Stress-Induced Changes in Wheat Grain Composition and Quality

Abiotic stresses such as drought, salinity, waterlogging, and high temperature cause a myriad of changes in the metabolism of plants, and there is a lot of overlap in these changes in plants in response to different stresses such as drought and salinity. These stress-induced metabolic changes cause impaired crop growth thereby resulting in poor yield. The metabolic changes taking place in several plant species due to a particular abiotic stress have been revealed from the whole plant to the molecular level by researchers, but most studies have focused on organs such as leaf, stem, and root. Information on such stress-induced changes in seed or grains is infrequent in the literature. From the information that is available, it is now evident that abiotic stress can induce considerable changes in the composition and quality of cereal grains including those of wheat, the premier staple food crop in the world. Thus, the present review discusses how far different types of stresses, mainly salinity, drought, high temperature, and waterlogging, can alter the wheat grain composition and quality. By fully uncovering the stress-induced changes in the nutritional values of wheat grains it would be possible to establish whether balanced supplies of essential nutrients are available to the human population from the wheat crop grown on stress-affected areas.     

Proteomics application of crops in the context of climatic changes

Abiotic stress caused by global climate change varies widely, which negatively affect crops growth and productivity throughout the world. Environmental changes can alter plant’s physiological state and trigger several signaling pathways for adaptation to unfavorable conditions. Plant response to abiotic stress includes changes in protein expression and post-translational modification of proteins to activate their defense system against the challenges. Research on plant proteomes has provided beneficial information for a comprehensive understanding of the protein networks in plants in response to external stimuli. Large-scale proteomics is a powerful approach for studies of complex biological processes in which a number of proteins take part; proteome analysis of sub-cellular structures and modified proteins has enabled identification of novel components of plant stress responses that had not previously been discovered. In this review, we have discussed the recent developments of crop proteomics in the context of several climatic factors including photosynthetic stress, air pollutants, thermal stress including heat and cold, and osmotic stress, including drought, salt, and flooding stress, and metal stress. The aim of this review is to take a snapshot of several proteomic approaches in crop plants that provide a comprehensive list of components affected by certain abiotic stresses in climate. The biological relevance of these proteins in regard to plant stress tolerance will be described as well.     

Drought‐proofing barley (Hordeum vulgare) and its impact on grain quality: A review

Barley starch research is currently focused on the biosynthesis (enzymatic pathways), structure and the properties of barley grown under optimal conditions. With only limited information available on the effects of abiotic stress (drought) on starch structure, the need arises to determine the effects of genetic expression, inferring drought tolerance and its impact on starch biosynthesis and structure under terminal drought stress. Using size‐exclusion chromatography for the first time can bring an understanding of how starch molecular structure is influenced by drought tolerance trait expression; this has the potential to improve our current knowledge of starch biosynthesis, structure and properties. This understanding may aid plant breeders in producing varieties that are drought‐tolerant whilst maintaining the desired starch quality characteristics required by industry. In this review, starch hierarchical structure and molecular structural characterization methods are summarized. This is followed by an overview of our current knowledge of abiotic stress, stress tolerance and its impact on grain quality. Copyright © 2015 The Institute of Brewing & Distilling     

Selenium (Se) improves drought tolerance in crop plants – a myth or fact?

Climate change has emerged as one of the most complex challenges of the 21st century and has become an area of interest in the past few decades. Many countries of the world have become extremely vulnerable to the impacts of climate change. The scarcity of water is a serious concern for food security of these countries and climate change has aggravated the risks of extreme events like drought. Oxidative stress, caused by a variety of active oxygen species formed under drought stress, damages many cellular constituents, such as carbohydrates, lipids, nucleic acids and proteins, which ultimately reduces plant growth, respiration and photosynthesis. Se has become an element of interest to many biologists owing to its physiological and toxicological importance. It plays a beneficial role in plants by enhancing growth, reducing damage caused by oxidative stress, enhancing chlorophyll content under light stress, stimulating senesce to produce antioxidants and improving plant tolerance to drought stress by regulating water status. Researchers have adopted different strategies to evaluate the role of selenium in plants under drought stress. Some of the relevant work available regarding the role of Se in alleviating adverse effect of drought stress is discussed in this paper. © 2015 Society of Chemical Industry     

干旱胁迫对芝麻生长与产量性状的影响及其抗旱性综合评价

利用盆栽法在苗期和花期对5个芝麻品种进行10d的干旱胁迫处理,测定了苗期胁迫处理后17个生长相关性状指标和苗期、花期胁迫处理后的13个产量性状指标。结果表明：（1）苗期干旱胁迫处理使芝麻植株生长速率减缓,根系发育缓慢,叶片数量减少,叶片变小,株高变矮,生物量降低,严重影响芝麻的生长发育;（2）花期干旱胁迫处理后除千粒重之外的其他产量性状指标值均低于苗期处理,花期干旱胁迫对芝麻的影响大于苗期,苗期处理对芝麻株高、蒴果数和蒴果大小等性状影响较小,对千粒重和单株种子干重等影响较大,而花期处理对芝麻株高、蒴果大小、每蒴粒数、单株种子干重和根系干重等性状影响较大;（3）不同基因型品种间对干旱胁迫的反应存在较大差异;（4）利用主成分分析法和隶属函数法相结合通过43个单项指标抗旱系数对5个芝麻品种进行了综合评价,为芝麻抗旱性鉴定提供了参考方法,并认为苗期干旱胁迫及胁迫后的生长相关性状指标可以作为芝麻抗旱性鉴定的简单方法和抗旱性评价的简易指标;（5）获得黑芝09-1和金黄麻为抗旱性较强的芝麻品种。     

Seed biopriming as a promising approach for stress tolerance and enhancement of crop productivity: a review

Chemicals are used extensively in agriculture to increase crop production to meet the nutritional needs of an expanding world population. However, their injudicious application adversely affects the soil's physical, chemical and biological properties, subsequently posing a substantial threat to human health and global food security. Beneficial microorganisms improve plant health and productivity with minimal impact on the environment; however, their efficacy greatly relies on the application technique. Biopriming is an advantageous technique that involves the treatment of seeds with beneficial biological agents. It exhibits immense potential in improving the physiological functioning of seeds, thereby playing a pivotal role in their uniform germination and vigor. Biopriming-mediated molecular and metabolic reprogramming imparts stress tolerance to plants, improves plant health, and enhances crop productivity. Furthermore, it is also associated with rehabilitating degraded land, and improving soil fertility, health and nutrient cycling. Although biopriming has vast applications in the agricultural system, its commercialization and utilization by farmers is still in its infancy. This review aims to critically analyze the recent studies based on biopriming-mediated stress mitigation by alteration in physiological, metabolic and molecular processes in plants. Additionally, considering the necessity of popularizing this technique, the major challenges and prospects linked to the commercialization and utilization of this technique in agricultural systems have also been discussed. © 2023 Society of Chemical Industry.     

烟草中脱落酸的相关研究进展

烟草的生长发育极易受到不良环境的影响,导致烟叶产量和品质下降,其对不利环境因素的抗性受植物激素的调控。植物激素脱落酸是植物体内五大类激素之一,参与植物的生长发育,可提高植物对非生物逆境胁迫的抗性。以脱落酸为核心的基因工程技术是目前作物抗逆育种的重点策略之一,本文重点总结烟草中脱落酸的相关研究进展,包括一般功能、抵御非生物逆境的功能、代谢和信号转导途径等,以期为烟草抗逆育种提供理论支持和技术方法借鉴。     

干旱胁迫下钾对烤烟生长及抗旱性的生理调节

严重干旱胁迫条件下烟株的生长明显受阻，产量下降。增施钾肥可提高烟叶中钾的含量，增加干物质积累，并能使叶片中的各种化学物质充分转化、含量协调，从而提高了干旱条件下烤烟的产量，并能改善品质。钾素的生理调节机理是增强烤烟叶片的保水力，降低失水速率和蒸腾速率。细胞膜在干旱条件下保持其完整性，表现为叶片的相对电导率和伤害率下降。另外，干旱胁迫下钾素能够增强烟株对超氧化物歧化酶（ＳＯＤ）活性的调节，有利于消除活性氧自由基，减轻了干旱胁迫对细胞膜的伤害，从而增强烤烟的抗旱能力，并使恢复供水后的烟株迅速恢复生长。     

Effects of water-saving superabsorbent polymer on antioxidant enzyme activities and lipid peroxidation in oat (Avena sativa L.) under drought stress

BACKGROUND: Drought stress significantly limits oat (Avena sativa L.) growth and productivity. Thus an efficient management of soil moisture and study of metabolic changes in response to drought are important for improved production of oat. The objective was to gain a better understanding of drought tolerance mechanisms and improve soil water management strategies using water‐saving superabsorbent polymer (SAP) at 60 kg ha^?1 under three irrigation levels (adequate, moderate and deficit) using a new type of hydraulic pressure‐controlled auto irrigator. RESULTS: The results showed that the relative water content and leaf water potential (ψ₁) were much higher in oats treated with SAP. Although the SAP had little effect on plant biomass accumulation under adequate and moderate irrigation, it significantly increased the biomass by 52.7% under deficit irrigation. Plants treated with SAP under deficit irrigation showed a significant decrease in superoxide dismutase, catalase, peroxidase, ascorbate peroxidase and glutathione reductase activities in leaves compared with control plants. CONCLUSION: Our results suggested that drought stress leads to production of oxygen radicals, which results in increased lipid peroxidation and oxidative stress in the plant, and the application of SAP could conserve soil water, making same available to plants for increased biomass accumulation and reduced oxidative stress especially under severe water stress. Copyright © 2010 Society of Chemical Industry     

葡萄耐旱性研究进展

本文综述了水分胁迫对葡萄营养生产，葡萄生殖生长及其对葡萄光合作用的影响；展望了葡萄耐旱性研究发展方向。并指出今后应用从葡萄抗旱生理过程与葡萄耐旱生物学机理相结进一步深入研究。     

隶属函数法鉴定油菜甘芥种间杂交后代的抗旱性

在大田水分胁迫条件下,采用隶属函数值法、灰色关联度分析法结合聚类分析,研究58份甘蓝型油菜和芥菜型油菜的种间杂交后代,分析其单株产量、主花序产量和品质性状的差异。结果表明,单株分枝数和有效角果数与抗旱性显著相关,而角粒数和千粒重与抗旱性关联性较弱。在水分胁迫条件下,抗旱材料主花序的三个性状,即含油量、蛋白质含量和千粒重,在强抗、较抗、不抗材料间的差异均达到1%显著水平,且与单株产量的关联度在50%以上,其中主花序籽粒的含油量及千粒重升高,蛋白质含量降低。利用水分胁迫下三个性状的差异变化可对抗旱油菜进行初步筛选。通过筛选,获得2007M004、2007M018和2007M027三份平均隶属函数值≥0.413的抗旱材料。     

Influence of rootstock on drought response in young 'Gale Gala' apple (Malus domestica Borkh.) trees

BACKGROUND: Drought is a major environmental stress limiting plant growth, productivity, and survival worldwide. Rootstocks are widely used to enhance plants resistance to drought stresses. This study determined influence of rootstock on drought responses in 1‐year‐old ‘Gale Gala’ apple trees grafted onto Malus sieversii or M. hupehensis. RESULTS: Choice of rootstock resulted in differential response to drought stress. Specifically, M. sieversii caused less drought‐induced reduction in relative growth rate, biomass accumulation, leaf area, leaf chlorophyll content, relative water content, photosynthesis rate and maximum chlorophyll fluorescence yield but greater increase in whole‐plant water use efficiency compared to M. hupehensis. Secondly, compared with M. hupehensis, M. sieversii caused less drought‐induced accumulation of reactive oxygen species but more increase in activities of antioxidant enzymes. In addition, xylem sap abscisic acid concentration was greater in trees grafted onto M. hupehensis than in those grafted onto M. sieversii under drought stress. CONCLUSION: ‘Gale Gala’ trees' response to drought stress was associated with the rootstock's genotype onto which it was grafted. Trees with M. sieversii as rootstock are more drought resistant than trees with M. hupehensis as rootstock, which suggests that M. sieversii can be widely used as rootstock in arid and semi‐arid regions. Copyright © 2012 Society of Chemical Industry     

Ecophysiological Analysis Of Drought And Salinity Stress Of Quinoa (Chenopodium Quinoawilld.)

We assessed the relative influence of drought or salinity stress with similar soil water potentials on growth, plant water relations, and photosynthesis rate of Chenopodium quinoaWilld., as well as the suitability of common techniques used in stress physiology studies. Our results from greenhouse pot experiments showed that salt stress induced better absolute and relative growth rates, and that the plant developed adaptation mechanisms to drought through high water use efficiency and high root shoot ratios. The stomatal resistance and the leaf water potential increased with an increased stress level. Variable to maximal chlorophyll fluorescence (Fv/Fm) and quenching analysis (qP and qN) showed that dehydrated plants are less protected from photoinhibition. The dynamic diffusion porometer is of limited use in leaves with salt glands.     

Ecophysiological Analysis Of Drought And Salinity Stress Of Quinoa (Chenopodium Quinoawilld.)

We assessed the relative influence of drought or salinity stress with similar soil water potentials on growth, plant water relations, and photosynthesis rate of Chenopodium quinoaWilld., as well as the suitability of common techniques used in stress physiology studies. Our results from greenhouse pot experiments showed that salt stress induced better absolute and relative growth rates, and that the plant developed adaptation mechanisms to drought through high water use efficiency and high root shoot ratios. The stomatal resistance and the leaf water potential increased with an increased stress level. Variable to maximal chlorophyll fluorescence (Fv/Fm) and quenching analysis (qP and qN) showed that dehydrated plants are less protected from photoinhibition. The dynamic diffusion porometer is of limited use in leaves with salt glands.

     

油菜AP2／ERF家族转录因子的分离及其生物学功能

油菜的生长发育受病害、干旱、高盐和低温等逆境胁迫的影响较大。油菜植株中很多被上述胁迫诱导而表达的基因,如产物能直接增强油菜对逆境抗性的功能基因,和产物为转录因子而作为信号转导调控其它基因的表达而间接提高抗性的调控基因。很多转录因子涉及到油菜逆境抗性,AP2／ERF是其中重要的一个家族。目前通过不同方法从不同种类的油菜中共克隆了24个AP2／ERF家族转录因子,属于ERF和DREB／CBF亚族。这些基因分别能够被低温、干旱、高盐、乙烯、ABA和茉莉酮酸酯诱导,并启动油菜中一些相关下游基因的表达,从而增强油菜的抗逆性能。本文综述了油菜中AP2／ERF家族转录因子的克隆、进化关系分析、空间结构及生物学功能。     

Prospects of Breeding Quinoa for Tolerance to Abiotic Stress

Aspects related to the breeding of quinoa for increased tolerance against frost, drought, and salinity are presented with special emphasis on the conditions existing in the Peruvian Andes. Evidence from the literature indicates that plants' responses to these stresses are essentially similar, and the physiological processes involved are interrelated. The evidence suggests that tolerance to abiotic stress is polygenicallyinherited, justifying the application of appropriate plant breeding methods. A compilation of meteorological studies is presented that can be used to define the specific climatic phenomena of night frosts occurring in the quinoa-growing region of the Andes and to specify the conditions for selection of tolerant varieties. A composite-bulk breeding scheme is proposed that could be useful for highly efficient breeding of quinoa varieties. Possible future application of molecular-marker-assisted selection is discussed.