低温胁迫下硫化氢调控黄瓜光合碳同化的机理研究

Hydrogen sulfide （H2S）is a kind of endogenous gas signal molecule. It plays an important role in regulating plant growth and development, as well as in response to abiotic stress. However, but no information have been provided on the signal transduction way, downstream cascade reaction of H2S and the interaction of H2S with other signal molecules under adversity. This work focuse on the problems, such as inhibition of photosynthesis, limitation of growth, decrease in yield etc. of cucumber caused by chilling stress in solar-greenhouse. We will carried out the following researches by the means of biochemistry, pharmacology, and molecular biology, with the donors or scavengers of H2S, NO, Ca2+， ROS, ABA, IAA, etc. 1) We will study on the response of H2S, NO, Ca2+ and ROS to chilling stress; 2) We will reveal the cross and interaction of H2S with NO, Ca2+ and ROS signals, and the regulation mechanism of H2S signal on photosynthetic carbon assimilation in improving the cold tolerance of cucumber. 3) The interactive response way of H2S and phytohormones signal molecules (ABA, SA) to chilling stress will be analysed, and Subsequently, the signal transduction pathway of H2S and phytohormones in photosynthetic carbon assimilation regulation will be explored. This research may provide guidance for study on the physiological roles of H2S in plants and its signal transduction network, and has significance in alleviating the adversity effect by increasing adaptability of cucumber in solar-greenhouse.

硫化氢（H2S）是一种内源气体信号分子，在调控植物生长发育和对非生物胁迫响应中发挥重要作用，但逆境下H2S的信号转导路径和下游级联反应及H2S与其他信号分子的互作关系尚不清楚。本项目针对日光温室低温逆境经常导致黄瓜光合受抑，生长滞缓、产量降低等问题，拟利用外源H2S与NO、Ca2+、ROS、ABA、IAA等信号分子供体和清除剂，通过生化、药理和分子生物学等技术手段开展研究：1）探讨H2S与NO、Ca2+、ROS信号分子对低温胁迫的响应；（2）揭示H2S与NO、Ca2+、ROS信号分子的交叉互作及调控光合碳同化提高黄瓜耐冷性机理；3）解析H2S与植物激素信号分子（ABA、SA等）对低温的交互应答方式，探索H2S与植物激素相互应答在调控光合碳同化中的信号转导通路。该研究可为深入开展H2S在植物中的生理功能及其信号转导网络研究提供借鉴，对缓解逆境障碍和增强日光温室黄瓜的适应能力具有重要意义。

针对日光温室低温逆境经常导致黄瓜光合受抑，生长滞缓、产量和品质降低等问题，以黄瓜为试材，利用H2S与NO、Ca2+、ROS等信号分子供体（NaHS、SNP、CaCl2、H2O2）和ABA、IAA及其清除剂或抑制剂（HT、HB、EGTA、DMTU、Na2WO4、NPA）等，探讨H2S与NO、Ca2+、ROS信号分子及ABA、IAA等激素信号互作调控黄瓜光合碳同化和耐冷性机理。结果表明：.1. 黄瓜内源H2S、NO、Ca2+、H2O2、ABA和IAA均受低温诱导。叶面喷施NaHS可促进黄瓜内源NO、Ca2+、H2O2、ABA、IAA产生，SNP、CaCl2和ABA也激发内源H2S合成，但H2O2和IAA对黄瓜H2S含量影响不大。.2. NaHS、SNP、CaCl2、H2O2、ABA和IAA可使低温（5 ℃）下黄瓜幼苗的Pn、Gs、Tr、φPSⅡ和Fv/Fm明显升高，Ci显著降低，NaHS、SNP、CaCl2、H2O2、ABA和IAA处理的RuBPCase、SBPase、FBA和TK活性及基因表达明显高于H2O处理。加入NO、Ca2+、H2O2、ABA、IAA清除剂或抑制剂后，H2S对黄瓜光合作用的促进效应被减弱或逆转； H2S 清除剂也会减弱NO、Ca2+和ABA对黄瓜光合碳同化的诱导效应，但H2O2和IAA诱导的黄瓜碳同化变化不大。.3. 低温下NaHS、SNP、CaCl2、H2O2、ABA和IAA处理的黄瓜冷害症状较轻，ROS和EL较低。清除或抑制NO、Ca2+、H2O2、ABA或IAA会减弱H2S对黄瓜冷胁迫伤害的缓解效应。清除H2S也会减弱Ca2+、ABA等对黄瓜冷胁迫伤害的缓解效应，但对H2O2和IAA的作用无显著影响。.4. NaHS、SNP、CaCl2、H2O2、ABA和IAA预处理提高了低温下黄瓜幼苗的抗氧化酶活性与mRNA表达，增加了AsA和GSH含量及AsA/DHA、GSH/GSSG比值，冷胁迫响应基因显著上调。清除或抑制NO、Ca2+、H2O2、ABA或IAA会减弱H2S对低温下抗氧化系统和冷胁迫响应基因的促进，清除H2S也会减弱Ca2+和ABA的作用，而对H2O2和IAA的作用无显著影响。.可见，H2S可以诱导黄瓜碳同化和耐冷性，NO、Ca2+和ABA与H2S具有互作效应，而IAA和H2O2作为下游信号参与H2S诱导的黄瓜幼苗碳同化和耐冷性。