中文摘要：

【目的】低温是影响作物产量和品质的主要环境因素之一，而表皮蜡质是植物抵御外界胁迫的第一层保护性屏障。研究低温胁迫对拟南芥表皮蜡质组分含量、结构及相关蜡质基因表达的影响，有助于进一步理解植物表皮蜡质与低温互作机制，从而对后续作物的抗性机制研究起指导作用。【方法】以野生型拟南芥与蜡质突变体口cer1、cer3、cer4、ce46,cer10、cer20及kcsl为试验材料，待植株生长至5—6周时进行4℃胁迫处理10d和18d。利用扫描电子显微镜观察表皮蜡质晶体结构变化；利用气相色谱一质谱联用仪（Gc—Ms）分析蜡质组成及含量变化；利用qRT—PCR技术检测蜡质基因CERl．CER3、CER4．KCSl．W1N1的表达。【结果】低温胁迫后，拟南芥蜡质晶体结构在分布密度、形状与大小方面发生了不同程度的变化。野生型拟南芥蜡质晶体熔融成片，大面积覆盖茎秆表面，这可能一定程度上起到了低温阻隔作用，并减少水分散失。cerl突变体表现出松针状晶体显著减少，并以小型树枝状结构为主；cot3与cer]护杆状晶体显著减少；而cer6与cer20蜡质晶体在低温胁迫后有所增加；kcsl蜡质晶体在低温胁迫后垂直杆状结构显著减少，水平杆状结构出现，并伴有蜡质晶体熔融现象。低温胁迫对一级醇减少突变体cer4结构无显著影响。Gc—Ms分析结果表明，拟南芥野生型与各突变体在低温胁迫下表皮蜡质组分含量也发生了不同程度的变化。野生型中醛类与酮类含量显著减少、一级醇类含量显著增加。各突变体则表现出相反的变化，蜡质组分中醛类、酮类含量增加或无显著变化、一级醇含量减少或无显著变化；受低温胁迫较重的cer3，cer10表皮蜡质中一级醇含量显著下降。拟南芥表皮蜡质在低温胁迫下显著积累（cer3无显著变化、cer10蜡质总量减少），且主要通过增加烷类与次?

英文摘要：

[ Objective ] Cold stress is one of the factors influencing the quality and quantity of crops while the epicuticular wax is believed to be the first protective barrier of the plant to external stresses. In the current study, the effects of cold stress on epicuticular wax morphology and constituents and expression of wax related genes in Arabidopsis stems were examined, aiming to understand the interactive mechanism between plant epicuticular wax and cold stress, and to provide suggestions on researchesrelated to crop resistance to abiotic stresses. [ Method]The materials used in current experiment included wild type Arabidopsis （WT） and wax mutants （cerl, cer3, cer4, cer6, cerlO, cer20 and kcsl）. The seedlings were grown for 5-6 weeks after germination, and then were placed in a temperature controlled cabinet at 4~C for ten days and eighteen days, seperately. Scanning electron microscope technology was used to investigate the changes of crystal structure. Gas chromatography and mass spectrometry technology were used to measure the contents of total wax and wax constituents. Real-time Q-PCR was used to analyze the transcripts of wax related genes. [ Result ] Under cold stress, the density, shape and size of wax crystalloids on stem of mutants and WT changed. Wax crystal structures on WT fused to big horizontal plates, greatly covering the surface of stems, which might help protect plant from cold hardness and decrease water loss. The pine-needle crystals on cerl reduced significantly and some small dendrites appeared. The rod crystals on cer3 and eerlO reduced significantly while the crystals on cer6 and cer20 increased. The vertical rods on kcsl surface reduced while the horizontal rods appeared with the fusion of crystals. The cold stress had no effect on the crystal moq0hology on cer4. The GC-MS analysis showed that the contents of wax constituents and total wax also changed under cold stress. The contents of aldehydes and ketones in Arabidopsis wild type reduced significantly while the content of prima