کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5515489 | 1541909 | 2017 | 10 صفحه PDF | دانلود رایگان |
- A new possible mechanism of how suitable concentration of exogenous SA enhances tolerance to water stress is proposed.
- SA-induced increase of PSIIefficiency (ФPSII) under water stress is mainly by strengthening photochemical quenching.
- Alternative respiration and chlororespiration play important roles in SA-mediated resistance to water stress.
The aim of this study is to investigate whether exogenous application of salicylic acid (SA) could modulate the photosynthetic capacity of soybean seedlings in water stress tolerance, and to clarify the potential functions of terminal oxidase (plastid terminal oxidase (PTOX) and alternative oxidase (AOX)) in SAⲠs regulation on photosynthesis. The effects of SA and water stress on gas exchange, pigment contents, chlorophyll fluorescence, enzymes (guaiacol peroxidase (POD; EC 1.11.1.7), superoxide dismutase (SOD; EC 1.15.1.1), catalase (CAT; EC 1.11.1.6), ascorbate peroxidase (APX; EC 1.11.1.11) and NADP-malate dehydrogenase (NADP-MDH; EC1.1.1.82)) activity and transcript levels of PTOX, AOX1, AOX2a, AOX2b were examined in a hydroponic cultivation system. Results indicate that water stress significantly decreased the photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (E), pigment contents (Chla + b, Chla/b, Car), maximum quantum yield of PS⠡photochemistry (Fv/Fm), efficiency of excitation capture of open PS⠡center (Fv'/Fm'), quantum efficiency of PS⠡photochemistry (ΦPS⠡), photochemical quenching (qP), and increased malondialdehyde (MDA) content and the activity of all the enzymes. SA pretreatment led to significant decreases in Ci and MDA content, and increases in Pn, Gs, E, pigment contents, Fv/Fm, Fv'/Fm', ΦPS⠡, qP, and the activity of all the enzymes. SA treatment and water stress alone significantly up-regulated the expression of PTOX, AOX1 and AOX2b. SA pretreatment further increased the transcript levels of PTOX and AOX2b of soybean seedling under water stress. These results indicate that SA application alleviates the water stress-induced decrease in photosynthesis may mainly through maintaining a lower reactive oxygen species (ROS) level, a greater PS⠡efficiency, and an enhanced alternative respiration and chlororespiration. PTOX and AOX may play important roles in SA-mediated resistance to water stress.
Journal: Plant Physiology and Biochemistry - Volume 112, March 2017, Pages 19-28