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Liu S.-Y.,South China Agricultural University | Liu S.-Y.,Key Laboratory of Ecological Agriculture | Liu Y.-X.,South China Agricultural University | Liu Y.-X.,Nanjing Forestry University | And 5 more authors.
Chinese Journal of Applied Ecology | Year: 2010

Soil samples were collected from the Eucalyptus plantations in the north, east, and west Guangdong and Pearl River Delta region to study their organic carbon content and density, and the main factors affecting the organic carbon density. In the plantations, the soil organic carbon content and density in A and B horizons were significantly different, with the values of (23.94±2.97) g · kg -1 and (9.68 ± 1.05) g · kg -1, and (27.64±7.72) t · hn -2 and (108.36±9.37) t · hn -2, respectively. In 0-50 cm soil layer, the organic carbon density was 66.72 ± 6.53 t · hm -2, being slightly higher than that in Masson pine and Chinese fir plantations in Guangdong. In both A and B horizons of Eucalyptus plantations, soil organic carbon density was significantly positively correlated with altitude, soil total porosity, capillary porosity, capillary moisture capacity, and total nitrogen content. Soil capillary porosity, capillary moisture capacity, and pH value were the main factors affecting the soil organic carbon density.


Mahmood K.,Key Laboratory of Ecological Agriculture | Mahmood K.,South China Agricultural University | Mahmood K.,Copenhagen University | Khan M.B.,South China Agricultural University | And 6 more authors.
Plant Growth Regulation | Year: 2014

This study examines allelopathic potential of genetically modified rice. The experiment was conducted on two isogenic lines Bacillus thuringiensis (Bt) and non-Bacillus thuringiensis (non-Bt). Both isogenic lines have same allelopathic ability before insect feeding and after limited insect feeding (Spodoptera litura) non-Bt rice genotype demonstrates more allelopathic potential. The S. litura cannot feed Bt rice genotype. The role of shoot herbivory in allelopathic induction is further supported when Bt plants also exhibited higher allelopathic potential after insect regurgitant application to the damaged leaves. Allelopathic potential was assessed through several methods after treatments of mechanical damage, insect feeding and insect regurgitant application to damaged rice leaves. Rhizosphere soil and leaf leachates of non-Bt rice cultivar exhibited higher allelopathic potential on lettuce and barnyard grass after herbivore feeding. Enzyme activities (PAL and C4H) responsible for biosynthesis of phenolic compounds and their concentration were significantly higher in non-Bt plant after herbivore feeding and attain the same level in Bt plants after insect regurgitant application to damaged leaves. Similarly, genes (OsPAL and OsCYC1) responsible for biosynthesis of allelopathic compounds showed high expression in non-Bt plants after herbivore feeding. Our results indicate that herbivore feeding enhance rice allelopathic potential and no insect feeding as incase of Bt plants may reduce allelopathic potential of genetically modified rice. © 2014 Springer Science+Business Media Dordrecht.


Zhao B.-L.,South China Agricultural University | Zhao B.-L.,Key Laboratory of Ecological Agriculture | Peng H.,South China Agricultural University | Zhang J.-E.,South China Agricultural University | And 3 more authors.
Chinese Journal of Ecology | Year: 2013

Golden apple snail is one of the 100 pernicious alien invasive species in the world. In this study, the shell powder of golden apple snail was used as the adsorbent to approach its characteristics and mechanisms of lead (Pb 2+ ) removal from aqueous solution under laboratory condition. It was found that the removal rate of Pb2+ by the shell powder was related to the shell powder amount, initial Pb2+ concentration, solution pH, and reaction time, while solution temperature had lesser effects. The fitting of Langumir model indicated that the Pb2+ adsorption capacity of the shell powder was 89.29 mg · g-1. The analysis of scanning electron microscopy showed that the Pb2+ removal process was mainly happened at the surface of the powder, and small particle was more active. The X-ray diffraction indicated that the adsorbed Pb2+ was in the form of PbCO3 existing on the powder. The mechanisms of the Pb2+ removal could be the ion exchange and precipitation on the aragonite and calcite in the powder. It was suggested that the shell of golden apple snail could be used as an effective bio-adsorbent for Pb2+ removal.


Chi G.-L.,South China Agricultural University | Chi G.-L.,Key Laboratory of Ecological Agriculture | Chi G.-L.,Higher Education Institutions | Tan B.-C.,South China Agricultural University | And 5 more authors.
Chinese Journal of Applied Ecology | Year: 2010

By the methods of headspace enrichment and GC-MS, this paper studied the composition and quantity of the volatiles emitted from two transgenic Bt maize varieties ( 5422Bt1 and 5422CBCL) and their homologous regular variety (5422) after the feeding by Spodoptera litura. As for the intact plants, the volatiles emitted from variety 5422 were (E)-ß-ocimene, linalool, (3E) -dimethyl-1 , -nonatviene (DMNT) , and (E)-ß-farnesene, those from5422Bt1 were linalool and DMNT, while 5422CBCL only emitted linalool. After the feeding by S. litura, a total of twelve volatiles including terpenoid, alcohol, ester, and indole were emitted from 5422 and 5422Bt1, and ten volatiles were emitted from 5422CBCL, with a lack of (Z)-3-hexen-l-yl acetate and nerolidol. The kinds and quantities of terpenoids emitted from the test three varieties were increased significandy, with eight kinds increased for varieties 5422 and 5422Bt1, and seven kinds increased for 5422CBCL. The emitted amounts of linalool and DMNT from the Bt maize varieties were higher than those from the regular variety, while the emitted amounts of other volatiles were in reverse. Especially for (E)-ß-farnesene, its emitted amount from the Bt maize varieties was much lower than that from the regular variety. It was obvious that after the feeding by S. litura, the composition and quantity of the volatiles emitted from the Bt maize varieties differed with those emitted from the regular variety, and there was a difference between varieties 5422Bt1 and 5422CBCL.


Xie L.J.,Key Laboratory of Ecological Agriculture | Xie L.J.,South China Agricultural University | Zeng R.S.,Key Laboratory of Ecological Agriculture | Zeng R.S.,South China Agricultural University | And 9 more authors.
Allelopathy Journal | Year: 2010

Invasion of exotic species is a global ecological problem and has tremendous impact on economy, environment and human health. The success of invasion for exotic plants depends on many mechanisms and in recent years the novel weapons hypothesis has been argued as an important mechanism to elucidate the invasion process. This review summarizes a large body of research including the observations of potential allelopathic phenomenon, isolation and identification of allelochemicals and the role of allelopathy in invasion of common exotic invasive plants in China such as Eupatorium adenophorum, Eucalyptus spp., Spartina anglica, Chro1molaena odoratum, Eichhornia crassipes, Solidago canadensis, Alternanthera philoxeroides, Ambrosia artemisiifolia. Ambrosia triftda, Lantana camara, Wedelia trilobata, Bidens pliosa, Ageratum conyzoides and Mikania micrantlia. We suggest that allelopathy plays a vital role in successful invasion of alien species in new areas. The allelochemicals of invasive alien species also sere as defence chemical weapons against native plant pathogen and herbivorous insects.


Wang Y.,University Putra Malaysia | Wang Y.,Guangdong Institute of Eco environmental and Soil Sciences | Wang Y.,Key Laboratory of Ecological Agriculture | Liang J.B.,University Putra Malaysia | And 5 more authors.
Industrial and Engineering Chemistry Research | Year: 2010

Sulfadiazine, a potent antibacterial agent belonging to the group of antibiotics called sulfonamides, has been reported to be present in surface and groundwater. This study investigated the degradation of sulfadiazine in a goethite (α-FeOOH)-oxalate Fenton-like system under UV irradiation. The results showed that sulfadiazine could be effectively photodegraded by the goethite-oxalate Fenton-like system as a result of the formation of the highly oxidizing hydroxyl radicals, ·OH. Among the iron oxides tested (α-FeOOH, γ-Fe2O3, γ-FeOOH, and α-Fe2O3), α-FeOOH was found to be the most effective. Degradation of sulfadiazine depended significantly on the pH and initial concentration of oxalic acid in the system, with optimal values of 3.5 and 4.0 mM, respectively, under UV irradiation. Five intermediate products of sulfadiazine degradation were identified using high-performance liquid chromatography-mass spectrometry (HPLC-MS), gas chromatography-mass spectrometry (GC-MS), and ion chromatography (IC), and a possible sulfadiazine degradation pathway in such a system was proposed. Organic sulfur and organic nitrogen mineralization were also observed, and the results indicated that cleavage of the sulfonylurea bridge was easier than the other potential cleavage bonds under the goethite-oxalate system. In addition, results from Biolog assays suggested that the ecological toxicity of the sulfadiazine solution was effectively reduced after degradation. © 2010 American Chemical Society.


Cai Q.-Y.,South China Agricultural University | Cai Q.-Y.,Key Laboratory of Ecological Agriculture | Cai Q.-Y.,Key Laboratory of Arable Land Conservation South China | Huang H.-J.,South China Agricultural University | And 9 more authors.
Archives of Environmental Contamination and Toxicology | Year: 2012

Low molecular-mass nonylphenol ethoxylates (NPEOs) and 4-nonylphenol (NP) are biodegradation products of higher molecular mass NPEOs used as surface active agents, and they are endocrine-disrupting contaminants. In this study, surface soil (0-20 cm) samples and different vegetable samples were collected from 27 representative vegetable farms located in Shenzhen, Dongguan, and Huizhou within the Pearl River Delta region, South China, and NP and nonylphenol monoethoxylate (NP1EO) were analyzed using high-performance liquid chromatography with ultraviolet detection. The results show that NP and NP1EO were detected in soil and vegetable samples. The concentrations of NP and NP1EO in soil samples ranged from nondetectable (ND) to 7.22 μg kg -1 dry weight (dw) and from ND to 8.24 μg kg-1 dw, respectively. The average concentrations of both NP and NP 1EO in soil samples decreased in the following order: Dongguan>Huizhou> Shenzhen. The levels of NP and NP1EO in vegetable samples varied from 1.11 to 4.73 μg kg -1 dw and from 1.32 to 5.33 μg kg -1 dw, respectively. The greatest levels of both NP and NP 1EO were observed in water spinach, and the lowest levels of NP and NP 1EO were recorded in cowpea. The bioconcentration factors (the ratio of contaminant concentration in plant tissue to soil concentration) of NP and NP 1EOwere<1.0 (mean 0.535 and 0.550, respectively). The occurrences of NP and NP 1EO in this study are compared with other studies, and their potential sources are discussed. © Springer Science+Business Media, LLC 2011.


Li Y.,South China Agricultural University | Li Y.,CAS South China Botanical Garden | Zeng S.-C.,South China Agricultural University | Zeng S.-C.,Key Laboratory of Ecological Agriculture | And 2 more authors.
Chinese Journal of Applied Ecology | Year: 2011

An in situ field experiment was conducted to study the effects of simulated nitrogen (N) deposition on soil acid phosphomonoesterase activity (APA) and soil available phosphorous (AP) content in Pinus massoniana forest (PF), coniferous and broad-leaved mixed forest (MF), and monsoon evergreen broad-leaved forest (MEBF) in Dinghushan Mountain. In PF and MF, three treatments were installed, i. e. , CK (0 kg N.hm -2 . a -1), low N (50 kg N.hm -2 . a -1), and medium N (100 kg N.hm -2 . a -1); in MEBF, four treatments were installed, i. e. , CK, low N, medium N, and high N (150 kg N . hm -2 . a -1). The soil APA and soil AP content decreased with soil depth. The soil APA was the highest in MEBF, while the AP content had no significant difference in the three forests. The effects of N addition on soil APA differed with forest types. In MEBF, the APA was the highest (19.52 μmol.g -1 .h -1) in low N treatment; while in PF and MF, the APA was the highest (12.74 and 11.02 μmol.g -1 .h -1, respectively) in medium N treatment. In the three forests, soil AP content was the highest in low N treatment, but had no significant differences among the N treatments. There was a significant positive correlation between soil APA and soil AP content.


Song Y.-Y.,Key Laboratory of Ecological Agriculture | Song Y.-Y.,South China Agricultural University | Wang R.-L.,Key Laboratory of Ecological Agriculture | Wang R.-L.,South China Agricultural University | And 12 more authors.
Chinese Journal of Applied Ecology | Year: 2011

Arbuscular mycorrhiza (AM) can not only improve host plants nutrient absorption, but also enhance their disease resistance. Taking the tomato (Lycopersicon esculentum) seedlings pre-inoculated with arbuscular mycorrhizal fungus (AMF) Glomus versiforme as test materials, this paper studied their protective enzyme activities and defense-related genes expression, and their resistance against a fungal pathogen Alternaria solani Sorauer which causes early blight. The seedlings pre-inoculated with AMF and later inoculated with A. solani showed significantly higher activities of superoxide dismutase (SOD) and peroxidase (POD) in leaves. The leaf SOD activity of the dually inoculated plants reached the maximum 18 h after pathogen inoculation, being 28.6%, 79.2%, and 82.8% higher than that of the plants with G. versiforme inoculation alone, pathogen inoculation alone, and non-inoculation, and the leaf POD activity reached the maximum 65 h after pathogen inoculation, being 762%, 18.3%, and 1710% higher, respectively. Real time RT-PCR analysis showed that dual inoculation with G. versiforme and A. solani strongly induced the expression of three defense-related genes. The transcript levels of pathogen-related protein (PR), basic type β-1,3-glucanase (PR-2), and chitinase (PR-3) in leaves were 9.67-, 8.54-, and 13.4-fold higher, as compared with the non-inoculation control, respectively. Bioassay showed that the disease incidence and disease index of the seedlings pre-inoculated with G. versiforme were reduced by 36.3% and 61.4%, respectively, as compared with the non-mycorrhizal control plants. These findings indicated that mycorrhizal colonization could induce stronger and quicker defense responses of host tomato plants, and priming could be an important mechanism of the enhanced disease resistance of mycorrhizal tomato plants.


PubMed | Key Laboratory of Ecological Agriculture
Type: Journal Article | Journal: Ying yong sheng tai xue bao = The journal of applied ecology | Year: 2011

Arbuscular mycorrhiza (AM) can not only improve host plants nutrient absorption, but also enhance their disease resistance. Taking the tomato (Lycopersicon esculentum) seedlings preinoculated with axbuscular mycorrhizal fungus (AMF) Glomus versiforme as test materials, this paper studied their protective enzyme activities and defense-related genes expression, and their resistance against a fungal pathogen Alternaria solani Sorauer which causes early blight. The seedlings pre-inoculated with AMF and later inoculated with A. solani showed significantly higher activities of superoxide dismutase (SOD) and peroxidase (POD) in leaves. The leaf SOD activity of the dually inoculated plants reached the maximum 18 h after pathogen inoculation, being 28.6%, 79.2% and 82.8% higher than that of the plants with G. versiforme inoculation alone, pathogen inoculation alone, and non-inoculation, and the Leaf POD activity reached the maximum 65 h after pathogen inoculation, being 762%, 18.3%, and 1710% higher, respectively. Real time RT-PCR analysis showed that dual inoculation with C. versiforme and A. solani strongly induced the expression of three defense-related genes. The transcript levels of pathogen-related protein (PR1), basic type beta-1,3-glucanase (PR-2), and chitinase (PR-3) in leaves were 9.67-, 8.54-, and 13.4-fold higher, as compared with the non-inoculation control, respectively. Bioassay showed that the disease incidence and disease index of the seedlings pre-inoculated with C. versiforme were reduced by 36.3% and 61.4%, respectively, as compared with the non-mycorrhizal control plants. These findings indicated that mycorrhizal colonization could induce stronger and quicker defense responses of host tomato plants, and priming could be an important mechanism of the enhanced disease resistance of mycorrhizal tomato plants.

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