title: Exogenous sodium sulfide improves morphological and physiological responses of a hybrid Populus species to nitrogen dioxide.
abstract: 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.
authors.affiliation: College of Life Science, Northeast Forestry University, China. Electronic address: huybnefu@yahoo.com.
authors.forename: Yanbo
authors.initials: Y
authors.lastname: Hu
authors.affiliation: USDA-ARS, Crop Genetics Research Unit, Stoneville, USA.
authors.forename: Nacer
authors.initials: N
authors.lastname: Bellaloui
authors.affiliation: College of Life Science, Northeast Forestry University, China. Electronic address: sungy@vip.sina.com.
authors.forename: Guangyu
authors.initials: G
authors.lastname: Sun
authors.affiliation: Swedish University of Agricultural Sciences, Southern Swedish Forest Research Centre, P.O.Box 49, SE-230 50, Alnarp, Sweden.
authors.forename: Mulualem
authors.initials: M
authors.lastname: Tigabu
authors.affiliation: College of Landscape, Northeast Forestry University, China.
authors.forename: Jinghong
authors.initials: J
authors.lastname: Wang
mesh_terms: D002245:Carbon Dioxide / Q000494:pharmacology*; D002734:Chlorophyll / Q000378:metabolism; D050901:Nitrate Reductase / Q000378:metabolism; D009566:Nitrates / Q000378:metabolism; D009585:Nitrogen Dioxide / Q000494:pharmacology*; D010788:Photosynthesis / Q000187:drug effects; D018515:Plant Leaves / Q000033:anatomy & histology / Q000187:drug effects / Q000201:enzymology / Q000502:physiology; D010940:Plant Proteins / Q000378:metabolism; D018526:Plant Transpiration / Q000187:drug effects; D032107:Populus / Q000033:anatomy & histology / Q000187:drug effects* / Q000201:enzymology / Q000502:physiology; D013440:Sulfides / Q000494:pharmacology*; D014197:Trees
chemical_list: D009566:Nitrates; D010940:Plant Proteins; D013440:Sulfides; D002734:Chlorophyll; D002245:Carbon Dioxide; D050901:Nitrate Reductase; D009585:Nitrogen Dioxide; C033479:sodium sulfide
keywords: Nitrate reductase activity; Nitrogen dioxide; Photosynthesis; Populus trees; Sodium sulfide