星天牛蛹的发育及成虫补充营养特性的研究

星天牛是沿海防护林木麻黄的主要害虫。该虫以老熟幼虫在木麻黄主干木质部内越冬 ,化蛹集中于 4月中、下旬 ,蛹期 2 1～ 2 6d。日平均温度 1 9 5℃时蛹期 2 5d,2 1 5℃时蛹期 2 1d,蛹的发育起始温度为( 1 3 91± 0 69)℃ ,有效积温为 ( 1 44 0 4± 1 5 96)日度。羽化盛期为 5月中、下旬。根据蛹的形态和颜色的变化 ,整个蛹期可分为 4个时期 ,每一时期都具备各阶段蛹的形态特征。野外调查和室内外人工饲养表明成虫期补充营养最喜欢取食苦楝树。取食苦楝树的雌虫每头产卵在 1 5 6～ 1 98粒 ,平均 1 76 4粒 ,是取食木麻黄的 3 1 4倍 ,日平均产卵量是取食木麻黄的 1 5 7倍 ;取食苦楝树的雌虫寿命 72～ 1 1 0d,平均 91 8d ;雄虫寿命 88～ 1 2 5d,平均 1 0 3d ,雌、雄成虫分别比取食木麻黄的多存活 3 0 2、40d。     

楝树育苗技术及苗木生长规律研究

对楝树苗木物候、苗高、径生长规律进行了初步研究,结果表明：楝树1年生苗木苗高生长出现2个高峰期,分别在8月中旬和10月上旬;而地径也呈现出相同规律,第1次比苗高早30天左右,第2次与苗高时间相同;苗木生长期可分为出苗期、生长初期、生长盛期、生长后期和休眠期5个阶段,年生长周期245天.根据各阶段苗木的生长特点,提出了育苗关键技术措施.     

苦楝中国分布区的物候区划

苦楝 (Meliaazedarach)是我国优良的乡土树种 ,它具生长快、材质优良、驱虫、耐腐、吸附烟尘能力强等特性 ;根、皮、花、果均可入药 ,对昆虫具有很强的杀伤力 ,有“天然杀虫剂”之美誉 ,是高效、低毒的广谱生物农药的原材料之一 ;苦楝也是良好的蜜源植物 ,同时苦楝果实是榨油和     

Tree leafing phenology and crop productivity in semi-arid agroforestry systems in Kenya

The hypothesis that temporal separation of resource use between trees and crops minimises competition for wa ter in agroforestry systems during the cropping period and increases utilisation of annual rainfall was tested at Machakos in semi-arid Kenya. Four popular tree species were chosen to provide a range of leafing phenologies. These included Melia volkensii, which sheds its leaves twice a year, Senna spectabilis and Gliricidia sepium, which shed their leaves during the long dry season, and the evergreen Croton megalocarpus. All four species retained their foliage during the long rains, offering little scope for temporal separation of resource use. Maize (Zea mays) yields were reduced by 50–70% in the agroforestry treatments. Reductions in crop yield were strongly correlated with tree growth (r ² =0.94) and available soil moisture (r ² =0.88). G. sepium remained leafless for much of the short rains despite the presence of available soil water, and was least competitive with the bean crops (Phaseolus vulgaris) grown at this time. Reductions in crop yield in the agroforestry treatments were closely correlated with tree growth (r ² =0.99) and available moisture (r ² =0.79) during the 1996/97 short rains (158 mm), but not during the much wetter 1997/98 season (608 mm). Shading by trees or shade nets reduced crop yield, in contrast to previous studies in the semi-arid tropics. Low off-season rainfall during the study period (9% of annual rainfall compared to the long-term average of 20%) limited the potential for temporal separation of growing periods. Where the prospects for temporal or spatial separation in resource use are limited, shoot and/or root pruning may be necessary to manage competition between trees and crops. This revised version was published online in June 2006 with corrections to the Cover Date.     

川楝苗木失水处理对其活力及造林效果的影响

通过对金沙江干热河谷上段乡土树种川楝1年生苗木进行5种晾晒处理试验,测定不同晾晒处理后根系的相对含水率、相对电导率、根系活力和移植后的成活率,分析探讨川楝苗木水分与苗木活力的关系.结果表明:川楝苗木活力与其苗木水分密切相关,在晾晒的过程中苗木失水使相对含水量下降,相对电导率增加,根系活力下降,最终导致苗木成活率降低和影响幼林生长情况.在川楝造林时,要做好起苗后的苗木保护工作,尤其是根系的保护,这对于维持苗木活力,提高造林成活率和保存率有重要的意义.     

不同林龄杂交楝(Azadirachta indica×Melia azedarach)人工林土壤水土保持功能研究

为了明确林龄对杂交楝（印楝×苦楝）人工林土壤水土保持功能的影响,通过测定土壤持水能力、渗透能力和抗蚀能力来综合评价不同林龄杂交楝人工林保持水土功能。结果表明,随着杂交楝林龄增加,林地土壤孔隙结构得到改善、持水性能增加、渗透能力增大,提高了土壤水稳性指数,增加了土壤抗蚀性,土壤水土保持功能得到增强。3年生杂交楝林分的土壤持水性能、渗透能力和抗蚀性与1年生林分之间无显著差异,5年生杂交楝林地各指标均比1年生和3年生林分有显著提高。5年生杂交楝林地的土壤最大持水量、总孔隙度、非毛管孔隙度、平均渗透速率和水稳性指数分别比1年生林地增加18.6%、11.4%、19.8%、45%、30.1%。因此,种植杂交楝可以在短期内提高林分的土壤水土保持功能,在山地丘陵地区值得大力发展杂交楝。     

Effects of Melia azedarach on nutritional physiology and enzyme activities of the rice leaffolder Cnaphalocrocis medinalis (Guenée) (Lepidoptera: Pyralidae)

Laboratory assays were done to evaluate the effect of Melia azedarach L. (Rutales: Meliaceae) seed extract on nutritional indices and gut enzymes acid phosphatases, alkaline phosphatases, adenosinetriphosphatases, and lactate dehydrogenase of the rice leaffolder (RLF) Cnaphalocrocis medinalis (Guenée) (Lepidoptera: Pyralidae). Larvae were fed a treated rice-leaf diet containing the seed extract and their midgut was used for enzyme determination. Laboratory experiments showed that the seed extract suppressed the larval activity of C. medinalis even at a low dose. Gross dietary utilization (efficiency of conversion of ingested and digested food) of RLF decreased after ingesting the treated rice-leaf diet. Food consumption, digestion, relative consumption rate, efficiency of conversion of ingested food, efficiency of conversion of digested food, and relative growth rate values declined significantly. As compared to the control, consumption of the extract containing rice-leaf diet resulted in a 69% reduction of the acid phosphatases activity, a 71% reduction of the alkaline phosphatases activity, a 46% reduction of the adenosine triphosphatases activity, and a 52% inhibition of the lactate dehydrogenase activity.     

Effect of Melia azedarach extract on the activity of NADPH-cytochrome c reductase and cholinesterase in insects

The effect of Melia azedarach extract on the activity of NADPH-cytochrome c reductase and cholinesterase was studied in Spodoptera frugiperda. Larvae were fed an artificial diet containing fruit extract and their midgut was used for enzyme determination. As compared to the control, consumption of the extract containing diet resulted in a 31% inhibition of the cholinesterase activity and a 34% activation of the NADPH-cytochrome c reductase activity. In the cockroach Leucophaea maderae, the effect on reductase activity was even more pronounced (43%).     

不同种源苦楝种子形态特征和播种品质差异研究

本研究以苦楝自然分布区内8个种源的种子为研究对象,对种子形态特征和播种品质等生物学特性进行了测定,结果如下：（1）苦楝种子大小存在显著的产地差异,不同种源苦楝种子纵径、横径、纵横径比及千粒重差异均达0．01极显著水平。（2）不同种源苦楝种子发芽率均较高,变幅为50％～81％,平均发芽率为65％,变异系数为15％;发芽指数变化幅度为1．531—2．919,变异系数为19．45％;活力指数变幅为0．054～0．330,变异系数达56．64％。（3）综合种子形态指标和播种品质指标可以分析得出福建平潭,陕西杨凌、广西武鸣、安徽歙县等种源种子品质较好,湖北黄冈种源种子品质较差。     

Effects of the lignan, pinoresinol on the moulting cycle of the bloodsucking bug Rhodnius prolixus and of the milkweed bug Oncopeltus fasciatus

The furano-lignan pinoresinol was toxic to fourth-instar larvae of the milkweed bug Oncopeltus fasciatus and of the haematophagous insect Rhodnius prolixus, a vector of Chagas disease. At lower doses, it also exerted antifeedant activity and dose-dependent antimoulting activity on both insects.