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1.
In observation-cage experiments some new contact kairomones for the egg parasiteTrichogramma evanescens Westwood are demonstrated.T. evanescens females search significantly longer on cabbage leaves treated with the wing scales of two hosts,Pieris brassicae L. andP. rapae L. Further, egg washes ofP. brassicae containing an oviposition deterrent pheromone for the butterflies, were found to have a contact-kairomonal effect on the parasite.T. evanescens females search significantly longer on cabbage leaves sprayed with a methanol or water wash ofP. brassicae eggs than on leaves treated with the solvent only.Hymenoptera: Trichogrammatidae.Lepidoptera: Pieridae. 相似文献
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Fourteen volatile compounds occurring in leaf trichomes of yellow squash (Cucurbita pepo L. cv. Early Prolific Straightneck) were identified. These compounds accounted for 83.5% of the volatile matrix. Ubiquitous constituents of the epidermis (myristic, palmitic, and stearic acids,n-tricosane, andn-pentacosane) accounted for 73.7%; these compounds were not bioassayed. The volatileso-,m-, andp-xylene, toluene, 2-heptanone, (R)-(+)- and (S)-(–)-limonene, and germacrene D were tested for their influence on attraction and oviposition by the pickleworm moth (Diaphania nitidalis Stoll.). No single compound, except germacrene D, was attractive. (R)-(+)-Limonene and 2-heptanone were weakly repellent. Mixtures of the highly volatile fractions were as attractive as volatiles emanating from whole, intact leaves. Oviposition levels on treated artificial sites corresponded with levels of visitation. Oviposition was significantly stimulated by whole-leaf volatiles, and (S)-(–)-limonene caused a slight but significant reduction.Mention of a trade name or proprietary product does not constitute a warranty or guarantee by the U.S. Department of Agriculture, nor does it imply exclusion of other products that may also be suitable. 相似文献
3.
Chemical mediation of egg capsule deposition by mud snails 总被引:1,自引:0,他引:1
Mud snails (Ilyanassa obsoleta = Nassarius obsoletus = Nassa obsoleta) deposit eggs in protective capsules on hard substrata in soft bottom environments. We studied sites of egg capsule deposition and snail movement responses to odors to determine if chemoreception plays a role in deposition site selection. From results of field surveys, laboratory experiments, and field experiments, we conclude that mud snails use chemoreception for capsule deposition. Attractive odors originate from mud snail and whelk egg capsules and from living bivalves. Evidence for attractive odors from conspecifics is equivocal. Capsules are deposited on living odor sources and nearby hard substrates. We hypothesize that deposition of capsules on living substrates increases the likelihood that embryos will survive by decreasing the chance of smothering of embryos by sediments. 相似文献
4.
开发海绵橡胶球(固)-水(液)两相清洗系统,用于豆浆污染的管式膜的清洗.通过海绵橡胶球清洗与传统大量水冲清洗方法对水通量恢复率和蛋清截留率的比较,确认了前者具有良好的清洗效果.前者恢复率比后者高约10%,蛋清截留率基本不受影响,对膜孔径无明显影响. 相似文献
5.
多种植物纤维复合制备纸质蛋盒及其静力学特性研究 总被引:1,自引:0,他引:1
研究了一种把大米草处理成热磨机械浆后,再与化学浆料复配,制备纸质蛋盒包装的方法,对所研制的蛋盒包装材料进行了静态压缩实验。结果表明:在相同湿度与温度条件下,利用瓦楞纸板浆制备的蛋盒材料承载性能最强,其最终承载能力达到了380N,利用废报纸浆复配40%(质量分数)大米草纤维以及纯白竹浆复配30%(质量分数)大米草纤维制备成的蛋盒,最终承载能力分别为302,300N,说明利用大米草复配化学浆料制备蛋盒包装材料具有良好的应用前景。 相似文献
6.
预处理蛋清料液溶菌酶的超滤工艺 总被引:4,自引:0,他引:4
采用超滤法从预处理的蛋清料液中提取蛋清溶菌酶。研究了卷式膜组件的膜孔径、膜材质、超滤时间、压力、温度等对渗透通量的影响。采用截留分子量为3万的PES膜进行超滤,膜透压为0.35MPa,温度为15℃,当超滤进行了150min后进行清洗,酶得率为63%,纯度为98.5%,酶活为14610U/mg或16831U/mg蛋白质。 相似文献
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The eggshell and the cement that attaches the eggs of the seed-beetle Callosobruchus maculatus to the seeds of cowpea (Vigna unguiculata) contain vicilins, the main storage protein found in seeds. These proteins are derived from both males and females, which originally sequester them during the larval phase from their seed hosts. In this test, females received vicilin from different males during mating as a seminal nuptial gift, and transmitted this sequestered blend of proteins to the eggs. The presence of vicilin in the cement and eggshell was demonstrated by light microscopy and Western blotting. Quantification using ELISA showed that the concentration of vicilin from seminal vesicles of a virgin male is approximately double that measured following the first copula to a virgin female, suggesting that the investment of vicilin by the males is very important. This is the first demonstration showing that at least two different males can make a direct contribution of a sequestered protein which is used in oogenesis. 相似文献
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