堆肥过程中氮素损失的控制

概述了影响堆肥过程中氮素损失的因素,并总结了目前国内外关于堆肥氮素损失控制的方法,其中包括添加化学物质、调节堆料的C/N、加入微生物固氮、利用吸附性物质,以期为堆肥过程中有效地控制氮素损失提供理论基础和实践参考。     

顶尖防除春小麦田野燕麦的效果

用15%顶尖可湿性粉剂200~300 g/hm2,对水300 kg/hm2,于小麦苗期茎叶喷雾,对春小麦田野燕麦防除效果达95%以上,增产20%以上,与对照药剂6.9%骠马EW 750 m l/hm2除草效果相当。     

白木香解剖构造及抽提物化学成分分析

以内含物不同的白木香样品为研究对象,对比分析其微观构造和离析组织结构,研究了白木香抽提物的主要化学成分变化,探讨了其结香机理。结果表明：白木香的树脂分布在木射线薄壁细胞及内含韧皮部,在内含韧皮部中伴胞为合成树脂的主要细胞,筛管等为辅助细胞;白木香结香是由于木射线、伴胞等薄壁细胞受到胁迫的生理机能作用所形成,与木材心材的形成机制相同;抽出物与木质素含量变化均为白木香受到刺激后产生的现象,灰分含量与抽出物含量呈负相关,间接说明白木香结香与木质部中的水分含量有重要关系。     

Resistance selection and biochemical characterization of spinosad resistance in Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae)

A Helicoverpa armigera population was collected from Shandong province, China. After 15 generations of selection in the laboratory, the H. armigera strain developed more than 20-fold resistance to spinosad. At LD₅₀ level, no significant cross-resistance was found between spinosad and chlorpyrifos, methomyl, avermectin and chlorfenapyr except for fenvalerate with a low cross-resistance of 2.4-fold. However, LD₉₉ values of fenvalerate against the parental and resistant strains were not different significantly. After inhibitors were used, spinosad resistance could be partially suppressed by piperonylbutoxide (PBO) and triphenylphosphate (TPP), but not by diethylmaleate (DEM). Activities of p-nitroanisole O-demethylase (ODM) developed to 8.26-fold compared with the parental strain, but no obvious changes were found in activities of carboxyl esterase (CarE) and glutathione-S-transferase (GST). The results indicated that resistance to spinosad in the cotton bollworm might be associated with an increase in cytochrome P450 monooxygenase.     

High-throughput screening reveals small molecule modulators inhibitory to Acidovorax citrulli

Acidovorax citrulli is a seed-transmitted gram-negative bacterium that can cause substantial economic yield loss in watermelon and melon production worldwide. Four small-molecule libraries containing 4,952 compounds were selected for high-throughput screening against A. citrulli wild-type strain Xu3-14 by evaluation of growth inhibition. One hundred and twenty-seven molecules (2.5% hit rate) were identified as bactericidal or bacteriostatic against A. citrulli at 100 μM. Secondary screens indicated that 27 candidate compounds were more effective against A. citrulli Group II strains than Group I strains (classified using repetitive element PCR). Several compounds were inhibitory to other pathogenic bacteria, including Clavibacter michiganensis subsp. michiganensis and Xanthomonas campestris pv. campestris, but did not affect the growth of plant beneficial bacteria Pseudomonas fluorescens and Bacillus subtilis. More than half of the compounds did not inhibit germination of Arabidopsis or watermelon seeds. The effect of small molecules on A. citrulli seed-to-seedling transmission was evaluated by applying each compound to inoculated watermelon seeds and assessing seedling infection. Nine compounds were chosen for further investigation based on their reduction of percentage seedling infection and compiling scores on their specificity, sensitivity, and phytotoxicity obtained in the secondary screens. The five best compounds were selected (thiamphenicol, nadifloxacin, pipemidic acid, ciclopirox, and zinc pyrithione) for greenhouse tests and were found to effectively reduce the seed-to-seedling transmission of A. citrulli in both artificially and naturally infested seeds. These top five compounds provide a basis for future development of an A. citrulli-specific bactericide.     

杀虫剂对中黑苜蓿盲蝽的毒力测定方法及9种杀虫剂的室内毒力测定

中黑苜蓿盲蝽（Adelphocoris suturalis Jakovlev）目前是河南省关键棉花害虫之一。本文研究了中黑苜蓿盲蝽成虫的日龄、性别、密度和食物的有无对瓶膜法毒力测定结果的影响,确定了农药对中黑苜蓿盲蝽毒力的生物测定方法。将羽化10 d内的成虫（不分雌雄）1～3头装入具有待测药膜的20 mL闪烁瓶中,每瓶加1块四季豆作为食物, 24 h检查死亡率。用此法测定的9种杀虫剂对郑州中黑苜蓿盲蝽种群的毒力为： 毒死蜱>硫丹>氯氟氰菊酯>甲萘威>吡虫啉>高效氯氰菊酯>啶虫咪>抗蚜威>溴氰菊酯,LC50分别为0.275、0.335、8.130、16.782、18.684、23.805、27.767、63.420 μg/mL和68.451 μg/mL。     

草间小黑蛛对亚洲玉米螟捕食作用的研究

在实验室条件下,研究了草间小黑蛛〔Ｅｒｉｇｏｎｉｄｉｕｍｇｒａｍｉｎｉｃｏｌｕｍ（Ｓｕｎｄｅｖａｌ）〕对亚洲玉米螟〔Ｏｓｔｒｉｎｉａｆｕｒｎａｃａｌｉｓ（Ｇｕｅｎｅｅ）〕二、三龄幼虫的捕食功能反应及其寻找效应。其功能反应属Ｈｏｌｉｎｇ－Ⅱ型,相应模型为Ｎａ＝１．１４６３Ｎ／（１＋０．０２２０５Ｎ）。草间小黑蛛寻找效应和自身密度之间的关系可用Ｈａｓｓｅｌ＆Ｖａｒｌｅｙ（１９６９）模型Ｅ＝０．３９８９Ｐ－０．６３４３和Ｂｅｄｄｉｎｇｔｏｎ（１９７５）模型Ｅ＝０．３５７９／〔１＋０．３１２５（Ｐ－１）〕进行模拟。寻找效应与草间小黑蛛自身密度和玉米螟幼虫密度三者之间的关系可用Ｂｅｄｄｉｎｇｔｏｎ（１９７５）模型Ｅ＝０．３５７９／（０．６８７５＋０．００６８８６Ｎ＋０．３１２５Ｐ）进行描述,表明寻找效应（Ｅ）随草间小黑蛛密度（Ｐ）和玉米螟幼虫密度（Ｎ）的增大而下降。     

《中国贵州山区社区自然资源管理》项目参与性评估报告

《中国贵州山区社区自然资源管理》项目已实施了近6年。为了解项目实施效果，于2000年12月18日和2001年1月3－4日，项目组与试验区及周边非试验区的干部村民一起对项目实施情况进行了参与性的综合评估。评估结果，使项目组研究人员与试验区村民对项目取得的成绩，存在问题及解决问题的办法达成了共识，为也进一步的推广研究提供了依据。     

3WZ-700型自走式果园风送定向喷雾机

针对现代果园低矮密植的种植特点,设计了3WZ-700型自走式果园风送定向喷雾机。通过理论计算和虚拟样机技术,完成整机结构设计和各关键部件技术参数的确定。设计了适应于低矮密植果园的圆环双流道风送雾化装置,确定叶轮直径0.7 m、出风口宽度0.13 m。实现风机转速0～2 000 r/min的无级变速。田间试验结果表明,树膛内部枝叶正、反面雾滴附着率分别为61.22%、20.90%;树膛外部枝叶正、反面雾滴附着率分别为77.22%、37.17%;作业效率为1.02 hm2/h。     

老江河底栖动物变化动态及渔业利用

１９９１－１９９４年对老江河底栖动物进行了连续４ａ的季节采样,共获底栖动物３２各,其中寡毛类８种,水生昆虫１０种,软体动物１２种,其他２种,底栖动物年的均密度变动于２９７－３７３个／ｍ＾２,年龄生物量变动于８３．６１２－１８．２１７ｇ／ｍ＾２。对底栖动物的季节变动,多样性指数变化进行了分析,并对底栖动物的渔产潜力进行了估算。