柑桔抗寒研究的现状与展望

柑桔是一种经济价值极高但又常受冻害影响的亚热带果树,本文总结了柑桔抗寒研究取得的成果,介绍了对于柑桔抗寒研究还是空白但是在其他植物抗寒研究上取得的新进展,并由此提出了柑桔抗寒可在冷诱导蛋白、冷诱导基因和抗寒基因工程等方面进行探讨以及作者粗浅的研究设想。     

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。     

抗寒剂诱导仁用杏花期抗寒力研究

在仁用杏花芽膨大期分别喷施ABA、‘杏花防冻剂’、‘冻害必施’和‘天达-2116’等4种抗寒剂,测定花蕾、花朵和幼果中电解质渗出率、SOD和POD活性以及可溶性糖、可溶性蛋白质和MDA含量,研究4种抗寒剂诱导仁用杏花期抗寒力的差异。结果表明,(1)4种抗寒剂均能不同程度地降低仁用杏半致死温度,诱导抗寒力提高,其中,‘杏花防冻剂’对仁用杏抗寒力的诱导效果最好,ABA次之;(2)‘杏花防冻剂’和ABA均能提高仁用杏花期的可溶性糖和可溶性蛋白质含量,增强SOD和POD活性,降低MDA含量,进一步证明抗寒剂可提高仁用杏花期的抗寒能力。     

植物抗冻基因

介绍植物抗寒冻基因研究中一些已分离和鉴定出的低温诱导表达基因及其抗寒功能、低温信号转导以及调控方式的研究进展.     

诱抗剂诱导水稻抗寒蛋白研究

诱抗剂是从中草药中筛选出来的植物性药剂,它能显著提高水稻抗寒和抗稻瘟病能力,为了进一步明确诱抗剂诱导水稻抗寒机制,进行了诱抗秀导水稻抗寒 蛋白研究,用1000倍诱抗剂浸种湘早籼9号,89－229和V56三个水稻品种或相合,三叶期喷1000倍诱抗剂经6度低温胁迫48h后,进行SDS－PAGE分析,结构表明三个水稻品种经诱抗剂诱导均未发现分子质量在14ku-97ku之间新的蛋白质。     

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.     

蛋白质的变化与植物抗寒性的关系研究进展

蛋白质的变化在植物抗寒生理研究中一直被广泛关注。低温胁迫期间在蛋白质含量变化的同时,还可能发生质的变化,合成新的蛋白质——低温诱导蛋白。综述了低温胁迫期间植物体内蛋白质的变化,重点阐述了抗冻蛋白、脱水蛋白和热激蛋白等3种低温诱导蛋白的特性及其与植物抗寒性的关系,并对该领域今后的研究做了展望,为进一步阐明植物抗寒的分子机制、提高植物的抗寒力提供了新的思路。     

植物抗寒及其基因表达研究进展

植物经过逐渐降低的温度从而提高抗寒能力 ,这个过程被人们称为低温驯化。植物低温驯化过程是一个复杂的生理、生化和能量代谢变化过程 ,这些变化主要包括膜系统的稳定性、可溶性蛋白的积累和小分子渗透物质 ,比如脯氨酸、糖等 ,这些变化中的一些是植物抗寒必需的 ,而另外一些变化不是必需的。主要对冷害和低温生理生化变化、低温诱导表达基因的功能和作用、低温驯化的调节机制及其信号转导方面进行了综述。通过差别筛选 c DNA文库的方法已经鉴定了许多低温诱导表达、进而提高植物抗寒能力的基因 ,其中有脱水素、COR基因和 CBF1转录因子等。低温信号的感受、转导和调节表达是低温驯化的关键环节 ,低温信号的转导过程与干旱胁迫之间具有一定的交叉 ,这为利用 ABA等来提高植物抗寒能力成为可能 ,相信不久的将来人们可以通过提高植物抗寒能力从而增加经济产量成为现实。     

棉铃虫滞育与抗逆性研究进展

本文综述了棉铃虫滞育与抗逆性的研究进展 ,包括滞育的类型、滞育的诱导与解除 ,以及抗寒性、抗热性、抗旱性等。其中着重论述了棉铃虫的越冬滞育及其抗寒能力     

植物低温诱导转录因子CBF研究进展

植物在低温驯化过程中能诱导许多基因的表达。其中CBF转录因子是目前植物抗寒分子生物学领域研究的热点之一。它通过与低温诱导基因启动子区域中的CRT/DRE调控元件结合,调控一系列低温诱导基因的表达,从而提高植物的抗寒性。对植物低温诱导CBF转录因子的结构、功能及其表达调控等方面的研究进展进行了综述。     

柑橘抗寒育种早期鉴定的一种指标

以５个抗寒性不同的柑橘品种或杂交后代：“山金柑”（ＦｏｒｔｕｎｅｌａｈｉｎｄｓｉＳｗｉｎｇｌｅ）、“伏令夏橙”（ＣｉｔｒｕｓｓｉｎｅｎｓｉｓＯｓｂ．ｃｖ．Ｖａｌｅｎｃｉａ）、“伏令夏橙”＋“宁波金柑”（Ｃ．ｓｉｎｅｎｓｉｓｃｖ．Ｖａｌｅｎｃｉａ＋Ｆ．ｃｒａｓｉｆｏｌｉａＳｗｉｎｇ．ｃｖ．Ｍｅｉｗａ）、“Ｐａｇｅ”橘柚（Ｃ．ｒｅｔｉｃｕｌａｔａＢｌａｎｃｏ×Ｃ．ｇｒａｎｄｉｓＯｓｂ．ｃｖ．Ｐａｇｅ）、“Ｍｕｒｃｏｔ”橘橙（Ｃ．ｒｅｔｉｃｕｌａｔａＢｌａｎｃｏ×Ｃ．ｓｉｎｅｎｓｉｓＯｓｂ．ｃｖ．Ｍｕｒｃｏｔ）为材料,研究了低温锻炼期间柑橘原生质体抗寒性的变化及其田间植株的冬季抗寒性,表明离体原生质体抗寒性与田间植株抗寒性之间有显著的正相关,因而前者可以作为衡量后者的指标。     

Evidence for a robust sex-specific trade-off between cold resistance and starvation resistance in Drosophila melanogaster

In insects changes in lipid metabolism may underlie a trade-off between cold resistance and starvation resistance. To test this we examined correlated responses in independent sets of Drosophila melanogaster lines selected for increased cold resistance and increased starvation resistance. The starvation lines showed correlated patterns found in other D. melanogaster populations selected for this trait, including higher lipid levels and increased resistance to desiccation, although the selected lines did not show a longer development time as found in some other studies. Consistent with the trade-off hypothesis, selected lines with increased starvation resistance showed decreased resistance to a cold stress as measured by mortality, whereas selected lines with increased cold resistance showed a decrease in starvation resistance. To counter the possibility of inadvertent selection accounting for these patterns, selected and control lines from both selection regimes were crossed to form mass bred populations, which were left for four generations prior to establishing isofemale lines. By scoring starvation and cold resistance in these lines derived from both sets of selection regimes, we confirmed the negative association between resistance to these stresses in females but not in males. Potential implications of this trade-off for surviving cold conditions when food resources are limiting are discussed.     

Role of HSF activation for resistance to heat, cold and high-temperature knock-down

Regulation of heat shock proteins (Hsps) by the heat shock factor (HSF) and the importance of these proteins for resistance to heat stress is well documented. Less characterized is the importance of Hsps for cold stress resistance although Hsp70 is known to be induced following long-term cold exposure in Drosophila melanogaster. In this study, a temperature-sensitive HSF mutant line was used to investigate the role of HSF activation following heat hardening, rapid cold hardening (RCH) and long-term cold acclimation (LTCA) on heat and cold resistance, and this was correlated with Hsp70 expression. In addition, the effect of HSF activation on high-temperature knock-down resistance was evaluated. We found a significantly decreased HSF activation in the mutant line as compared to a corresponding control line following heat hardening, and this was correlated with decreased heat resistance of the mutant line. However, we did not find this difference in HSF activity to be important for resistance to cold stress or high-temperature knock-down. The findings indicate that induction of stress genes regulated by HSF, such as Hsps, although occurring following LTCA, are not of major importance for cold stress resistance and neither for RCH nor high-temperature knock-down resistance in D. melanogaster.     

Establishment of an Index to Appraise Cold-resistant Breeding for Citrus in Early Stage

Cold-resistance of citrus protoplasm and field plants in 5 different varieties was studied. The relative analysis between cold resistance of citrus protoplasts and that of field plants indicates that the cold resistance of citrus protoplasm can be considered as an index of cold resistance of field plants.     

Effects of cold- and heat hardening on thermal resistance in Drosophila melanogaster

The effects of cold- and heat hardening on resistance to both low and high temperature stress was examined in Drosophila melanogaster lines selected for resistance to either cold or heat. The hardening effect was positive when the hardening was of the same type as the stress in all selection regimes. The effect of cold hardening on survival after heat stress was further examined in the lines selected for cold resistance and corresponding controls. A cross-protection effect (increased heat resistance after cold hardening) was present and this effect was lower in the lines selected for resistance to cold than in the controls. The level of Hsp70 expression induced by a non-lethal cold hardening was examined, showing that cold hardening induced Hsp70 expression. The results suggest that the cross-protection effect is at least partly due to Hsp70 expression induced by cold exposure.     

Stability of wheat Protoplasts during Freezing-Thawing in Relation to Cold Resistance of Its Varieties

Freezing tolerance of isolated protoplasts of three wheat, varieties which differ from each other in cold resistance has been measured. The results obtained in the present study indicate that the survival percentage of wheat protoplasts after freezing treatment is indirect correlation with the cold resistance of its varieties. It is discussed that the change in plasmolemma plays a role in the mechanism of chilling injury and cold resistance of plants, and the results obtained may be used as an indicator for determining the cold resistance of the plants.     

Resistance to temperature extremes between and within life cycle stages in Drosophila serrata, D. birchii and their hybrids: intraspecific and interspecific comparisons

Intraspecific Drosophila studies suggest that resistance to heat and cold stresses are largely independent and that correlations across life cycle stages are low whereas comparisons of Drosophila species indicate correlations between heat and cold resistance as well as between resistance levels in different life cycle stages. These inconsistent results may reflect differences in associations among traits at the interspecific and intraspecific levels or interspecific correlations arising because of correlated selection pressures. These alternatives were tested using Drosophila serrata, D. birchii and hybrids derived from these species. Variation among hybrid lines and families was used to test associations at the interspecific level while intraspecific variation was examined using isofemale lines ol'D. serrata. There was a significant association between adult heat knockdown time at 38^oC and adult cold resistance in one set of hybrid lines. An association between female knockdown resistance to heat and larval heat resistance was also evident in one set of hybrids. Resistance to heat and cold at the larval stage were not correlated at either the intraspecific or interspecific levels. At the intraspecific level, larval heat resistance and two measures of adult heat resistance were uncorrected. Moreover, adult and larval cold resistance measures were not correlated at either the intraspecific or interspecific levels. These results suggest that there arc no associations between resistance to heat and cold extremes and that extreme temperature resistance is largely independent across life cycle stages at both the intraspecific and interspecific levels. Species associations may therefore arise from correlated selection pressures rather than trait correlations.     

3种番荔枝属植物对低温胁迫的生理响应及抗寒性评价

选取凤梨释迦Annona×atemoya、圆滑番荔枝A.glabra、刺果番荔枝A.muricata等3种番荔枝属2年生苗进行低温胁迫处理,并以自然状态下生长为对照,测定可溶性总糖、可溶性蛋白、丙二醛(MDA)含量,以及过氧化物酶(POD)、超氧化物歧化酶(SOD)活性。通过对抗寒性生理指标对比分析,得出3种番荔枝抗寒能力强弱顺序为刺果番荔枝>圆滑番荔枝>凤梨释迦。