Response of Gas Exchange, Chlorophyll α Fluorescence, and Activities of Antioxidation Enzymes to Osmotic Stress in YF2-1 Derived from Oryza sativa × Echinochloa caudata

YF2-1 is obtained by distant cross between rice (Oryza sativa) and Echinochloa caudate. To assess its osmotic stress resistance at physiological level, the gas exchange, chlorophyll a fluorescence, and antioxidation enzyme activities under osmotic stress simulated by PEG-6000 were studied in seedlings of upland rice YF2-1 and H65. The results showed that YF2-1 maintained higher net photosynthetic rate and stomatal conductance under osmotic stress condition, indicating that YF2-1 suffered less inhibition in photosynthesis. This may be related to its high water retaining capacity and its effective functions for high excessive light energy dispersing (high non-photochemical quenching) and high activities of antioxidation enzymes effectively clearing reactive oxygen species) produced by excessive light energy. The result shows that distant crossing may increase the resistance to osmotic stress in rice.

摘要为了明确旱稻×稗草杂交后代YF2-1对渗透胁迫的耐性是否得到了改善, 以YF2-1及其母本旱稻品种H65为材料, 在苗期采用PEG-6000进行渗透胁迫处理, 研究它们的气体交换参数、叶绿素荧光参数及抗氧化酶活性对渗透胁迫的响应。结果表明, 在渗透胁迫处理下, YF2-1更能维持较高的净光合速率(Pn)和气孔导度(Gs)。这可能与YF2-1具有更好的持水能力, 并能有效地通过热耗散(NPQ高)消耗过剩光能, 通过高活性的抗氧化酶诱导来清除活性氧, 从而避免活性氧伤害相关。旱稻与稗草的远源杂交提高了旱稻对渗透胁迫的抗性。