摘要:

SummaryAn attempt is made to correlate the stage of maturity of the tubers with certain characters in the ontogeny of the vines.Data obtained with regard to the physiological behaviour and the chemical composition of potatoes of different stages of maturity indicate the existence of three more or less distinct stages—adolescence, maturity and ripening—during the development of potato tub

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1937.tb05847.x

出版商:Blackwell Publishing Ltd    

年代:1937

数据来源: WILEY

摘要:

Summary1In view of the similarity between certain cytological changes induced by virus disease and treatment with molybdenum, pot‐and water‐culture experiments were carried out to determine further the effect of this element on plant growth. Sodium molybdate was used throughout.2Toxic symptoms were produced with the larger dressings of molybdate, injury being shown at much lower concentrations in solanaceous species than in barley.3The shoots of tomato andSolanum nodiflorumturned a golden yellow, and potato tubers a reddish yellow colour when the plants were grown with the larger quantities of molybdate.4These colour changes were shown to be due to the presence of yellow globules of a tannin‐molybdenum compound which had formed within the tissues.5Blue granular accumulations occurred in large numbers in molybdenum‐treated plants. Their distribution was confined to tissues that contained anthocyanin pigment, and their composition was apparently of an anthocyanin‐molybden

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1937.tb05848.x

出版商:Blackwell Publishing Ltd    

年代:1937

数据来源: WILEY

摘要:

Summary1Heart‐rot of sugar beet occurred on experimental plots at Rothamsted during 1935, the severity of the attack decreasing steadily with later sowing, but the effects of spacing of the rows and of treatment with sulphate of ammonia were not significant. Where the number of affected plants per row was high, a higher proportion of affected plants showed severe symptoms.2Unaffected sugar beets and others showing slight and severe symptoms of heart‐rot were transplanted to sand cultures and treated with light and heavy dressings of boric acid or with none.3In the absence of boric acid the characteristic signs of boron deficiency appeared in the shoots, the apices of the stems and the flower buds blackening and dying. This occurred even when no symptoms were present before transplanting.4In the presence of boric acid all plants produced healthy shoots, with no deficiency symptoms. Where heart‐rot was originally present and the main axis killed, a number of healthy, lateral shoots were produced.5A certain number of plants failed to survive transplanting, the proportion being greatest with the heavy dose of boric acid, with which one‐half of the plants died. This suggests a possible toxic action of the heavy dose which did not come into play if the plants were constitutionally able to withstand the initial poisoning and start away into growth.6The later addition of boron did not improve the condition of the roots of affected plants, as irremediable damage had been done before transplanting.7The possibility of producing healthy shoots in the second year from affected roots is important from the point of view of seed production, as considerable loss may be saved by the use of small amounts of boron co

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1937.tb05849.x

出版商:Blackwell Publishing Ltd    

年代:1937

数据来源: WILEY

摘要:

Summary1Uredospore cultures ofPuccinia coronataCorda were established in the greenhouse, on their appropriate hosts, by inoculation with uredoor aecidiospores collected in the field. Their pathogenicity was tested by inoculating the uredospores on to a series of grass genera and oat varieties.2Seven varieties ofP. coronatahave been distinguished in Great Britain:3All these varieties have previously been identified on the continent of Europe and some have been identified in North America.4Some varieties are confined to a single host genus; others infect several genera.5Four physiologic races were distinguished in the var.avenae: race 6, previously identified in North America and Australia, and races 42, 43 and 44, hitherto undescribed. Races 6, 42 and 44 were obtained in Great Britain and race 43 in Portugal.6Experiments carried out under different conditions of temperature and illumination showed that variation in these conditions had only a slight influence upon the infection type produced.7Marked variation in reaction to the rust was shown by plants of the same species of grass inoculated with the same culture under identical conditions. This was probably due to genetic impurity of the grasses.8There were no clear‐cut differences, either in morphological or pathological characters, between the varieties assigned by Klebahn toP. coronataKleb. and those assigned toP. coroniferaKleb. (P. LoliiNiels.

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1937.tb05850.x

出版商:Blackwell Publishing Ltd    

年代:1937

数据来源: WILEY

摘要:

SummaryThe results of Day's original investigation of the watermark disease of the cricket‐bat willow have been, confirmed by repeated inoculations and reisolations of an organism agreeing withBacterium salicisDay. The organism has been studied in pure culture and has been compared with a similar bacterium isolated from watermarked white willow from which it differs very slightly. The morphological, cultural and physiological characters ofB. salicisare recorded and it is shown that in these respectsB. salicisis closely akin toB. tracheiphilusand to a lesser degree toB. amylovorus.A new method is described for the determination of the optimum temperature for growth based upon acid production from sucrose.The author gratefully acknowledges his indebtedness to Prof. Brooks for his interest and helpful criticism throughout, to Mr W. R. Day for assistance in getting into touch with willow growers and to Mr J. Bryce for unstinted co‐operation in the field and for Fig

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1937.tb05851.x

出版商:Blackwell Publishing Ltd    

年代:1937

数据来源: WILEY

摘要:

Summary“Enation mosaic” (caused by a strain oftobacco virus1), a disease of tomato characterized by extreme leaf malformation and the development of leafy outgrowths from the undersides of deformed leaves, is described.An account of an investigation of the effects of environmental conditions on the symptoms of enation mosaic is given and the literature is reviewed and discus

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1937.tb05852.x

出版商:Blackwell Publishing Ltd    

年代:1937

数据来源: WILEY

摘要:

Summary1Aphis infestation of the first‐year's growth ofHyoscyamus nigergrown as a biennial crop, was reduced by spraying with a solution of nicotine and soft soap for the first 8 or 9 weeks.2The greatest effect was obtained by spraying at weekly intervals, but spraying fortnightly and spraying weekly in June or weekly in July, also slightly reduced the infestation.3The percentage of infection by aphis‐transmitted viruses was lower on the sprayed plots than on the unsprayed.4No effect of treatments on yield was obtained at the first cropping in the first year of growth which coincided with the end of the spraying period.5As a result of weekly spraying in the first year a 30 per cent increase of yield was obtained in the third crop taken in May of the second y

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1937.tb05853.x

出版商:Blackwell Publishing Ltd    

年代:1937

数据来源: WILEY

摘要:

Summary1The history and identification of the asparagus miner.Melanagromyza simplexH. Loew, are outlined. The fly was described in 1869, and associated with asparagus in the United States of America in 1896 and 1897. In Europe it was recognized about the same date.2The salient points of the morphology of all stages are briefly described.3Its geographical range is the United States of America and Europe. In Europe it has been reported from Hungary, France, Germany and England. In U.S.A. the most numerous records are from the eastern states but it has also been reported from Iowa and California.4There are two generations a year at Harpenden, England. The flies of the first flight are on the wing from early June to the end of July, those of the second from the beginning of August until about the second week in September. Details of the life history are given.5The damage caused by the larvae mining the stems of asparagus is not considered important in cutting beds, although seedling beds might suffer more. When, however, the mining is followed by an attack by the larvae ofLonchaea flavidipennisZett. the damage is more important.6An attempt to assess the local abundance of the flies by direct field observation is described.7Three parasites—the braconid,Dacnusa ?bathyzonaMarsh.; a pteromalid,Sphegigastersp.; and a eulophid,Pleurotropis epigonusWalk.—have been identified by Dr Ferriere and in addition an unidentified parasite has been reared. Brief observational notes have been given concerning these parasites. It is noted thatDacnusa rondaniiGiard has previously been recorded as a parasite.8Control measures recommended by other workers have been mentio

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1937.tb05854.x

出版商:Blackwell Publishing Ltd    

年代:1937

数据来源: WILEY

摘要:

SummaryA survey has been made of the distribution ofPlatyedra malvellaHübn. in Great Britain and it has been found that the larvae are restricted on hollyhock to the south‐eastern counties of England.Apion radiolusKirby and a gall midgeClinodiplosisspecies which are also found in the seed‐heads of hollyhock are generally distributed throughout England; theClinodiplosisspecies also occurs in Wales and Ireland.The life cycle ofPlatyedra malvellahas been described. There is only one generation a year. The moths are on the wing late in June until the beginning of August. The larvae feed on the seeds of hollyhock perforating the seeds characteristically. When full grown from the middle of August onwards, the larvae descend to the soil where they spend the winter in cocoons. In May the larvae become active again and tunnel through the soil. They spin up again towards the end of May and in June for pupation. The host plants areAlthaea rosea, A. officinalisand there is at least one record on co

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1937.tb05855.x

出版商:Blackwell Publishing Ltd    

年代:1937

数据来源: WILEY

摘要:

Summary1The present paper is intended to form an introduction to a short series on studies of the biology of the death‐watch beetle,Xestobium rufovillosumDe G.2The status of the insect as a pest in this country is discussed, and a review is given of the literature and past work on its life history and habits.3A general description is given of the developmental stages (egg, larva, pupa, adult) and includes a short account of external sex characters in the pupa.4Special attention is devoted to the morphology of the reproductive organs and to their state of development at the time of emergence of the adult.5A brief account of the alimentary canal is also include

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1937.tb05856.x

出版商:Blackwell Publishing Ltd    

年代:1937

数据来源: WILEY