Saud Shah, Yajun Chen, Fahad Shah, Hussain Saddam, Na Li, Xin Li, Alhussien Safa Abd Alaleem Fadal Elseed
College of Horticulture, Northeast Agricultural University Harbin, Heilongjiang, China, 150030.
College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China.
Environ Sci Pollut Res Int. 2016 Sep;23(17):17647-55. doi: 10.1007/s11356-016-6957-x. Epub 2016 May 28.
Drought stress is the most pervasive threat to plant growth, which disrupts the photosynthesis and its associated metabolic activities, while silicate (Si) application may have the potential to alleviate the damaging effects of drought on plant growth. In present study, the role of Si in regulating the photosynthesis and its associated metabolic events in Kentucky bluegrass (cv. Arcadia) were investigated under drought stress. Drought stress and four levels (0, 200, 400, 800 mg L(-1)) of Si (Na2SiO3.9H2O) were imposed on 1-year-old plants removed from field and cultured under glasshouse conditions. After 20 days of drought stress, the plants were re-watered to reach soil field capacity for the examination of recovery on the second and the seventh day. The experiment was arranged in completely randomized design replicated four times. Drought stress severely decreased the photosynthesis, water use efficiency, stomatal conductance, cholorophyll contents, Rubisco activity, and Rubisco activation state in Kentucky bluegrass. Nevertheless, application of Si had a positive influence on all these attributes, particularly under stress conditions. As compared to control, Si application at 400 mg L(-1) recorded 78, 64, and 48 % increase in photosynthesis, Rubisco initial activity, and Rubisco total activity, respectively, at 20 days of drought. Higher photosynthesis and higher Rubisco activity in Si-applied treatments suggest that Si may have possible (direct or indirect) role in maintenance of more active Rubisco enzyme and Rubisco activase and more stable proteins for carbon assimilation under stress conditions, which needs to be elucidated in further studies.
干旱胁迫是对植物生长最普遍的威胁，它会扰乱光合作用及其相关的代谢活动，而施用硅（Si）可能有潜力减轻干旱对植物生长的破坏作用。在本研究中，研究了硅在干旱胁迫下对草地早熟禾（品种：阿卡迪亚）光合作用及其相关代谢事件的调节作用。对从田间移出并在温室条件下培养的1年生植株施加干旱胁迫和四个水平（0、200、400、800 mg L⁻¹）的硅（Na₂SiO₃·9H₂O）。干旱胁迫20天后，对植株重新浇水至土壤田间持水量，以在第二天和第七天检查恢复情况。试验采用完全随机设计，重复四次。干旱胁迫严重降低了草地早熟禾的光合作用、水分利用效率、气孔导度、叶绿素含量、Rubisco活性和Rubisco活化状态。然而，施用硅对所有这些指标都有积极影响，尤其是在胁迫条件下。与对照相比，在干旱20天时，施用400 mg L⁻¹的硅使光合作用、Rubisco初始活性和Rubisco总活性分别提高了78%、64%和48%。施用硅处理中较高的光合作用和较高的Rubisco活性表明，硅可能在胁迫条件下维持更活跃的Rubisco酶和Rubisco活化酶以及更稳定的碳同化蛋白方面具有可能的（直接或间接）作用，这需要在进一步研究中阐明。
