随着人为活动产生的大气CO₂浓度的增加, 全球气候持续变暖。过去5年是自有温度记录以来最热的5年。高温胁迫已经成为影响植物生长发育的主要逆境因子之一。光合作用是地球生命活动的基础, 对环境波动高度敏感。解析植物在高温环境下光合作用的响应特性, 可为探索植物抵御高温的生理生态机制、培育抗高温新品种以及采取合理措施适应未来极端气候提供科学依据。该文论述了高温胁迫对植物光合电子传递及碳固定过程的影响, 从光质和光强角度综合分析了光照对高温胁迫下光合作用的影响; 从植物自身及外源缓解物质等方面阐述了植物增强抗高温胁迫的途径和机制。同时, 对植物光合作用响应高温胁迫的研究方向及多组学联合分析在揭示植物抵御高温胁迫机制中的应用进行了展望。

Heat shock transcription factors (Hsfs) are modular transcription factors encoded by a large gene family in plants. They bind to the consensus sequence 'nGAAnnTCCn' found in the promoters of many defence genes, and are thought to function as a highly redundant and flexible gene network that controls the response of plants to different environmental stress conditions, including biotic and abiotic stresses. Hsf proteins encoded by different genes exhibit a high degree of complexity in their interactions. They can potentially bind and activate their own promoters, as well as the promoters of other members of their gene family, and they can form homo- or heterotrimers resulting in altered nuclear localization, as well as enhanced or suppressed transcription.In this review, we summarize recent studies on Hsf function in Arabidopsis and tomato and present evidence obtained from microarray expression studies in Arabidopsis that the Hsf gene network is highly flexible and specialized, with specific members and/or member combinations controlling the response of plants to particular stress conditions. In addition, we describe recent studies that support the hypothesis that certain Hsfs function as molecular sensors that directly sense reactive oxygen species (ROS) and control the expression of oxidative stress response genes during oxidative stress.

以耐热和热敏的黄瓜自交系R1和R29及其杂交、回交世代(F1,F2,B1,B2)为材料进行了黄瓜耐热性遗传模型和遗传参数估算,结果表明:黄瓜耐热性符合加性-显性模型,以加性效应为主,显性效应不显著;广义遗传力和狭义遗传力均较高.以个耐热自交系P1(R1,R2,R5)和4个热敏自交系P2(R21,R25,R28,R29)按不完全双列杂交方法配制杂交组合,配合力分析表明:群体一般配合力方差与特殊配合力方差之比较高,群体广义遗传力和狭义遗传力亦较高,控制杂交组合耐热性的主要是一般配合力.

Plants have evolved a variety of responses to elevated temperatures that minimize damage and ensure protection of cellular homeostasis. New information about the structure and function of heat stress proteins and molecular chaperones has become available. At the same time, transcriptome analysis of Arabidopsis has revealed the involvement of factors other than classical heat stress responsive genes in thermotolerance. Recent reports suggest that both plant hormones and reactive oxygen species also contribute to heat stress signaling. Additionally, an increasing number of mutants that have altered thermotolerance have extended our understanding of the complexity of the heat stress response in plants.

为了探明褪黑素(MT)和钙离子(Ca²⁺)在调控植物耐热性中是否存在互作关系,以黄瓜幼苗为试材,分析了内源MT和Ca²⁺对高温胁迫的响应;并通过叶面喷施100 μmol·L^-1 MT、10 mmol·L^-1 CaCl₂、3 mmol·L^-1乙二醇二乙醚二胺四乙酸(EGTA,Ca²⁺螯合剂)+100 μmol·L^-1 MT、0.05 mmol·L^-1氯丙嗪(钙调素拮抗剂,CPZ)+100 μmol·L^-1 MT、100 μmol·L^-1氯苯丙氨酸(p-CPA,MT合成抑制剂)+10 mmol·L^-1 CaCl₂和去离子水(H₂O),研究高温下(42/32 ℃)外源MT和Ca²⁺对黄瓜幼苗活性氧积累、抗氧化系统及热激转录因子(HSF)和热激蛋白(HSPs)等的影响。结果表明: 黄瓜幼苗内源MT和Ca²⁺均受高温胁迫诱导;外源MT可上调常温下钙调素蛋白(CaM)、钙依赖蛋白激酶(CDPK5)、钙调磷酸酶B类蛋白(CBL3)、CBL结合蛋白激酶(CIPK2)mRNA表达;CaCl₂处理的MT合成关键基因色氨酸脱羧酶(TDC)、5-羟色胺-N-乙酰转移酶(SNAT)和N-乙酰-5-羟色胺甲基转移酶(ASMT)水平也显著升高,MT含量快速增加。MT和CaCl₂可显著增强高温下黄瓜的抗氧化能力,减少活性氧(ROS)积累,同时上调HSF7、HSP70.1和HSP70.11 mRNA表达,从而减轻高温胁迫引起的过氧化伤害,植株热害症状明显减轻,热害指数和电解质渗漏率显著降低。加入EGTA和CPZ后,MT对黄瓜幼苗抗氧化能力和热激蛋白表达的促进效应明显减弱,Ca²⁺对高温下黄瓜幼苗过氧化伤害的缓解效应也被p-CPA逆转。可见,MT和Ca²⁺均可诱导黄瓜幼苗的耐热性,二者在热胁迫信号转导过程中存在互作关系。