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ABSTRACT: Four-year-old Gingko (Ginkgo biloba L.) trees were exposed to ambient and elevated concentrations of CO2 and O3, and their combination for 1year, using open-top chambers in Shenyang, China in 2006. Growth parameters and endogenous plant
hormones were measured simultaneously over the experiment period. Elevated CO2 increased leaf area and leaf dry weight but had no effect on shoot length, increased indole-3-acetic acid (IAA), gibberellins
A3 (GA3), zeatin riboside (ZR), dihydrozeatin (DHZR) and isopentenyl-adenosine (iPA) content but decreased abscisic acid (ABA) content.
Elevated O3 significantly decreased leaf area, leaf dry weight, shoot length, and decreased IAA, GA3, ZR content but increased ABA content and had a little effect on iPA, DHZR content. Elevated CO2+O3 decreased IAA, iPA and DHZR content while increased ABA and GA3 content in the early stage of the exposure and then decreased in the late stage. The evidence from this study indicates that
elevated CO2 ameliorated the effects of elevated ozone on tree growth, and elevated CO2 may have a largely positive impact on forest tree growth while elevated O3 will likely have a negative impact.
KeywordsElevated CO2 and O3
–ELISA–Endogenous plant hormones–
Ginkgo biloba
–Growth parameter
Acta Physiologiae Plantarum 04/2012; 33(1):129-136. · 1.64 Impact Factor
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ABSTRACT: Endophyte infected and uninfected seedlings of rice (Oryza sativa L.) were subjected to five different levels of Na(2)CO(3) for 2 weeks. Under both Na(2)CO(3) stress as well as no stress, endophyte-infected plants were higher for above-ground dry weight and shoot length, but lower for root length compared to non-infected controls, and there was no significant difference for below-ground dry weight. Chlorophylls and carotenoid contents, net photosynetic rate, transpiration rate, catalase and peroxidase activities increased, but malondialdehyde content declined in the infected plants compared to non-infected controls under Na(2)CO(3) stress. Compared to non-infected controls, water use efficiency, stomatal conductance, chlorophyll fluorescence parameters (F(v)/F(m), F(v)/F(o)) and superoxide dismutase activity in infected plants increased under high concentrations of Na(2)CO(3) while there was no significant difference under low concentrations of Na(2)CO(3). Endophyte infection was concluded to be beneficial to the growth and antioxidative mechanisms in Oryza sativa under Na(2)CO(3) stress.
Ecotoxicology and Environmental Safety 12/2011; 78:35-40. · 2.29 Impact Factor
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ABSTRACT: Hydroponic experiments were carried out to study the role of oligochitosan in enhancing wheat (Triticum aestivum L.) resistance to salt stress. Data were collected on plant biomass, chlorophyll content, photosynthetic rate (P (n)), stomatal conductance (g (s)), proline content, antioxidant enzyme activities, and malondialdehyde (MDA) content. Under 150 mM salt stress, plant growth was significantly inhibited. Shoot length, root length, and dry weight were sharply reduced by 26%, 31%, and 20%, respectively, of the control. Superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) were increased by 28%, 13%, and 26%, respectively, of the control and MDA content largely accumulated, which was 1.5-fold of the control. However, 0.0625% oligochitosan pretreatment alleviated the adverse effects of salt stress, which was reflected by increasing root length, shoot length, dry weight, chlorophyll content, P (n,) and g (s). Furthermore, it also showed that oligochitosan pretreatment significantly increased antioxidant enzyme (SOD, CAT and POD) activities, and reduced MDA content in leaves. Meanwhile, the accumulation of proline was markedly accelerated. The results indicated that oligochitosan pretreatment ameliorated the adverse effects and partially protected the seedlings from salt stress during the following growth period.
Protoplasma 05/2011; 249(2):393-9. · 1.92 Impact Factor
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ABSTRACT: The rates of photodegradation of pyrene (Pyr) on soil surfaces under UV light have been studied. Different parameters such as temperature, soil particle sizes, soil depth, and humic acid (HA) concentration responsible for photodegradation have been monitored. The results obtained indicated that Pyr photodegradation follows pseudo-first-order kinetics. Pyr degradation was fastest at 30 degrees C, while the photodegradation rate was increased with the temperature from 20 to 30 degrees C. The degradation loss was about 35% at 30 degrees C, 30% at 25 degrees C and 25% at 20 degrees C, respectively. The rates of Pyr photodegradation at different soil particle sizes followed the order: less than 1mm>less than 0.45 mm>less than 0.25 mm. The results showed that the relationship of Pyr half-life with soil depth was linear (significant correlation, p<0.01). When the soil depth increased from 1 to 4mm, the half-life increased from 19.80 to 37.46 d. HA treatments significantly increased the photodegradation of Pyr on soil surfaces under UV light. However the concentration of HA increased from 5 to 40 mg kg(-1), the pseudo-first-order rates of Pyr decreased due to the shielding effect of HA.
Journal of hazardous materials 09/2009; 173(1-3):168-72. · 4.14 Impact Factor
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ABSTRACT: The photocatalytic degradation of phenanthrene (PHE), pyrene (PYRE) and benzo[a]pyrene (BaP) on soil surfaces in the presence of TiO(2) using ultraviolet (UV) light source was investigated in a photo chamber, in which the temperature was maintained 30 degrees C. The effects of various factors, namely TiO(2), soil pH, humic acid, and UV wavelength, on the degradation performance of polycyclic aromatic hydrocarbons (PAHs) were studied. The results show that photocatalytic degradation of PAHs follows the pseudo-first-order kinetics. Catalyst TiO(2) accelerated the photodegradation of PHE, PYRE and BaP significantly, with their half-lives being reduced from 533.15 to 130.77 h, 630.09 to 192.53 h and 363.22 to 103.26 h, respectively, when the TiO(2) content was 0.5%. In acidic or alkaline conditions, the photocatalytic degradation rates of the PAHs were greater than those in neutral conditions. Humic acid significantly enhanced the PAH photocatalytic degradation by sensitizing radicals capable of oxidizing PAHs. Photocatalytic degradation rates of PYRE and BaP on soil surfaces with 2% TiO(2) were different at UV irradiation wavelengths of 254, 310 and 365 nm, respectively. The synergistic effect of UV irradiation and TiO(2) catalysis was efficient for degradation of PAHs in contaminated soil.
Journal of Hazardous Materials 04/2008; 158(2-3):478-84. · 4.17 Impact Factor
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ABSTRACT: This paper studied the effects of short- and long term abscisic acid (ABA) treatments on the CO2 assimilation (Pn), carboxylation efficiency (CE), response of Pn to CO2, and antioxidant enzyme activities of wheat seedlings exposed to UV-C. The results showed that under no UV-C, short- and long term ABA treatments increased Pn by 14.69% and 20.46%, and decreased stomatal conductance (Gs) by 14.74% and 17.31%, respectively, compared to the control, while no effects were observed on intercellular CO2 concentration (Ci) and CE. Under UV-C, the Pn, CE, Gs and Ci decreased, with the least decrease in long term ABA treatment, less in short term ABA treatment, and the most in control. ABA could increase the response of Pn to CO2, while UV-C inhibited it. In ABA treatments, antioxidant enzyme activities were enhanced, while MDA content was decreased. Under UV-C, CAT activity increased first, reached its maximum after 1 h, and decreased then. The activities of SOD and POD in ABA treatments increased first and decreased then, with the greater increase in long term ABA treatment than in short term ABA treatment, while those in the control decreased. It was suggested that through enhancing Pn and antioxidant enzyme activities, ABA could enhance the resistance of wheat to UV-C, and long term ABA treatment had better effects than short term ABA treatment.
Ying yong sheng tai xue bao = The journal of applied ecology / Zhongguo sheng tai xue xue hui, Zhongguo ke xue yuan Shenyang ying yong sheng tai yan jiu suo zhu ban 06/2006; 17(5):822-6.
