Lu H.,South China Agricultural University |
Lu H.,CAS Guangzhou Institute of Geochemistry |
Lu H.,Key Laboratory of Ecological Agriculture of Ministry of Agriculture of the Peoples Republic of China |
Cai Q.-Y.,South China Agricultural University |
And 6 more authors.
Science of the Total Environment | Year: 2010
Seasonal and diurnal variations of carbonyl compounds were investigated at two sampling sites (Liwan and Wushan) in the ambient air of Guangzhou, China. Air samples were collected during 2005 from January to November, and carbonyl compounds were analyzed with HPLC. The results show that carbonyls exhibit distinct seasonal variation. The total concentrations of 21 carbonyls detected ranged from 2.64 to 103.6μgm-3 at Liwan and from 5.46 to 89.9μgm-3 at Wushan, respectively. The average total concentrations of carbonyls at both Liwan and Wushan decreased in order of summer>spring>autumn>winter. Formaldehyde, acetaldehyde, and acetone were the most abundant carbonyl compounds, which accounted for more than 60% of the total concentrations of carbonyls. The mean concentration ratios of summer/winter were all >1.0 for the total concentrations and the individual carbonyl compound. The diurnal variation of carbonyls was not distinct in this study. The average concentration ratios of formaldehyde/acetaldehyde (C1/C2) varied from 0.71 to 1.32 and 0.65 to 1.14 at Liwan and Wushan, respectively, and the average concentration ratios of acetaldehyde/propionaldehyde (C2/C3) varied from 5.42 to 7.70 and 5.02 to 13.9 in Liwan and Wushan, respectively. Regarding photochemical reactivity of carbonyls and the ozone production, acetaldehyde, butyraldehyde, formaldehyde, and valeraldehyde account for 75-90% to the total propene-equivalent concentrations, while formaldehyde, acetaldehyde, valeraldehyde, butyraldehyde, and propionaldehyde contribute 89-96% to the total ozone formation potentials (ranging from 105 to 274μgm-3). The ozone formation potentials in summer were higher by 1-2 times than those in the other seasons. © 2010 Elsevier B.V.
Ou Y.,South China Agricultural University |
Ou Y.,Key Laboratory of Ecological Agriculture of Ministry of Agriculture of the Peoples Republic of China |
Su Z.,South China Agricultural University |
Su Z.,Key Laboratory of Ecological Agriculture of Ministry of Agriculture of the Peoples Republic of China |
And 5 more authors.
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2011
Effects of a snowstorm on forest disturbance and the canopy changes caused by forest rehabilitation resulted in changes in tree seedling composition. The species and number of tree seedlings vary with the canopy-density dynamics and are embodied in the future species composition and structure of tree layer. With the aim of revealing the seedling regeneration pattern and its response to canopy changes (as indicated by changes in leaf area index [LAI]), a 3-year investigation from 2008 to 2010 was undertaken in Chebaling montane evergreen broadleaved forest. The dominant tree seedling dynamics under the recovering canopy was studied by establishing a 2 hm2 sampling area (comprised of fifty 20 m× 20 m plots) following the snow storm in 2008. Data from sampling in 2008 identified the top 12 species ranked by their importance as the dominant tree seedling as follows: Castanopsis carlesii, Schima superba, Castanopsis fargesii, Neolitsea chuii, Styrax suberifolia, Alniphyllum fortunei, Cinnamomum porrectum, Randia canthioides, Machilus chinensis, Rhododendron moulmainense, Cinnamomum austrosinensis and Lithocarpus glaber. Dynamic analysis of these 12 species over the 3 years showed that fluctuation was detected in the ranking of the specie's importance values, among which 2009 and 2010 shared similar trends while 2008 showed a different trend. Castanopsis carlesii, Schima superba, Randia canthioides and Rhododendron moulmainense showed an increase in their ranking by importance value, whereas Neolitsea chuii, Lithocarpus glaber, Cinnamomum porrectum and Alniphyllum fortunei showed a decrease in their ranking. Styrax suberifolia, Cinnamomum austrosinensis and M. chinensis showed a decreased and then increased ranking while Castanopsis fargesii showed the opposite trend. The 12 dominant tree seedling species showed notable responses to canopy recovery. Permutation-based MANOVA (PerMANOVA) indicated that a highly significant difference was found in composition and distribution of dominant tree seedlings among the 3 years (P<0.001), which mainly existed between 2008 and 2009 (P< 0.001), and 2008 and 2010 (P<0.001), with no significant difference occurring between 2009 and 2010. Variation in LAI showed a corresponding trend, with the lowest LAI obtained in 2008 and a great increase in LAI occurred in 2009, with a lower increment and tendency for a stable LAI observed in 2010 compared with LAI in 2009. The responses to LAI changes varied according to the seedling species. Heliophilous tree seedlings showed a sharp reduction in number with canopy recovery and shade increase, while shade and shade-tolerant tree seedlings increased in number with canopy recovery. Indicator species analysis (ISA) yielded distinct results. Eight species of heliophilous tree seedlings, namely Alniphyllum fortunei, Styrax suberifolia, Cinnamomum porrectum, Lithocarpus glaber, Schima superba, Neolitsea chuii, Machilus chinensis and Cinnamomum austro-sinensis were identified as indicator species in 2008, but only Randia canthioides, a shade-tolerant species, was determined as such in 2010, which further demonstrated the response of tree seedlings to canopy recovery from another aspect. Differences between tree seedling species in the 2 years after the snowstorm diminished gradually in the early stage of forest succession. Fluctuation in the importance-value ranking of the dominant tree seedling species inferred that understory acclimatization was still in equilibrium, and the canopy of the undamaged and less-damaged trees would continue to grow and expand to take advantage of the unused canopy space.
Zeng Q.,South China Agricultural University |
Zeng Q.,Key Laboratory of Ecological Agriculture of Ministry of Agriculture of the Peoples Republic of China |
Mo C.,Jinan University |
Cai Q.,South China Agricultural University |
Wen R.,South China Agricultural University
Huanjing Kexue Xuebao/Acta Scientiae Circumstantiae | Year: 2010
Two genotypes of Brassica parachinensis, the DEHP high-accumulator Youqing-60 and the low-accumulator Teqing-60, were grown in hydroponic systems contaminated with DEHP(20 and 50 mg · L-1). The morphology and physiology of the roots were measured, and their effects on uptake of DEHP in roots and shoots are discussed. The results showed that the root morphology of the two genotypes varied with DEHP concentrations in solution. As DEHP concentration increased in solution, the root biomass, total root length and root surface area of the two genotypes decreased and the root diameter decreased in Youqing-60 but increased in Teqing-60. Similarly, total absorption area, active absorption area, specific surface area and root lipid concentration increased(except root activity) for Youqing-60, while root physiology indexes decreased(except active absorption area) for Teqing-60. In general, the root morphological and physiological indexes of Youqing-60 were higher than those of Teqing-60(except root diameter), which was favorable for uptake of DEHP.
Cai Q.-Y.,South China Agricultural University |
Cai Q.-Y.,Key Laboratory of Ecological Agriculture of Ministry of Agriculture of the Peoples Republic of China |
Mo C.-H.,Jinan University |
Lu H.,South China Agricultural University |
And 6 more authors.
Bioresource Technology | Year: 2012
In order to investigate the occurrence and removal of semivolatile organic chemicals (SVOCs) in the compost of sewage sludge, three different composting treatments, including manual turned compost (MTC), intermittent aerated compost (IAC), and naturally aerated compost (NAC) were conducted. Thirty SVOCs in composts were Soxhlet-extracted and analyzed by GC/MS. After 56 days of composting, the total concentrations of 16 polycyclic aromatic hydrocarbons (ΣPAHs) ranged from 0.55 to 8.20 mg kg-1 dry weight, decreasing in order of IAC > MTC > NAC. The total concentrations of six phthalic acid esters (ΣPAEs), five chlorobenzenes or three nitroaromatic compounds were less than 5.0 mg kg-1. Compared with the initial concentrations in sewage sludge, a significant reduction of ΣPAHs, ΣPAEs and chlorobenzenes was observed. The removal rates of ΣPAHs and ΣPAEs ranged from 54.6% to 75.9% and from 58.3% to 90.6%, respectively. Compared with different composting processes, MTC showed the highest potential for removal of SVOCs. © 2011 Elsevier Ltd.
Zhao B.,South China Agricultural University |
Zhao B.,Key Laboratory of Ecological Agriculture of Ministry of Agriculture of the Peoples Republic of China |
Zhang J.,South China Agricultural University |
Zhang J.,Key Laboratory of Ecological Agriculture of Ministry of Agriculture of the Peoples Republic of China |
And 2 more authors.
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2012
The golden apple snail (Pomacea canaliculata) is considered one of the 100 worst invasive alien species by the Invasive Species Specialist Group of the International Union for Conservation of Nature. The golden apple snail was introduced into China around 1980 from South America for commercial purposes. However, it proved to be a failure on the market over the next few years. Consequently, golden apple snails were disposed of into rivers, canals and paddy fields. Since then, P. canaliculata has resulted in massive rice production losses in South China. Although P. canaliculata is a tropical mollusk species, its cold-hardiness has been reported recently in some studies. Supercooling point is an important index for reflecting the resistance of many creatures including mammals, insects and molluscs in low temperature environments. According to many studies, molluscs also exhibit diverse physiological responses to low temperature environments. However, no studies on supercooling points and physiological responses were performed on P. canaliculata from South China to low temperature stress. In this study, supercooling points of P. canaliculata from South China were determined using a device composed of multimeter determination connected with thermistors. Moreover, mortalities and organ injuries to P. canaliculata of different shell heights during supercooling periods were studied. Results showed that the mean value of supercooling points of snails of different heights was -6. 96°C, ranging from -6. 21°C to -7. 32°C. The mean value of maximum body temperature in recovery stage was -4. 07°C, ranging from -3. 07°C to -4. 93°C; the mean supercooling time of P. canaliculata of different heights was 45. 97 min, ranging from 18. 60 min to 75. 34 min. Change in the supercooling point value correlated with the height of P. canaliculata, and the supercooling point of snails with a height of 35 mm≤H<45 mm was significantly higher than those of snails with heights of 5 mm≤H<15 mm, 15 mm≤H<25 mm and 25 mm≤H<35 mm, respectively. It was concluded that the supercooling point of P. canaliculata whose height ranged from 5 to 35 mm was consistent to some extent. The mortality of P. canaliculata in the supercooling stage ranged from 23. 33% to 36. 67%, and there were no significant differences among mortalities of P. canaliculata of different heights. Mortality of P. canaliculata correlated with increased exposure time, and ranged from 20. 9% to 100% in 15 min. This experiment showed that exposure time could greatly influence the mortality of P. canaliculata. Photographs of organs colorstained by 2,3,5-triphenyltetrazolium chloride(TTC) showed a slight red staining on the mantle, which was not obvious on the digestive gland or the kidney of a dead snail, obtained after supercooling for 15 min. Low temperatures resulted in significant organ injury in P. canaliculata. Results obtained from this study will assist further investigation of the ecological adaptation, the northern limit to potential areas of invasion and the survival mechanism of P. canaliculata over winter.