双季超级稻的生长与光合特性研究

分别以金优402和黄华占为对照,研究了超级稻早稻株两优819和晚稻丰源优299的生长及光合特性。株两优819分蘖数低于对照,但成穗率较高,最终形成较高的有效穗数,叶面积指数和生物量累积速率在前期高于对照,但在后期低于对照。整个生育期的单叶净光合速率与对照无显著差异,灌浆期叶绿素荧光参数与对照无显著差异。丰源优299分蘖数和有效分蘖低于对照,但一直保持叶面积指数的较大优势,生长中后期的光合速率显著高于对照,所以生物量较高。在灌浆期,在最小荧光Fo、最大荧光Fm和最大量子效率Fv/Fm方面,丰源优299与对照均无显著差异,而在光下即时荧光Ft、光下最大荧光Fm′、实际量子效率Fv′/Fm′、表观光合电子传递速率ETR、光化学猝灭系数qP和非光化学猝灭系数NPQ等方面丰源优299高于对照。株两优819和丰源优299均表现出高产特性,分别比对照产量高出1629%和544%,但其高产机理有所不同。前期较高的生物量积累和后期较高的光合产物运转效率是早稻株两优819高产的主要原因,而中后期较高的光合能力以及高收获指数是晚稻丰源优299高产的主要原因     

资源环境对南京市经济发展的“增长阻尼”

由于土地与其他自然资源的限制,经济增长速度相比没有限制情况下降低的现象,即为资源对经济增长的阻尼效应。本文将土地资源与生态环境影响因素合并,利用生态足迹模型解释资源环境复合要素,对传统的阻尼模型进行修正,定量测算资源环境对南京市经济发展的增长阻尼。结果表明,南京市经济发展迅速,土地资源和生态环境对经济发展产生了较为明显的制约作用,其对经济发展的增长阻尼为0.03611。充分发挥资本对资源环境的替代作用,合理利用土地资源,优化产业结构,降低人口的增长率是实现南京市经济可持续发展的基本途径。     

An International Comparative Analysis on China's Economic Growth and the Convergence in Energy Intensity Gap and Its Economic Mechanism

In this paper,the authors have empirically analyzed the convergence in per capita GDP gap and the convergence in the variation of energy intensity with respect to the change of per capita GDP between China and eight developed countries.Then,the authors run a regression on the impact of decisive factors of economic growth on energy intensity and its change,so as to find out the economic mechanism of energy intensity gap changing with respect to the variation of economic growth.This study concludes that:First,there is a convergence in per capita GDP gap between China and the eight developed countries.With the convergence in per capita GDP gap,the energy intensity gap between China and eight different countries also converge,and the convergence rate of the latter is faster than that of the former,i.e.if the per capita GDP gap between China and the eight developed countries decreases by 1%,the energy intensity gap between them will correspondingly decrease by 1.552%.Second,the energy intensity decreases with the improvement of industrial structure,the rising of energy prices,the advances of technology,and the expansion of investment in fixed assets,and it slightly increases with the increase of FDI.Third,the energy intensity gap between China and eight developed countries narrows with the lessening of the difference in fixed assets investment,energy prices,and technological progress between China and eight developed countries,yet increases with the narrowing of the difference in FDI,and has no significant correlation with the difference in industrial structure.Fourth,the narrowing of difference in per capita GDP between China and the eight developed countries can result in the lessening of energy intensity gap,whose economic mechanism is that the decisive factors,such as difference in investment,technology,and the competition mechanism of prices,which can determine the difference in economic growth,can significantly affect the energy intensity gap.     

中国经济增长与耕地资源数量变化阶段性特征研究——协整分析及Granger因果检验

利用Eviews 6.0软件,基于协整分析与Granger因果关系检验方法,探讨经济增长和耕地资源数量变化的相互关系和相互作用,以协调耕地保护和经济发展的矛盾。研究结果表明,不同经济增长阶段,我国耕地资源数量变化与经济增长存在长期均衡关系;自1952年以来,我国经济增长和耕地资源数量变化经历了3个阶段,具体表现为:(1)互为因果(1952～1978年),这一阶段农业在国民经济中具有重要地位,耕地的产出在经济增长中占据较大的份额;(2)前者是后者的Granger原因(1978～1992年),此阶段耕地资源投入量顺应了经济增长的要求,发挥了自己应有的作用;(3)后者是前者的Granger原因(1992～2008年),耕地资源作为要素投入支撑了经济的低质量增长,由此产生了重复建设、土地低效利用等问题。因此,关注经济增长和耕地资源数量变化在不同经济发展阶段的均衡关系,发现其中的规律,掌握其中的因果变化趋势,适时调整土地政策以适应经济增长的要求是亟待解决的战略问题。     

中国碳排放与经济增长的协整与因果关系分析

中国碳排放与经济增长的关系是目前热点问题。研究碳排放与经济增长关系有助于实现中国2020年碳减排目标。选取1953～2008年中国碳排放量和经济增长数据,运用协整和误差修正模型及Granger因果关系,研究碳排放与经济增长关系。研究结果表明：从长期来看,碳排放与经济增长之间存在长期均衡关系(协整关系),GDP增加1%,碳排放将增加036%,即碳排放对经济增长的长期弹性为036;在短期内,两者存在着动态调整机制,非均衡误差项的存在,保证了两者之间长期均衡关系的存在。误差修正系数(-0669 4)为负,调整方向符合误差修正机制,并且误差修正模型的拟合效果比较理想。Granger因果关系研究表明：总体来说,碳排放与经济增长之间互为双向因果关系。针对研究结果,提出了“发展低碳经济、提高能源效率和发展非化石能源”的策略,减少能源消费和降低碳排放,实现碳排放与经济增长的相对脱钩     

武陵山经济协作区低碳发展模式选择分析

建立武陵山经济协作区已成为国家的发展战略,选择适合的发展模式至关重要。把经济发展模式划分为传统的经济发展模式和低碳经济发展模式,并对武陵山经济协作区存在的这两种经济发展模式进行分析。从发展前景和政策支持方面考虑,该地区选择低碳发展模式是必然的。武陵山经济协作区发展低碳经济应从开发清洁能源、发展旅游业、转变观念等方面着手。     

In situ phytoremediation of arsenic- and metal-polluted pyrite waste with field crops: effects of soil management

Sunflower, alfalfa, fodder radish and Italian ryegrass were cultivated in severely As-Cd-Co-Cu-Pb-Zn-contaminated pyrite waste discharged in the past and capped with 0.15 m of unpolluted soil at Torviscosa (Italy). Plant growth and trace element uptake were compared under ploughing and subsoiling tillages (0.3 m depth), the former yielding higher contamination (∼30%) in top soil.Tillage choice was not critical for phytoextraction, but subsoiling enhanced above-ground productivity, whereas ploughing increased trace element concentrations in plants. Fodder radish and sunflower had the greatest aerial biomass, and fodder radish the best trace element uptake, perhaps due to its lower root sensitivity to pollution. Above-ground removals were generally poor (maximum of 33 mg m⁻² of various trace elements), with Zn (62%) and Cu (18%) as main harvested contaminants. The most significant finding was of fine roots proliferation in shallow layers that represented a huge sink for trace element phytostabilisation.It is concluded that phytoextraction is generally far from being an efficient management option in pyrite waste. Sustainable remediation requires significant improvements of the vegetation cover to stabilise the site mechanically and chemically, and provide precise quantification of root turnover.     

Sexual difference in mercury concentrations of lake trout (Salvelinus namaycush) from Lake Ontario

We determined total mercury (Hg) concentrations in 50 female lake trout (Salvelinus namaycush) and 69 male lake trout from Lake Ontario (Ontario, Canada and New York, United States). Results showed that, on average, males were 8% higher in Hg concentration than females in Lake Ontario. We also used bioenergetics modeling to determine whether a sexual difference in gross growth efficiency (GGE) could explain the observed sexual difference in Hg concentrations. According to the bioenergetics modeling results, male GGE was about 3% higher than female GGE, on average. Although the bioenergetics modeling could not explain the higher Hg concentrations exhibited by the males, a sexual difference in GGE remained a plausible explanation for the sexual difference in Hg concentrations of the lake trout. In an earlier study, male lake trout from Lake Ontario were found to be 22% higher in polychlorinated biphenyl (PCB) concentration than females from Lake Ontario. Thus, although males were higher in both Hg and PCB concentrations, the degree of the sexual difference in concentration varied between the two contaminants. Further research on sexual differences in Hg excretion rates and Hg direct uptake rates may be needed to resolve the disparity in results between the two contaminants.     

小规模养殖场CDM项目案例分析

以新疆某地集约化养猪场粪便管理甲烷回收项目为案例,利用《气候变化框架公约》清洁发展机制理事会批准的小规模甲烷回收系统方法学(AMS Ⅲ.D)分析了该项目的减排效应和带来的经济效益。本项目可实现减少CO2排放量9 366 t,每年可带来65万元人民币的经济效益,在提高项目收益情况下减少温室气体排放,减少对当地环境的污染,能够在很大程度上提高其他类似项目的企业及项目业主的积极性。     

我国实施循环经济的制度初探

循环经济是在资源与环境约束下追求有效经济增长的一种新的经济发展模式。循环经济本质上是一种生态经济,以资源利用的生态性、技术基础的复杂性、经济运行的社会性等为根本特征。制度与循环经济相互依存、相互制约,发展循环经济离不开制度的规范和引导。论述了我国当前在市场经济条件下发展循环经济中遇到的制度障碍,如市场机制障碍、产权制度障碍和政策法规障碍等,并提出解决循环经济发展的制度障碍需要建立一个完整的、相互补充的制度体系。