Hu Yanbo, Bellaloui Nacer, Sun Guangyu, Tigabu Mulualem, Wang Jinghong
College of Life Science, Northeast Forestry University, China.
USDA-ARS, Crop Genetics Research Unit, Stoneville, USA.
J Plant Physiol. 2014 Jun 15;171(10):868-75. doi: 10.1016/j.jplph.2013.10.018. Epub 2014 Mar 11.
Gaseous nitrogen dioxide (NO2) can disturb normal plant growth and trigger complex physiological responses. NO2-induced responses are influenced by biotic or abiotic factors. In this study, we investigated the effects of exogenous sodium sulfide (Na2S, 5mmolL(-1)) on epidermis and stomata related physico-chemical responses of hybrid poplar cuttings (Pouplus alba×P. berolinensis) to gaseous NO2 (4μl1(-1)) for three time periods (0, 14 and 48h). We also investigated hydrogen sulfide (H2S), nitrate-nitrogen and nitrate reductase activity (NR) in control and Na2S treated plants. Our results showed that NO2 exposure for 48h led to the decline of NR, maximal PSII quantum yield (Fv/Fm), net photosynthetic rate (Pn), and dark respiration rate (Rd). The maximum rate for the post-illumination carbon dioxide burst (PIB) occurred in 48-h exposed leaves 13-15s after darkening. Moreover, NO2 exposure resulted in a significant increase in nitrogen percentage (from 0 to 33%) and a decrease in the macro and micro-elements of leaf surface. Spraying Na2S aqueous solution on the leaf surfaces significantly increased the thicknesses of palisade/spongy tissue and H2S content. Na2S pretreatment alleviated NO2-caused toxic effects as indicated by increased NR and higher values of Pn, Fv/Fm, and actual photochemical efficiency in light (ФPSII) compared with the control. Na2S pretreatment had no significant impacts on PIB-based photorespiration or elements composition of a leaf surface.
气态二氧化氮（NO₂）会干扰植物的正常生长并引发复杂的生理反应。NO₂诱导的反应受生物或非生物因素影响。在本研究中，我们研究了外源硫化钠（Na₂S，5 mmol·L⁻¹）对杂交杨树插条（银白杨×毛白杨）表皮和气孔相关物理化学响应的影响，该插条在三个时间段（0、14和48小时）内暴露于气态NO₂（4 μL·L⁻¹）中。我们还研究了对照植物和经Na₂S处理的植物中的硫化氢（H₂S）、硝态氮和硝酸还原酶活性（NR）。我们的结果表明，暴露于NO₂ 48小时会导致NR、最大光系统II量子产量（Fv/Fm）、净光合速率（Pn）和暗呼吸速率（Rd）下降。光照后二氧化碳猝发（PIB）的最大速率出现在48小时暴露叶片在黑暗后13 - 15秒时。此外，NO₂暴露导致氮含量显著增加（从0增加到33%），叶片表面的大量和微量元素减少。在叶片表面喷洒Na₂S水溶液显著增加了栅栏组织/海绵组织的厚度和H₂S含量。与对照相比，Na₂S预处理减轻了NO₂引起的毒性作用，表现为NR增加以及Pn、Fv/Fm和实际光化学效率（ФPSII）更高。Na₂S预处理对基于PIB的光呼吸或叶片表面的元素组成没有显著影响。
