长江下游棉花落叶型黄萎病发生消长与气象因子关系分析

１９９３～１９９７ 年, 在江苏省常熟市徐市镇棉花落叶型黄萎病地（致病小种为落叶型ＪＣ５）,对苏棉８ 号从６ 月初至９ 月中旬进行棉花黄萎病调查, 并结合当地的气温、雨日等气象因子对黄萎病的发生消长关系进行统计分析。结果表明, 平均气温２３℃最适宜发病, 平均气温大于２８℃时发病停止（隐症）。黄萎病的日增病指与平均气温、雨日相关性较强, 与雨量相关性较差。合并５ 年的资料, 通过多因子筛选, 得出日增病指（Ｙ）与雨日（Ｘ２）、大于２３℃的有效积温值（Ｘ１）的关系式： Ｙ＝ － ０．１４９４９Ｘ１＋ ０．１４５４４Ｘ２＋ ０．９３５５１。     

Responses of Spodoptera littoralis larvae to Tunisian plant extracts and to neo-clerodane diterpenoids isolated from Ajuga pseudoiva leaves

Thirteen plants growing in Tunisia were tested against Spodoptera littoralis larvae. From the acetone extract of Ajuga pseudoiva leaves, showing interesting antifeedant activity, three new (1-3) and two known (4-5) active clerodane diterpenoids were isolated following a bioassay-guided chromatography.     

Antioxidant compounds from Ebenus pinnata

Activity-guided fractionation of the methanol extract of Ebenus pinnata aerial parts led to the isolation of ombuoside (1), kaempferol 3-O-rutinoside (2), rutin (3), catechin (4), and picein (5), along with beta-sitosterol and beta-sitosterol glucoside. Compounds 1-4 showed significant antioxidant activity in the DPPH, and TEAC, reducing power assays.     

择伐对阔叶红松林细根生物量及其时空分布的影响

以择伐40年后的阔叶红松林过伐林(以下简称为择伐林)和未砍伐的典型阔叶红松林(以下为原始林)为研究对象,探讨了择伐对细根生物量时空分布的影响。结果表明生长季原始林和择伐林死细根生物量、活细根生物量和总细根年平均生物量没有显著差异(P0.05);总细根生物量以及活细根在6月以及9月存在显著差异(P0.05),死细根在5月、7月以及8月存在显著差异(P0.05);原始林和择伐林的细根生物量随土层深度的增加逐渐减少,80%的活细根和75%以上的死细根分布在0 20 cm的土层中,其总细根生物量、活根和死根仅在3040 cm存在显著差异(P0.05);原始林和择伐林的不同直径级(2 5 mm和≤2 mm)的活细根的生物量比、死细根的生物量比以及总细根生物量比在相同土层内没有显著差异(P0.05)。     

红河州部分湿地越冬水鸟快速调查

为配合禽流感监测,西南林学院保护生物学学院与红河州林业局于2006年2月7~9日对红河州越冬水鸟进行了一次快速调查,共记录到越冬水鸟9目8科43种,约3万余只。     

Weed biomass dynamics in planted fallow systems in the humid forest zone of southern Cameroon

Interest in planted fallow systems has focused on soil fertility improvement, neglecting other potential benefits of such systems. It is important to quantify other processes responsible for crop yield increases under planted fallows, such as weed control. The suppressive potential on weeds of Flemingia macrophylla [(Willd.) Merrill] and Pueraria phaseoloides (Roxb.) Benth, planted fallows was evaluated in field trials in three villages in southern Cameroon. In each village, experiments were set up in 4–5 year-old bush fallow dominated by Chromolaena odorata (L.) R. M. King & H. Rob. and 20 year-old secondary forest. Total aboveground biomass production of P. phaseoloides was 7.45 Mg ha⁻¹, 4.2 times higher than F. macrophylla (1.78 Mg ha⁻¹ ; P < 0.05). The high biomass of P. phaseoloides resulted in a significantly greater reduction in total weed biomass compared to Flemingia macrophylla in both wet and dry seasons. In the wet season (11 and 18 MAP), there were significant fallow system × land use and fallow system × village interactions for total weeds and broadleaf weeds. P. phaseoloides in bush (0.55 Mg ha⁻¹), and P. phaseoloides at Ngoumou (0.09 Mg ha⁻¹) had the lowest total weeds in the wet seasons. After the dry season, the lowest total weed mass was consistently recorded in P. phaseoloides while the highest was in the natural regrowth. The population of grasses was always higher in the F. macrophylla system than in P. phaseoloides system throughout the wet and dry seasons. Grass biomass in the P. phaseoloides-forest LUS was the least (0.01 Mg ha⁻¹), 58 times lower than in F. macrophylla-bush (0.58 Mg ha⁻¹). Biomass production of P. phaseoloides was highly significantly correlated with total weed biomass (r = −0.64; P = 0.004) while no relationship was found between biomass production of F. macrophylla and total weed biomass (r = −0.08, P = 0.747). It was concluded that P. phaseoloides was a suitable leguminous species for weed control. But for F. macrophylla, its low biomass production coupled with a compact plant architecture compromised it as an appropriate species for weed control in a planted fallow system.     

EurSafe Congress. Wageningen University, March 4–6, 1999: Summing up and future prospects

Until recently, ethics was a highlyabstruse activity, with little reference to everydayaffairs. It dealt largely with what is calledmetaethics, and was in danger of becoming moribund asan intellectual activity. But for some years,ethics has been undergoing a process of rejuvenationand development. We now seem to be experiencing thebirth of this new discipline (or at least in the EU –the US has been engaged in it somewhat longer). The EurSafeCongress held at Wageningen University, March 4–6,1999 exemplifies this rejuvenation, and itstrongly suggests that a new discipline is emerging, that is not only exciting from an intellectualperspective, but also addresses issues of fundamentalsocial and political concern. It can beargued that, in this context, ethicists are in the position of guides.It is not their job to pronounce on what is right andwrong, but having trodden many of the theoreticalpaths through the forest, they are in a position toadvise and facilitate sound ethical decision-making byothers. The need for ethical insight in this field islikely to progressively increase over the comingyears. Ethicists have a duty to respond to this need.     

推广新型农业科技 大力发展节约型农业

为改善农民的生存环境,搞好农村新型清洁能源的开发利用,减缓全社会能源紧张局面,沼气作为优质可再生能源,具有不可比拟的优点,必须重视起来。