小麦白粉病和赤霉病兼治研究

为解决我省小麦白粉病、赤霉病、叶锈病、叶枯病混合危害的严重问题，研制成功了２种复配兼治新农药：３６％粉霉灵悬浮剂和３０％增效粉锈宁悬浮剂。毒力测定表明，２种新农药配方都有明显的增效作用；在小样加工工艺成熟的基础上，完成了中试工艺研究；建立了快速准确的分析方法和产品标准，１５ｔ２种新农药的试产品，各项理化指标均达到或超过国家标准，质量优异、稳定，证明配方合理，生产工艺成熟，达到工业化生产水平；克服了“粉锈宁”易结晶析出的难题，把“多菌灵”和“粉锈宁”复配加工成稳定的悬浮剂以及增效粉锈宁用纸浆废液加工，国内均未见报道；通过田间药效试验，明确了２种新农药的使用效果和技术。小区试验结果表明：（１）粉霉灵７５０ｇ／ｈｍ２对小麦白粉病、赤霉病、叶锈病、叶枯病都有特效，防治１次的综合平均防效达８７．９％；（２）粉霉灵悬浮剂与相同有效成份复配加工的可湿性粉剂产品（麦病宁、纹霉净、防霉宝）相比，药效提高１倍左右；大田示范结果表明：粉霉灵６００ｇ／ｈｍ２，防治赤霉病、白粉病的平均效果分别为８２％和９６％，比多菌灵７５０ｇ／ｈｍ２＋粉锈宁１２０ｇ／ｈｍ２的平均效果（分别为７１．９％和９４％）提高１０．１％和２％，增产率提高３％；?     

花卉学教学方法探索

花卉学是一门研究花卉的分类、生物学特性、栽培技术、繁殖方法及经营管理与应用等综合性很强的科学,是与生态学、气象学、土壤学、植物生理学、遗传学和栽培学等紧密联系的学科,为了提高花卉学教学效果,必须将传统和多媒体手段相结合,紧密联系相关课程,理论教学与实践教学协调一致,注重培养学生创新能力.     

土地退化经济学分析与防治对策

中国土地退化普遍存在,全国退化土壤总面积为4.65亿hm2,占国土面积的48.44%,局部地区退化严重,中度以上(含中度)退化土壤面积1.58亿hm2,占34%。笔者从经济学的角度剖析土地退化的深层原因。发现私人利益、集团利益与国家利益不一致时,受集团势力的影响,政策难以发挥作用,导致土地过度使用;外部不经济性难以实现内部化,导致土地破坏严重;地权“四权”分离导致土地护理不力、滥占严重。针对土地退化的原因,提出行政干预、完善法律、经济手段以及工程技术等防治措施,共同防治土地退化,可较好达到防治的预期目的。     

Comparison of traditional and improved methods for estimating the stability of organic growing media

Organic growing media employed in hydroponic crops could change their characteristics due to organic matter degradation during culture growing season. Traditional methods for measuring the stability of growing media (Biochemical Stability Index, Lemaire) do not take into account the activity of crop roots, nutrients in the growing media or microorganism presence. Three experiments were performed to determine the stability of six organic substrates. Stability was measured as the percentage of organic matter remaining in substrates. In experiment one (short duration and small scale without plant) 500 ml samples were incubated for 180 days following original methodology proposed by Lemaire (L) and with three modifications: (1) Inoculation with compost (I), (2) watered with nutrient solution (NS), and (3) both combined (I + NS). In experiment two (Long duration, medium scale) 10 l samples were incubated with and without a lolium crop for 720 days in a greenhouse. In experiment 3 stability of each substrate was real measured in 20 l hydroponic bags after use in four cycles of tomato production in a commercial greenhouse (2 years). All incubations were triplicated. Physicochemical properties of substrates were measured. Correlations between stability estimated in experiment one and two and real determinations in experiment three were analyzed. Lemaire methodology modified by adding and inoculum an nutrients (I + NS) was the best method to estimate the stability of organic growing media measured in real conditions in experiment 3. This new method greatly improves the estimation performed with original Lemaire methodology. Long term incubations with lolium also reproduce well the real stability of growing media but this methodology is not feasible because it requires four times longer and the amount of substrate required is 20 times larger for each sample.     

Habitat and food choice of the critically endangered cao vit gibbon (Nomascus nasutus) in China: Implications for conservation

Knowledge of habitat and feeding ecology is essential for developing an effective conservation management plan for threatened primates. Despite having been rediscovered nearly a decade ago, very little is known of the critically endangered cao vit gibbon (Nomascus nasutus) or its habitat. We analysed forest cover, made direct observations and conducted interviews of local elders to better understand forest changes and to determine the forest characters and species important to the survival of the gibbon. Interviews indicated human-induced forest resource exploitation focused on species-specific and larger trees most easily accessed. Gibbon forest habitat comprised four primary forest types. The mean canopy height over the whole site was 10.52 m. Gibbons consumed 81, or nearly half of the tree and liana species recorded in the site; however, only 19 species provide 77.8% of the diet. Six of the 19 food species were logged for different reasons throughout the history of the site. We conclude that effective conservation management of primates with highly limited distributions, focused dietary needs, and in degraded ecosystems will require active forest restoration, such as planting important food species in degraded sites.     

Deg2蛋白酶在拟南芥光损伤D1降解及光保护中的作用

己有研究表明叶绿体内有200种蛋白酶,然而,多数蛋白酶的作用机制尚不清楚,尤其哪些蛋白酶参与了D1蛋白周转。其中Deg2蛋白酶体外实验证明,其参与了光损伤D1蛋白的的初步剪切。为了进一步研究Deg2蛋白酶在植物体内的作用机制,我们筛选了拟南芥De醇蛋白酶功能缺陷型突变体。在120μmol·m-2：·S^-1光照生长条件下,出萨突变体与野生型的生长曲线基本一致;在进一步的高光胁迫（1800μmol·m-2·S^-1）处理及相同的光胁迫处理条件下,无论林可霉素存在与否,突变体PSⅡ的最大光化学效率（Fv／Fm）都和野生型没有区别;利用蛋白免疫印迹实验同样证明了光损伤D1蛋白的降解速度在cfe霞突变体和野生型之间也没有明显区别。我们认为Deg2蛋白酶在光抑制情况下对于光损伤D1蛋白的降解以及PsⅡ的修复不是必需的。     

刺桐姬小蜂在东莞市城区绿地的发生情况及其防治技术初探

文章通过对东莞城区各主干道、广场、大型绿地上的刺桐属植物进行调查,摸清了东莞城区刺桐属植物上刺桐姬小蜂的发生和为害情况,同时,通过田间的试验研究和比较,初步评价了刺桐姬小蜂的各种田间防治方法,提出了城市园林绿地中刺桐姬小蜂的无公害防治对策。     

Effects of physicochemical interactions and microbial activity on the persistence of Cry1Aa Bt (Bacillus thuringiensis) toxin in soil

Genetically modified crops, that produce Cry insecticidal crystal proteins (Cry) from Bacillus thuringiensis (Bt), release these toxins into soils through root exudates and upon decomposition of residues. The fate of these toxins in soil has not yet been clearly elucidated. Persistence can be influenced by biotic (degradation by microorganisms) and abiotic factors (physicochemical interactions with soil components, especially adsorption). The aim of this study was to follow the fate of Cry1Aa Bt toxin in contrasting soils subjected to different treatments to enhance or inhibit microbial activity, in order to establish the importance of biotic and abiotic processes for the fate of Bt toxin. The toxin was efficiently extracted from each soil using an alkaline buffer containing a protein, bovine serum albumin, and a nonionic surfactant, Tween 20. The marked decline of extractable toxin after incubation of weeks to months was soil-dependent. The decrease of extractable toxin with incubation time was not related to microbial degradation but mainly to physicochemical interactions with the surfaces that may decrease immunochemical detectability or enhance protein fixation. Hydrophobic interactions may play an important role in determining the interaction of the toxin with surfaces.     

Cross-enhancement of accelerated biodegradation of organophosphorus compounds in soils: Dependence on structural similarity of compounds

Rates of degradation of seven organophosphate nematicides and insecticides were examined in two soils known to show accelerated biodegradation of fenamiphos and one soil known to show accelerated biodegradation of chlorpyrifos. The results indicated that several organophosphate insecticides and one nematicide were susceptible to cross-enhanced degradation in the soil showing accelerated biodegradation of chlorpyrifos. No cross-enhancement was observed in the two soils showing accelerated degradation of fenamiphos. Fumigation resulted in the complete inhibition of pesticide degradation in all soils. The data suggested that the cross-enhancement of selected pesticides in chlorpyrifos-degrading soil was dependent on the structural similarity of the compounds. Mechanisms of degradation of pesticide in soil support this hypothesis, where structurally similar compounds (diazinon, parathion, coumaphos and isazofos) were hydrolysed by microbial activity in chlorpyrifos-degrading soil but the degradation products were accumulated. Enhanced degradation of chlorpyrifos and fenamiphos was found to be stable in the laboratory condition for a period of one year.     

Influences of alpine ecosystem responses to climatic change on soil properties on the Qinghai–Tibet Plateau, China

Alpine ecosystems are quite sensitive to global climatic changes. Drawing from two sets of remote sensing data (1986 and 2000) and field investigations, the ecological index method was used to document ecosystem changes in the Yangtze and Yellow River source regions of central Qinghai–Tibet. Although crucial to understanding alpine ecosystem responses to global climatic changes, and in assessing the potential for their rehabilitation, the impact of such changes on alpine soil characteristics, including structure, composition, water retention, as well as chemical and nutrient contents, is poorly understood. Over a 15-year period (1986–2000), climatic changes led to considerable degradation of alpine meadows and steppes. In the meadows, the surface layers of the soil became coarser, bulk density, porosity and saturated hydraulic conductivity rose, while water-holding capacity decreased. In comparison, steppe soils showed little changes in soil physical properties. Degradation of alpine ecosystems led to large losses in soil available Fe, Mn and Zn. Important losses in soil organic matter (SOM) and total nitrogen (TN) occurred in badly degraded ecosystems. Climate warming in the Qinghai–Tibet Plateau, caused by the impact of greenhouse gas, has resulted in changes of cold alpine ecosystem such as the significant alteration of the soil C and N cycles.