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Zhang M.,Shandong Agricultural University | Wang J.,Shandong Agricultural University | Cui X.-M.,Shandong Agricultural University | Wang X.-F.,Shandong Agricultural University | Wang X.-F.,Key Laboratory of Biology and Genetic Improvement of Horticultural Crops Huanghuai Region
Journal of Ecology and Rural Environment | Year: 2014

In order to determine quality of the ambient air in solar greenhouses and its variation pattern, three solar green-houses, different in operation age, (1, 5 and 10 a), were chosen for monitoring of indoor temperature, relative humidity, Cl2, NH3, NO, O3, inhalable particle (PM10) and total suspended particles (TSP), using the insitu fixed site monitoring method. And on such a basis, quality of the indoor air was evaluated. Results show that the temperature, relative humidity, concentrations of Cl2, NH3, NO and O3 inside the greenhouses were closely related to the outside meteorological conditions, and the concentration of suspended particles increased with the operation age of the greenhouse. Diurnal and monthly variations of Cl2, NH3, NO and O3 did not differ much between greenhouses different in age. The highest concentrations of Cl2, NH3 and O3 occurred at about 14:00, while that of NO did around the times of mat uncovering and covering, NO was negatively correlated with O3 in concentration(r = -0.964). The daily mean concentrations of Cl2 and the highest concentrations of NH3 in the greenhouses, regardless of age, all exceeded the national standard, but those of O3 and NO did not. In terms of concentration of PM10 and TSP, the 10 a greenhouse was the highest, and followed by the 5 a greenhouse and 1 a greenhouse. The concentration of PM10 and TSP in January and February was the highest in a year, and especially in the 10 a greenhouse, where PM10 exceeded the national standard for indoor air quality. © 2014, China Environmental Science Press. All rights reserved. Source

Li S.,Shandong Agricultural University | Huang M.,Shandong Agricultural University | Di Q.,Shandong Agricultural University | Ji T.,Shandong Agricultural University | And 9 more authors.
Plant Physiology and Biochemistry | Year: 2015

Plant phospholipase D (PLD), which can hydrolyze membrane phospholipids to produce phosphatidic acid (PA), a secondary signaling molecule, has been proposed to function in diverse plant stress responses. In this research, a qRT-PCR analysis indicated that the expression of a cucumber phospholipase D alpha gene (CsPLDα) was induced by salt and drought stresses in the roots and leaves. To further study the roles of CsPLDα in regulating plant tolerance to salt, polyethylene glycol (PEG) and abscisic acid (ABA) stresses, transgenic tobacco plants constitutively overexpressing CsPLDα were produced. A qRT-PCR analysis showed that the CsPLDα transcript levels were high in transgenic tobacco lines, whereas no expression was found in wild type (WT) tobacco, indicating that CsPLDα was successfully transferred into the tobacco genome and overexpressed. Under normal conditions for 30 d, seeds of transgenic lines germinated neatly, and the seedlings were robust and bigger than WT plants. When treated with different concentrations of NaCl, PEG and ABA, germination rates and seedling sizes of the transgenic lines were significantly greater than WT. In addition, the germination times for transgenic lines were also remarkably shorter. Further studies indicated that transgenic lines had longer primary roots and more biomass accumulation than WT plants. The water loss in transgenic lines was also much lower than in WT. These findings suggest that the CsPLDα overexpression positively regulates plant tolerance to hyperosmotic stresses, and that CsPLDα is involved in the ABA regulation of stomatal closure and the alleviation of ABA inhibition on seed germination and seedling growth. © 2015 Elsevier Masson SAS. Source

Wang X.H.,Shandong Agricultural University | Wang S.J.,Shandong Agricultural University | Chen Z.,Shandong Agricultural University | Gong B.,Shandong Agricultural University | And 8 more authors.
Russian Journal of Plant Physiology | Year: 2016

Putrescine (Put), spermidine (Spd), and spermine (Spm) are the major polyamines (PAs) in plant, which are not only involved in the regulation of plant developmental and physiological processes, but also play key roles in modulating the defense response of plants to diverse environmental stresses. In this study, Cucumis sativus L. seedlings were cultivated in nutrient solution and sprayed with three kinds of PAs (Put, Spd, and Spm). The effects of PAs were investigated on excess nitrate stress tolerance of C. sativus by measuring growth and nitrogen (N) metabolism parameters. The contents of NO3- −N, NH4- +N, proline and soluble protein in leaves were increased; while plant height, leaf area, shoot fresh and dry weight, root fresh weight were decreased under 140 mM NO3 − treatment for 7 d. In addition, the activities of nitrate reductase (NR), glutamate synthase (GOGAT), and glutamate dehydrogenase (GDH) were significantly inhibited under 140 mM NO3 − treatment for 7 d. With foliar treatment by 1 mM Spd or Spm under stress treatment, the contents of Spm, Put, and Spd in leaves increased significantly, except that Spm content decreased under Spd treatment. The activities of NR, glutamine synthetase (GS), GOGAT and GDH and plant height, leaf area, shoot fresh and dry weights were significantly increased. The contents of proline and soluble protein in leaves were significantly enhanced. In contrast, the accumulation of NO3- −N and NH4- +N were significantly decreased. However, there were minor differences in activities of N metabolism enzymes and the content of osmotic adjustment substances under 1 mM Put treatment. These findings suggest that 1 mM exogenous Spm or Spd could enhance the capacity of N metabolism, promote growth and increase resistance to high concentrations of NO3 −. The ameliorating effect of Spd was the best, and that of Put the worst. © 2016, Pleiades Publishing, Ltd. Source

Zhang P.-Y.,Shandong Agricultural University | Gao R.-G.,Shandong Agricultural University | Yang F.-J.,Shandong Agricultural University | Yang F.-J.,State Key Laboratory of Crop Biology | And 10 more authors.
Chinese Journal of Applied Ecology | Year: 2014

The effects of spraying exogenous silicon(Si)(0, 1, 2, 3, 4 and 5 mmol·L-1) on the growth, photosynthetic characteristics and activity of antioxidant enzymes in continuous-cropped 'Jinyan NO. 4' cucumber seedlings were studied. The results showed that with the application of 1-3 mmol·L-1 Si, electrolyte leakage(EL) and malondialdehyde(MDA) content in leaves were significantly decreased, while the contents of chlorophyll a(Chl a), chlorophyll b(Chl b), carotenoids(Car), chlorophyll(a+b) and photosynthetic rate(Pn) in leaves were significantly improved, the activities of superoxidase(SOD), peroxidase(POD), catalase(CAT) and ascorbic acid peroxidase(APX) were significantly increased, and the plant height, stem diameter and dry mass accumulation of cucumber seedlings were promoted. Compared with the low Si concentrations, excessive Si(4-5 mmol·L-1) resulted in higher EL and MDA, which were still lower than that in control, decreased the antioxidant enzymes activity and photosynthesis, and inhibited the growth of cucumber seedlings. These findings indicated that exogenous Si could enhance the capacity of scavenging active oxygen species and improve photosynthesis, protect cucumber seedlings from the lipid peroxidation, and increase the resistance to continuous-cropped cucumber obstacle. The optimal silicon concentration was 2 mmol·L-1. Source

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