bluuebunny/crossref_metadata_2025_split huggingface dataset:
STUDIES IN FRUIT STORAGE. I. INFLUENCE OF THE STAGE OF MATURITY AND STORAGE TEMPERATURE ON RESPIRATORY DRIFTS DURING THE RIPENING OF TOMATO FRUITS
Authors: SINGH B. N. , MATHUR P. B. 
Published: February 2008

Summary

The growth curves obtained by plotting successive fresh as well as dry weights are of the usual sigmoid type. The percentage of dry matter is the highest in young fruits and thereafter declines and remains fairly constant during maturity and ripening of fruits. The respiration curve during the growth of the fruits shows two high values separated in time: one is initial and represents a high rate of respiration in young fruits, while the other occurs at the onset of senescence.
Irrespective of the stage of ripening at picking, winter‐grown tomatoes show the usual “climacteric” rise during the colour change from orange to red. In certain tomatoes there was no evidence of the occurrence of the climacteric, though the sequence of colour change from green through yellow and orange to red was of the usual type.
The storage life of the fruits is longest at 5·7 followed by 9·8 and 14·7°C. At a given temperature the storage life is longest in fruits picked green as compared to those picked in the yellow and orange stages.
The respiration curves obtained in fruits after transference from low to high temperatures are divisible into two parts: (i) high R.Q. associated with a rapidly falling respiration intensity, and (ii) a value of R.Q. approximating to unity accompanying either a falling or a steady respiration rate.
INTERACTION OF SOIL MICRO‐ORGANISMS WITH OPHIOBOLUS GRAM IN IS SACC, THE FUNGUS CAUSING THE TAKE‐ALL DISEASE OF WHEAT
Authors: LAL AKSHAIBAR 
Published: February 2008

Summary

Isolations of Ophiobolus from infected wheat roots gave the maximum percentage of recovery 2–4 weeks after inoculation. Later the percentage of recovery declined. Disappearance of Ophiobolus mycelium was most rapid in acid soils, and slower in sand and in alkaline soil. In soils of more normal type an intermediate behaviour was shown.
From such infected roots a large number of soil fungi and bacteria were isolated and, in part, identified. It is suggested that disappearance of Ophiobolus mycelium from invaded roots is conditioned by the activity of these contaminants, and more particularly of such species as Trichoderma lignorum. Long persistence of the parasitic mycelium in roots growing in sand suggests that this is a poor medium for the growth of micro‐organisms.
A systematic study in plate cultures of the interaction between Ophiobolus and the various soil contaminants isolated showed various degrees of interference with the growth of the former. These effects are described and tabulated. Similar interference effects were seen when Ophiobolus was grown in sterilized soil which had been inoculated with each of the contaminants.
These effects of the living contaminants can, to some extent, be reproduced by their metabolic products, viz. by filtered cultural solutions in which these organisms have grown. The inhibiting or retarding effects so produced are not due to the abstraction of food substances but to the presence of deleterious metabolites. In certain cases it was shown that Ophiobolus mycelium when exposed to such metabolic products was killed. This result was established both by cultural and pathogenic tests.
Tests with wheat seedlings planted over Ophiobolus mycelium, with or without the simultaneous presence of the various contaminating organisms, showed that the antibiotic effect varied from no appreciable effect to complete inhibition of attack. The various organisms are divided into three groups on this basis.
STUDIES EST BACTERIOSIS. XXIV: STUDIES ON A BACTERIUM ASSOCIATED WITH LEAFY GALLS, FASCIATIONS AND “CAULIFLOWER” DISEASE OF VARIOUS PLANTS. PART ILL FURTHER ISOLATIONS, INOCULATION EXPERIMENTS AND CULTURAL STUDIES1
Authors: LACEY MARGARET S. 
Published: February 2008

Summary

Bact. fascians (Tilford), the causal agent of fasciation of sweet peas, leafy galls, etc., has been isolated from abnormal growths on plants of twenty‐five different genera belonging to sixteen families, including both Monocotyledons and Dicotyledons.
All these strains of Bact. fascians were inoculated on to sweet pea seedlings which, in the majority of cases, became severely fasciated.
Characteristic galls have been produced on chrysanthemums, carnations, Schizanthus sp., Nicotiana sp., Heuchera sanguinea, petunia, Asparagus sprengeri, Pisum sativum, Phaseolus vulgaris and Vicia Faba by inoculation with various strains of Bact. fascians. No distinct biological variations among the strains could be detected.
Inoculation of gladiolus, tomato and potato gave negative results.
The galls are invariably produced in the region of bud tissue. In young growths the bacteria are mainly confined to the exterior of the galls.
The organism may be carried on the seeds of Schizanthus.
A study of the physiological reactions of forty strains of Bact. fascians has failed to disclose any means by which virulent and a virulent strains can be distinguished in culture.
LETTUCE MOSAIC
Authors: AINSWORTH G. C. , OGILVIE L. 
Published: February 2008

SummaryPrevious records of lettuce mosaic are cited. The symptoms of the disease on lettuce are described, and the variation in the reaction of different varieties of cabbage lettuce indicated. The host range is extended to certain composite weeds (including groundsel, Senecio vulgaris) and to members of the family Leguminosae (Pisum sativum. Laihyrus odoratus). Experiments in which the virus was seed transmitted through lettuce to the extent of about 6 % are described, and the results of experiments with aphis vectors reported. An account of field observations on the influence of the weather on the disease is given. Certain properties of the virus are described and the status of the virus is discussed. Control measures are suggested.
A GAMASID MITE (TYPHLODROMUS THRIPSI N.SP.), A PREDATOR OF THRIPS TABACI LIND.
Authors: MACGILL ELSIE I. 
Published: February 2008

Summary

Typhlodromus thripsi n.sp., of which a description is given, is a predacious mite feeding on Thrips tabaci Lind. It appears to be one of the few natural enemies of this insect.
There are five stages in the life cycle of the mite; these are: egg, larva, protonymph, deutonymph and adult.
The mites first appear in June and are found on the plants until December, by which time the thrips have disappeared for the season.
SKIN SPOT (OOSPORA PUSTULANS OWEN & WAKEF.) OF THE POTATO, AND ITS CONTROL BY TUBER DISINFECTION
Authors: GREEVES T. N. , MUSKETT A. E. 
Published: February 2008

Summary

Experiments carried out during 1933‐8 with the object of investigating the control of skin spot (Oospora pustulans Owen & Wakef.) by seed‐tuber disinfection are described.
Compounds of mercury were effective when used in solution as steeps. Formalin and a proprietary dusting compound proved to be non‐effective. Proprietary organo‐mercury compounds gave the most promising results, and were satisfactory when used as “instantaneous” dips (0·5‐1·0 min.); mercuric chloride solution was efficient but the 90 min. dipping period employed made the method too tedious.
The time at which the treatment is carried out is of great importance in determining the measure of control obtained. Disinfection of the seed at the time of digging was far more effective than immediately before planting. If too long an interval (more than 8 weeks) is allowed to elapse between digging and disinfection, the value of the treatment is substantially reduced.
A study of the time of digging the crop upon the incidence of the disease, made during one year only, indicated that for that year early digging did not reduce the amount of the disease which developed during subsequent storage. Disinfection carried out at each of the five diggings gave satisfactory control in each case.
The method of treatment recommended is the same as that previously suggested for the control of common scab (Actinomyces scabies (Thaxt.) Güss.) and blight (Phytophthora infestans (Mont.) de Bary). Some evidence was obtained of its also being effective against storage diseases. It would, therefore, appear that disinfection of seed tubers at the time of digging may prove effective against a group of tuber diseases many of which are transmissible to the resultant crop.
INVESTIGATIONS UPON THE PEA STRAIN OF HETERODERA SCHACHTII SCHMIDT AND ITS RÔLE IN THE CAUSATION OF PEA SICKNESS
Authors: POWELL A. K. 
Published: February 2008

Summary

A series of experiments was carried out upon the etiology of pea sickness, a disease which is invariably associated with Heterodera schachtii.
In addition to this eelworm, a fungus, Aphanomyces euteiches, was found to be concerned in the production of the diseased condition of the plants in the soil studied.
Both Heterodera schachtii and Aphanomyces euteiches can singly produce a pathological condition of the host in the absence of any other pathogenic factor.
The effects upon the plants of attack by Heterodera schachtii alone indicate that it is the primary cause of pea sickness.
FURTHER OBSERVATIONS ON ANGUILLULINA DIPSACI IN RHUBARB
Authors: JOHNSON L. R. 
Published: February 2008

SummaryContinued field observations on disease in rhubarb accompanied by infection by Anguillulina dipsaci are recorded. The symptoms, both in the foliage and in the root stock, are similar to those described for bacterial crown rot by Millard.In infection experiments using the rhubarb strain of A. dipsaci symptoms of disease similar to those found in the field were reproduced in rhubarb seedlings and setts. The course of eelworm infection in the young leaves and in the crown in these experiments is recorded.Host transference experiments have shown that the rhubarb strain of A. dipsaci is not rigidly restricted in its feeding habits for it is capable of producing persistent infection in oats, pea and chickweed. It is also capable of producing only temporary infection in cabbage and mangold. Infection is also recorded in Rumex spp. but insufficient evidence is available as to its persistence on these hosts.Incidence of A. dipsaci is recorded in rhubarb from Scotland and southern England in addition to Yorkshire.
THE GROWTH AND ANATOMICAL STRUCTURE OF THE CARROT (DAVCUS CAROTA) AS AFFECTED BY BORON DEFICIENCY
Authors: Warington Katherine 
Published: February 2008

SUMMARYcarrots grown in nutrient solution without the addition of boron were unable to complete their normal development and exhibited both external and internal deficiency symptoms:I pnrt boric acid in 2 million was sutticient to maintain healthy growth when the culture solutions were renewed regularly.The effect of a lack of boron at late stages of growth was determined by transferring plants to a boron‐free solution after they had received an initial supply.The chief deficiency symptom were:

E x t d. The leaves curled back, pointed downwards and often turned red or yellow. The laminae of the youngest leaves were much reduced and the growing apex of the shoot died. The flowering stage was not reached. A small tap root was formed but the laterals were abnormal m appearance, being short and thickened in places. When the boron de‐ ficiency only arose in the later stages of development, certain additional symptoms appeared, viz. the flowering heads bent over and died, those of the side shoots succumbing first. In some cases small wart‐like excrescences arose on the outside of the tap root.
Intmrol. Although no marked degeneration within the tap root was evident to thenaked eye, microscopic investigation showed that most of the tissues of the shoot and root were af ected by a lack of boron. Breakdown began in the region of the growing point of the shoot, patches of irregular and blackened tissue appearing in the young leaves and in the vascular tissue close behind the tip, though the meristematic apex itself was not necessarily h t involved. Later, similar patches were found in the cortex and occasionally also in the pith. Hypertrophy usually preceded or accompanied the formation of these lesions. All cmponents of the vascular bundles were affected, blocking occurring in the xylem and phloem, and hypertrophy and breakdown in the thin‐walled tissues. The formation of the wart‐like growth on the tap roots and the swellings on the laterals was explained by the fact that in the absence of boron, repeated branching and radial extension of lateral roots contin, when elongation and emergence were prevented through death of the apices.

Recovery took place in both shoot and root when boron was supplied, even after prolonged growth in its absence. Traces of the earlier deficiency period could be detected in the anatomical structure of the older parts of the plants although the external appearance was quite normal.
FACTORS INDUCING MINERAL‐DEFICIENCY SYMPTOMS ON THE POTATO PLANT
Authors: Cowie G. A. 
Published: February 2008

SummaryThe data are based upon observations derived chiefly from twenty‐four replicated manurial trials made on the potato crop in 1937 and from twenty‐five further trials of a different design in 1938. They deal with the manurial and other factors that induce deficiency symptoms relating to potash, phosphates and calcium respectively on the potato plant. Leaf scorch, and the other potash‐deficiency symptoms on the aerial part of the plant are normally induced by NP and not by nitrogen treatment. The presence of leaf scorch on the nitrogen plots in a number of trials has been satisfactorily correlated with a high level of available phosphates in the soil, as indicated both by a chemical test for phosphate solubility and the degrees of response to phosphate applications. An increase in the level of nitrogen in the NP treatment results in the intensification of potash‐deficiency symptoms. A certain interaction between nitrogen and phosphates is shown to be the primary factor in inducing potash‐deficiency symptoms on the part of the plant above ground. The blackening of cooked tubers which has hitherto been assumed to indicate potash deficiency has been found to result from a combination of high nitrogen with low potash in the soil. Phosphate deficiency is induced by nitrogen and NK treatments, but more strongly by the latter. Phosphate‐deficiency symptoms and not potash‐deficiency ones become evident on the nitrogen plants under conditions of low phosphates and low potash in the soil. Calciumdeficiency symptoms appeared at three centres on poor sandy soils with pH values ranging between 45 and 5. Observations failed to detect signs of magnesia deficiency on the plants at any centre and in either season. The results of this observation were borne out by the absence of significant yield responses to magnesia with one exception in each season.
The statistical treatment of toxicological data relating to ore than one dosage factor
Authors: Finney Br D. J. 
Published: February 2008

Experiments on the biological measurement of toxicities, and others requiring the use of the probit transformation in the statistical analysis, have in die past been largely of a unifactorial nature. In order to reach a fuller understanding of the action of insecticides and other poisons it is necessary that experiments be performed in‐which two or more factors relating to the dosage are subjected to variation. Bliss has recently described methods for the analysis of two‐factor experiments, but his technique is not a direct extension of the simple case for the fitting of a probit regression line, nor will it generalize easily when more factors are involved.In the present paper it is shown that probit regression planes and hyper‐planes can be fitted in a way exactly analogous to that used for the regression line. Tests of heterogeneity and of parallelism, and standard errors of parameters are readily derived. The notion of relative potency of two poisons does not extend so easily, and it is suggested that the mean probit difference should be used in its stead as a measure of their relative effectiveness. As in the unifactorial analysis, the routine of fitting the. regression equations may be repeated until satisfactory accuracy in the estimation of the parameters is attained, but usually one, or at the most two, cycles of the process gives values sufficiently near to the maximum likelihood solution for practical purposes.A more general class of equations is introduced for use when the probit mortality is linearly related to each dosage factor separately, but the individual effects are not additive. The suggestion made by Bliss (1040) for this case lacks symmetry and does not completely fulfil the linearity conditions, but the present proposal avoids these defects and permits the making of tests for the significance of the im‐proval in fit effected by the additional parameters.The arithmetical procedure for the fitting of a probit plane is described in detail for data on the toxicity to Tribolium castameion of a pyrethrin oil spray at various levels of concentration and deposit weight. Two methods of applying the poison were compared in this experiment, and the two series of results were excellently fitted by parallel probit planes. Direct spraying gave slightly, but not significantly, higher kills than the film method of application, and under the particular conditions obtaining, increasing the concentration of pyrethrin in the spray was a far more effective means of increasing kill than was a proportionate increase in the total amount of spray available to the insects. Numerical examples used by Bliss are also discussed in relation to die methods of fitting and forms of equation given in this paper.
Observations on the biology of the potato‐root eelworm, Heterodera schachtii Schmidt
Authors: Boyd A. E. W. 
Published: February 2008

Results are presented of experiments on the effect of low temperature and of soil type upon the potato‐root eelworm, Heterodera schachtii.In some experiments exposure of cysts, to low temperatures had a definite lethal effect, but in others the cysts were unharmed. The reason for this variation was not apparent. Exposure of the larvae of die nematode to even a relatively slight degree of frost resulted in the death of the larvae, provided mat die surrounding medium was completely frozen. In this respect the larvae appear to differ markedly from those of the beet strain of H. schachtii. That the larvae had actually been killed was shown by the fact that they produced no cysts on the roots of potato plants and also by their almost immediate absorption of iodine.It was confirmed that H. schachtii cysts produced on the roots of potato plants grown in a heavy medium are smaller in size and fewer in number than those formed on the roots of plants grown in a light medium. The heavy medium used was pure clay, the light one pure sand, while equal numbers of eelworm larvae served in each case as inoculum. The difference in cyst size was significant, and fewer larvae emerged from the cysts formed in clay than from those produced in sand.
Biological methods of determining the insecticidal values of pyrethrum preparations (particularly extracts in heavy oil)*
Authors: Tattersfield F. , Potter C. 
Published: February 2008

Pyrethrum extracts in non‐volatile oil carriers are effective insecticides in the field because they act as a direct spray killing the insect and also form a toxic film over which the insect crawls: it is necessary to study both these effects for a complete laboratory assessment of toxicity. Suitable laboratory techniques and methods for the assessment of results are described together with an account of experiments on the effect of various factors on the insecticidal efficiency of pyrethrum‐in‐oil preparations, both as direct sprays and as toxic films.The programme necessitated some duplication of work, but discussions that took place from time to time between the workers concerned at the two laboratories during the progress of the investigations reduced this to a minimum.
The appearance and spread of mosaic infection in the tomato crop and the relation to seed transmission of the virus
Authors: Selman Ireson W. 
Published: February 2008

Appearance and spread of infection with mosaic‐inducing viruses were studied for three seasons in tomato crops under glass. Comparison was made between the reactions of plants raised from virus‐free seed and those of plants raised from virus‐infected seed, on plots distributed at random in a house in which no precautions against entry and spread of virus were taken. Freedom from mosaic infection was maintained longest in plants raised from virus‐free seed. An experiment was carried out after steam sterilization of the soil and under exceptionally favourable weather conditions. Appearance of mosaic symptoms occurred later in the life of the plants in this season and plants raised from virus‐free seed did not react differently from other plants.The location of plants first showing mosaic symptoms was related to the depth and texture of soil beneath those plants.Tests were made of the apparent virus content of infected tomato seed during germination and differences were found in the persistence of virus during germination in seeds of differing origin.Apparent, ‘delayed’ seed transmission of mosaic‐inducing viruses occurs in the tomato crop, but as yet, this condition can only be interpreted in terms of differences in the resistance of plants raised from seed of differing origin to the multiplication and systemic spread of those viruses. The use of virus‐free seed taken from well‐nourished vigorous plants is essential to the production of a virus‐free tomato crop under commercial conditions.