Physiological Mechanism for Anthocyanins to Strengthen the Drought Tolerance of Plants

This paper summarized the possible physiological mechanism by which anthocyanins strengthen the tolerance of plants to drought. Drought stress can in-duce plant cel s to synthesize and accumulate anthocyanins. The photochemical properties, subcel ular accumulation sites and spatial distributions in plant organs and tissues of anthocyanins determine their function of strengthening plant tolerance, which is realized by three possible physiological mechanisms： （1） anthocyanins and their chelated metal ions can optimize the osmoregulation ability of the plant cel s by directly acting as the osmoregulation substances of the cel s, （2） anthocyanins with suitable spatial locations can reduce the photoinhibition of the plants under drought stresses, （3） anthocyanins can effectively maintain and improve the active oxygen-scavenging capacity of the plant cel s under drought conditions. Therein, that the anthocyanins enhance the antioxidant capacity of the plant cel s under drought stresses is probably the main reason for the anthocyanins to strengthen the drought tolerance of plants. This review could provide a reference for the mechanism re-search of the drought resistance and the breeding of the drought-resistant cultivars for the plants holding the ability to synthesize and accumulate anthocyanins.

Effect of Various Intensities of Drought Stress on δ¹³C Variation among Plant Organs in Rice: Comparison of Two Cultivars

The δ13C value is widely used to assess the effects of drought on water status in plants. However, there is little information regarding the δ13C signature in different organs of rice. We conducted a field study to examine whether the δ13C among different plant parts would be affected by the intensities of drought, and to evaluate genotypic variation in δ13C fluctuation among plant parts affected by drought intensities. Two cultivars, “Nipponbare” (Oryzasativa ssp. japonica) and “Kasalath” (O. sativa ssp. indica), were grown in the field with a line-source sprinkler system. The δ13C values of panicles, flag leaves, straws, culms, and roots were measured from plant samples. The δ13C value increased as drought stress increased, especially in the panicles and roots. “Nipponbare” showed higher values of δ13C than “Kasalath” under the well-watered and mild drought stress conditions, but there was no significant difference between the genotypes in the δ13C value under the severe drought stress condition. The variation in δ13C value among different plant parts was also increased with increasing drought stress. In contrast, these variations were small under well-watered conditions. Furthermore, there was much greater variation in the δ13C value among different plant parts in “Kasalath” than in “Nipponbare” when the plants were grown under drought stress conditions. A significant negative relationship was observed between the δ13C value of panicles and shoot dry matter production, suggesting that the δ13C value of panicles may be the best indicator of plant water status in rice.

TaMIR1119, a miRNA family member of wheat(Triticum aestivum),is essential in the regulation of plant drought tolerance

Through regulating target genes via the mechanisms of posttranscriptional cleavage or translational repression, plant miRNAs involve diverse biological processes associating with plant growth, development, and abiotic stress responses, in this study, we functionally characterized TaMIR1119, a miRNA family member of wheat （Triticum aestivum）, in regulating the drought adaptive response of plants. TaMIR1119 putatively targets six genes categorized into the functional classes of transcriptional regulation, RNA and biochemical metabolism, trafficking, and oxidative stress defense. Upon simulated drought stress, the TaMIR1119 transcripts abundance in roots was drastically altered, showing to be upregulated gradually within a 48-h drought regime andthat the drought-induced transcripts were gradually restored along with a 48-h recovery treatment. In contrast, most miRNA target genes displayed reverse expression patterns to TaMIR1119, exhibiting a downregulated expression pattern upon drought and whose reduced transcripts were re-elevated along with a normal recovery treatment. These expression analysis results indicated that TaMIR1119 responds to drought and regulates the target genes mainly through a cleavage mechanism. Under drought stress, the tobacco lines with TaMIR1119 overexpression behaved improved phenotypes,, showing increased plant biomass, photosynthetic parameters, osmolyte accumulation, and enhanced antioxidant enzyme （AE） activities relative to wild type. Three AE genes, NtFeSOD, NtCAT1;3, and NtSOD2,1, encoding superoxide dismutase （SOD）, catalase （CAT）, and peroxidase （POD） proteins, respectively, showed upregulated expression in TaMIR1119 overexpression lines, suggesting that they are involved in the regulation of AE activities and contribution to the improved cellular reactive oxygen species （ROS） homeostasis in drought-challenged transgenic lines. Our results indicate that TaMIR1119 plays critical roles in regulating plant drought tolerance through transcriptionally regulating the target genes that modulate osmolyte accumulation, photosynthetic function, and improve cellular ROS homeostasis of plants.

Alterations of Endogenous Hormonal Levels in Plants under Drought and Salinity

The phytohormones are pivotal chemical messengers produced within the plant that regulate its growth and development, and responses to environmental stimuli. Drought and salinity are adverse environmental factors that disturb the plant hormonal balance. Accordingly, these hormonal fluctuations modify the cellular dynamic and hence they play a central role in regulating plant growth responses to abiotic stresses such as drought and salinity. The present review gives an update about the alterations of endogenous phytohormones such as abscisic acid (ABA), auxins (Aux), cytokinins (CKs), ethylene (ET), gibberellins (GAs), jasmonates (JAs), salicylic acid (SA), brassinosteroids (BRs), strigolactones (SLs) and nitric oxide (NO) that occur as part of the adaptative responses of plant against drought and salt stresses. Better understanding of the endogenous hormonal changes during the plant response to both abiotic stresses will contribute, in part, to the development of stress-tolerant plants.

Application Research of Water-saving and Drought-resistant Landscape Plants:A Case Study of Inner Mongolia Drought-resistant Mongolian Grasses

Construction of "water-saving landscape architecture" is a crucial content of building "conservation-minded society'',an important approach of ensuring the sustainable development of landscaping industry.It targets at exploring a reasonable means of using the nature,so as to improve ecological conditions and environment,save resources and energies,and promote the harmonious coexistence of man and nature.Landscape plant is a significant component of landscape architecture,it is a key section to choose proper drought-resistant plant species for the landscape construction.

RNAi Mediated Drought and Salinity Stress Tolerance in Plants

RNAi mediated gene silencing demonstrated to serve as a defence mechanism against abiotic stress. Some endogenous small RNAs (microRNA and siRNA) have emerged as important players in plant abiotic stress response. Drought and salinity are the major environmental stresses that limit the agricultural food production. miRNA involved in drought and salinity stress response, including ABA response, auxin signalling, osmoprotection and antioxidant defence by downregulating the response target gene. It is observed that some of the microRNAs are upregulated or downregulated in response to drought and salt stress. We reviewed that miR167, miR393, mir474, miR169g are upregulated whereas miR168, miR396, miR397 are downregulated in rice plant during drought stress. Moreover, our detail categorical analysis on the basis of mechanism of action found that miRNA involved in drought stress was 28% in ABA signalling and response, 14.2% in auxin signalling, 9.52% in miRNA processing, 14.2% in cell growth, 9.52% in antioxidant defence, 4.76% in CO2 fixation and 9.52% in osmotic adjustment. Similarly, miRNA involved in salinity stress was 5.8% in auxin signalling, 23.5% in vegetative phase change and root, shoot, leaf and vascular development, 11.76% in gynoecium and stamens development, 8.82% in metabolic adaptation, 2.74% in early embryogenesis and 41.17% not known. Importantly, some common miRNAs such as miR159, miR167, miR169, miR393 and miR397 play an important role in both drought and salinity stress conditions. Here, in this review, we mainly focused on the current status of miRNAs, mechanism of action and their regulatory network during drought and salinity stress in plants.

Osmoregulation Mechanism of Drought Stress and Genetic Engineering Strategies for Improving Drought Resistance in Plants

Drought, one of the main adverse environmental factors, obviously affected plant growth and development. Many adaptive strategies have been developed in plants for coping with drought or water stress, among which osmoregulation is one of the important factors of plant drought tolerance. Many substances play important roles in plant osmoregulation for drought resistance, including proline, glycine betaine, Lea proteins and soluble sugars such as levan, trehalose, sucrose, etc. The osmoregulation mechanism and the genetic engineering of plant drought-tolerance are reviewed in this paper.

Risk Regionalization of Drought for Flue-cured Tobacco Planting in Qujing City Based on GIS

The risk regionalization of drought for flue-cured tobacco planting in Qujing City was studied to provide reference for drawing on advantages and avoiding disadvantages in flue-cured tobacco planting,disaster reduction,and disaster relief services.According to the production practice of flue-cured tobacco and local climate analysis,the risk of disaster-causing factors,sensitivity of disaster-breeding environment,vulnerability of carriers,and disaster prevention and reduction capability were analyzed and evaluated quantitatively.Secondly,starting from the formation mechanism of drought,a risk assessment model of the meteorological disaster was established by GIS technology.Finally,the risk assessment and regionalization of drought in the critical periods for drought-stricken flue-cured tobacco (transplanting period,root extending stage and vigorous growth period) in Qujing City were carried out.The results showed that in Qujing City,the risk areas of drought for flue-cured tobacco planting were divided into five grades in the transplanting period and six grades in the root extending stage and vigorous growth period.

Influence of Symbiotic Interaction between Fungus, Virus, and Tomato Plant in Combating Drought Stress

The influence of the three-way interaction between the fungus (Curvularia protuberata), virus (CThTV), and tomato (Solanum lycopersicum) in combating drought stress was evaluated in this study. The plants in this greenhouse experiment were grown under conditions of 400 ± 150 μmol·m-2·s-1 photon flux density, 45% to 50% relative humidity (RH), and 30°C ± 2°C. Tomato seeds were germinated and inoculated with the combination of the fungus and virus at the seedling stage. The plants were allowed to grow for two weeks and randomly selected individuals were utilized. The selected plants were grown in one gallon pots containing organic potting soil. The treatments included non-symbiotic (NS), virus-free (VF), and symbiotic (An) plants. Each treatment received twelve samples and each sample was allowed to grow for an additional two weeks under drought stress. At that time, plants were exhibiting drought stress symptoms including visible wilting. Six samples from each treatment were utilized in determining selected physiological responses of tomato at pre-anthesis stage. The remaining six samples from each treatment were re-watered once and allowed to grow until they reached the anthesis stage. When they showed visible signs of wilting, the same physiological responses measured during pre-anthesis were conducted. The samples of each treatment were utilized at the end of each stage in determining photosynthetic rate, stomata conductance, photosynthetic pigments, water potential, and soluble sugar content. Plant growth, chlorophyll a, chlorophyll b, photosynthetic rate, stomata conductance, water potential, and soluble sugar content were similarly affected by the various treatments. However, carotenoids were significantly higher at pre-anthesis in the symbiotic plants in comparison to other treatments. Additionally, photosynthesis appeared to be significantly higher at anthesis compared to pre-anthesis for all treatments.

2018—2022年“干旱胁迫对植物的影响研究”可视化分析

【目的】深入了解植物干旱胁迫领域的研究现状、研究热点及未来发展趋势,对我国2018-2022年植物干旱胁迫研究进行文献计量和可视化分析。【方法】利用Citespace和VOSviewer软件,以2018-2022年发表在中国知网(CNKI)和Web of Science(WOS)数据库的植物干旱胁迫研究文献为研究对象,分析我国2018-2022年干旱胁迫对植物生长、生理和基因表达的影响研究热点与趋势。【结果】国内干旱胁迫对植物影响的研究热点主要集中在“干旱胁迫对植物外在形态和叶片内部结构的影响”“干旱胁迫对植物光合特性的影响”“干旱胁迫对植物渗透调节物质和抗氧化酶的影响”及“干旱胁迫对植物基因表达的影响”4个方面。该领域研究重点主要包括干旱或干旱与盐复合胁迫对植物生理生化和抗旱基因的鉴定与转移。其中知网文献的关键词为“耐盐性”“苗期”和“抗旱鉴定”;WOS文献的关键词则是“抗坏血酸过氧化物酶”“水分利用”和“异位表达”。【结论】纳米材料在缓解植物干旱胁迫中的作用、多组学联合分析(基因组、转录组、蛋白组、代谢组)以及转基因、基因编辑、基因沉默等技术在提升植物抗旱性中的综合应用将成为未来研究热点。

不同温度下PEG模拟干旱对濒危植物狭叶坡垒种子萌发的影响

狭叶坡垒(Hopea chinensis)种子为典型的顽拗性种子。为探究种子萌发对温度和水分的适应性,该研究在人工气候培养箱内设置3种温度(15、20、25℃),采用6个聚乙二醇(PEG-6000)浓度(0%、5%、10%、15%、25%和35%)模拟干旱胁迫处理,研究狭叶坡垒种子的萌发特性。结果表明:(1)温度对种子萌发具有显著影响。同一干旱胁迫浓度下,种子的萌发率、萌发势、萌发指数、胚根长、芽长和活力指数随着温度升高呈上升趋势,萌发时滞随温度升高而降低,萌发历期随温度升高而波动性上升。(2)干旱胁迫对种子萌发具有显著影响。同一温度下,种子的萌发率、萌发势、萌发指数、萌发历期、胚根长、胚芽长和活力指数随着干旱胁迫程度加重呈降低的趋势,萌发时滞随干旱胁迫程度加重而升高。(3)温度和干旱胁迫的交互作用对种子萌发具有显著影响。干旱胁迫下,不同温度条件下种子萌发的表现不同。在35%PEG-6000胁迫下,20℃和25℃时,种子萌发率分别为8.89%和15.55%,显著高于15℃(0%)。综上所述,适宜种子萌发的温度为20℃和25℃,适宜幼苗早期生长最佳温度为25℃;干旱程度越大,种子萌发受到的抑制作用越强,干旱胁迫对种子萌发的影响高于温度因素,适当增温可缓解干旱胁迫对种子萌发的抑制作用。

雌雄香榧嫩枝扦插生根及响应干旱的生理差异

【目的】探究香榧Torreya grandis‘Merrillii’雌雄植株的生根差异和响应干旱胁迫的生理差异,为香榧抗干旱种质资源的培育提供科学依据。【方法】以香榧新生雌雄株枝条为材料,比较两者夏季扦插生根差异,对生根状况较一致的香榧雌雄株施加聚乙二醇(PEG)模拟干旱处理,比较不同时间下香榧雌雄株幼苗的抗氧化酶活性、渗透调节物质、膜脂过氧化和活性氧质量摩尔浓度的变化。【结果】夏季扦插的香榧雄株成活率普遍高于雌株,雌雄株扦插的最佳时间不同,与7和8月相比,6月扦插的香榧雌株成活率和生根率更高,侧根数更多,而8月扦插的香榧雄株较6和7月的成活率和生根率更高,侧根数更多。在扦插相同时间下,雄株的成活率和生根率均高于雌株。干旱胁迫引起香榧叶片抗氧化酶活性发生显著变化,并扰乱其渗透调节功能和活性氧代谢平衡。在干旱胁迫下,与雄株相比,雌株具有更高的超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性,以及较低的丙二醛(MDA)、脯氨酸(Pro)、超氧阴离子(O^(2−))和过氧化氢(H2O2)质量摩尔浓度。【结论】夏季扦插的香榧雄株比雌株具有更高的扦插成活率。干旱胁迫下,香榧雌株能够更好地利用抗氧化系统来减少干旱胁迫引起的活性氧积累和细胞损伤,从而使香榧雌株比雄株更耐干旱。

旱优3015在永定县种植表现及高产栽培技术

旱优3015是用沪旱7A与旱恢3015配组育成的籼型三系杂交节水抗旱稻新品种,2020年通过了国家农作物品种审定。2022年引进旱优3015在永定县坎市镇灌溉条件不保障的烟后稻区和复垦地作中稻种植,结果表现群体生长整齐、株型集散适中、分蘖力强、穗大粒多、耐旱抗倒、产量高。总结了旱优3015在永定县的种植表现和高产栽培技术。

干旱地区植物根际促生菌鉴定及促生和耐旱特性研究

本试验以干旱区3种植物为材料,利用选择性培养基从植物根际分离筛选具有固氮、溶磷、分泌植物激素及耐旱的菌株,进行16S rRNA分子生物学鉴定,并通过纸上发芽试验验证菌株促生效果,以期为干旱地区专用微生物菌肥提供优良菌种资源。结果表明:从3种植物根际共分离出37株菌株,其中兼具溶磷、固氮促生特性的占35.1%,菌株固氮酶活性介于17.92~169.74 nmol C2H4/(h·mL),溶无机磷量为13.39~363.31μg/mL,溶有机磷量为58.69~99.37μg/mL。选择12株固氮、溶磷能力较好的菌株进行分泌植物激素及耐旱特性测定,发现12株菌株均能分泌吲哚乙酸且分泌量为2.86~27.60μg/mL;大部分菌株也均能分泌玉米素和脱落酸,分泌量分别为1.75~7.78μg/mL、1.98~4.61μg/mL。从中筛选出特性优良的菌株5株,经鉴定菌株YB6和HC7分别为枯草芽孢杆菌(Bacillus subtilis)和氧化微杆菌(Microbacterium oxydans),菌株HL7、HC9和HC3分别属于无色杆菌属(Achromobacter sp.)、苍白杆菌属(Ochrobactrum sp.)和叶杆菌属(Phyllobacterium sp.)。纸上发芽试验结果显示,5株植物根际促生菌既能促进种子的萌发,又能缓解干旱胁迫对种子生长的抑制作用,其中,菌株YB6和HC9对种子的萌发和生长效果较为突出,具有作为微生物肥料菌种资源在干旱区应用的潜力。

小车前(Plantago minuta Pall.)种子表面粘液物质的吸水特性及其对种子在干旱环境中萌发的影响

为了理解荒漠短命植物小车前(Plantago minuta Pall.)种子表面的粘液物质对种子在干旱环境中萌发的作用,在室内控制条件下研究了粘液物质的吸水保水特性、剥离粘液物质的种子(无粘液种子)和保留粘液物质的种子(粘液种子)在-1.15^-0.15MPa不同渗透胁迫条件下的萌发状况。结果表明:(1)小车前种子表面的粘液物质干重占粘液种子干重的5.6%;在去离子水中,粘液物质可以吸收相当于其自身干重217.1倍的水分;粘液物质的存在使得小车前种子的吸水倍数由2倍增加至14倍,从而保证为种子萌发提供充足的水分;(2)干燥的粘液种子吸水2h后即达到饱和,而吸水饱和后的粘液种子在室温下晾置,经过48h后又干燥失水恢复至原重;(3)在去离子水中或低渗透胁迫(-0.33^-0.15MPa)条件下,粘液物质吸水作用能促进小车前种子萌发,粘液种子3d的发芽势和10d的总萌发率均显著高于无粘液种子;在高渗透胁迫(-1.15^-0.73MPa)条件下,粘液种子3d的发芽势显著低于无粘液种子的,而10d的总萌发率与无粘液种子的没有显著差别,表明粘液物质在干旱条件下可能从种子而非外界环境中吸取水分,减缓了种子萌发速率。通过上述结果可以认为小车前种子表面的粘液物质在早春干湿交替剧烈的荒漠生境中起到通过调节水分来调节种子萌发的作用,这种萌发策略大大降低了因大批种子同时萌发导致幼苗受旱甚至种群灭亡的潜在风险。

木本植物应对干旱胁迫的响应机制:基于水力学性状视角

干旱最显著的影响表现在区域尺度的森林死亡事件中,可以在短时间内杀死数百万棵树木。鉴于未来极端干旱事件的频率和强度可能随温度的升高而增加,迫切需要明确树木对干旱胁迫的响应对策以及衰退死亡机理,揭示木本植物在干旱环境中存活和死亡的生理机制,了解树木在未来气候下的适应机制,提高预测树木对干旱反应的准确性。在常用植物功能性状的基础上,重点纳入与植物水分运输能力及耐旱性相关的水力学性状,系统总结了:1)植物木质部水分运输的物理机制;2)植物应对干旱胁迫的水力响应过程:3)干旱胁迫下木本植物水分利用对策;以及4)干旱胁迫下木本植物衰退/死亡机理。最后,提出3个尚待解决的主要问题:1)加强纳入水力性状阐明植物对干旱胁迫的响应和调节机制;2)加强从全株植物的角度考虑植物不同组织性状间的关系;3)深入探究树木干旱致死机理。

内生菌提高植物抗旱性和耐盐性分子机制研究进展

植物-内生菌共生体在缓解植物的非生物和生物胁迫方面发挥着重要作用。在干旱和盐胁迫下,内生菌可以通过调控植物光合作用、激素浓度、渗透调节物质含量、抗氧化酶活性以及相关基因表达等来保证植物正常生长和发育,从而增强植物抗逆性。近年来,植物促生菌(Plant growth promoting bacteria,PGPB)接种剂也被广泛研究应用。本文综述了植物内生菌的多样性、共生内生菌和PGPB在干旱和盐胁迫下对植物基因的调控,为内生菌提高植物耐旱性和耐盐性的分子机制的深入研究提供参考。

水稻D1基因新等位突变体的鉴定与功能分析

[目的]株高是作物重要的农艺性状,挖掘株高控制基因并解析其分子功能,可为作物高产育种提供更多有用的基因资源。[方法]利用EMS诱变水稻日本晴获得的矮化突变体d1-11为材料,进行表型和细胞学观察,通过图位克隆的方法鉴定d1-11基因并对基因表达、激素含量和抗旱性进行了分析。[结果]d1-11突变体表现出植株矮化、叶片变短变宽和籽粒形态变圆表型;d1-11突变体叶片中脉萎缩,大脉和小脉数量和面积减少,导致叶片形态变异。d1-11基因被定位到水稻5号染色体R5M15.2和R5M15.8两个分子标记之间;图位克隆结果表明d1-11突变体中D1基因第11外显子和内含子交界处单碱基替换导致基因功能缺失。D1基因在苗期各组织中表达量较高,从分蘖期开始表达量降低;外源脱落酸(ABA)处理24 h后诱导D1基因表达,外源赤霉素(GA)处理抑制D1基因表达,盐胁迫处理24h诱导D1基因剧烈上调表达。d1-11突变体植株GA、油菜素内酯(BR)和生长素(IAA)等激素含量均上升,叶片相对含水量上升、叶片失水速率降低,植株对干旱胁迫抗性显著增强。[结论]鉴定到水稻D1基因新等位突变d1-11,发现d1-11突变体多种内源激素水平上升、叶片含水量增加、植株对干旱胁迫抗性增强。本研究进一步丰富了水稻矮化基因资源并揭示D1基因新的生物学功能。

植物生长促进微生物对干旱胁迫条件下植物生长的影响

干旱胁迫是植物受到的重要非生物胁迫之一,不仅对植物的生长繁殖有严重影响,造成作物的减产,还会破坏生态环境。目前,人们除了通过建设灌溉工程等措施人为改善植物的生长环境来提高植物的存活率外,还以植物生长促进微生物(PGPM)作为植物生长调节剂来维持植物正常的生理生化反应,缓解干旱胁迫对植物造成的不良响应。本文以干旱胁迫下植物生长促进微生物如何促进植物生长为研究目的,通过查阅文献资料,对相关内容进行总结,旨在阐明干旱胁迫下植物生长促进微生物对植物生长的正向调控作用。

城市道路绿化对极端高温干旱气候的响应特征研究

随着城市化的不断推进和全球气候变化的加剧,高温、干旱等极端气候频发对城市园林绿化造成重大影响.城市道路绿化作为城市绿地一种典型的带状绿地,其对高温干旱气候的响应机制尚不明确.以2022年南昌市所遭受的极端高温干旱气候为契机,对南昌市昌北经济技术开发区15条主次干道绿化树种进行受害特征调查分析,结果表明:①受高温旱害影响的植株分布呈现出一定的空间聚集性和规律性,南北向道路植物受灾较为严重,东西向道路植物受灾相对较轻;②随着树下铺装面积的增加,乔木、灌木受损情况呈上升趋势,随着铺装透水率的增加,乔木、灌木受损情况呈下降趋势;③乔木个体越大、长势越好,其抗干旱能力越强.建议加强对耐旱性较差、胸径小、树高低矮树种的日常养护,适当增加南北朝向道路的人工浇灌及管护频次,并适当减少树下铺装的面积,以此来缓解高温干旱对城市道路绿化的影响.