植物抗旱基因工程研究进展

干旱、高温、低温、盐胁迫等是影响植物生存的主要逆境因子,它们均引起植物失水,导致细胞生理干旱,作者对植物抗旱的生物学原理及其基因工程研究进展进行了论述。     

植物响应非生物胁迫的磷酸化修饰组学研究进展

植物具有固着生活的特点,高温、低温、干旱和盐等生境中常见的非生物胁迫会严重影响植物的生长发育。蛋白质磷酸化是植物应对非生物胁迫的重要机制,主要通过蛋白质的磷酸化和去磷酸化修饰来调控植物细胞对外界胁迫的应激反应,在植物细胞快速传递胁迫信号并激活对胁迫环境的形态、生理和分子水平适应机制的过程中起重要作用。该文主要介绍了植物磷酸化蛋白质的富集、检测和鉴定技术,并对近年来国内外有关植物响应高温、低温、干旱、淹水、盐、养分亏缺和元素毒害等非生物胁迫的磷酸化修饰蛋白组学研究进展进行综述。     

生物逆境和共生状态下植物的蛋白质组学研究

蛋白质组技术已广泛应用于植物遗传、发育和生理生态等诸多生物学领域,主要研究植物的遗传多样性、植物发育、组织分化、植物对非生物逆境(包括高温、低温、高盐和干旱等)和生物逆境(病虫害)的适应机制和植物与微生物(根瘤共生体)相互作用机制。本文综述了微生物与植物互作的蛋白质组研究进展,包括有害和有益的相互作用,同时对植物蛋白质组学的发展前景进行了讨论。     

植物蛋白质组学研究进展Ⅱ.蛋白质组技术在植物生物学研究中的应用

蛋白质组技术已广泛应用于植物遗传、发育和生理生态等诸多生物学领域, 主要研究植物的遗传多样性、植物发育(如种子成熟与发芽过程)、组织器官的分化过程、不同亚细胞结构的新蛋白组分的发现及其功能鉴定、植物对非生物逆境(包括高温、低温、高盐和干旱等)和生物逆境(病虫害)的适应机制和植物与微生物(根瘤共生体)相互作用机制。同时对植物蛋白质组学的发展前景进行了讨论。     

高温条件下稀土尾砂干旱对4种植物生理特性的影响

稀土矿尾砂区地表大面积裸露,土壤结构遭到破坏,保水性能差,植物生长受到严重的干旱胁迫,季节性高温干旱期甚至威胁植物的生存。以稀土矿区周边广泛分布的枫香、木荷、樟树和桉树4种植物为研究对象,对比分析高温干旱条件下4种植物幼苗的光合特征、水分利用效率(WUE)、渗透调节物质和抗氧化酶活性等生理特征及适应性,为稀土尾砂矿区生态修复中植物的筛选提供理论依据。结果显示,高温干旱(空气温度40℃,土壤含水量2%左右)条件下,4种植物的光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)和叶绿素(Chl)含量显著低于高温丰水条件(空气温度40℃,土壤含水量15%左右),光合作用受到抑制,WUE升高;不管高温丰水还是干旱条件下,樟树WUE最高;干旱条件下枫香和桉树的丙二醛(MDA),木荷和桉树的可溶性糖、脯氨酸(Pro)和可溶性蛋白,以及所有植物的过氧化物酶活性(超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT))均显著高于丰水条件。隶属函数评价得出4种植物幼苗抗高温干旱的等级为樟树桉树木荷枫香;灰色关联分析发现WUE和可溶性糖与抗旱性关联最大,其次为CAT、Pro和MDA,可溶性蛋白与抗旱性关联最小。其中,樟树通过提高WUE、可溶性糖和CAT来应对干旱,桉树通过可溶性糖和MDA响应干旱胁迫,木荷在Pro调节下体现抗旱性,枫香则通过可溶性蛋白来抗旱。因此,在稀土尾砂植被恢复中关于乔木树种的选择可优先考虑樟树。     

植物感应干旱信号的机制

干旱导致渗透胁迫，是造成作物减产的主要自然灾害。自达尔文时代，科学家开始探索植物感知和应答干旱胁迫的机制。现已阐明胁迫激素脱落酸信号途径，并逐步获得植物感知干旱和渗透胁迫的一些线索。本文总结了近年来干旱和渗透信号在植物中感知和传导的研究进展，对干旱胁迫可能的输入信号以及植物潜在的感知方式进行阐述，并提出了干旱胁迫信号研究中尚需解决的核心科学问题，期望为解析植物干旱信号感知和作物抗逆遗传改良提供线索。     

岩溶区植物生态适应性研究进展

对岩溶植物在强光高温、干旱、土壤养分和生境异质性等岩溶典型环境下适应性的相关研究进行了综述。结果发现:强光高温和地质性干旱迫使植物改变自身生理结构和形态结构来应对岩溶环境所带来的损伤;特殊的土壤性质也使岩溶植物进化出较强的生化调节功能;空间异质性与植物功能性状的关系是近些年来国内研究的热点。目前在岩溶植物适应特殊生境方面研究有较大进展,但在研究广度上存在不足,应加强群落演替与不同功能性状间关系等方面的研究,为岩溶区生态恢复治理提供依据。     

高温和干旱胁迫对鳞叶藓游离脯氨酸和可溶性糖含量的影响

研究了高温和干旱胁迫对鳞叶藓 (Taxiphyllumtaxirameum)游离脯氨酸和可溶性糖含量的影响。结果显示 ,高温和干旱均能诱导植物体内可溶性糖的积累。在 60℃高温胁迫下处理 ,可溶性糖含量随处理时间的延长而增加 ,最高值比对照增加了 2倍。PEG 60 0 0胁迫下处理可使可溶性糖含量分别增加 2 .4倍。经统计学检验 ,逆境条件与游离脯氨酸含量变化无关     

高温干旱复合胁迫对构树幼苗抗氧化酶活性和活性氧代谢的影响

近年来,全球气温不断升高,亚热带部分地区夏季高温和临时性干旱现象日益显著,高温与干旱严重威胁着植物的生存与生长。采用盆栽和人工气候室方式模拟不同的温度和土壤水分梯度,研究了高温与干旱复合胁迫对构树幼苗超氧化物歧化酶(SOD)、过氧化物酶(POD)与过氧化氢酶(CAT)活性、活性氧代谢和丙二醛(MDA)含量的影响。结果表明:(1)高温或干旱单一胁迫下,构树幼苗SOD、POD、CAT活性增加,复合胁迫下,SOD和POD酶活性高于单一胁迫,且随着复合胁迫时间延长而升高。SOD活性受温度和土壤水分双因素影响极其显著,复合胁迫对SOD活性有一定程度的叠加效应;(2)复合胁迫下,活性氧代谢物与MDA含量均显著高于单一胁迫,表明复合胁迫加剧对植物的伤害。通过改变抗氧化酶活性以减轻膜脂过氧化的伤害作用是有限的。     

高温干旱对不同品种辣椒生长及呼吸作用的影响

研究了高温干旱胁迫对不同品种辣椒生长及呼吸作用的影响。结果表明,高温胁迫对正椒13号的生长无影响,对鸡爪×吉林的生长稍有抑制;干旱及高温干旱严重地抑制了辣椒的生长。干旱导致叶片相对电导率的增加高于高温,而高温加剧了干旱伤害程度,并且对鸡爪×吉林的伤害更大。高温处理引起了辣椒总呼吸、细胞色素呼吸和交替呼吸的增加。干旱胁迫抑制了细胞色素呼吸,但诱导了交替呼吸的增强;高温干旱共同胁迫加剧了总呼吸和细胞色素呼吸的下降,交替呼吸只在胁迫第一天被促进,随后立即下降。高温、干旱和高温干旱胁迫下正椒13号表现出了较鸡爪×吉林更强的交替呼吸和总呼吸。说明高温、干旱和高温干旱胁迫下辣椒保持较高的总呼吸和交替呼吸与其抗高温和/或干旱能力相关。     

噪声和高温对机体健康影响的复合效应

当今社会随着经济和科技的发展,多种有害职业因素往往共同存在于同一岗位。复合因素对机体健康影响的相互作用包括四种情况:协同作用、相加作用、拮抗作用和无关作用。噪声和高温作为有害的职业因素常存在于同一岗位,那么噪声复合高温对机体健康会产生怎样的影响,这两种环境因素是否存在复合效应?文献报道不一。噪声和高温联合对听觉系统、心血管系统、神经系统的影响可能表现为协同、相加、拮抗和无关作用,对呼吸系统的影响表现为拮抗作用,目前,研究结果不一致主要原因是实验条件和暴露方法的不一致。我们认为将来的研究热点集中在噪声和高温联合产生复合效应的条件及剂量反应关系研究、机制及防治措施研究,噪声和高温联合对其他系统如消化、免疫系统是否存在复合效应也值得深入研究。     

Cross‐generational effects of temperature on flight performance,and associated life‐history traits in an insect

Nongenetic parental effects may affect offspring phenotype, and in species with multiple generations per year, these effects may cause life‐history traits to vary over the season. We investigated the effects of parental, offspring developmental and offspring adult temperatures on a suite of life‐history traits in the globally invasive agricultural pest Grapholita molesta. A low parental temperature resulted in female offspring that developed faster at low developmental temperature compared with females whose parents were reared at high temperature. Furthermore, females whose parents were reared at low temperature were heavier and more fecund and had better flight abilities than females whose parents were reared at high temperature. In addition to these cross‐generational effects, females developed at low temperature had similar flight abilities at low and high ambient temperatures, whereas females developed at high temperature had poorer flight abilities at low than at high ambient temperature. Our findings demonstrate a pronounced benefit of low parental temperature on offspring performance, as well as between‐ and within‐generation effects of acclimation to low temperature. In cooler environments, the offspring generation is expected to develop more rapidly than the parental generation and to comprise more fecund and more dispersive females. By producing phenotypes that are adaptive to the conditions inducing them as well as heritable, cross‐generational plasticity can influence the evolutionary trajectory of populations. The potential for short‐term acclimation to low temperature may allow expanding insect populations to better cope with novel environments and may help to explain the spread and establishment of invasive species.     

共生与非共生爪哇伪枝藻对高温胁迫的响应

研究以自由生长的爪哇伪枝藻(Free-living S. javanicum, fs)和分离自地衣的爪哇伪枝藻(Symbiotic S. javanicum, ss)为研究对象, 探究了不同生长状态爪哇伪枝藻对高温(45℃)胁迫的响应。结果发现在高温胁迫下, 爪哇伪枝藻光合活性、叶绿素a及类胡萝卜素含量下降; 丙二醛(MDA)、胞外多糖及可溶性蛋白含量上升。在高温处理下, 与fs相比, ss光合活性下降较慢, 且高温处理后ss的叶绿素a及类胡萝卜素含量也明显高于fs。高温处理下, 与fs相比, ss的MDA含量和增长速度均较低; 并且在面临高温胁迫时, ss能够更快的分泌胞外多糖和可溶性蛋白质, 从而在一定程度上达到自我保护的目的。研究结果表明, 在暴露于高温胁迫时, 相较于自由生长状态, 来自地衣的爪哇伪枝藻具有更高的自我保护效率。     

棉纤维发育响应高温胁迫的关键时间窗口

以温度弱敏感性棉花品种(科棉1号)和温度敏感性棉花品种(苏棉15)为材料,在人工气候室模拟自然温周期设置高温(34 ℃\[38/30 ℃\],HT)和对照(26 ℃\[30/22 ℃\],CK)2个温度处理,研究了花铃期不同时段进行高温胁迫后纤维发育重要相关物质的变化及其与纤维品质的关系.结果表明： 在花后不同时间开始高温胁迫持续处理5 d,苏棉15纤维长度、纤维比强度、马克隆值响应高温胁迫的关键时间窗口分别为花后0～18.3 d,花后10.9～26.1 d和花后10.5～34.0 d.因此,花后11～18 d左右是棉花综合纤维品质形成响应高温胁迫的关键时间窗口.在关键时间窗口对棉花进行高温处理5 d后,苏棉15纤维中的蔗糖含量相对常温条件下呈先降低后增加的变化趋势,胼胝质含量上升,纤维素含量下降4.2%,纤维长度变短(最大变幅为23.3%),纤维比强度上升(最大变幅为4.3%),马克隆值下降(最大变幅为10.5%)并偏离最适范围,纤维品质变差.科棉1号的上述纤维发育主要相关物质含量及纤维品质与苏棉15变化趋势一致、最敏感时间相近,仅变化幅度相对较小.     

Effect of growth conditions on isoprene emission and other thermotolerance‐enhancing compounds

Isoprene is emitted from the leaves of many plants in a light‐dependent and temperature‐sensitive manner. Plants lose a large fraction of photo‐assimilated carbon as isoprene but may benefit from improved recovery of photosynthesis following high‐temperature episodes. The capacity for isoprene emission of plants in natural conditions (assessed as the rate of isoprene emission under standard conditions) varies with weather. Temperature‐controlled greenhouses were used to study the role of temperature and light in influencing the capacity of oak leaves for isoprene synthesis. A comparison was made between the capacity for isoprene emission and the accumulation of other compounds suggested to increase thermotolerance of photosynthesis under two growth temperatures and two growth light intensities. It was found that the capacity for isoprene emission was increased by high temperature or high light. Xanthophyll cycle intermediates increased in high light, but not in high temperature, and the chloroplast small heat‐shock protein was not expressed in any of the growth conditions. Thus, of the three thermotolerance‐enhancing compounds studied, isoprene was the only one induced by the temperature used in this study.     

Influence of Drought on Graminicide Phytotoxicity in Wild Oat (Avena fatua) Grown under Different Temperature and Humidity Conditions

Controlled environmental experiments were carried out to determine the phytotoxicity of several graminicides on wild oat (Avena futua L.) as influenced by combination of drought and temperature stress or drought and low relative humidity. Compared with unstressed conditions (20/15°C plus adequate soil moisture), imazamethabenz phytotoxicity to wild oat was reduced significantly when plants were exposed to a combination of drought and high temperature (30/20°C) stress. Imazamethabenz phytotoxicity was reduced almost as much by high temperature stress alone as by a combined temperature and drought stress. When herbicides were applied to wild oat plants subjected to drought alone or to drought plus high temperature, the observed reduction in phytotoxicity from greatest to least was: fenoxaprop = diclofop > flamprop > imazamethabenz. Fenoxaprop performance was most inhibited by the combination of drought plus high temperature, although drought alone and to a lesser degree, high temperature alone, inhibited fenoxaprop action. High temperature had an adverse effect on the efficacy of fenoxaprop at lower application rates. Raising fenoxaprop application rates to 400 g ha⁻¹ overcame the inhibition caused by high temperature alone but only partially alleviated the effect of drought combined with high temperature. When plants were grown under a low temperature regimen the imposition of drought stress had little effect on imazamethabenz phytotoxicity but did reduce fenoxaprop phytotoxicity. At 25/15°C drought reduced the phytotoxicity of fenoxaprop and diclofop greatly but had no significant impact on the performance of any of the herbicides examined, regardless of soil moisture regimen. Received April 14, 1997; accepted September 22, 1997     

The influence of antimycin A on pigment composition and functional activity of photosynthetic apparatus in <Emphasis Type="Italic">Triticum aestivum</Emphasis> L. under high temperature

The purpose of the current investigation was to evaluate the influence of antimycin A (AA) as an activator of the alternative respiratory pathway (AP) on photosynthetic pigment composition and functional activity of the photosynthetic apparatus of wheat seedlings (Triticum aestivum L.) under exposure to high temperature as well as their acclimation. Our results indicated that a significant decrease (44–74%) of photosynthetic pigment contents was caused by a long-term exposure to high temperature (42°C), while the short-term exposure resulted in 20–46% decline. However, a combined effect of AA and long-term high temperature reduced the total pigment contents by 28–41%. Our results demonstrated that the reduction of the chlorophyll a/b ratio was less significant under the combined effect of AA and high temperature than that under the stressful condition without AA. We observed that short-term and long-term high temperature modified PSII functionality of the first leaves in wheat seedlings, which was manifested by the low maximal quantum yield of PSII photochemistry, maximum fluorescence yield in the dark-adapted state, and by high minimum fluorescence yield in the dark-adapted state. The quantum yield of PSII photochemistry decreased rapidly by 16–24% under the combination of AA and high temperature. Overall, these results suggest that the activation of the alternative pathway, induced by AA, contributed to the stabilization of the photosynthetic apparatus in wheat seedlings under high temperature.     

新型日光温室人工生态系统中生态因子的优化配置

针对日光温室中的午间高温、高湿、病虫害发生率高 ,频繁地使用农药等一系列问题 ,已研制了具有阴、阳棚结构的新型日光温室 ,它通过阴、阳棚之间的热交换 ,既可降低阳棚的午间高温 ,推迟并缩短了阳棚午间 30℃以上的高温 ,又可提高夜间低温 ,其日平均温度比对照 (二代日光温室 )气温提高了 3.8℃ ,地温提高了 4.2℃ ;光照总入射量比对照平均增加 1 3.5 % ;≥ 85 %湿度平均减少 4.7h/d;病虫害发生率及农药使用量比对照减少 85 %以上。将阳棚午间多余的热量补充给阴棚 ,可使其温度提高 3～ 5℃ ,把单屋面日光温室背面的遮荫区 (大多都闲置 )转化为生产区 ,使土地利用率从 43.8%提高到 68.8% ;该日光温室可提供两种不同光照、温度等条件的温室人工生态系统。在该系统中基本实现了光、温、水、土、CO2 等生态因子的优化配置 ,有效提高了系统的生产力。新型日光温室 -集水工程 -沼气池联体构筑为半干旱地区农业可持续发展提供了很好的技术平台。     

IDENTIFICATION OF THE HIGH‐TEMPERATURE RESPONSE GENES FROM PORPHYRA SERIATA (RHODOPHYTA) EXPRESSION SEQUENCE TAGS AND ENHANCEMENT OF HEAT TOLERANCE OF CHLAMYDOMONAS (CHLOROPHYTA) BY EXPRESSION OF THE PORPHYRA HTR2 GENE1

Temperature is one of the major environmental factors that affect the distribution, growth rate, and life cycle of intertidal organisms, including red algae. In an effort to identify the genes involved in the high‐temperature tolerance of Porphyra, we generated 3,979 expression sequence tags (ESTs) from gametophyte thalli of P. seriata Kjellm. under normal growth conditions and high‐temperature conditions. A comparison of the ESTs from two cDNA libraries allowed us to identify the high temperature response (HTR) genes, which are induced or up‐regulated as the result of high‐temperature treatment. Among the HTRs, HTR2 encodes for a small polypeptide consisting of 144 amino acids, which is a noble nuclear protein. Chlamydomonas expressing the Porphyra HTR2 gene shows higher survival and growth rates than the wild‐type strain after high‐temperature treatment. These results suggest that HTR2 may be relevant to the tolerance of high‐temperature stress conditions, and this Porphyra EST data set will provide important genetic information for studies of the molecular basis of high‐temperature tolerance in marine algae, as well as in Porphyra.