein that was transiently expressed in both epidermal cells of onion and leaves of tobacco. Confocal microscopic analysis determined that the IbGGPS-GFP protein was localized to specific areas of the plasma membrane of onion and chloroplasts in tobacco leaves. The coding region of IbGGPS was cloned into a binary vector under the control of 35S promoter and then transformed into Arabidopsis thaliana to obtain transgenic plants. High performance liquid chromatography (HPLC) analysis showed a significant increase of total carotenoids in transgenic plants. The seeds of transgenic and wild-type plants were germinated on an agar medium supplemented with polyethylene glycol (PEG). Transgenic seedlings grew significantly longer roots than wild-type ones did. Further enzymatic analysis showed an increased activity of superoxide dismutase (SOD) in transgenic seedlings. In addition, the level of malondialdehyde (MDA) was reduced in transgenics. qRT-PCR analysis showed altered expressions of several genes involved in the carotenoid biosynthesis in transgenic plants. These data results indicate that IbGGPS is involved in the biosynthesis of carotenoids in sweetpotato storage roots and likely associated with tolerance to osmotic stress.     

Amelioration of Cd-Induced Oxidative Stress,MT Gene Expression,and Immune Damage by Vitamin C in Grass Carp Kidney Cells

Biological Trace Element Research - Cadmium (Cd) is the most common heavy metal and is easily detected in aquatic environments on a global scale. Vitamin C was a widely used vitamin in aquaculture....