bluuebunny/crossref_metadata_2025_split huggingface dataset:
YIELD STUDIES IN OATS: III. The Inter‐Relationship Of The Parts Of The Oat Plant During Development
Authors: Tincker M. A. H. , Jones Martin G. 
Published: February 2008

Summary.1. This paper is the third report of a series dealing with the oat crop, and is concerned with the inter‐relationship of the developing parts of the plant in the field.2. Experiments are reported in which the various component parts of the sub‐aerial growth of spaced plants growing at stated intervals were removed at successive stages of development. The after‐effect of such treatment was observed upon the rate of growth of both the roots and shoots.3. Whilst the removal of lateral branches in their developmental stages, during which they are dependent upon the parent branch, resulted in an acceleration of the rate of growth of the parent axis, the removal of any part of the sub‐aerial growth which is actively engaged in photosynthesis caused a reduction of the rate of growth of the plant as a whole. Such changes in the rate of growth are reflected in the root system and the ratio of root to shoot.4. The influence of the removal of part of the shoot system is a lasting one. It can be traced out upon the time of flowering, and its effect noticed upon the rate at which the remaining parts ripen.5. These Considerations are closely related to the previous agronomic observations dealing with the relative yield of grain and straw obtained from a variety. The late, multi‐tillered varieties, are the straw yielders par excellence. In them the relationship of the parts of the plant more closely corresponds to that observed under conditions of wide space than under limited space. The early varieties in general behaviour more closely resemble the plants grown at close intervals and those plants grown at wide intervals from which the side tillers were removed.The authors desire to express their thanks to Prof. R. G. Stapledon, the Director of the Welsh Plant Breeding Station where this work was carried out, for so kindly providing the facilities necessary, but more particularly are they indebted to him for his enthusiastic interest and the encouragement given at all stages. To the members of the technical staff we are indebted for assistance in the cutting, counting, and weighing of the large number of plants.
Further Results Of An Investigation Into The Resistance Of Basket Willows To Button Gall Formation
Authors: Barnes H. F. 
Published: February 2008

Summary.1. Twelve commercial varieties of S. triandra have been proved, under experimental conditions, to be very susceptible to attack by the button top midge (R. heterobia).2. Three varieties of S. purpurea, one variety of S. viminalis, three hybrids of S. viminalis and purpurea and S. alba var. vitellina have proved to be totally immune. Notwithstanding eggs sometimes being laid and the larvae hatching, no galls or side‐branching have occurred.3. From field observations a closely allied gall midge, R. terminalis, is known to attack S. alba var. vitellina, but has not been known to attack any variety of S. triadra.4. Reference has been made to a similar phenomenon with regard to attacks on willows by the Chrysomelid beetles; viz. to Galerucella lineola which appears to be confined to varieties of S. triandra; and to Phyllodecta vitellinac which is known to attack S. alba var. vitellina and S. purpurea and its varieties, while it is not known to attack any variety of S. triandra.5. It is suggested that hybridisation of S. triandra×S. purpurea or ×S. viminalis or ×S. alba should be attempted. Mention is made of three aspects of host plant, preference needing special attention in connection with willow gall midges.In conclusion it is desired to express the indebtedness the writer owes to Mr Hutchinson, who was responsible for the choice of the varieties of willows to be tested in the various trial beds and the supply of sets. Dr Walton, of the Long Ashton Research Station and Mr Kearns of Bristol University have taken part in several very helpful conversations. Thanks are also due to Dr Imms for the generous aid he has given throughout the period of the investigations.
Studies IN Bacteriosis: XIX. Researches on the Group of Green‐Fluorescent Bacteria, Part I; Bacterium Trifoliorum (Jones ET AL.) AS THE Cause OF A Disease OF Vicia Faba
Authors: Lacey. Margaret S. 
Published: February 2008

SummaryA disease of Vicia faba is described and the causal organism identified as B. trifoliorum. This species is compared with other members of the green‐fluorescent group of bacteria.
The Biological Decomposition OF Plant Materials: Part IV. The Biochemical Activities on Straws of Some Cellulose‐Decomposing Fungi
Authors: Norman A. Geoffrey 
Published: February 2008

Summary1. A number of common soil fungi isolated from rotting straw were inoculated into sterile straw with the addition of available nitrogen.2. The amount of decomposition effected, the losses of various straw constituents, and the immobilisation of nitrogen which took place, were all determined, and compared with mixed flora decompositions at various temperatures.3. Though none of the organisms develop appreciably on a cellulose‐agar plate, all were found to decompose cellulose to a considerable extent.4. Certain minor differences in ability to utilise the carbohydrate constituents were noted, but in general all substances but lignin were attacked to a degree relatively proportional to the apparent total loss of organic matter.5. The “nitrogen factor” or nitrogen immobilised by 100 gm. straw rotting with a particular organism was determined in each case. There is no correlation between the “nitrogen factor” and the loss of organic matter or of any particular straw constituent. The differences appear to be varietal.6. Some indication of the relative efficiencies of the organisms was obtained from a factor for which the name “nitrogen equivalent” is proposed. This represents the nitrogen immobilised as microbial protein in the course of the removal of 100 gm. organic matter from any given plant material.7. Attention is drawn to difficulties which restrict the absolute value of the “nitrogen equivalent” as a measure of efficiency in decomposition.8. The value of single factor studies as a preliminary to the synthetic method of investigation of such a process as biological decomposition is discussed.The author‐is indebted to Sir John Russell, F.R.S., Director of the Rothamsted Experimental Station, for placing at his disposal the facilities of that Station, and to the Department of Scientific and Industrial Research for a Senior Research Award, during the tenure of which this work has been carried out.Especially are his thanks due to Dr W. B. Brierley, and Mr E. H. Richards, Heads of the Departments of Mycology and Fermentation, for their ready assistance and advice.
A Botanical Study of Pasture Formation
Authors: Fenton E. Wyllie 
Published: February 2008

Summary.Where summer drought is liable to occur it is impossible to form a satisfactory turf in pasture without Wild White Clover. White or Dutch Clover cannot replace Wild White Clover except during the first year of grazing.Italian Rye Grass is of considerable value, not merely on account of its early growth, the shelter afforded slower‐growing species and helping to conserve surface moisture, but it greatly assists Wild White Clover by competing against Red Clover.The two most successful plots were those with Italian Rye Grass in the seeds mixture.The addition of Rough‐Staked Meadow Grass was a distinct success and it should be included in seeds mixtures for long leys or permanent pastures in South Devon.With sound mixed grazing, all the plots—except No. III—gradually developed a flora of very similar proportions, in spite of initial differences.The chief feature of the best plots was the Wild White Clover— Perennial Rye Grass association plus Cocksfoot, and in one case plus Rough‐Stalked Meadow Grass.Timothy was not successful in the pasture owing to severe grazing by sheep and the effect of summer drought. It was much more successful and permanent in the hay sub‐plots.Cocksfoot is a splendid drought resister and invaluable where summer drought is usual.Perennial Rye Grass, Wild White Clover, and Rough‐Stalked Meadow Grass tend to hold Cocksfoot in check and prevent any coarseness in its growth.The marked fluctuations in growth, as measured by the percentage ground covered, by the leading species in the plots is an annual occurrence of considerable regularity, the inter‐specific competition being well shown by the graphs.The close resemblance in results between the pastures and experimental pasture plots previously considered is a point of considerable importance.
The Susceptibility Of Certain Potato Varieties To Leaf‐Roll And Mosaic Infection
Authors: WHITEHEAD T. , CURRIE J. F. 
Published: February 2008

Summary.1. A trial planned to ascertain whether any differences in susceptibility to leaf‐roll and mosaic infection existed in seven varieties—two of which had been included in a revious trial—was laid down in 1929. It consisted of four replicated plots for each disease; the varieties being randomised in the plots to secure uniform chances of infection. Sources of infection were provided by drills of diseased plants alternating with varieties under test.2. Mosaic was generally transmitted but with such faint symptoms that percentage infection could not be determined. The apparent loss of vigour was very slight, but losses ascertained by weighing the crop, against that given by normal plants, ranged from 0·8 to 24·4 per cent.3. Leaf‐roll infection was very heavy; most varieties showing from 90 to 100 per cent. infection of the plants. Tuber infection on the infected plants was also heavier than in 1924, and ranged from 77·3 to 99·9 per cent. Both haulm (or plant) infection and tuber infection thus showed a marked dependence upon seasonal factors which affect the breeding of insect vectors.4. The loss in yield due to leaf‐roll was found to be the most reliable guide to the susceptibility of a variety. This loss cannot be estimated from the degree of stunting or the number of rolled leaves on a plant, but only by weighing and grading the crop. Some evidence is presented to show that loss in yield of an infected plant is less dependent upon seasonal factors than percentage haulm or tuber infection, and that, therefore, figures showing such losses have a more general applicability to other localities and seasons. On this assumption a table of susceptibility of fifteen varieties has been constructed.5. Although the variety Field Marshal suffered little from leaf‐roll infection, heavy losses occurred when mixed leaf‐roll and mosaic viruses entered the plant. In large tubers receiving mixed infection the effect was to produce neither leaf‐roll nor mosaic symptoms, but “crinkle.” The small tubers, however, gave apparently pure leaf‐roll.6. The value to be attached to field trials of this kind, and their applicability to other conditions, is discussed in detail. Suggestions are offered for improvement in the technique for such trials.
THE INTIONS OF ENVIRONMENTAL CONDITIONS ON THE DEVELOPMENT OF THE ANGULAR LEAF‐SPOT DISEASE OF COTTON: III. The Influence Of Air Temperature On Infection
Authors: STOUGHTON R. H. 
Published: February 2008

Summary.Experiments carried out in the Rothamsted control chambers on the influence of air temperature on the angular leaf‐spot disease of cotton plants, resulting from spray inoculation of young plants, show that high air temperatures favour the development of the disease. Maximum infection occurs at an air temperature of 35–36° C. with decreasing incidence at progressively lower temperatures. At a constant air temperature of 39–40° C. cotton plants make no growth and eventually die.Infection takes place more readily when the inoculation is carried out during the non‐illuminated period.The relation of these results to the experiments on the influence of soil temperature is discussed.
The Absorption Of Water By Seeds Of Lolium Perenne (L.) AND Certain Other Gramineae
Authors: BROWN R. 
Published: February 2008

Summary.1. The methods used in these investigations into the problems of absorption of water by seeds are described. A modification in the method of direct weighing is suggested.2. The rôle of the pale in absorption is discussed. The pale exercises a retarding effect on water absorption, so long as it is attached to the caryopsis. But the attachment is broken as the absorption of water with consequent swelling extends from base to apex.3. The cuticular membranes of the seed retard the absorption of water, but the permeability is increased by the stretching of the cuticle, consequent upon swelling.4. The earliest absorption takes place through the micropyle. This water can diffuse upwards to a certain extent. At the higher level it causes the endosperm to swell, which in its turn induces greater permeability of the cuticular membranes. The water absorbed at this higher level diffuses upwards to a slight extent, and causes greater permeability at a still higher level. Thus, there is a progressive extension upwards of the area of absorption induced by the slight upward diffusion of water.The writer wishes to acknowledge his indebtedness to Prof. W. Stiles for help in the preparation of the manuscript of this paper; to Mr F. R. Horne for help in the course of the work; and to Mr R. L. Stevenson for making the diagrams which accompany this paper.
The Problem Of “Potato Sickness”: A Report Upon Certain Experiments
Authors: BUCKHURST A. S. , FRYER J. C. F. 
Published: February 2008

Summary.1. A study of the causes of “potato sickness” has been made during the past two years, both in the field and by means of pot experiments.2. The sickness does not occur in the absence of the nematode H. schachtii, but potato plants may grow normaliy even when heavily attacked by this eelworm. No correlation was found between the cyst content of the soil and the intensity of the sickness.3. There is no reason to suspect that the fungus C. Solani plays any primary part in causing the sickness, and no other parasitic organism (apart from the eelworm) likely to be responsible for the trouble was discovered.4. The evidence suggests that the sickness is due to an attack by the eelworm in conjunction with a soil factor that inhibits a vigorous early growth of roots; it is possible that this second factor is a nutritional defect which is not made good by the ordinary manurial measures adopted in potato‐growing districts.
FUSARIUM SPECIES ON BRITISH CEREALS
Authors: BENNETT P. T. 
Published: February 2008

SUMMARY

F. Scirpi Lamb, et Fautr., previously described in its pseudopionnotal form, occurs in a mycelial form also; the cultural characters and method for conversion of the forms are given.
This variety is designated pallens to distinguish it from a new variety designated nigrans. also occurring on cereals. The relationship of the two varieties is discussed.
Both varieties are associated with Fusarium disease in cereals, but are of little economic importance except when the variety pallens prevails on the ears of wheat and barley; infected grains used for seed, if still viable, give less vigorous plants and reduced yield of corn.
Studies on plant virus diseases1
Authors: SMITH KENNETH M. 
Published: February 2008

SUMMARYFurther studies upon a ringspot virus are described and the following points in the work are emphasised:

The insect Thrips tabaci Lind. is found to be an efficient vector of the virus.
The technique and methods of Thrips management are described.
Evidence is presented which indicates that the ringspot virus previously described from Solatium capsicastrum is identical with the tomato virus known in Australia as spotted wilt.
The host range of the virus has been studied. All species of Solanaceae tested, i.e. twenty in number, were found to be susceptible to the disease, and in addition the virus has been transmitted to Lupins, Dahlias, Asters, Zinnias and Plantains.
The spotted wilt virus was found not to pass an ix Pasteur‐Chamberland candle, and its viability was lost after 4 hours' ageing in vitro. An accurate method of testing the longevity in vitro of the virus is obtained by making use of the special reaction of the Petunia plant to the disease.
A comparison is given of the virus of tomato spotted wilt with a tomato virus of the stripe or mosaic type associated with it.
CULTURAL STUDIES ON THE ASPERGILLI, WITH SPECIAL REFERENCE TO LIPASE PRODUCTION OF STRAINS ISOLATED FROM STORED COPRA AND CACAO
Authors: EYRE J. C. 
Published: February 2008

SUMMARY

‐Thirteen strains of Aspergillus, including four of A. niger and two of A. flavus, one strain each of Mucor racemosus and Syncephalastrum cinereum and a blue‐green Penicillium are dealt with in this paper. They were isolated from stored products, mainly copra and cacao. Determinations were made of the lipolytic activity of the dried mould, the weight of dried mould produced and the lipolytic activity, titratable acidity, and pH. of the liquid Czapek medium in which the moulds were grown. The influence of an increase in temperature was also investigated.
Figures are given for the lipolytic activity for 2 weeks' growth and in the case of some species also for 4 and for 8 weeks' growth. All the strains were found to be lipolytically active both as regards the medium and as regards the dried mould. On a basis of 2 weeks' growth the strains of Aspergillus were divided into two distinct classes in relation to the amount of lipase found in the medium. In the case of the activity of the dried mould two classes were again found. With two exceptions the same moulds were found to be in the same class in both cases.
It was found that while the lipolytic activity of the dried mould and of the medium were materially the same at 2 weeks as at 4 weeks, determinations made at 8 weeks indicated an increase in the activity of the medium and a decrease in the activity of the dried mould coincident with a decrease in the weight of growth. It is therefore suggested that the increase in the activity of the medium is due to autolysis and probably also to an increased excretion of enzyme.
As it was found that the amount of lipase in a medium containing coconut oil as the source of carbon was much greater than in a sucrose medium it is concluded that the coconut oil stimulated the production of the enzyme.
In the case of the Aspergilli there was a definite correlation between the colour of the mould, the colour of the medium and the titrat‐able acidity of the medium. The lighter coloured forms produced least acid and most colour in the medium, while the dark forms produced most acid and least colour. On autolysis the depth of colour of the medium increased and the titratable acidity decreased.
Marked differences in the titratable acidity of the medium were found between the four strains.of A. niger. An mcrease of temperature had the effect of bringing about still more marked differences and in addition, differences in lipolytic activity. No qualitative differences were found.
A. niger (copra), A. flavus (light), A. tamarii and A. sydowi were grown on a coconut oil emulsion. The rates at which the different species clarified the emulsion were noted. A. niger and A. flavus clarified the emulsion in the shortest time. The addition of sucrose had the effect of considerably retarding the assimilation of the oil in the emulsion.
ON A SUGGESTED METHOD FOR DETERMINING THE NUMBER OF LARVAL INSTARS IN SITODREPA PANIGEA L.
Authors: METCALFE MARGOT E. 
Published: February 2008

SUMMRY AND CONCLUSIONS

A number (887) of larvae of Sitodrepa panicea L. were examined with a view to testing the application of Dyar's law and the possibility estimating the number of larval instars by measuring the head capsule a random population.
The measurements were found to fall into two groups, one slightly larger than the other, whose growth ratios approximated to two geometrical series, one with a common ratio of 1–12, the other with a common ratio of 1.11.
It is suggested that these two groups represent the sexes.
On this hypothesis it would appear that the males undergo a minimum of four larval ecdyses, and the females a minimum of five. Miles (loc. cit,) postulates a similar phenomenon for several species of Tenthredinidae. Furthermore, the sex ratio is not unity.
The method of investigating the growth ratio of the larva by the measurement of a large population, is not entirely satisfactory. Owing to diversity of causes such as the periodicity of egg‐laying, insufficient numbers of the young larvae were obtained, and no satisfactory conclusions with regard to the number of these early instars can be reached.
The analysis of the data is further complicated by the variation in size and presumed overlapping of the instars in both sexes.
Until much larger and more representative populations, or many more samples of small populations can be examined, such a method of determining the number of larval instars in a given insect can be but of debatable value.
THE EFFECT OF SEED DISINFECTION UPON THE OAT CROP IN NORTHERN IRELAND
Authors: MUSKETT ARTHUR E. , CAIRNS HUGH 
Published: February 2008

SUMMARY

This paper deals with a series of experiments carried out in Northern Ireland over a period of three years in order to determine the value of various seed treatments for controlling smuts and for use as general seed disinfectants in connection with the cultivation of the oat crop.
In so far as the control of oat smuts is concerned and at the concentrations used in these experiments, copper sulphate and copper carbonate proved to be of some value but caused definite injury to the crop, while sulphur and gypsum proved to have no fungicidal value. Formaldehyde gave complete control in nearly every case, the sprinkle method being considered more satisfactory than steeping, as it is more easily carried out and as the results obtained indicate that in some cases steeping may cause crop injury. The organic mercurial–“Ceresan”– gave almost as good results as formaldehyde.
As general seed disinfectants the organic mercurials–“Ceresan” and “Abavit B”–proved to be more satisfactory than formaldehyde, the average increase in grain yield from these plots being approximately 30 per cent, above the yield from the formaldehyde plots which in turn showed a yield increase of 16 per cent above the controls.
It is suggested that the greater efficiency of organic mercurials is due to the fact that the fungicide is retained by the grain at the time of sowing and remains operative during the early stages of crop development without causing injury to the plants.

The fact that oat grain has been treated with “Ceresan” and “Abavit B” at varying intervals before sowing with complete success indicates that this method of treatment possesses a distinct advantage over the formaldehyde method where, in order to preclude possibly injury during germination, it is necessary to carry out the treatment immediately prior to sowing. No causes of poisoning as a result of the use of organic mercurials have occurred so far and it is possible that by taking reasonable precaution the. use of these compounds for seed dressing may be safely advocated.