[Objective] To analyze the positioning of low-carbon agriculture development in local governments of China. [Method] The emissions of green-house gas, the connotation and characteristics of low-carbon agriculture, and the necessity of developing low-carbon agriculture were analyzed, obtaining the positioning and measures for the development of low-carbon agriculture in local government. [Result] Government plays a leading role in the development of low-carbon agriculture. The development of low-carbon agriculture can be promoted through the formulation of scientific low-carbon agricultural development plan, culturing new talents on low-carbon agriculture, promoting low-carbon agricultural technology, establishing low-carbon agricultural risk prevention mechanisms. [Conclusion] Making economy, environment and resources coordinated with each other, leading by the concept of scientific development with the concept of sustainable development, is where the future of agricultural development in China lies.
Variations in cadmium （Cd） tolerances and accumulations among fifteen wetland plant species in moderately （0.5mg.L-1） and heavily （1.0mg-L 1） Cd- polluted wastewaters were investigated in constructed wetlands. Cd removal efficiencies from the wastewaters were more than 90%, and 23.5% and 16.8% of the Cd in the water accumulated in wetland plants for 0.5 and 1.0 mg - U1 Cd treatments, respectively. The variations among the plant species were 29.4-fold to 48.7-fold in plant biomasses, 5.4-fold to 21.9-fold in Cd concentrations, and 13.8-fold to 29.6-fold in Cd accumulations. The plant species were also largely diversified in terms of Cd tolerance. Some species were tolerant of heavy Cd stress, and some others were sensitive to moderate Cd level. Four wetland plant species were selected for the treatment of Cd-polluted wastewater for their high Cd accumulating abilities and relative Cd tolerances. Plant Cd quantity accumulations are correlated positively and significantly （P 〈 0.05） with plant biomasses and correlated positively but insignificantly （P 〉 0.05） with plant Cd concentra- tions. The results indicate that the Cd accumulation abilities of wetland plant species are determined mainly by their biomasses and Cd tolerances in growth, which should be the first criteria in selecting wetland plant species for the treating Cd-polluted wastewaters. Cd concentration in the plants may be the second consideration.
[Objective] To investigate the appropriate low-carbon agriculture model in Southern Jiangsu Province. [Method] Through the analysis of regional features in Southern Jiangsu and several matured low-carbon agriculture development models at present, the low-carbon agriculture development modes suitable for Southern Jiangsu were investigated, and corresponding supporting measures for the development of the models were put forward. [Result] Low-carbon agriculture is the environment- friendly agriculture which achieves low emissions, low pollution, high efficiency and high-yield through efficient recycling of energy and resources and continuous im- provements on ecological environment. With a variety of development models, the specific development model for practical use should be determined according to the local conditions, and supported by corresponding supporting measures, to achieve the rapid development of low-carbon agriculture. [Conclusion] This study laid the foundation for the development of low-carbon agriculture model in Southern Jiangsu.
The current study investigated the effects of nano-silicon （Si） and common Si on lead （Pb） toxicity, uptake, translocation, and accumulation in the rice cultivars Yangdao 6 and Yu 44 grown in soil containing two different Pb levels （500 mg.kg-1 and 1000 mg.kgl）. The results showed that Si application alleviated the toxic effects of Pb on rice growth. Under soil Pb treatments of 500 and 1000mg.kg-1, the biomasses of plants supplied with common Si and nano-Si were 1.8%-5.2% and 3.3%- 11.8% higher, respectively, than those of plants with no Si supply （control）. Compared to the control, Pb concentra- tions in rice shoots supplied with common Si and nano-Si were reduced by 14.3%-31.4% and 27.6%-54.0%, respectively. Pb concentrations in rice grains treated with common Si and nano-Si decreased by 21.3%-40.9% and 38.6%--64.8%, respectively. Pb translocation factors （TFs） from roots to shoots decreased by 15.0%-29.3% and 25.6%-50.8%, respectively. The TFs from shoots to grains reduced by 8.3 %--13.7% and 15.3%-21.1%, respectively, after Si application. The magnitudes of the effects observed on plants decreased in the following order： nano-Si treatment 〉 common Si treatment and high-grain- Pb-accumulating cultivar （Yangdao 6）〉 low-grain-Pb- accumulatir~ cultivar （Yu 44） and heavy Pb stress （1000 mg.kg-1） 〉 moderate Pb stress （500 mg-kg-1） 〉 no Pb treatment. The results of the study indicate that nano-Si is more efficient than common Si in ameliorating the toxic effects of Pb on rice growth, preventing Pb transfer from rice roots to aboveground parts, and blocking Pb accumulation in rice grains, especially in high-Pb- accumulating rice cultivars and in heavily Pb-polluted soils.
