THE EFFECT OF TEMPERATURE ON THE MECHANICAL ACTIVITY OF THE GILLS OF THE OYSTER (OSTREA VIRGINICA Gm.)

1. The method is described whereby the rate of flow produced by the gills of the oyster can be measured accurately. 2. The rate of doing work in maintaining a constant current along the glass tube can be expressed by the formula W = 2πlµ S ², where W = ergs/sec., l = length of the tube, µ = viscosity in poises, and S = speed at the axis of the tube. 3. The relationship between the rate of doing work and the temperature cannot be described by the equation of Arrhenius. 4. The optimum temperature for the mechanical activity of the gills lies between 25° and 30°C. Below 5° no current is produced, though the cilia are beating. Ciliary motion stops entirely at the freezing temperature of sea water. 5. The factors responsible for the production of current are discussed. The study of the relations between the variability of the rate of flow and the temperature shows that between 15° and 25°C. the absolute variability remains constant and increases considerably above 25° and below 15°. The rôle of the coordination in the production of current is discussed, and the conclusion is reached that coordination is affected by the changes in temperature.     

几种载体对红铃虫性诱素引诱效应的影响

红铃虫性诱素(Gossyplute,顺、顺-和顺、反-7、11-十六碳二烯醋酸酯 1:1)对红铃虫[Pectinophora gossypiella(Saund.)]雄蛾具有强烈的引诱作用(Hummel et al.,1973)。但是,以前用滤纸、棉绳和尼龙布作载体(Shorey etal.,1974),无法控制挥发速度,前期挥发量高,后期量低,再加日晒雨淋,性诱素损失较大,以致引诱效果不稳定,残效短。因     

THE EFFECT OF DARKENING ON THE SUSCEPTIBILITY OF PLANTS TO INFECTION WITH VIRUSES

The susceptibility of French bean plants to infection by the Rothamsted strain of tobacco necrosis virus as measured by the local-lesion method is increased by a rise in temperature and usually by darkening the plant before inoculation. If part only of a leaf is darkened, that part becomes more susceptible. Plants in full light also become more susceptible if carbon dioxide is removed from the air, whereas the susceptibility of plants in the dark is not altered.
Darkening leaves decreases their content of malic, fumaric, succinic and glycolic acids and increases the content of citric acid; the content of oxalic and malonic acids remains constant. These changes occurred in winter and summer and whether or not darkening increased susceptibility.
The effect on susceptibility of individual acids infiltrated into the leaf was measured in leaves kept in the light or in the dark before inoculation. None of the acids used produced any large change in susceptibility.     

低浓度DDT对越冬松毛虫幼虫的毒效及若干生理指标变动的分析

前言 马尾松毛虫(Dendrolimus punctatus Walker)是马尾松的主要害虫,国内外在松毛虫群体的数量变动、预测预报、化学、生物及物理等防治上的研究,已作了不少工作,并有很大进展,但化学药剂对越冬松毛虫的毒效以及幼虫内部生理生化的研究资料,目前还不多(蒋三俊 1957;赵善欢 1961;赵善欢 1962;蔡邦华 1964)。越冬松毛虫在许多地区为害程度以其他各代为大,且繁殖力强。至于越冬虫处于静止状态,若能进行有效防治,将有很大意义。本文旨在探索越冬期间利用DDT对马尾松毛虫防治的可能性以及由幼虫的某些生理代谢指标阐明药剂作用机制。     

THE EFFECT OF pH ON THE PERMEABILITY OF COLLODION MEMBRANES COATED WITH PROTEIN

The permeability of gelatin-coated collodion membranes, as measured by the flow of water or of dilute solutions through the membranes, has been found to vary with the pH of the solutions. The permeability is greatest near the isoelectric point of the protein; with increasing concentration of either acid or alkali it decreases, passes through a minimum, and then increases. These variations with pH are qualitatively in accord with the assumption that they are due to swelling of the gelatin in the pores of the membrane, the effects of pH being similar to those observed by Loeb on the swelling of gelatin granules. Indications have been found of a similar variable permeability in the case of membranes coated with egg albumin, edestin, serum euglobulin, and serum albumin.     

环境因子对SeNPV杀虫剂防治效果的影响

本文研究了不同的温度、不同的日照时间和不同的雨淋时间对甜菜夜蛾Spodoptera exigua Hubner核多角体病毒(SeNPV)杀虫剂的防治效果的影响,结果表明:温度在22℃时的LC50值为20.4242μg/ml,防治效果最好,低于或高于22℃的LC50值都增大;秋季日照对防治效果的影响不大,日照在4小时之内,防治效果在97.42%以上,而夏季日照对防治效果的影响则较较为明显;在降雨强度为5mm/hr的条件下,雨淋1小时后其防治效果仍为100%,雨淋4小时内防治效果为89.80%,但当雨淋6小时和雨淋8小时后,防治效果降低为83.67%和81.63%.     

湖南稻田蜘蛛群落生态特点及控虫作用研究

总结近年来对湖南省境内不同地理、生态类型的稻田蜘蛛群落结构的研究结果;报道湖南稻田蜘蛛198种,隶属25科87属,及其常见类群和主要优势种:拟水狼蛛、食虫沟瘤蛛、八斑鞘腹蛛。并应用测定群落结构特征的多种指数公式比较分析不同地理、生态类型的稻田蜘蛛群落的时空格局特点、物种多样性差异、主要优势种差异以及农药对稻田蜘蛛群落结构的影响和蜘蛛群落对目标害虫的控制效应的定性定量分析结果。     

THE EFFECT OF SUPPLEMENTATION OF THE GROWTH MEDIUM WITH YEAST EXTRACT, ON DEHYDROGENASE ACTIVITY OF ESCHERICHIA COLI

SUMMARY: Dehydrogenase activities have been determined of washed suspensions of Escherichia coli prepared from cultures grown in a synthetic medium, and in the same medium supplemented with yeast extract, under conditions of controlled aeration. This supplementation resulted in increased activity of enzymes attacking L (+)-alanine, DL -serine, formate and succinate, no apparent change in activity of enzymes attacking L (+)-gmlumate and D (—)-ribose, and decreased action on D (+)-glucose, mannitol and lactate. The results are discussed in the light of present knowledge of the metabolism of E. coli.     

EFFECT OF POLYOXIN ON THE MORPHOGENESIS OF THE FUNGUS, ALTERNARIA TOMATO WITH SPECIAL REFERRENCE TO PHOTOSPORULATION

Photosporulation of Alternaria tomato was very little influenced by polyoxin at concentrations below 10 μg/ml, although hyphae and conidia were morphologically affected. The hyphae grown in the presence of polyoxin were easily disrupted.     

THE EFFECT OF TEMPERATURE ON INFECTION WITH STRAINS OF CUCUMBER MOSAIC VIRUS

Cucumber mosaic virus strains differed in their ability to multiply in plants at 37° C. Some strains multiplied in inoculated leaves and produced systemic symptoms in plants at this temperature; plants systemically infected with one such strain remained infected after prolonged treatment at 37° C. Other strains did not appear to multiply in inoculated leaves at 37° C. and heat treatment was successful in freeing plants from infection with these. Tests with one strain of each type showed both to be rapidly inactivated in expressed sap at 37° C.
Strains of cucumber mosaic virus forming small necrotic local lesions in leaves of french bean var. Canadian Wonder, produced many fewer lesions in plants kept after inoculation at 25° C. for 24 hr. and then at 15° C. than in plants kept continuously at the lower temperature.     

野生植物苦皮藤种油对几种主要害虫防治研究报告

室内测定表明:苦皮藤种油对菜青虫、黄守瓜、猿叶虫、28星瓢虫,丝绵木金星■蠖、缀叶丛螟等六种害虫有明显的拒食作用;田间试验效果:防治菜青虫,用2%、0.66%、0.5%的苦皮藤种油防效分别为86.5%、91.16%、85.37%,10%氯氰菊酯5000倍液为89.6%,苦皮藤根皮粉为79.81%,所以,苦皮藤种油与氯氰菊酯的效果相近,但优于苦皮藤根皮粉;防治黄守瓜,其防效与增产均优于DDVp。苦皮藤资源丰富,其种油将有可能成为一种很有发展前途的植物性天然产物杀虫剂或拒食剂。     

EXPERIMENTS ON SPRAYING WITH DDT TO PREVENT THE FEEDING OF SCOLYTUS BEETLES ON ELM AND CONSEQUENT INFECTION WITH CERATOSTOMELLA ULMI

Experiments were done for three years on street elms at Folkestone and Aldenham to repeat American work on the use of insecticidal sprays to prevent feeding by Scolytus beetles, which carry Ceratostomella ulmi , the cause of elm disease. Although the fungus can remain alive in the older annual rings of an infected tree, active disease usually results from fungus freshly introduced by Scolytus. Thus spraying is of value on infected, as well as uninfected elms.
The results of the experiments supported American conclusions that DDT was superior to benzene hexachloride. A 1.5% solution of DDT in miscible oil gave reasonably good, but not perfect, control, and was much superior to solutions made from DDT in the form of a dispersible powder.
Spraying of trees 20–30 ft. high cost over £1 per tree per year, which is considered prohibitive, except for small trees of special amenity or sentimental value.     

THE EFFECT OF GESTATION ON THE RATE OF DECLINE OF MILK SECRETION WITH THE ADVANCE OF THE PERIOD OF LACTATION

1. Data are presented showing that the course of decline of milk secretion with the advance of the period of lactation in farrow cows follows the course of decline of a monomolecular chemical reaction, that is each month''s milk production is a constant percentage of the production of the preceding month (94.77 per cent in the case of the cow under consideration), from which it is inferred that milk secretion is limited by a chemical reaction initiated at parturition, and declining with the decrease of the concentration of the limiting substance as it is transformed into milk. 2. Data are presented showing that the decline in milk secretion due to pregnancy is related to the increase in weight of gestating animals, from which it is inferred that growth of the fetus is in part, at least, responsible for the decline in the milk flow due to the demand of the fetus for nutrients to support its life processes.     

STUDIES ON THE PHYSIOLOGY OF ABSCISSION: EFFECT OF TREATMENTS WITH GIBBERELLIC ACID

Abscission of debladed petioles of Coleus was observed following spray applications of gibberellic acid (GA) to the foliage. Sprays were applied to some branches which were left intact (inducing branches), or to adjacent branches whose leaves were later debladed (induced branches). In all experiments three applications of GA were made after which the induced branches were debladed, but in one series deblading was delayed for a week after the last spray application. All treatments resulted in accelerated petiole abscission relative to the controls. Differences between the results of these experiments and the results of similar, earlier experiments with indoleacetic acid (IAA) are discussed. The evidence suggests that GA accelerates abscission by a different mechanism than does IAA.     

Na_2SeO_3对血影收缩蛋白(spectrin)与肌动蛋白(actin)相互作用的影响

Na_2SeO_3不影响肌动蛋白(actin)的聚合,但它可通过与血影收缩蛋白(spectrin)作用而间接促进actin的聚合。Na_2SeO_3的作用具有浓度依赖性:低浓度(0.5-5.0ppm)可提高actin聚合过程的成核速度及延伸速度,高浓度则产生相反的效应。巯基试剂如N-乙基马来酰亚胺(NEM)可消除硒的效应。因此,推测适量的硒可能导致spectrin构象发生一定变化,增强spectrin与actin的结合,降低actin链解聚的倾向性,从而稳定红细胞膜骨架。