甜菜碱对干旱胁迫下棉花幼苗生理特性的影响

以新疆广泛种植的棉花品种新陆早18号为试材,通过测定棉花幼苗体内脯氨酸、可溶性糖和丙二醛（MDA）的含量及抗氧化酶包括超氧化物歧化酶（SOD）、过氧化氢酶（CAT）和过氧化物酶（POD）的活性,研究叶面喷施不同浓度甜菜碱（Glycine betaine,GB）对干旱胁迫下棉花幼苗生理特性的影响。结果表明,干旱胁迫下,与对照相比,脯氨酸、可溶性糖、MDA含量及SOD和POD活性都显著提高,喷施甜菜碱后促进脯氨酸和可溶性糖含量进一步提高,酶活也显著升高,同时有效抑制了丙二醛含量的增加,CAT活性受干旱胁迫及甜菜碱的影响较小。研究表明喷施低浓度甜菜碱在一定程度上可以缓解干旱胁迫对棉花幼苗的伤害。     

盐分胁迫下棉花幼苗对外源甜菜碱的生理响应

通过研究盐分胁迫下棉花幼苗对外源甜菜碱的生理响应,为盐分胁迫下施用甜菜碱提高棉花幼苗抗逆提供参考。以新疆广泛种植的新陆早18号为试验材料,200 mmol/L氯化钠胁迫,用5、10 mmol/L甜菜碱喷施处理,7 d后测定棉花幼苗体内主要生理指标含量的变化。结果表明非盐胁迫下,甜菜碱处理显著提高脯氨酸和可溶性糖含量,而丙二醛含量和抗氧化酶活性不受甜菜碱影响;盐胁迫下棉花幼苗体内丙二醛含量显著高于对照,并且脯氨酸、可溶性糖含量增加,抗氧化酶活性提高,盐分胁迫下棉花幼苗经过甜菜碱处理后,有效抑制丙二醛的产生,同时脯氨酸、可溶性糖和抗氧化酶含量进一步提高。甜菜碱处理有效缓解盐胁迫对棉花幼苗的伤害,以施用5 mmol/L甜菜碱(glycine betaine/GB)效果较好。     

重金属铅镉短期胁迫对蓬莱蕉生理生化指标的影响

为了探讨蓬莱蕉在Pb、Cd胁迫下的生理变化规律,采用盆栽试验研究土壤重金属Pb、Cd单一及其复合胁迫对蓬莱蕉部分生理指标的影响。结果表明:(1)相同处理水平下,随着处理时间的延长,重金属Pb、Cd单一和复合胁迫下,可溶性糖和可溶性蛋白含量降低,超氧化物歧化酶活性下降,游离脯氨酸、丙二醛含量增加,过氧化氢酶活性升高。在Pb单一胁迫下,总叶绿素含量先升后降,过氧化物酶活性升高;在Cd单一胁迫和Pb、Cd复合胁迫下,总叶绿素含量和过氧化物酶活性先升后降。(2)随着处理浓度的增加,重金属Pb、Cd单一和复合胁迫下,可溶性糖、可溶性蛋白、游离脯氨酸和丙二醛含量增加,过氧化物酶、过氧化氢酶和超氧化物歧化酶活性升高,而总叶绿素含量则表现为下降趋势。说明蓬莱蕉在一定重金属胁迫范围内,可通过增加叶片渗透调节物质和诱导活性氧清除系统,以减少由于胁迫带来的代谢失衡对植株的伤害。     

高温干旱共胁迫下外源甜菜碱和CaCl2对烟草生理响应的影响

以烤烟品种云烟85为材料,采用盆栽试验研究了对高温干旱共胁迫的反应,以及外源甜菜碱（GB）和CaCl2对烟草抗高温干旱共胁迫方面的作用。结果表明,叶面喷施GB和CaCl2能显著提高烟草植株生物量。在高温干旱共胁迫下,叶面喷施GB较蒸馏水处理能极显著提高烟草叶片叶绿素含量、SOD和POD活性,维持较高的脯氨酸含量及较低的丙二醛（MDA）含量和质膜相对透性;叶面喷施CaCl2较蒸馏水处理能极显著提高烟草叶片叶绿素含量、SOD和POD活性,极显著降低质膜相对透性,显著降低丙二醛（MDA）含量,维持较高的脯氨酸含量。高温干旱共胁迫恢复生长后,GB、CaCl2和蒸馏水处理的烟草其叶绿素含量、SOD和POD活性均有不同程度回升,丙二醛含量、脯氨酸含量、细胞质膜透性都有所下降。因此,GB和CaCl2对有效减轻双逆境胁迫引起的伤害,提高烟草的抗高温干旱胁迫能力具有积极的作用。     

干旱胁迫下壳寡糖对番茄幼苗生理指标的影响

研究叶面喷施壳寡糖（COS）后番茄幼苗生长及保护酶活性的变化,以改善番茄幼苗叶片对干旱胁迫的适应性,从而增强番茄的抗旱能力,为番茄抗旱提供参考。以番茄幼苗为供试材料,在吉林农业大学资源与环境学院进行盆栽试验。以壳寡糖和干旱处理番茄幼苗,共设6个处理（1.非干旱+清水,对照;2.非干旱+COS 50 mg/L;3.非干旱+COS 100 mg/L;4.干旱+清水;5.干旱+COS 50 mg/L;6.干旱+COS 100 mg/L）,喷施COS后,在土壤相对含水量达到干旱胁迫条件（土壤含水量为田间持水量的40%～50%）后,测定番茄幼苗株高、茎粗、SPAD值,在喷施COS后土壤含水量达到设定干旱水平后的第0、2、4、6 d测定叶片保护酶活性、丙二醛、脯氨酸、可溶性蛋白含量。结果显示,COS能够显著缓解由于干旱造成的番茄幼苗株高、茎粗、SPAD值的下降;增加番茄幼苗叶片的过氧化氢酶（CAT）、过氧化物酶（POD）、超氧化物歧化酶（SOD）3种保护酶活性;增加脯氨酸、可溶性蛋白等渗透物质的含量,同时COS可缓解丙二醛含量的升高,且高浓度（100 mg/L）COS效果最好。综上,100 mg/...     

水分胁迫对春小麦陇春27号光合参数和渗透调节物质的影响

为明确水分胁迫下春小麦的抗旱机制,模拟半干旱与干旱条件下春小麦的生存机理,采用盆栽法进行了中度和重度水分胁迫下春小麦旗叶光合参数和渗透调节物质含量变化的研究.结果表明,土壤持水量从80％、60％至40％,春小麦陇春27号旗叶的叶绿素含量、光合速率、气孔导度、胞间CO2浓度、蒸腾速率逐渐降低,可溶性糖和酸性转化酶活性呈先增后减趋势,脯氨酸和丙二醛含量及过氧化物酶活性逐渐增强.60％持水量下的可溶性糖含量和酸性转化酶活性显著高于80％与40％持水量下的可溶性糖含量和酸性转化酶活性,可溶性蛋白含量显著低于40％和80％的可溶性蛋白含量,40％持水量下的脯氨酸和丙二醛含量及过氧化物酶活性显著高于60％和80％持水量下的脯氨酸和丙二醛含量及过氧化物酶活性.说明春小麦陇春27号旗叶对水分胁迫十分敏感,中度或重度水分胁迫下光合速率下降是气孔因素与非气孔因素综合作用结果,中度胁迫下光合速率降低是由叶绿素含量下降引起而非光合原料缺乏所致,而重度胁迫下光合速率降低是由叶绿素含量降低和光合原料缺乏所致,可溶性糖、脯氨酸和丙二醛含量及过氧化物酶活性升高是春小麦陇春27号抵御半干旱和干旱胁迫的主要机制.     

喷施拉肖皂苷C提高黄瓜幼苗对抗干旱胁迫的生理效应

【目的】拉肖皂苷C(LG-C)与茶甾酮类油菜素甾醇化合物结构相似,都含有3-糖苷基-6-酮等活性官能团,表现出一定的油菜甾醇类植物激素的活性,且LG-C具有含量丰富、 制备简单及成本低的优点。但是LG-C对于植物抗旱生理效应的研究迄今未见报道,因此本试验研究了LG-C对干旱胁迫下黄瓜幼苗的生理效应,以期为LG-C后续的研究奠定基础。【方法】以黄瓜幼苗为试材,进行了喷施拉肖皂苷C(LG-C)的盆栽试验。设置了基质含水量分别为田间持水量的80%(对照)、 60%(轻度胁迫)和50%(重度胁迫)3个水分处理。以水为对照,在黄瓜三叶一心期,叶面喷施LG-C(0.05 mg/L),每株喷施20 mL,连续喷施7天。然后立即取样分析植株的理化性质。【结果】与对照相比,轻度干旱胁迫下,喷施LG-C能够使黄瓜幼苗叶片中可溶性蛋白、 游离脯氨酸、 可溶性糖含量分别显著提高21.06%、 41.75%、 29.65%; 叶片中叶绿素a、 叶绿素b、 类胡萝卜素含量分别显著提高26.83%、 13.33%、 23.21%; 叶片中超氧化物歧化酶、 过氧化物酶、 过氧化氢酶活性分别显著提高10.06%、 19.34%、 33.08%; 叶片中电解质渗透率、 丙二醛含量、 自动氧化速率和组织失水率分别显著降低10.16%、 30.68%、 22.48%、 9.69%。重度干旱胁迫下,喷施LG-C能够使黄瓜幼苗叶片中可溶性蛋白、 游离脯氨酸、 可溶性糖含量分别显著提高19.35%、 37.05%、 25.23%; 叶绿素a、 叶绿素b、 类胡萝卜素含量分别显著提高28.17%、 20.00%、 28.42%; 超氧化物歧化酶、 过氧化物酶、 过氧化氢酶活性分别显著提高6.03%、 37.10%、 30.72%; 电解质渗透率、 丙二醛含量、 自动氧化速率和组织失水率分别显著降低10.15%、 47.10%、 16.97%、 8.85%。【结论】喷施LG-C可通过提高抗氧化酶活性、 渗透调节物质含量、 叶绿素含量和保水能力来增强黄瓜幼苗的抗旱能力。     

不同桃自根砧对干旱胁迫的生理响应及抗逆机理研究

砧木的抗旱能力直接影响桃品种生长发育,选择适宜抗旱性桃砧木对桃产业发展有积极的促进作用。为阐明不同桃砧木对干旱胁迫生理响应机制,以5种桃砧木扦插苗为试材,通过盆栽控水方式,研究不同程度干旱胁迫下5种桃自根砧的叶片水分特性、渗透调节物质、抗氧化物酶及叶绿素含量变化。结果表明,随着干旱程度加重,5种砧木相对含水量、临界含水量下降,自然饱和亏、临界饱和亏及需水程度上升,组织密度和自由水含量逐渐减少,束缚水含量则增大,持水能力、组织水势和耐旱系数下降。各干旱胁迫处理的丙二醛(MDA)含量、 游离脯氨酸(Pro)含量、可溶性糖含量和叶绿素含量均增加;过氧化物酶(POD)、超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性提高,其中随干旱程度加重,丙二醛(MDA)含量、游离脯氨酸(Pro)含量均呈增加趋势,SOD活性、CAT活性也均呈提升趋势,可溶性糖含量、叶绿素含量、POD活性变化不尽相同。综合隶属函数分析可知,桃自根砧品种间抗旱性由强到弱依次为樱桃李5号、RA、樱桃李3号、GF677、樱桃李1号。     

湿地匍灯藓（Plagiomnium acutum）对Pb胁迫的生物标志物响应

采用浸没培养实验研究了不同浓度Pb胁迫下湿地匍灯藓（Plagiomniumacutum）的总叶绿素、丙二醛、可溶性糖、游离脯氨酸含量以及抗氧化酶活性等生理生化生物标志物的变化,以探讨Pb胁迫下湿地匍灯藓的受损和耐受机理。结果表明,湿地匍灯藓外表伤害症状与Pb胁迫浓度存在明显的剂量-效应关系;低浓度（20mg·L-1）Pb胁迫可以显著地促进湿地匍灯藓的总叶绿素含量增加,而中、高浓度（50mg·L-1）Pb胁迫则导致总叶绿素含量显著降低。湿地匍灯藓对Pb具有较强的生物富集能力,且藓体Pb的累积量与环境Pb浓度呈显著正相关。湿地匍灯藓体内MDA和游离脯氨酸含量随Pb胁迫浓度的增加表现为显著升高。可溶性糖含量仅在高浓度Pb胁迫下显著升高。可溶性蛋白含量、过氧化物酶（POD）和过氧化氢酶（CAT）活性均随Pb胁迫浓度的增加而显著下降,其中CAT活性的降幅最大,SOD活性随Pb胁迫浓度的增加逐渐显著增加。在高浓度Pb胁迫下,由于细胞膜脂过氧化和蛋白质变性失活所导致的膜保护体系损伤可能是湿地匍灯藓Pb中毒的主要原因,而渗透调节可能是其缓解Pb毒害的一种主要方式,SOD则在清除Pb胁迫产生的活性氧自由基过程中起重要作用。总叶绿素、丙二醛、游离脯氨酸、可溶性蛋白、CAT和SOD可以作为湿地匍灯藓受Pb胁迫的敏感生物标志物。     

水稻品种耐热性与相关生化指标的关联分析

研究高温胁迫下水稻生化特性变化及其与品种耐热性的关系,可为水稻耐热性育种、耐热品种的鉴定和热害后补偿栽培技术研究提供依据。采用人工智能温室对水稻幼穗分化期到抽穗开花期进行高温处理,研究了高温胁迫对水稻叶片叶绿素、可溶性糖、脯氨酸、可溶性蛋白等6项生化指标含量变化的影响,对各品种生化指标变化与热敏感指数进行多元回归分析筛选水稻耐热性鉴定指标。结果表明,高温胁迫后,水稻叶片叶绿素、可溶性糖以及内源多胺含量在3个处理阶段均呈下降趋势,但耐热品种下降幅度明显小于热敏感品种;脯氨酸和丙二醛含量变化趋势与之相反,耐热品种脯氨酸含量上升幅度明显大于热敏感品种,而丙二醛含量上升幅度则明显小于热敏感品种;高温处理7 d后,叶片可溶性蛋白含量上升,处理14 d和21 d后呈逐渐下降趋势。高温胁迫后,叶绿素、可溶性糖、脯胺酸、可溶性蛋白、丙二醛以及内源多胺等含量变化与水稻耐热相关性存在较大差异。叶绿素、可溶性糖、脯氨酸、可溶性蛋白、丙二醛以及内源多胺含量可以作为水稻幼穗分化期到抽穗开花期耐热性鉴定的生化指标。     

贵州本土半野生番茄砧木介导ABA生物合成信号通路调控植株耐旱性的机理研究

随着全球气候变暖,干旱胁迫成为限制番茄等蔬菜作物安全生产的重要因素之一。前期研究发现嫁接贵州本土半野生番茄GZ-01砧木其可以提高植株的耐旱性。为探究野生番茄GZ-01增强植株耐旱性的分子机理,以半野生番茄GZ-01砧木和红果番茄为试验材料,结合形态生理学和分子生物学,比较嫁接番茄和自嫁接番茄植株对干旱胁迫的响应。结果表明,干旱胁迫下,与自嫁接植株R/R相比,GZ-01/R嫁接植株细胞膜的损伤显著降低,植株的抗氧化能力、干物质累积量、CO2同化率和水分利用率显著提高,离体叶片失水率显著降低,下气孔闭合比率显著提高,脱落酸（ABA）合成相关基因表达量和ABA含量显著提高。嫁接植株GZ-01/R可能通过调控ABA的合成来影响气孔开闭,调控叶片失水率,提高植株水分利用率,从而影响植株对干旱胁迫的响应。本研究为开发利用贵州本土半野生番茄资源奠定了基础,为增强干旱胁迫和分子调控网络途径提供了理论支撑。     

Exogenous glycinebetaine application improves yield under water-limited conditions in hybrid sunflower

Limited water availability is a severe threat to the sustainability of crop production. Exogenous application of glycinebetaine (GB) has been found very effective in reducing the adverse affects of water scarcity. This study was conducted to examine the role of exogenous GB application in improving the yield of hybrid sunflower (Helianthus annuus L.) under different irrigation regimes. There were three levels of irrigation: Control (four irrigations), three irrigations (irrigation missing at budding stage) and two irrigations (irrigation missing at budding and grain formation stage) in the experiment. While GB was applied exogenously at 100 mM GB each at budding and grain formation stages, the Control treatment did not receive any GB application. Data regarding yield, yield components and quality parameters showed that water stress reduced the head diameter, number of achene per head, 1000-achene weight and yield. Nonetheless, it was significantly improved by the exogenous GB application. Among the qualitative characteristics, protein contents were significantly increased by water stress at different growth stages but were reduced by exogenous GB application. Whilst oil contents were reduced by drought at different stages, GB application, however, did not ameliorate the negative effect of drought stress on achene oil contents. The effects of water stress and foliar application of GB were more pronounced when applied at vegetative stage than at the reproductive stage. Moreover, exogenous GB application was only advantageous under stress conditions.     

Arbuscular mycorrhizal fungi affect the growth,nutrient uptake and water status of maize (Zea mays L.) grown in two types of coal mine spoils under drought stress

Drought stress greatly affects the growth and development of plants in coal mine spoils located in the Inner Mongolia grassland ecosystem. Arbuscular mycorrhizal fungi (AMF) can increase plant tolerance to drought. However, little is known regarding the contribution of AMF to plants that are grown in different types of coal mine spoils under drought stress. To evaluate the mycorrhizal effects on the drought tolerance of maize (Zea mays L.) grown in weathered (S1) and spontaneously combusted (S2) coal mine spoils, a greenhouse pot experiment was conducted to investigate the effects of inoculation with Rhizophagus intraradices on the growth, nutrient uptake, carbon:nitrogen:phosphorus (C:N:P) stoichiometry and water status of maize under well-watered, moderate and severe drought stress conditions. The results indicated that drought stress increased mycorrhizal colonization and decreased plant dry weights, nutrient contents, leaf moisture percentage of fresh weight (LMP), water use efficiency (WUE) and rehydration rate. A high level of AMF colonization ranging from 65 to 90% was observed, and the mean root colonization rates in S1 were lower than those in S2. In both substrates, inoculation with R. intraradices significantly improved the plant growth, P contents, LMP and WUE and decreased the C:P and N:P ratios of plants under drought stress. In addition, maize grown in S1 and S2 exhibited different wilting properties in response to AMF inoculation, and plant rehydration after drought stress occurred faster in mycorrhizal plants. The results suggested that inoculation with R. intraradices played a more positive role in improving the drought stress resistance of plants grown in S2 than those grown in S1. AMF inoculation has a beneficial effect on plant tolerance to drought and effectively facilitates the development of plants in different coal mine spoils.     

Effects of drought stress on some agronomic and bio-physiological traits of Trititicum aestivum,Triticale, and Tritipyrum genotypes

ABSTRACT

Drought tolerance is a complex trait that involves different biochemical and physiological mechanisms in plants. It was the objective of the present study to evaluate the agronomic and biochemical responses of triticale, tritipyrum, and wheat to drought stress. For this purpose, twenty-seven genotypes were evaluated under two levels (non-stress and drought stress) of irrigation during 2015?2017. The metabolic traits studied included relative water content (RWC), membrane stability index (MSI), chlorophyll a (Chla), chlorophyll b (Chlb), carotenoids (Car), leaf proline content (Pro), leaf soluble carbohydrates (LSC), glycine betaine (GB), malondialdehyde (MDA), hydrogen peroxide (H₂O₂), seeds per spike (SS), seed weight (SW), biological yield (BY) and seed yield (SY). Drought stress increased Pro, LSC, and GB contents as well as lipid peroxidation through increasing MDA and H₂O₂ activities. However, both RWC and MSI indices as well as SS, SW, SY and BY reduced as a result of drought treatment although the least decrease of SY was observed at triticale group. During the two years of study, the tritipyrum genotypes exhibited their drought tolerance by accumulation of more LSC and GB as well as lower decrease in SW while the triticale ones responded by maintaining higher levels of RWC but producing less MDA and H₂O₂. It may, therefore, be concluded that the three species studied exploit different mechanisms to maintain tolerance against drought stress. Finally, correlation analysis indicated the positive effects of LSC on SY under both drought and normal conditions, which is obviously a promising trait in wheat, triticale, and tritipyrum that can be beneficially exploited in drought tolerance improvement programs.     

利用叶绿素荧光动力学参数识别苗期番茄干旱胁迫状态

为实现作物干旱胁迫状态无损识别,该研究提出了基于叶绿素荧光动力学参数的苗期番茄干旱胁迫状态识别方法。首先利用叶绿素荧光成像系统采集不同干旱胁迫程度的植株冠层叶绿素荧光图像,并将顶层叶片图像像素均值作为该植株的叶绿素荧光参数值;然后,采用连续投影法(SuccessiveProjectionsAlgorithm,SPA)、迭代保留信息变量法(Iteratively Retains Informative Variables,IRIV)和变量空间迭代收缩法(Variable Iterative Space Shrinkage Approac,VISSA)分别提取与干旱胁迫高度相关的叶绿素荧光参数。并分析3种算法提取的5个公共荧光参数(光适应过程中L2时刻的实际光量子效率、光适应过程中L3时刻的非光化荧光淬灭、基于"Lake"模型光适应过程中L2时刻的光适应光化学淬灭、基于"Lake"模型的稳态光适应光化学淬灭和基于"Lake"模型暗弛豫过程中D3时刻的光适应光化学淬灭)在不同干旱等级下的变化趋势。最后,利用线性判别分析(Linear Discriminant Analysis,LDA)、支持向量机(Support Vector Machines,SVM)和k最近邻(k-Nearest Neighbor,KNN)建立干旱胁迫状态识别模型。其中,IRIV-LDA和VISSA-LDA建模效果最好,识别准确率均可达97.8%,且IRIV-LDA对干旱胁迫程度的区分度更好,对适宜水分、轻度干旱、中度干旱、重度干旱的识别率分别为100%、95%、98%、98%。仅用5个公共参数建立干旱识别模型的识别准确度最高可达83.7%,说明这5个荧光参数与番茄干旱胁迫高度相关。试验结果表明,利用叶绿素荧光动力学参数可以较准确的检测苗期番茄干旱胁迫状态。该研究为苗期番茄干旱胁迫早期监测和胁迫等级判定提供了一种新方法,也可为其他作物的干旱胁迫状态监测提供技术参考。     

Water deficit stress,ROS involvement,and plant performance

Crop productivity is impaired by stress factors, biotic or abiotic. The main are pathogens, diseases, insects, cold, heat, salinity, drought, radiation and others. Among these unfavorable conditions, drought is one of the main occurrences and negatively affects crop development. This environmental adversity generally induces the accumulation of reactive oxygen species (ROS). These molecules lead to oxidative stress, and at high levels cause cell effects, like loss of organelle functions, electrolyte leakage, and reduction in metabolic efficiency. High concentration of ROS in cells can still cause molecular damage that include damage in proteins, amino acids, and lipids, and even lead to cell death. To neutralize these damages, plants increase enzymatic antioxidant activity and non-enzymatic antioxidant contents. ROS are essential to life in plants, and at basal levels performs cellular functions, such as signaling and defense responses. Here, we focus on the ROS production, the involvement and damages of these species in water deficit condition, changes in activity of antioxidant enzymes and non-enzymatic antioxidant contents in plants under drought stress. In addition, the signaling reactions of ROS under stress water restriction, changes on yield components of species under water deficit and the antioxidant genes involved in plant responses to stress were also addressed.     

Roles of glycine betaine in mitigating deleterious effect of salt stress on lettuce (Lactuca sativa L.)

This study was conducted to evaluate the roles of glycine betaine (GB) in mitigating deleterious effect of salt stress on lettuce. Lettuce plants were subjected to two salinity (0 and 100 mmol l^?1 NaCl) and four GB levels (0, 5, 10, 25 mmol l^?1). Salinity resulted in a remarkable decrease in growth parameters, relative leaf water content and stomatal conductance. Plants subjected to salt stress exhibited an increase in membrane permeability (MP), lipid peroxidation (MDA), leaf chlorophyll reading value, H₂O₂ and sugar content. Exogenous foliar applications of GB reduced MP, MDA and H₂O₂ content in salt-stressed lettuce plants. Salt stress increased Na and generally decreased other nutrient elements. GB reduced Na accumulation, but significantly increased other element contents under salinity conditions. The study showed that gibberellic acid (GA) and salicylic acid (SA) content in salt-stressed plants were lower than those of nonstressed plants. However, salinity conditions generally increased the abscisic acid content. GB treatments elevated the concentrations of GA, SA and indole acetic acid (IAA) at especially 10 and 25 mmol l^?1 GB under salt stress conditions. It could be concluded that exogenous GB applications could ameliorate the harmful effects of salt stress in lettuce.     

Glycinebetaine mediates chromium tolerance in mung bean through lowering of Cr uptake and improved antioxidant system

A pot experiment was conducted to evaluate the role of glycinebetaine (GB) in chromium (Cr) tolerance in mung bean (Vigna radiata L.) grown in Cr-stressed soil. Three concentrations of Cr (0, 250 and 500 µM) were tested with three (0, 50 and 100 mM) concentrations of foliar-applied GB. Cr alone led to a significant decrease in plant growth, biomass, and concentrations of chlorophyll a, b and carotenoids. Cr concentration and electrolyte leakage significantly increased in plants with increasing Cr levels in the soil. Lower Cr stress enhanced the activities of superoxide dismutase (SOD), peroxidases (POD) and catalase (CAT), while higher Cr concentrations decreased the activities of these enzymes. Foliar application of GB successfully alleviated toxic effects of Cr on mung bean and increased plant growth, biomass and chlorophyll contents under Cr stress. GB application reduced Cr accumulation and electrolyte leakage in plants and enhanced the activities of antioxidant enzymes in both shoots and roots as compared with Cr treatments alone. These findings suggest that foliar-applied GB alleviated Cr-induced oxidative stress in mung bean by reducing Cr uptake. The protective effect of GB against Cr stress varies with the concentrations of GB and Cr stress applied. Thus, further studies are still needed to specify the concentrations of GB required for detoxification of specific Cr concentrations under various climatic conditions.     

Ca(NO3)2胁迫对番茄嫁接苗叶片不同形态多胺含量的影响

以耐盐番茄品种‘影武者’为砧木,‘宝大903’为接穗,研究了80 mmol/L Ca(NO3)2胁迫10 d条件下,嫁接苗与自根苗生长和叶片不同形态（游离态、结合态和束缚态）多胺含量的差异。结果表明,Ca(NO3)2胁迫后,嫁接苗的生物量显著高于自根苗。整个胁迫期内嫁接苗叶片3种形态的腐胺、亚精胺和精胺含量均呈上升趋势;自根苗叶片3种形态的腐胺含量下降;游离态、结合态亚精胺和精胺含量上升;束缚态亚精胺含量下降,束缚态精胺含量变化不显著。以上结果表明,3种形态的腐胺、束缚态亚精胺和精胺在番茄嫁接苗叶片耐盐性方面发挥重要作用。