植物抗寒机理研究进展

本文综合概述了国内外有关植物抗寒机理研究的动态,主要讨论了植物抗寒性与细胞膜系、酶系多态性及抗寒基因表达与调控之间的相关性。此外,亦提出了有关植物抗寒机制研究领域值得深入研讨的问题。     

植物抗寒机理进展

本文综合概述阵内外有关植物抗寒机理研究的动态。主要讨论了植物抗寒性与细胞膜系、酶系多态笥及抗寒基因表达与调控之间的相关性。此外,亦提出了有关植物抗寒机制研究领域值得深入研讨的问题。     

植物抗寒性与抗寒基因的表达和调控

综合概述了国内外有关植物抗寒机理的研究动态,主要讨论了抗寒基因的表达与调控在植物抗寒性中的反应。此外,亦提出了有关植物抗寒机制研究领域值得深入研讨的问题。     

植物抗寒冻基因工程研究进展

低温寒害是限制农作物产量和分布的一种全球性的自然灾害,提高农作物的抗寒性具有重要意义。目前随着植物寒害机理、抗寒冻和冷驯化分子机理的深入发展,已研究发现了多种抗寒基因,包括各种抗寒调控基因和各种抗寒功能基因,从而使植物抗寒冻基因工程的研究与应用得到了广泛开展,以期最终有效地提高农作物的抗寒性,增加农业产量。本文综合概述了国内外有关植物抗寒冻基因工程的最新研究方向、进展及成就,并提出了此领域尚存在的一些问题及其前景展望。     

植物抗寒冻基因工程研究进展

低湿寒害是限制农作物产量和分布的一种全球性的自然灾害。提高农作物的抗寒性具有重要意义。目前随着植物寒害机理、抗寒冻和冷驯化分子机理的深入发展,已研究发现了多种抗寒基因,包括各种抗寒调控基因和各种抗寒功能基因,从而使植物抗寒冻基因工程的研究与应用得以了广泛开展,以期最终有效地提高农作物的抗寒性,增加农业产量。本文综合概述了国内外有关植物抗寒冻基因工程的最新研究方向、进展及成就,并提出了此领域尚存在的一些问题及其前景展望。     

植物抗寒机理研究的新进展

近年来,在植物抗寒机理研究方面取得不少新进展,大体有以下几个方面:(1)确证细胞的膜体系与植物抗寒性存在密切关系;(2)抗寒植物避免细胞内结冰机制的一些新发现;(3)稳定越冬植物抗寒力机制的揭示;(4)关于抗寒特异性蛋白质研究的开展.现将有关文献资料分述如下.     

植物抗寒基因工程研究进展

温度是影响植物分布、产量及品质的重要环境因素,提高植物抗寒性对农业生产具有重要的意义.近年来,随着基因工程的发展,对植物的抗寒机理进行了深入的研究,并克隆了许多与抗寒相关的基因.本文从膜稳定性、抗氧化酶活性、抗冻蛋白、低温信号转录因子和渗透调节物质等方面对植物耐冷性基因工程研究进展进行了分析、归纳与总结,旨在为植物抗寒机理研究及植物抗寒育种提供参考.     

提高植物抗寒性的机理研究进展

低温胁迫是世界范围内影响植物产量和品质的主要非生物胁迫.植物抗寒生理生态研究是比较活跃和发展很快的领域.文章综述了提高植物抗寒性机理的研究进展.大量科学研究和生产实践表明,气象因素与植物自身因素是影响植物抗寒性的关键因素,前者主要是温度、光周期和水分,后者主要是植物的遗传学基础、生长时期、发育水平以及低温胁迫下细胞的抗氧化能力.保证植物抗寒基因充分表达对提高植物抗寒性有重要意义.植物抗寒性的遗传机制与调控主要通过5条路径实现:丰富多样的植物低温诱导蛋白,低温转录因子DREB/CBF可同时调控多个植物低温诱导基因的表达,DREB/CBF与辅助因子相互作用调控下游基因表达,Ca2+、ABA及蛋白质磷酸化上游调控低温诱导基因表达,以及不饱和脂肪酸酶基因的表达.基因工程改良植物抗寒性已获重要进展,但距产业化尚有许多开创性的工作要做,目前主要通过导入抗寒调控基因和抗寒功能基因而实现,后者主要是导入抗渗透胁迫相关基因、抗冻蛋白基因、脂肪酸去饱和代谢关键酶基因、SOD等抗氧化系统的基因以及与植物激素调节有关的基因.农林技术对提高植物抗寒性有重大实用价值,其中的不少技术蕴涵着深刻的科学机理,重点评述了抗寒育种、抗砧嫁接、抗寒锻炼、水肥耦合及化学诱导五大技术提高植物抗寒性的作用机理.展望了提高植物抗寒性的研究.     

植物抗寒基因工程研究进展

本文评述了近年来有关植物抗寒生理及分子生物学方面的研究进展,对冷诱导基因的功能,诱导调控以及抗寒转基因策略等做了总结。     

植物抗寒基因工程研究进展

本评述了近年来有关植物抗寒生理及分子生物学方面的研究进展,对冷诱导基因的功能,诱导调控以及抗寒转基因策略等做一总结。     

Pre-treating paclobutrazol enhanced chilling tolerance of sweetpotato

The objective of this work was to study changes in low molecular weight antioxidants and antioxidative enzymes in chilling-stressed sweetpotato, as affected by paclobutrazol (PBZ) pre-treatment 24 h prior to exposure to chilling conditions. Sweetpotato ‘TN71’ and ‘TN65’ were treated with 300 mg PBZ/5 ml/plant, after which plants were subjected to 7°C/7°C (day/night) for periods of 1, 3 and 5 days, followed by a 3-day recovery period at 24°C/20°C (day/night). A factorial experiment in completely randomized design with four replications was used in this study. Young fully expanded leaves at each temperature and period of time were clipped for antioxidative system measurement. We concluded that different varieties displayed variations in their oxidative system, and the differential expressions of each genotype were associated with chilling stress response. Plants with various antioxidative systems responded differently to chilling stress according to the duration of the chilling period and subsequent re-warming period. ASA, GSH and GSSG contents were enhanced in TN71 prior to chilling stress. Increased APX, GR, ASA and MDA activities accounted for chilling tolerance in TN65. Furthermore, our results indicate that the elevated levels of the antioxidative system observed after PBZ pre-treatments afforded the sweetpotato leaf improved chilling-stress tolerance. The levels of ASA and GSSG of both TN71 and TN65 under chilling were significantly raised by pre-treating with PBZ. PBZ pre-treatment exhibited the important function of enhancing the restoration of leaf oxidative damage under chilling stress and increasing the chilling tolerance of plants to mitigate chilling stress effects.     

不同胁迫预处理提高水稻幼苗抗寒性期间膜保护系统的变化比较

通过比较盐、冷和热激三种不同胁迫预处理提高水稻(Oryza sativa L.)抗寒性过程中膜保护系统的变化,探讨植物交叉适应机理。结果表明,水稻幼苗经不同胁迫预处理均可提高幼苗的抗寒性。与未预处理苗相比,不同胁迫(冷、热、盐)预处理之间在处理后、低温伤害后及恢复2d后的3个不同时期膜酶促和非酶促保护系统及同工酶酶谱变化各有异同,既有部分共性,也有其独特性。     

The effect of vesicular-arbuscular mycorrhizae and chilling on two hybrids of Zea mays L.

In order to investigate the effect of vesicular-arbuscular mycorrhizae on the chilling resistance of Zea mays, seeds of two hybrids (Pioneer 3902 and Pride 5) were grown in soil inoculated with Glomus mosseae. Germination tests at 10° C and 25° C showed that Pride 5 was more resistant to chilling than Pioneer 3902. Plants grown at 25° C for 6 weeks were given a 1-week chilling treatment at 10° C and the responses of mycorrhizal and nonmycorrhizal plants of the two hybrids were compared. At 10° C, the mycorrhizal plants had greater biomass, carbohydrate, and protein content than the nonmycorrhizal plants.     

瓜尔豆不同品种抗霜冻性与酯酶同工酶的关系分析

对瓜尔豆10个品种酯酶（EST）同工酶分析及抗霜冻性测试表明,酯酶同工酶带数及酶活性在品种间有明显差异．抗霜冻性强的品种同工酶带数多、活性高,其中品种G1抗霜冻性最强,且具有1条特异EST同工酶带。     

茄子种质资源的耐冷性鉴定

采用低温胁迫下幼苗叶片冷害指数、种子活力指数、叶片电导百分率为指标,对34份不同类型的茄子种质资源进行耐冷性鉴定.结果表明,活力指数与冷害指数、电导百分率均呈极显著负相关,电导百分率与冷害指数呈极显著正相关.通过耐冷隶属函数值和聚类分析,初步筛选出11份耐冷性较强的材料.     

Temporal organization of chilling resistance in cotton seedlings: effects of low temperature and relative humidity

The effect of temperature and relative humidity (RH) on the time course of the rhythmic endogenous changes of chilling resistance was studied in cotton (Gossypium hirsutum L. cv. Deltapine 50) seedlings grown under light-dark cycles of 12:12 h. The resistant phase to 5° C, 85% RH lasted during most of the dark period while to 5° C, 100% RH it was longer and extended into the last half of the light period because a transient phase advance occurred when chilling started at the middle of the light period. Seedlings acclimated by low temperature were resistant throughout the light-dark cycle. A treatment with 100% RH before chilling to acclimated seedlings introduced a sensitive phase that corresponded to that of non-acclimated seedlings. In non-acclimated seedlings, this treatment decreased the resistance but the basic pattern of the rhythm was sustained. Changes in chilling resistance were analyzed under fluctuating temperatures and RHs, and explained taking into consideration the functioning of the circadian clock and environmental induction of resistance.Abbreviations CR chilling resistance - LDC light-dark cycle of 24 h - RH relative humidity     

黄瓜的冷害及耐冷性

随着蔬菜反季节栽培面积的不断扩大,如何提高黄瓜(Cucumis sativus L.)耐冷性已成为选育新品种的研究重点.系统地综述近几年黄瓜耐冷性的鉴定、获得途径、冷害机理以及遗传和分子遗传学等方面的研究,以促进对黄瓜冷害机制的研究,加速耐冷品种的培育.耐冷性鉴定时要从耐冷指数、低温发芽能力、MDA(丙二醛)含量和电解质渗漏率等几个方面综合鉴定.耐冷性的获得途径主要有冷驯化、激素处理、热激处理和培育耐低温品种,最重要的途径是耐冷品种选育.黄瓜冷害机理包括细胞膜的流动性降低及透性增加,光合作用被抑制,根系吸收减弱,可溶性糖含量减少,淀粉粒积累增加,微管的稳定性受到破坏等.黄瓜低温发芽能力由非加性基因决定,而幼苗时期主要由加性基因控制.黄瓜耐冷的分子遗传学研究进展缓慢,目前已克隆出在低温锻炼中特异表达的功能未知的基因CCRl8.今后还应研究黄瓜低温胁迫时的信号转导系统,以进一步揭示黄瓜的冷害机理;利用野生资源的抗逆性状,拓宽栽培黄瓜的遗传基础,选育适于保护地栽培的耐低温品种.     

Differential responses of antioxidative system to chilling and drought in four rice cultivars differing in sensitivity

Responses of antioxidative defense systems to chilling and drought stresses were comparatively studied in four cultivars of rice (Oryza sativa L.) differing in sensitivity, two of them (Xiangnuo no. 1 and Zimanuo) are tolerant to chilling but sensitive to drought and the other two (Xiangzhongxian no. 2 and IR50) are tolerant to drought but sensitive to chilling. The seedlings of rice were transferred into growth chamber for 5 d at 8 degrees C as chilling treatment, or at 28 degrees C as control, or at 28 degrees C but cultured in 23% PEG-6000 solution as drought stress treatment. Under drought stress the elevated levels of electrolyte leakage, contents of H(2)O(2) and total thiobarbituric acid-reacting substances (TBARS) in Xiangzhongxian no. 2 and IR50 are lower than those in Xiangnuo no. 1 and Zimanuo. On the contrary, Xiangnuo no. 1 and Zimanuo have much lower level of electrolyte leakage, H(2)O(2) and TBARS than Xiangzhongxian no. 2 and IR50 under chilling stress. Activities of antioxidant enzymes (superoxide dismutase (SOD), catalase, and ascorbate-peroxidase (APX)) and contents of antioxidants (ascorbaic acid and reduced glutathione) were measured during the stress treatments. All of them were enhanced greatly until 3 d after drought stress in the two drought-tolerant cultivars, or after chilling stress in the two chilling-tolerant cultivars. They all were decreased at 5 d after stress treatments. On the other hand, activities of antioxidant enzymes and contents of antioxidants were decreased greatly in the drought-sensitive cultivars after drought stress, or in the chilling-sensitive cultivars after chilling stress. The results indicated that tolerance to drought or chilling in rice is well associated with the enhanced capacity of antioxidative system under drought or chilling condition, and that the sensitivity of rice to drought or chilling is linear correlated to the decreased capacity of antioxidative system.     

Polypeptide Changes in Cotyledons During Cucunlber Seedling Development and Chilling Acclimation

The changes of chilling resistance and polypeptide pattern during cucumber (Cucumis sativus L. ) seedling development and during chilling acclimation in light (CAL) and chilling acclimation in dark(CAD) have been studied. The results showed that the chilling resistance decreased gradually during seedling development ,CAL could enhance chilling resistance but CAD made the seedlings more sensitive to chilling temperature Two dimension PAGE study showed that during 6--12 days old seedling development some polypeptides disappeared and some appeared . CAL and CAD had different effects on those polypeptides. Both CAL and CAD induced a 58.0 kD polypeptide. There might be cooperation among several genes during chilling acclimation. Chilling endurance obtained from acclimation is based on the integration of metabolism correlated with development.     

Changes of Ca2+ -ATPase Activities in Cell of Rice Seed lings During the Enhancement of Chilling Resistance Induced by Cold and Salt Pretreatment

The changes of Ca2+ -ATPase activities of plasmolemma, and tonoplast membrane in roots and leaf chloroplasts in rice ( Oryza sativa L. ) seedlings were investigated for exploring the mechanism of cross adaptation to different stresses in the plants during the enhancement of chilling resistance induced by cold and salt pretreatment. The results indicated that the chilling resistance of rice seedlings was enhanced markedly by cold and salt pretreatment, but this enhancement was inhibited by Ca2+-chelate ethyleneglycol-bis-(β-aminoethyl ether) N, N-tetraacetic acid (EGTA) and the calmodulin inhibitor chlorpromazine (CPZ), it showed the calcium messenger system was involved in the course of chilling resistance formation. The Ca2+ -ATPase activity of root plasmolemma and tonoplast membrane as well as the Fe(CN)63- reduction in root plasmolemma in nonpretreated seedlings were declined markedly during the chilling stress. The Ca2+ -ATPase activities of plasmolemma, tonoplast membrane and chloroplasts as well as the Fe(CN)63- reduction of plasmolemma were enhanced by cold pretreatment. The activities of Ca2+ -ATPase and Fe(CN)63- reduction of plasmolemma, as compared with nonpretreated seedlings has increased by 86.80% and 93.93% respectively. The effect of salt pretreatmerit on the Ca2+ -ATPase activities of plasmolemma and chloroplast as well as Fe(CN)63- reduction of plasmolemma were similar to the effect of cold pretreatment. Although the Ca2+ -ATPase activity of tonoplast membrane was declined by salt pretreatment, the activity was none the less markedly higher than that of the nonpretreated seedlings. It showed that there was stronger ability of maintaining calcium homeostasis in the seedlings following two pretreatment. The results displayed that the enhancement of chilling resistance in rice seedlings with cold and salt pretreatment might be related to the effective activation of Ca2+ -ATPase in two pretreatment seedlings, because the activated Ca2+ -ATPase could bring back rapidly the raised cytoplasmic Ca2+ concentration from chilling stress to the state of calcium homeostasis, leading to the maintenance of normal functioning of the calcium messenger system and physiological metabolism. It seems that the adapated mechanism to chilling stress in two seedlings with cold and salt pretreatment was similar.