THE ADAPTATION OF FUNGI TO FUNGICIDES: ADAPTATION TO THIRAM, ZIRAM, FERBAM, NABAM AND ZINEB

The concentrations of thiram preventing germination of spores of Botrytis cinerea in drops of a 1% solution of sucrose, and on the surface of a sucrose-nitrate agar have been determined. Thiram had much less effect on germination in the agar medium, even when a purified agar was used. There was no growth on sucrose-nitrate agar if the concentration of thiram exceeded 31 p.p.m. Attempts to obtain strains able to grow at higher concentrations were unsuccessful.
Similar results were obtained with ziram, nabam and zineb.
Ferbam also was more effective in preventing spore germination in spore drops than on agar media; this effect was obtained with ordinary and with purified agar.
On a sucrose-nitrate agar generally there was no growth if the concentration of ferbam exceeded 125 p.p.m., but in one of forty-eight plates containing 250 p.p.m. ferbam, five slowly growing colonies were produced, and from these colonies arose mycelium which grew and sporulated rapidly on 500 p.p.m. ferbam agar. Agar disk inocula were transferred from these cultures to agar containing higher concentrations of ferbam and in this way, and by repeating the process, a strain was obtained which grew slowly but continuously, and sporulated on agar containing 5000 p.p.m. ferbam. However, the poor solubility of this fungicide made it difficult to assess quantitatively the degree of adaptation.
A proportion of the spores from this strain germinated in drops containing about twice the concentration of ferbam which prevented germination of parent spores.
The resistance of the mycelium of the resistant strain was not lost after repeated subculture on fungicide-free agar. The resistant strain was as susceptible as the parent strain to thiram, ziram, nabam and zineb.
Attempts to obtain strains of Venturia inaequalis resistant to thiram, ferbam, ziram and zineb were unsuccessful.     

STUDIES UPON THE COPPER FUNGICIDES

A study of the absorption of soluble copper by apple leaves was undertaken with a view to obtaining a better understanding of the mechanism of copper spray damage.
The ability of young apple leaves to absorb copper was found to be relatively high and this may be due to the large number of stomata and hairs present. As the leaves grew more mature this capacity fell, rose again to a maximum in July or August and then fell again as the leaves approached senescence. It is suggested that these changes may be due to seasonal changes in leaf metabolism, which probably affects nutrient absorption by leaves as in roots.
It has been observed in the field that apple leaves are often more susceptible to copper spray damage in the autumn. Since absorption is then at a low level it is concluded that the rate of absorption is not the only factor affecting damage to leaves caused by copper sprays.
The presence of injuries in the leaves has two effects: first, it causes an increased excretion of copper-dissolving substances (Arman & Wain, 1958) and, secondly, it increases the rate at which soluble copper is absorbed. A combination of these two factors may bring about localized spray damage. However, the increase in the absorption of soluble copper caused by the presence of extensive injuries in the leaves was sufficiently small for the conclusion to be drawn that injuries do not normally constitute a major route for the entry of copper into the leaf and it is probable that spray damage can occur in the absence of injuries.     

STUDIES UPON THE COPPER FUNGICIDES

Evidence is presented for the presence, on apple and dwarf bean leaves, of substances which can dissolve copper from dried Bordeaux deposit. The solution of copper is not associated with the bacterial breakdown of these substances. Copper was dissolved by the action of apparently uninjured as well as injured leaves and it is concluded that copper-dissolving substances are liberated from intact leaf surfaces. The capacity of leaves to dissolve copper from dried Bordeaux deposit was not lost by repeated washing of the leaf. This further evidence of the sustained activity of the host plant in bringing copper into solution emphasizes the importance of host action in relation to the fungicidal and phytotoxic action of Bordeaux mixture under field conditions.     

THE RELATION OF ENZYMATIC ADAPTATION TO THE METABOLISM OF ENDOGENOUS AND EXOGENOUS SUBSTRATES

The source of energy for enzymatic adaptation has been investigated. Aerobically, it is found that the endogenous carbohydrate reserves may be used as such a source. In cells depleted of their reserves, the adaptive substrate itself can be oxidized even while it cannot be fermented, and so can serve as a source of energy for the adaptation to a fermentative mode of utilization. Anaerobically, adaptation may occur at the expense of stored energy-rich compounds, while the reserves and the adaptive substrate are now useless as fuel. Such compounds appear to be more plentiful in young than in old cells. The addition of any fermentable substrate, such as glucose, leads to rapid anaerobic adaptation. Experiments in which maltose-adapted cells are adapted anaerobically to galactose with the aid of a little added maltose, and conversely, show that fermentability is the criterion of usefulness for an exogenous substrate in aiding the adaptive process. None of the endogenous and exogenous energy sources which have been investigated will facilitate adaptation unless the adaptive substrate is present while they are being consumed. The significance of these findings and the adequacy of "activation" hypotheses to explain enzymatic adaptation has been discussed.     

THE ADAPTATION OF ELECTROENCEPHALOGRAPHY TO MEDICINE

Electroencephalography is a valuable aid in diagnosis and prognosis of diseases affecting the brain. It has definite limitations.Abnormal electroencephalograms are either paroxysmal or non-paroxysmal. Both of these changes may be generalized or focal.Epilepsy is primarily associated with paroxysmal activity. Electroencephalography aids in the diagnosis and in determining the severity, course and response to treatment.Non-paroxysmal activity, although less specific in pattern, indicates either generalized or focal pathologic change or some alteration of the normal structure of the brain. Non-paroxysmal activity may give supportive evidence referable to conditions, systemic or intracranial, which disturb the state of consciousness.     

真菌在兰科植物种子萌发生长中的作用及相互关系

本文从真菌在兰科种子萌发中的应用、真菌侵染的过程、种子和根系消化真菌的途径及共生真菌的分布等方面,综述了真菌与兰科植物种子萌发及菌根关系的研究进展,讨论了该研究的有关问题及真菌在兰科种子萌发中应用的前景。     

中国洞穴蜘蛛多样性及其对洞穴环境的适应

对中国洞穴蜘蛛的多样性、地理分布信息进行了详细的闸述.初步探讨了洞穴蜘蛛对洞穴环境的适应性特征及其进化机制.我国洞穴蜘蛛目前已知16科27属80种,其巾暗蛛科、弱蛛科、泰莱蛛科和巨蟹蛛科物种最多;在属级阶元上,以弱蛛属Leptoneta14种、泰莱蛛属Telema lO种、龙角蛛属Draamar如和巾遁蛛属Sinopoda各9种,宽隙蛛属Platocoelotes 8种居多.我国洞穴蜘蛛主要集中分布在贵卅、海南、云南、北京、浙江、广西等喀斯特洞穴较为密集地区,在河北、河南、湖北和湖南也有部分报道.在不同地区分布的洞穴蜘蛛类群或优势类群及区系成分等都存在较大差异.洞穴蜘蛛中约有20%～30%的种类凶为长期生活在黑暗无光、食物匮乏以及缺乏温度和光周期的季节调节等特殊环境,出现了一些地表生境蜘蛛类群中所没有的刘洞穴环境的适应性特征,如缺乏体色素、眼退化共至无眼、附肢延长、全身牛有很多具较敏锐触觉和嗅觉功能的感觉毛、繁殖无季节性、耗氧量降低而新陈代谢缓慢、代谢率降低、产牛的后代少、单个卵粒包含更多的营养等.     

中国洞穴甲壳动物多样性及其对洞穴环境的适应性

简要阐述了洞穴环境的研究现状以及洞穴动物的生态特征,初步探讨了中国洞穴甲壳动物的形成过程、多样性、地理分布以及对洞穴环境的适应性。截止到2008年10月,我国已记录的洞穴甲壳动物(主要指十足目虾类和端足目钩虾类)共有33种,分别隶属6科10属,主要分布在贵州省、广西省等喀斯特洞穴密集地区。洞穴甲壳动物由于长期生活在洞穴的黑暗带,食物匮乏,水温恒定,CO2浓度过高,且O2浓度相对较少的环境中,其在形态结构、消化系统、生理及行为等方面逐渐表现出与地表甲壳动物不同的适应性特征。如:眼缺失、体无色、触角和附肢显著增长、新陈代谢减慢、代谢率小,昼夜节律降低,不能调节体温,生活步调放慢,寿命长,发育周期长等。     

FEEDING AND GROWTH RESPONSES TO COPPER, ZINC, MERCURY AND LEAD IN THE TERRESTRIAL GASTROPOD ARIONATER (LINNE)

Food consumption and growth variations related to several dosagesof heavy metals (Cu, Zn, Hg and Pb) in diet were studied inthe terrestrial slug Arion ater for 27 days of experimentaltreatment. The work reported here is part of a larger project to investigatethe histological effects of metal exposure in pulmonate gastropods. Graphics on food consumption and growth vs. time for each metal,and regression for each behaviour observed are presented. (Received 30 May 1985;     

木本植物对汞耐性的研究

土培与水培相结合的模拟试验结果表明:当年生木本植物对汞具有较强的耐受性,并依不同种而呈现差异。其中加拿大杨>晚花杨>旱柳>辽杨。加拿大杨体内汞的耐受阈值约为95—100ppm,每株体内最大汞吸收积累总量约为6779μg。超过耐受限度,植物生长发育将出现显著抑制伤害。根细胞壁对汞的亲合吸附,根系脱氢酶活性的提高,以及过氧化物同工酶含量与谱带的增加可直接或间接地有助于植物对汞耐性的增强。