bluuebunny/crossref_metadata_2025_split huggingface dataset:
THE BIOLOGY OF OAT SMUTS: I. VIABILITY OF THE CHLAMYDOSPORES
Authors: SAMPSON KATHLEEN 
Published: February 2008

Summary.

The viability of the chlamydospores of V. avenae and U. levis has been under investigation since 1925. Samples of spores were tested dating back to 1921. The results are expressed in terms of percentage germination. Tests were carried out for the most part on 2 per cent. cane‐sugar solution or on an extract made from the pales of oats.
Samples of U. levis showed a short “after ripening” period. They reached a maximum germination figure about two months after harvest and showed no loss in viability during a period of 2 to 21/2 years. Some samples were viable after 51/2 years.
Panicles of U. avenae collected soon after exsertion yielded immature spores which quickly lost their viability. Mature samples, collected by covering the panicles with pollen‐proof bags, showed only a slight loss in viability after nearly 2 years in storage.
The influence on viability of several methods of storage was investigated.
The data emphasise the importance of maturity as a critical factor in the viability of samples. Divergent results obtained with the same species from time to time are probably to be explained by differences in the maturity and age of the samples tested.
The significance of the results in connection with the different methods of contamination and infection current in the two species of oat smut is discussed.
AUTOCATALYSIS AND GROWTH
Authors: COPEMAN P. R. v. d. R. 
Published: February 2008

Summary.The autocatalytic equation in the form log x/(a ‐ x) =K (t‐t1) may be used to express closely the changes which occur during growth.The constant k, as given by K = ka, is not a constant which is independent of environmental conditions.The changes in growth may be more suitably expressed by means of the equation dx/dt= (k1+ k2x) (a ‐ x). In this case k1 may be regarded as a constant, dependent upon external conditions, while k2 is a measure of the internal factors governing the growth processes.
SOME EXPERIMENTS WITH CALCIUM CYANIDE AS A CONTROL FOR PLANT PARASITIC NEMATODES
Authors: HODSON W. E. H. , GIBSON GORDON W. 
Published: February 2008

Summary.

Considerable diversity of opinion has existed regarding the practicability of controlling plant parasitic nematodes by means of granular calcium cyanide.
Previous experiments with this substance have invariably been directed against eelworms of the genus Heterodera.
The experiments described in this paper were carried out in South Devon and in the Isles of Scilly and with the exception of one with Heterodera radicicola, in tomato, relate to Tylenchus dipsaci, in narcissus.
Doses of granular calcium cyanide, ranging from 300 lbs. to 2000 lbs. per acre, were employed under various conditions. Only with doses of from 1500 lbs. to 2000 lbs. per acre was any real indication of satisfactory control of T. dipsaci obtained, while H. radicicola remained unaffected by similar doses.
In the opinion of the writers the successful use of granular calcium cyanide for the control of plant parasitic nematodes, on a commercial scale, is not possible under conditions pertaining to this country. At the same time, where expense is of no account, small areas of soil may be rid of nematodes by means of exceedingly heavy doses of the substance.
LABORATORY EXPERIMENTS WITH NON‐ARSENICAL INSECTICIDES FOR BITING INSECTS
Authors: GIMINGHAM C. T. , TATTERSFEBLD F. 
Published: February 2008

Summary.

A convenient technique for experiments with insecticides for biting insects is described.
The silicofluorides of sodium, potassium, aluminium and calcium, used in the form of spray‐fluids, showed considerable toxicity to young larvae of several species of moths. The degree of resistance varies with different species and is greater with older larvae. Considerable, but irregular, injury to foliage was noted, and much further work is required to establish the conditions under which these compounds could be safely used.
Foliage sprayed with extracts of certain tropical plants is extremely repellent to young larvae. Even with high dilutions of the extracts, the foliage remained uneaten and the larvae eventually died of starvation.
A short review of some recent work on laboratory experiments with non‐arsenical insecticides for biting insects is given.
INVESTIGATION ON HETERODERA SCHACHTII IN LANCASHIRE AND CHESHIRE PART I. THE INFESTATION IN CERTAIN AREAS AS REVEALED BY CYST COUNTS; AN ESTIMATION OF THE ERRORS INVOLVED IN THE TECHNIQUE AND A CORRELATION WITH INTENSITY OF DISEASE
Authors: SMITH A. M. , PRENTICE E. G. 
Published: February 2008

SUMMARY.

Heterodera schacJitii has been identified in many parts of Lancashire and Cheshíre where severe losses have resulted from failure of the potato crop.
A detailed study of the errors involved in the technique of a method for estimating the infestation has been made.
The degree of infestation, as determined by cyst counts, has been compared with records of crop failure.
The conclusions that have been drawn are to the effect that: (a) where “eelworm disease” has been noted recently there is a positive association of intensity of disease and cyst content of the soil; b) where the disease was observed three or four years ago, disease and crop failure are always associated with a high cyst content of the soil, but there may be a moderately high infestation without apparent diminution of crop yield.
INVESTIGATIONS ON HETERODERA SCHACHTII IN LANCASHIRE AND CHESHIRE PART II. THE RELATIONSHIPS BETWEEN DEGREE OF INFESTATION AND HYGROSCOPIC MOISTURE, LOSS ON IGNITION AND pK VALUE OF THE SOIL
Authors: SMITH A. M. 
Published: February 2008

SUMMARY.

Soil samples taken for the purpose of measuring the infestation of Heterodera schachtii have been further examined for any association between cyst concentration and those physico‐chemical properties relating to the moisture, temperature and acidity of the soil.
The hygroscopic moisture and loss on ignition have been determined for three typical series of ten samples having significant variations in cyst counts. There is no simple association of the observations within any of the series. It appears improbable, therefore, that the rate of reproduction of Heterodera schachtii is influenced to a marked degree by the normal variations in the physical condition of the soil.
The pH of seventy‐eight samples has been measured electro‐metrically. When the samples are divided into two groups according to soil type, there is found to be a significant negative correlation between pK and cyst count for fifty‐three peat soils. There is not, however, a significant correlation in the case of the other twenty‐five sandy soils.
THE MOSAIC DISEASE OF THE HOP; GRAFTING EXPERIMENTS, II
Authors: MACKENZIE D. , SALMON E. S. , WARE W. M. , WILLIAMS R. 
Published: February 2008

Summary.

When scions of varieties susceptible to mosaic disease were grafted on German, American, Danish, English and Seedling varieties, they developed typical mosaic disease. It appears, therefore, that “carrier” varieties are common amongst commercial varieties of hops. Certain male hops also proved to be “carriers.”
In a few cases susceptible scions grafted on “carrier” stocks remained healthy. These anomalous cases require further investigation.
As a rule, the “carrier” varieties show no trace whatever of mosaic disease; the leaves are of normal colour and the plant shows normal growth with high fertility.
A case is recorded where one “carrier” variety (Red Vine Canada) exhibited in one season nascent symptoms of disease. The term “masked mosaic” is suggested for the appearance shown.
Scions of the commercial variety Fuggles, when grafted on “carrier” plants, invariably remained healthy.
A MOSAIC VIRUS OF GRASSES, NOT VIRULENT TO SUGAR CANE
Authors: Stokey H. H. 
Published: February 2008

Summary.This paper records studies of a mosaic disease observed in maize and Sorghum spp. in the Transvaal, South Africa. In these hosts the signs produced were not distinguishable from those produced by the common sugar cane mosaic virus. Leaf‐cage experiments showed that Aphis maidis Fitch was capable of transmitting the virus to maize.In the part of the Transvaal where the mosaic was found all sugar cane seen was free from mosaic. Sugar cane failed to contract the disease, both in a field experiment extending over three years in the Transvaal and in large cage experiments in Natal. The method employed in the Natal experiments was always successful in transmitting mosaic to sugar cane when the source of infection was either diseased cane or diseased grasses collected in the neighbourhood of diseased cane.It is concluded that the Transvaal virus is not virulent to sugar cane and is therefore different from the common sugar cane mosaic virus.
POLLINATION OF HARDY FRUITS: INSECT VISITORS TO FRUIT BLOSSOMS
Authors: WILSON G. FOX 
Published: February 2008

Summary.It was considered necessary to carry out observations on the insects concerned in the pollination of hardy fruit flowers over long periods in order to arrive at definite conclusions as to what insects may be considered essential for the carrying out of the work.The result of five years' work has shown the usefulness of th3 hive bee as a pollinating agent, yet the important work of pollination, under certain conditions, may be carried out entirely by wild insects, principally humble and other wild bees (Bombus and Andrena) and flies (Eristalis, Syrphus, Sciara, Anthomyiids and Calliphora).The district and the position of orchards govern to a large extent the numbers of wild insects, and the plantations at Wisley are favoured in this respect by their close proximity to open country and pasture land.The factors, other than the presence of pollinating agents, which influence fruitfulness in orchards are considered.The transference of pathogenic organisms by anthophilous insects is discussed.The species of insects taken on the various fruit flowers are listed together with data as to their individual habits and abundance.A census of the chief pollinating agents of hardy fruit flowers at Wisley is appended and the meteorological data covering the period over which observations were made.
THE LARVA AND PUPA OF SCATOPSE FUSCIPES MG. AND A COMPARISON OF THE KNOWN SPECIES OF SCATOPSID LARVAE
Authors: LYALL EDITH 
Published: February 2008

Summary.The larvae of Scatopse fuscipes were found in decaying green ginger at a London dock in 1927. The necessity for descriptions of larvae occurring in stored products is pointed out.The previous literature is discussed. General descriptions of the larvae and pupae are given, especial attention being paid to the mouth‐parts of the larvae, which have in common with larvae of several Dipterous families, “premandibles.”A short comparison of the larvae of S. fuscipes, S. notata and S. subnitens is made and the most important differences between them are emphasised. No other species have yet been described.I have to express my indebtedness to Mr O W. Richards for material and references and to Dr J. W. Munro for his assistance and advice.
SOME ASPECTS OF THE MORBID ANATOMY OF PLANTS
Authors: BUTLER E. J. 
Published: February 2008

Summary.The anatomical modifications in the tissues of plants caused by the action of gall‐inducing fungi and insects are illustrated by a number of examples, and compared with those produced by various processes of regeneration and wound healing or by factors that lead to anatomical changes without the intervention of wounds, such as nutrition, humidity, and the like. It is concluded that all living cells have the potentiality to react to various stimuli by hypertrophy, hyperplasy, or the development of meristeroatic tissues, and that the pre‐existing meristems are not, of necessity, primarily implicated in gall formation.
INTRACELLULAR INCLUSIONS IN MOSAIC OF SOLANUM NODIFLOBUM
Authors: SMITH J. HENDEESON 
Published: February 2008

Summary.A description is given of the intracellular inclusions found in S. nodi‐florum after inoculation with the virus of the yellow (aucuba) mosaic of tomato. In this plant these inclusions are unusually conspicuous and can be observed in the living cell with exceptional ease. They are of two main types, crystalline spikes and amoeboid bodies, the latter corresponding to the X‐bodies found in other plants. A detailed account is given of their appearance, structure, position in the cells, relation to the nucleus etc. The X‐bodies may be either coarsely granular, looking like aggregates of particles, or more homogeneous; and they have a pronounced tendency to crystallise into the forms commonly seen in protein crystals. They are vacuolate, and occur in all the tissues of the leaf.
THE CHLOROTIC DISEASE OF THE HOP
Authors: SALMON E. S. , WARE W. M. 
Published: February 2008

Summary.

A description is given of a new virus disease of the top characterised by weakness of growth and by the presence of yellowish (chlorotic) markings on the leaves, accompanied by distortion of the lamina. The name “chlorotic disease” is proposed.
Two instances are recorded where the disease has been transmitted artificially, in one to a healthy plant by budding with a diseased bud, and in the other to a healthy scion by grafting it on to a diseased stock.
THE EFFECT OF CERTAIN TREATMENTS ON THE GERMINATION OF TOMATO SEEDS1
Authors: JOZEFOWICZ MARY 
Published: February 2008

Summary.

The effect of soaking tomato seeds in certain compounds and of exposing them to varying periods of wet and dry heat has heen investigated.
Good seeds (germination power 98–99 per cent.) withstood solutions of formaldehyde, not stronger than 2 per cent. (1 part per volume 38–40 per cent, commercial formaldehyde to 19 parts water) for 10 minutes, and not stronger than 1 per cent, for 15 minutes, followed by drying at 15–18° C. A 5 per cent, solution for 10 minutes, which was without effect when seeds were sown wet, retarded the germination after drying but did not affect the seeds' vitality.
Seeds of an inferior quality (80 per cent, germination) withstood solutions of formaldehyde not stronger than 1 per cent, for 5 minutes when sown wet, and were affected even by 0.1 per cent, formaldehyde for 5 minutes when dried after treatment.
100, 50, 35, 10, 5 and 1 per cent, solutions of hydrogen peroxide (commercial 20 vols. hydrogen peroxide) for 10 and 30 minutes, followed by drying, retarded germination, which was more pronounced with stronger solutions, the vitality of the seeds being practically unaffected.
An 0.05 per cent, mercuric chloride solution for 10 minutes proved harmless, but higher concentrations and longer treatment either checked the germination of dried seeds or retarded it markedly.
The vitality of seeds was not affected by copper sulphate solutions as follows: 10 per cent, for 15 minutes, 5 per cent, for 20 minutes, 2 per cent, for 50 minutes, 1 per cent, for 100 minutes and 0.5 per cent. for 200 minutes, but the germination in some cases was markedly retarded. A 5 per cent, solution of copper suphate for 10 minutes proved practically harmless.
Good air‐dried seeds withstood hot water at 35–46° C. for 15 hours and at 50.5° C. for 1 hour without any important injury. Higher temperatures decreased the percentage germination markedly even after 10 minutes' soaking.
Air‐dry seeds were not affected by exposure to dry heat of 30–50° C. for 72 hours. They withstood dry heat up to 79.5° C. even for 72 hours, the germination, however, being more retarded as the temperature and time of exposure increased. Temperatures above 79.5° C. proved very injurious at 10 minutes' exposure.
SOME OBSERVATIONS ON TOMATO PLANTS FROM SEED SUBMITTED TO HIGH TEMPERATURES1
Authors: JOZEFOWICZ MARY 
Published: February 2008

Summary.

The results of pre‐drying seeds prior to heating at high temperatures and a description of abnormalities in tomato seedlings caused by heat are given.
Commercial tomato seeds withstood 90° C. and 88–100° C. for 1 hour better when previously dried at lower temperatures, their germination being, however, markedly retarded.
Part of the heated seeds germinated abnormally, and the developing plants were more or less abnormal. The primary root did not develop, the cotyledons were misshapen, and the plumule failed to develop into a normal shoot.
The longer the period of pre‐drying, the higher the rate of germination, and the less the degree of abnormality.
The basal growing point of a tomato embryo is least resistant to heat, the apical growing point, the hypocotyl, the inner and, lastly, the outer cotyledons following in order of resistance.
Embryos unable to push through the seed‐coats can grow for a certain period within them and develop chlorophyll.
THE TRANSMISSION OF STREAK DISEASE BETWEEN MAIZE, SUGAR CANE AND WILD GRASSES
Authors: STOREY H. H. , McCLEAN A. P. D. 
Published: February 2008

General summary.

This paper describes experiments in the transmission of streak disease between maize, sugar cane, D. horizontalis Willd. and E. indica Gaert. The leafhopper, Cicadulina (Balclutha) mbila Naude, acted as the transmitting agent and was usually manipulated by the single‐leaf cage method.
The virus of maize streak disease is incapable of causing permanent infections of sugar cane. This conclusion is based on a considerable series of leaf‐cage experiments, in the greenhouse and in the field, and upon a large‐cage experiment. It is confirmed by certain field observations.
The maize virus frequently caused transitory infections of Uba cane, in the form of a few large chlorotic streaks on the leaves. From these streaks the virus was re‐transferred to maize. All evidence indicated that the cane plant made a complete recovery from this transitory infection and ceased to harbour the virus.
The virus from Uba cane readily infected Uba cane. When transferred to maize it produced in this species only a mild form of streak disease, distinguishable with certainty from normal maize streak. Repeated passage of the cane virus through maize failed to enhance its virulence to maize. Infection by the cane virus afforded no protection to a plant from infection by the maize virus; nor were hoppers similarly protected.
Streak disease was discovered in the cane variety P.O.J. 213, hitherto regarded as immune. The virus from these plants produced normal streak in Uba cane and the mild form of streak in maize. After many failures the disease was transmitted experimentally to this variety from Uba cane and from P.O.J. 213 naturally infected in the field. Cuttings taken from diseased plants of P.O.J. 213 frequently produced entirely healthy plants.
Lists are given of cane varieties which have been proved to be susceptible to streak disease and of those provisionally regarded as immune.
A list is given of species of wild grasses believed to contract streak disease in the field.
Streak in D. horizontalis has been transmitted from D. horizontals and to and from maize, but not from cane. The virus from a naturally diseased Digitaria plant, however, showed a virulence to cane greater than the maize virus.
E. indica was not successfully infected from maize or Uba cane. It was once mildly infected from P.O. J. 213, and was temporarily infected from Eleusine.
In experiments infective leafhoppers survived in the open through the winter at Durban and infected maize in the following spring. The infection of maize in the spring in Natal is thought to be caused usually by survival of the virus in overwintering leafhoppers and not in perennial host‐plants.
OBSERVATIONS ON LEAF FALL IN THE DOUGLAS FIR WHEN INFECTED WITH RHABDOCLINE PSEUDOTSUGAE SYDOW
Authors: BROWN A.B. 
Published: February 2008

Summary.

In the Douglas fir the abscission layers and associated tissues are laid down early in the development of the leaf.
The extent of development of the protective layer has no causal relationship with leaf fall.
Infection with R. Pseudotsugae brings about a marked decrease in the water content of infected leaves.
The abscission mechanism is efficient at an early stage in the life of the leaf, provided the necessary physiological conditions are present and R. Pseudotsugae is capable of providing these conditions.

The author wishes to express his indebtedness to Dr Malcolm Wilson for his valuable supervision of the work and criticism of the manuscript.
CARBON DIOXIDE IN RELATION TO GLASSHOUSE CROPS
Authors: WHITE H. L. 
Published: February 2008

Summary.

Data are given showing that the process of enriching the atmosphere with carbon dioxide affects the tomato plant slightly in many different ways, the sum of these tending to an increased yield of fruit.
These effects include (1) shortening of the period between opening of the flower and picking of the fruit, (2) high percentage of blossom developing into fruit, (3) lower percentage of fruit retarded in ripening,(4) better development of the truss normally most poorly developed,(5) earlier development and ripening of trusses in the later part of the season, (6) better swelling of the fruit at the end of the season.
Conclusions are drawn from the data that the results of an increased concentration of carbon dioxide are most beneficial to the plant at periods of low fruit‐production. These periods are discussed as occurring in the life of the commercially grown tomato plant.
The greatest percentage increases in weight of fruit of the treated plants over the controls are picked from the trusses which develop at such periods in the life of the plant.

In conclusion the writer is indebted to Dr W. F. Bewley, Director of the Cheshunt Experimental Station, and Dr F. G. Gregory, of the Imperial College, for valuable suggestions in connection with the text.