Screening of Drought-tolerant Brassica napus L.Varieties and Analysis on Their Physiologic and Biochemical Variations under Drought Stress

[Objective] The aim of this study was to screen drought-tolerant Brassica napus L. germplasm resources by analyzing their physiological and biochemical changes under drought stress. [Method] Forty varieties of B. napus varieties were cultured under PEG-6000 osmotic stress and extreme drought stress in pots, re- spectively. Then, the contents of chlorophyll, carotenoid, proline, malondialdehyde （MDA）, soluble sugar, soluble protein, and the activities of superoxide dismutase （SOD）, catalase（CAT）, peroxidase（POD） were measured under drought stress. [Result] Sever- al drought-tolerant varieties of B. napus were screened out： YAU200908, Xiangyou No.15, YAU200903, YAU200907, YAU200906 and YAU200904. Physiological and biochemical analysis showed that, the contents of chlorophyll and carotenoid de- creased with drought stress increasing; the contents of proline, soluble sugar, solu- ble protein, MDA and the activities of SOD,CAT, POD raised with drought stress in- creasing. [Conclusion] In the rapeseed varieties with stronger drought tolerance, the decrease in carotenoid content and the increase in proline content, soluble sugar content, MDA content, SOD activity, CAT activity were more obvious, so all these physiological and biochemical indices can be used to evaluate the drought tolerance of rapeseed.

Effect and Mechanism of Cold Tolerant Seed-Coating Agents on the Cold Tolerance of Early Indica Rice Seedlings

To better understand the effect and mechanism of cold tolerant seed-coating agents on the cold tolerance of rice seedlings, the physiological and biochemical effects of four cold tolerant seed-coating agents （HET, YKJ, YKZYJ, and the ABA seed coating agents） on two early indica rice varieties were studied under chilling stress. The results showed that the rice seedlings treated with cold tolerant seed-coating agents under chilling stress maintained dramatically higher root vigor, POD, CAT and SOD activities, and chlorophyll content, had lower MDA content and electrolyte leakage, and accumulated more soluble sugar and free proline, when compared with the control without the treatment, and finally showed lower plant injury rate. It was indicated that the cold tolerant seed coating agent improved the ability of rice seedlings in resisting to chilling stress. YKZYJ was ranked the first in terms of the efficiency in cold tolerance among the four cold tolerant seed-coating agents tested.

Role and Mechanism of Action of Exogenous Salicylic Acid and Sodium Molybdate in Improving Cold Tolerance of Bougainvillea glabra

This study was conducted to comprehensively evaluate the effects of salicylic acid and sodium molybdate on cold tolerance of an ornamental plant Bougainvillea glabra and to provide a theoretical guidance for landscape maintenance.B.glabra plants were treated with 0.5 mmol/L salicylic acid and 2.0 μmol/L alone or in combination,and then exposed to low temperature stress before physiological indices were measured.The results showed that all salicylic acid and sodium molybdate treatments reduced the relative conductivity and malondialdehyde( MDA) content of B.glabra to varying extents under the stress of low temperature,and more significant effect was achieved by using the two agents in combination.Oxygen free radicals production rate increased with decreasing temperature from 20 to 6 ℃,but declined with temperature decreasing from 3 to-3 ℃.The SOD activity of the control( CK) was significantly lower than that of other treatments at 0 and-3 ℃.The treatments with salicylic acid and sodium molybdate alone and in combination increased POD activity of B.glabra plants,especially at 0 ℃,as the POD activity of treatments T1,T2 and T3 was significantly higher than that of CK at 0 ℃.In addition,under low temperature stress,the contents of soluble sugar,starch and proline increased initially and decreased subsequently with temperature decreasing.The soluble sugar content at 3 ℃,starch and proline contents at 0 and-3 ℃ in treatments with salicylic acid and sodium molybdate alone and in combination were significantly higher than those of CK.All above results proved that salicylic acid and sodium molybdate are able to improve cold tolerance of B.glabra,and better effect can be achieved by using them together.

Effects of an ectomycorrhizal fungus on the growth and physiology of Pinus sylvestris var. mongolica seedlings subjected to saline-alkali stress

This research investigates the mechanism of increased salinity tolerance of ectomycorrhizal fungiinoculated P. sylvestris var. mongolica to provide a theoretical basis for the application of the fungus in saline soils.Growth effects due to inoculation of seedlings with Suillus luteus(a symbiotic ectomycorrhizal fungus), were determined in four kinds of saline–alkali soils. Growth and physiological indicators, including photosynthetic characteristics, plant height, biomass, photosynthetic pigments,catalase(CAT) and superoxide dismutase(SOD) enzyme levels, and malondialdehyde(MDA), an organic marker for oxidative stress, and soluble protein levels were determined. Mycorrhizal colonization rate decreased with increasing saline–alkalinity and growth of inoculated seedlings was significantly enhanced. Biomass and chlorophyll contents also increased significantly. SOD and CAT activities were higher than in non-inoculated seedlings. However, MDA content decreased in inoculatedseedlings. Soluble protein content did not increase significantly. Inoculation with a symbiotic ectomycorrhizal fungus could enhance the saline–alkali tolerance of P. sylvestris var. mongolica. Growth and physiological performance of inoculated seedlings were significantly better than that of uninoculated seedlings. The results indicate that inoculated P. sylvestris var. mongolica seedlings may be useful in the improvement of saline–alkali lands.

Screening and Assessment of Selected Chilli (Capsicum annuum L.) Genotypes for Drought Tolerance at Seedling Stage

This study was undertaken to investigate oxidative stress tolerant mechanisms in chilli(Capsicum annuum L.)under drought genotypes through evaluating morphological,physiological,biochemical and stomatal parameters.Twenty genotypes were evaluated for their genetic potential to drought stress tolerant at seedling stage.Thirty days old seedlings were exposed to drought stress induced by stop watering for the following 10 days and rewatering for the following one week as recovery.Based on their survival performance,two tolerant genotypes viz.BD-10906 and BD-109012 and two susceptible genotypes viz.BD-10902 and RT-20 were selected for studying the oxidative stress tolerance mechanism.Drought reduced root and shoot length,dry weight,ratio,petiole weight and leaf area in both tolerant and susceptible genotypes,and a higher reduction was observed in susceptible genotypes.Lower reduction of leaf area and photosynthetic pigments were also found in tolerant genotypes.Moreover,tolerant genotypes showed higher recovery than susceptible genotypes after the removal of stress.A higher reduction of relative water content(RWC)may cause an imbalance between absorbed and transpirated water in susceptible genotypes.Higher accumulation of proline in tolerant genotypes might be helpful to for better osmotic maintenance than that in susceptible genotypes.Tolerant genotypes showed higher antioxidant activity as they showed DPPH radical scavenging percentage than the susceptible genotypes.Moreover,closer stomata in tolerant genotypes than susceptible ones helped to avoid dehydration in tolerant genotypes.Thus,the above morphological,physiological,biochemical and stomatal parameters helped to show better tolerance in chilli under drought stress.

Research Progress of Heat-tolerance of Brassica campestris ssp. Chinensis

Brassica campestris ssp. chinensis, also known as non-heading Chinese cabbage, is an important vegetable widely distributed in southern China. High temperature is the most common adversity factor in vegetable production, because Brassica campestris ssp. chinensis is a thermophilic vegetable, which can＇t well grow at high temperature. In summer and autumn, high temperature stress would prevent Brassica campestris ssp. chinensis from growing and result in poor quality of its seedlings, seriously influencing yield and quality of the vegetable in later period. In this paper, present situation and latest advances in heat resistance research of Brassica campestris ssp. chinensis in recent years were reviewed at home and abroad. The research tendency in Bassica campestris ssp. chinensis was also described, providing reference for breeding of heat-resistant Brassica campestris ssp. chinensis.

盐胁迫对平欧杂种榛根系生理生化特性的影响

以2年生平欧杂种榛‘达维’为试验材料,在水培条件下设置对照、轻度、中度和重度盐胁迫处理(NaCl浓度分别为0、50、100和200 mmol·L^(-1)),研究不同胁迫时间(1、3和7 d)下根系渗透调节物质、膜伤害程度、抗氧化酶活性以及离子特征的变化,探讨耐盐的生理机制。结果表明:盐胁迫显著促进了可溶性糖(SS)和脯氨酸(Pro)的积累。SS随着胁迫时间的延长呈持续增加趋势,Pro在重度胁迫至3 d时显著升高,较胁迫1 d时提高25.9%。相对电导率(REC)和丙二醛(MDA)随着盐胁迫程度的增强均呈不断升高,重度胁迫下二者较对照分别显著提高32.1%和55.6%。REC和MDA随着胁迫时间的延长呈不断升高。随着盐胁迫程度的增强,超氧化物歧化酶(SOD)表现为先下降后上升,过氧化氢酶(CAT)呈不断增加。SOD和CAT对盐胁迫的响应存在时间差异,二者分别在胁迫7和1 d时达到最大值。随着盐胁迫程度的增强,Na^(+)不断升高,K^(+)波动下降,w(K^(+))∶w(Na^(+))表现为不断下降。平欧杂种榛具有一定的耐盐性。轻度胁迫下,幼苗可以通过自身生理生化特性的调节以响应和适应盐胁迫;中度胁迫下,根细胞膜开始受到伤害,但仍能通过积累渗透调节物质和增强抗氧化酶活性来应对盐胁迫;当NaCl浓度达到200 mmol·L^(-1)且胁迫超过3 d时,植物开始遭受盐害。SS、Pro、CAT活性和Na^(+)质量分数可作为平欧杂种榛耐盐性评价的参考指标。

冷热应激对肉牛生理指标及基因表达影响的研究进展

冷热应激可导致肉牛的日增重、饲料转化率等重要指标降低,进而影响到整个产业的生产效率,基于此问题,本文就冷热应激下不同地区、不同品种的肉牛血液内分泌、免疫、抗氧化等生理生化指标变化情况进行了概述,对冷热应激的调控基因和分子机制做了挖掘,并在讨论部分展望了包括改变饲喂方式和基于GWAS的分子育种等增加肉牛冷热应激适应性的可行性方法。本文不但为更好地理解肉牛产业中冷热应激的机制提供了理论依据,还为我国提高冷热应激下肉牛的生产效率提供了育种参考,具有一定的理论和现实意义。

水稻耐低温研究进展

水稻是世界上的主要粮食作物之一,低温将导致水稻发育延缓,长期遭受低温胁迫易导致水稻枯萎死亡。全球每年约有1 500万hm^(2)的水稻面临低温胁迫危害,低温冷害已成为水稻减产的主要原因之一。为系统了解水稻耐低温机理研究进展,总结了低温对水稻细胞结构特征的影响、低温对水稻生理生化特性的影响、水稻耐低温优良品种选育和水稻耐低温的分子机理的研究现状,并展望了水稻耐低温品种的未来选育方向。

干旱对甘蔗生长影响及其响应机制研究进展

干旱是影响甘蔗生长发育以及产量的最主要非生物逆境胁迫之一,随着全球极端气候的发生愈加频繁,甘蔗遭受干旱胁迫的风险越来越大。干旱对甘蔗生长的影响是多方面的,不同器官会产生不同的表现。甘蔗为了抵御干旱胁迫会产生一系列调节机制,包括形态特征和生理生化特性改变。本文总结了干旱胁迫对甘蔗叶片、根系、茎等各器官生长以及不同生育期干旱对甘蔗生长的影响,从渗透调节、抗氧化酶、内源激素、根际微生物和基因表达方面论述了甘蔗对干旱胁迫的响应机制,并对甘蔗响应干旱的系统性机制、不同品种抗旱性差异与提高甘蔗抗旱性研究进行展望,以期为从事甘蔗生产和相关研究的工作者提供理论参考。

植物对低磷胁迫的适应机制

磷是植物生长和发育的重要限制因子之一,土壤中的可溶性无机磷酸盐极易被金属离子固定,形成难溶性磷或有机磷,造成低磷胁迫。为了适应低磷环境,植物体产生了包括形态学、生理生化反应在内的一系列适应机制。随着分子生物学技术的发展,大量参与植物体内磷动态平衡的基因如转运蛋白基因、PHR转录因子、SPX转录因子、miRNA等被相继克隆,其功能和作用机制也得到解析。这些基因相互作用形成了复杂的系统和局部磷信号调控网络,共同调控植物体内的磷稳态。文章回顾了低磷胁迫对植物生长发育的影响,综述国内外关于低磷胁迫分子机制及信号调控网络的研究进展。

辣椒响应热胁迫机制的研究进展

辣椒是重要的蔬菜作物和调味品,含有丰富的营养物质。然而,高温制约了辣椒的生长发育,严重影响其产量和品质。因此,研究热胁迫响应机制从而培育具有较强耐热能力的辣椒品种具有重要意义。本文从生理生化机制、分子机制、组学机制的角度详细阐述了辣椒热胁迫响应机制的研究进展,并对其中存在的问题及今后的研究方向进行了探讨,旨在推动解析辣椒的耐热机制和耐热品种选育进程。

白蜡窄吉丁成虫对短时高温的生理响应

【目的】从生理水平上探究白蜡窄吉丁成虫温度耐受性形成的原因,为揭示昆虫环境抗逆性形成机制提供参考。【方法】以25℃为对照,室内设置温度分别为30、33、37和41℃的高温条件,分别于4、8和12 h后收集放置于上述不同条件下的白蜡窄吉丁雌雄成虫。测定各处理样品的含水量、含脂量、糖原、葡萄糖、海藻糖和蛋白质含量的变化。【结果】随着温度升高和高温持续时间延长,白蜡窄吉丁雌雄成虫体内水分和脂类含量都大致呈下降趋势。温度越高时,雌雄虫体内糖原含量越高;而葡萄糖和海藻糖含量则先升高后降低,于33~37℃时达到最大值。随着雌雄虫经历高温持续时间的延长,其体内糖原、葡萄糖和海藻糖含量都大致呈增长趋势。雌雄虫体内蛋白质含量随温度升高波动性增加,而随高温持续时间延长表现出逐渐下降趋势。白蜡窄吉丁雄虫体内水分、脂类和糖原含量明显高于雌虫,而海藻糖和蛋白质含量与雌虫相比则相对较低。【结论】短时高温条件下,白蜡窄吉丁雌雄成虫体内含脂量、多种糖类和蛋白质含量均在一定程度上发生明显变化,水分和脂类含量受温度及其持续时间影响较小,糖类和蛋白质含量则受影响相对较大。糖类和蛋白质等多种抗逆物质都在白蜡窄吉丁成虫抵御高温胁迫时发挥了重要的调节作用。

弱光胁迫影响玉米产量形成的生理机制及调控效应

在全球气候变化背景下,生育期内光照不足已成为制约玉米产量提高的主要因素之一,增加了全球粮食生产和营养安全的风险。本文从光合性能、养分吸收特性、籽粒形成与灌浆特性等方面系统总结了弱光胁迫影响玉米产量形成的生理机制。弱光降低了叶片捕光能力,基质和基粒类囊体结构解体,相关酶活性降低,光系统受到损伤,碳同化能力降低,进而抑制根系发育,影响根系形态和功能,不利于养分吸收和代谢。由于营养供应不足,雌、雄穗发育受阻,花粉和花丝的形态功能受到影响,导致小花受精率低,穗粒数降低。弱光条件下,胚乳细胞数量——“库”容量降低,胚乳传递细胞结构和功能受到影响,内源激素平衡被打破,蔗糖-淀粉代谢相关酶活性下降,茎节维管束数目和面积减少,物质转运和转化能力降低,导致淀粉充实状态差,粒重降低。因此,为缓解弱光胁迫对玉米产量形成的影响,亟须创建系统评估耐阴品种的指标,利用现代育种技术加快培育出高光效耐阴新品种,采取增施氮肥、去除顶部叶、喷施生长调节剂和叶面肥等栽培措施提高产量。未来研究需要注重根冠协调,深入探讨弱光胁迫的作用机理,为玉米抗逆增产关键技术的创建提供理论依据。

非生物胁迫对冬青属植物生理生化机制影响的研究进展

冬青属植物是一类既可观赏又具有重要药用价值的新宠植物。我国对冬青属植物的研究及其开发利用还处于初步阶段,扩大引种栽培是增加种源量、实现利用的一种主要措施。干旱、低温等环境因子是影响冬青属植物南种北移的主要因素。本文查阅并总结了我国2000年以来冬青属植物对干旱、低温等非生物胁迫的生理生化响应机制研究进展,以期为冬青属植物的高效栽培及后续开发利用提供参考。

高温胁迫下辣椒生理生化响应机理初步探讨

为阐明辣椒耐热的生理生化机制,以耐热自交系A11和热敏自交系B22为材料,研究了高温(42℃)胁迫下辣椒相对电导率、丙二醛、游离脯氨酸、总叶绿素含量和保护酶活性的变化。结果表明:高温胁迫后,随着时间的延长,不同耐热性材料的相对电导率、丙二醛含量增加,热敏材料增幅高于耐热材料,而热敏材料的游离脯氨酸含量的上升幅度低于耐热材料;总叶绿素含量呈下降趋势,热敏材料总叶绿素含量的下降幅度大于耐热材料;SOD和POD活性均表现为先下降后上升趋势,其中热敏材料下降幅度高于耐热材料,上升幅度则相反。

水稻开花期高温胁迫条件下生理生化特性的变化及其与品种耐热性的关系

以5个杂交水稻组合为材料,研究了开花期人工高温胁迫处理对剑叶部分生理生化特性的影响。结果表明,水稻开花期高温胁迫处理降低了剑叶光合速率、叶绿素含量,增加了可溶性糖、游离脯氨酸、MDA含量及超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和过氧化物酶(POD)的活性。相关分析表明,开花期高温胁迫处理后叶绿素含量、游离脯氨酸含量、MDA含量和SOD活性的变化幅度与品种的热敏感指数呈显著或极显著相关关系,此4项指标的变化幅度可作为水稻开花期耐热性鉴定的生理指标。耐热性强的水稻品种,在开花期高温胁迫处理后剑叶叶绿素含量下降幅度小,游离脯氨酸含量和SOD活性增加幅度大,MDA含量增加小。建立了热敏感指数与MDA含量、游离脯氨酸含量和SOD活性变化幅度的逐步回归方程,可用于对水稻开花期的耐热性进行定量分析。

高温胁迫下五种杜鹃花属植物的生理变化及其耐热性比较

高温是制约分布于较高海拔地区杜鹃花迁地保育与园林应用的重要因子。为探讨杜鹃花属植物的高温致伤机理,该实验以隶属不同亚属的白花杜鹃、羊踯躅、毛棉杜鹃、红滩杜鹃及红棕杜鹃4年生实生苗为材料,通过人工气候箱的盆栽实验,研究了30℃、38℃高温胁迫下其叶片生理生化指标的变化,并利用隶属函数法及系统聚类分析法对其种间耐热性进行了综合评价。结果表明:高温胁迫下,5种杜鹃叶片的过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)活性及脯氨酸(Pro)、过氧化氢(H_2O_2)、丙二醛(MDA)含量均随着胁迫温度的升高而增大;超氧化物歧化酶(SOD)活性在30℃轻度胁迫时均小幅度上升,而38℃重度胁迫时下降。2个高温条件下,SOD、CAT的变化幅度与杜鹃种间耐热性总体呈正相关,而H_2O_2、MDA增幅与种间耐热性呈负相关;Pro增幅在30℃轻度胁迫时与种间耐热性呈负相关,而38℃重度胁迫时与耐热性呈正相关;APX增幅与种间耐热性的相关性较弱。隶属函数与聚类分析综合评判得出5种杜鹃耐热性强弱顺序为:白花杜鹃>羊踯躅、毛棉杜鹃>红滩杜鹃>红棕杜鹃,与其田间耐热性表现一致。

大豆响应高温胁迫的生理和分子遗传机理研究现状与展望

大豆是重要的经济作物,是植物油脂和蛋白质的重要来源。近年来,因全球气候变化引起的高温胁迫频发,危及到大豆生长的各个时期,成为制约大豆产量和品质的重要因素之一。为了揭示大豆耐高温性的遗传机理,建立综合高效大豆耐高温评价体系,促进大豆耐高温特性的遗传改良,现对大豆响应高温胁迫的生理生化基础和分子调控机制进行综述。相较于适温条件,高温胁迫可使大豆植株发生叶片增厚、气孔导度下降、细胞膜透性增加、细胞微观组织结构受损以及渗透调节物质(脯氨酸、可溶性糖和可溶性蛋白)含量变化和抗氧化防御系统关键酶活性丧失等生理异常反应,导致植株光合、蒸腾和呼吸作用及物质含量等一系列生理生化过程紊乱。高温胁迫还造成大豆花粉形态异常,绒毡层细胞结构松散、空泡化和自溶化,花粉活力及其萌发率明显下降,花粉败育率增高,致使大豆结荚率和结实率显著降低,进而影响大豆籽粒的正常发育、蛋白的积累和产量形成等,最终导致减产;高温胁迫对大豆籽粒外观品质性状也能造成一定损伤,进而对其经济价值带来不利影响。高温胁迫从转录、翻译和代谢水平影响大豆正常的生理代谢调控。目前,已通过高通量测序等方法鉴定出多个与大豆高温胁迫响应相关的转录因子、蛋白及代谢产物,但与水稻、拟南芥的研究相比仍存在较大差距;初步建立了以花粉活力和多项生理指标为基础的大豆耐高温鉴定方法,但在生产上尚缺乏系统高效耐高温评价体系,耐高温大豆育种工作进展缓慢。国内在大豆耐高温预防措施、耐高温综合评鉴体系建立、优异耐高温大豆种质资源筛选及耐高温关键功能基因挖掘等方面仍然存在挑战。为应对极端生态环境给大豆生产造成的不利影响,未来应通过建立综合高效大豆耐高温评价技术体系,提高大豆优异种质资源鉴定水平,重点解析大豆耐高温的分子遗传机理、挖掘耐高温关键基因,结合常规育种和分子育种技术培育综合性状优异的耐高温大豆新品种,以实现大豆品种耐高温性与高产、优质的统一。

芝麻不同抗旱基因型对花期干旱胁迫的生理响应机理

【目的】研究干旱胁迫对不同抗旱性芝麻品种叶片和根系生理生化特性的影响,分析不同基因型芝麻对花期干旱胁迫的生理响应差异,为芝麻抗旱性研究和改良提供理论参考。【方法】采用盆栽法,以抗旱品种金黄麻和干旱敏感品种竹山白为试验材料,在花期进行轻度(T1)、中度(T2)和重度(T3)干旱胁迫处理,以正常浇水为对照(CK),分别测定植株叶片和根系的丙二醛(MDA)、过氧化氢(H_2O_2)、脯氨酸(Pro)、可溶性糖(SS)、可溶性蛋白(SP)、游离氨基酸(AA)、还原型谷胱甘肽(GSH)、还原型抗坏血酸(AsA)等含量,超氧化歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)和苯丙氨酸解氨酶(PAL)活性,分析干旱胁迫下2个基因型间生理响应机理的差异。【结果】干旱胁迫后,芝麻叶片中MDA、H_2O_2、Pro、SS、SP、GSH含量和SOD、POD、PAL酶活性以及根系中MDA、SS、SP、AA、GSH、AsA含量和CAT、PAL活性随着胁迫程度的不断加剧呈不断上升趋势,叶片中的AA、AsA含量和CAT活性以及根系中H_2O_2、Pro含量和SOD、POD活性随着胁迫程度的加剧呈先升后降趋势。相关分析结果显示,叶片中各项指标测定值与根系中指标值均呈正相关,品种抗旱性与膜脂过氧化伤害物质(MDA和H_2O_2)含量呈负相关,与部分渗透调节物质、防御系统物质含量和保护酶活性呈正相关。【结论】在花期干旱胁迫下,对2个不同基因型芝麻测定的12个生理生化指标均出现不同程度上升,响应差异较大,叶片大于根系。抗旱品种较干旱敏感品种表现为细胞膜脂过氧化伤害较轻,渗透调节物质积累量较多,保护酶(SOD和CAT)活性较强,抗氧化物质(GSH和AsA)含量较高。芝麻抗旱性生理机理表现为多方面的综合防御。