Abstract

To explore the physiological response characteristics of plant photosynthesis under acid precipitation stress (A stress), snow-melting agent stress (S stress), and freeze-thaw stress (F stress) as well as their various combinations, the net assimilation rate (NAR), intercellular CO₂ concentration (Ci), stomatal conductance (Gs) and water use efficiency (WUE) of tall fescue (Festuca arundinacea Schreb.) under these three stresses respectively and four kinds of combined stresses were measured. The effects of these different kinds of stresses on the photosynthesis parameters were then evaluated, and the major mechanisms of main factors affecting the interactions between stresses were speculated. The experimental results indicated that both NAR and WUE decreased significantly in response to all stresses and Ci increased dramatically in response to all stresses, while Gs ascended under F stress but descended in response to A stress and S stress. The photosynthetic efficiency significantly decreased as the temperature decreased and did not clearly recover as the temperature increased. Moreover, the combination of A stress and S stress had fewer effects on photosynthesis than did the S stress alone, while the effects resulting from F stress were similar at low temperature. The major controlling mechanism is most likely the strong inhibition of photosystem II and the promotion of antioxidant enzymes resulting from acid precipitation as well as NaCl may strengthen the freezing tolerance of plants.

中文翻译：

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融雪剂，酸沉淀和冻融胁迫下高羊茅的光合特性

摘要

为了探讨植物在酸沉淀胁迫（A胁迫），融雪剂胁迫（S胁迫）和冻融胁迫（F胁迫）及其光合作用下的光合作用的生理响应特征，以及净同化率（NAR）高羊茅（Festuca arundinacea）的细胞间CO ₂浓度（Ci），气孔导度（Gs）和水分利用效率（WUE）Schreb。）在这三个应力下分别测量了四种组合应力。然后评估了这些不同压力对光合作用参数的影响，并推测了影响压力之间相互作用的主要因素的主要机理。实验结果表明，NAR和WUE均响应所有应力而显着下降，Ci响应所有应力而显着增加，而Gs在F应力下上升，而在A应力和S应力下下降。随着温度降低，光合作用效率显着降低，而随着温度升高，光合作用效率并未明显恢复。而且，A胁迫和S胁迫的结合对光合作用的影响比单独的S胁迫要少，F应力在低温下产生的影响相似。主要的控制机制很可能是对光系统II的强抑制作用，以及由酸沉淀以及NaCl引起的抗氧化酶的促进可增强植物的抗冻性。