bluuebunny/crossref_metadata_2025_split huggingface dataset:
THE TOXIC ACTION OF TRACES OF COAL GAS UPON PLANTS
Authors: PRIESTLEY J. H. 
Published: February 2008

Summary.

1. There is clear evidence in the literature that the toxic action of traces of illuminating gas upon plants may be traced to the presence of gaseous unsaturated hydrocarbons. A concentration of one part of ethylene in ten million of air is toxic to the etiolated epicotyl of a pea.
The effect of these unsaturated hydrocarbons can be traced in the case of root or etiolated stem to their inhibition of the formation of a functional primary endodermis, which is usually present in these plant structures.
The unsaturated hydrocarbons prevent the formation of a functional endodermis, by preventing the normal accumulations of unsaturated acids in the region of the future Casparian strip.
It is suggested that the effect of traces of these gaseous unsaturated hydrocarbons upon cork formation may be due to the arrest of the normal deposit of fatty acids in the membranes of the cork cells.
The practical significance of this work lies in the fact that definite diagnostic features may now be sought for when injuries to plants are suspected to be due to gas poisoning.
STUDIES ON THE APPLE CANKER FUNGUS II. CANKER INFECTION OF APPLE TREES THROUGH SCAB WOUNDS1
Authors: WILTSHIRE S. P. 
Published: February 2008

Summary.The infection of apple trees by the canker fungus through scab infections is described.The conidia alighting on the exposed scab stroma give rise to a mycelium which attacks the latter and then grows out into the cortex. The fungus is able to pass through any immature cork layer and finally reach the wood.
STUDIES IN THE VARIETAL IMMUNITY OF POTATOES TO WART DISEASE (SYNCHYTRIUM ENDOBIOTICUM SCHILB., PERC.)
Authors: ROACH W. A. 
Published: February 2008

Summary.

Grafting experiments of a preliminary nature have been carried out to throw light on the functions of the various organs of the potato plant in rendering the tubers immune or susceptible to Wart Disease (Synchytrium endobioticum Schilb., Perc).
It is hoped that such knowledge may facilitate a biochemical study of the problem by indicating which part of the plant to investigate first, and to give some clue to the general nature of the chemical differences to be sought.
Composite plants were built up by grafting in the following ways:3 plants of the type Immune grafted on Immune.3 plants of the type Susceptible grafted on Immune4 plants of the type Immune grafted on Immune Susceptible.2 plants of the type Susceptible grafted on Immune
The results are in harmony with the conclusion that the character of the foliage has no influence on the immunity or the susceptibility of the tubers to Wart Disease.
It follows that no compound synthetised in the leaves is likely to be responsible for separating potatoes into “immunes” and “suscep‐tibles.”
The investigation is being continued, and it is hoped to determine whether any one part of the plant influences the immunity or susceptibility to the disease of any other part. The desirability of investigating a portion possessing such an influence is obvious. If the several parts of the plant have no such effect on each other, a search for differences in substances, such as the proteins, which are only translocated with difficulty, if at all, would be indicated.
STUDIES IN BACTERIOSIS. X
Authors: PAINE SYDNEY G. , LACEY MARGARET S. 
Published: February 2008

Summary.

Serum agglutination has been used in order to determine possible relationship with Bacillus lathyri of certain yellow organisms which occur in the tissues of plants infected by that organism.
One of these gave all the reactions of Pseudomonas Phaseoli.
Pseudomonas Phaseoli and Bacillus lathyri gave distinct cultural characters, and these were retained even after the two organisms had been “trained” by ten transfers through the same medium.
The two organisms seem to be susceptible to group agglutination, Bacillus lathyri being agglutinated with the serum of Pseudomonas Phaseoli.
Intermediate forms between these two organisms are found which agglutinate equally with the sera of both species.
The suggestion is made that one species may have arisen in the tissues of the plant as a mutant from the other.
Aplanobacter dissimulans, another organism often associated with Bacillus lathyri, appears to bear no sort of relationship with the latter.
Aplanobacter michiganense failed to produce an agglutinating serum on inoculation into a rabbit.
A STUDY OF THE FAUNA OF RIVERS POLLUTED BY LEAD MINING IN THE ABERYSTWYTH DISTRICT OF CARDIGANSHIRE
Authors: CARPENTER KATHLEEN E. 
Published: February 2008

Summary.

The relative poverty of the fauna and flora of certain streams in the Aberystwyth district can only be related to their pollution by lead mining and lead washing operations.
Such operations affect the rivers by the discharge into their waters of galena particles in all stages of division, and also by the formation of lead salts in diffusible form through chemical interaction with the natural water.
Only a single case is known of the clogging of fish‐gills by adhering particles of galena‐grit: there is no definite evidence that this is a usual cause of death.
Statistics locally collected shew, however, that such lead grit is present in practically all the streams of the neighbourhood, particularly in the Lower Clarach, where a rich fauna, including Fishes, subsists.
The correlation of fauna lists with tables of analyses of water samples shews that poverty of fauna, with absence of fishes in particular, always accompanies the presence of lead salts in diffusible form.
The cessation of the last of the lead mining and washing operations affecting the Rheidol and Ystwyth was followed by a marked and rapid increase in the flora and fauna of the rivers, which was accelerated by the spring drought of 1922. At this season, the amount of lead in diffusible form in these waters was, if any, too small to be estimated, while the proportion of lead grit remained high.
Observations made since May, 1922, shew that the original proportion of lead in diffusible form has not been restored, while the flora and fauna have continued to increase.
The general inference is that, while the presence of lead grit is no doubt in some cases directly harmful to Fishes, the general fauna of the rivers is undoubtedly impoverished by the presence of lead salts in diffusible form.
POTATO LEAF‐ROLL AND DEGENERATION IN YIELD
Authors: WHITEHEAD T. 
Published: February 2008

Summary and Conclusions

The present communication summarises the first results of work now being carried out at the College farm, Aber, Bangor. It is to be regarded as a first progress report.
Quanjer's statement as to communicability of leaf‐roll by grafting tubers is confirmed.
The unlikelihood that ‘seed’ sterilisation will be useful as a measure of control is indicated by the failure to effect any control by steeping infected ‘seed’ in 1/1000 mercuric chloride for an hour and a quarter.
Cutting diseased tubers before planting did not affect the yield.
The loss in yield due to leaf‐roll was 55.8 per cent. in 1921, 45.6 per cent, in 1922 and 52.6 per cent, in 1923.
The effects of leaf‐roll do not appear to be cumulative under the conditions at Bangor.
The proportion of seed‐size and small tubers—as determined by relative weights and numbers—to total crop was not increased in the variety Arran Comrade as a result of infection with leaf‐roll.
The reduction in total number of tubers produced by a leaf‐roll crop was = 54.4 per cent, in 1922 and 61 per cent, in 1923.
The transference of leaf‐roll to healthy plants at Bangor in 1921 and 1922 has been studied. Evidence of soil transmission in 1921 is submitted. In 1922 both aerial and soil transmission is believed to have taken place.
Maximum infection in 1921 did not affect the yield in that year.
The relation of leaf‐roll to seed‐potato production is discussed.
THE INFLUENCE OF HYDROGEN‐ION CONCENTRATION ON THE GROWTH OF CERTAIN BACTERIAL PLANT PARASITES AND SAPROPHYTES
Authors: BERRIDGE EMILY M. 
Published: February 2008

Summary and Discussion.It is interesting to see in the foregoing series of experiments that most of the bacterial plant parasites, especially those of the Pseudomonas type, and the non‐parasitic species of the fluorescens type seem to possess three associated characteristics, namely high acid agglutination points and limits of growth, and a capacity to produce alkali rapidly in the presence of nitrogenous food materials. This latter capacity is shown in a less marked degree by other non‐sporing saprophytio organisms such as B. lactis aemgenes.Many sporing species, on the other hand, appear to possess a different physiological constitution, since they produce acid in the earlier stages of growth in sugar‐free peptonized broth, and are characterized by comparatively low agglutination points and growth limits. Tests by Marchal and other observers (14) at a later period of their development have caused these sporing organisms to be regarded as the chief ammonia producers in the soil.The experiments also show that the hydrogen‐ion only begins to act injuriously on the bacteria at concentrations about pH 5.0–4.4. Such hydrogen‐ion concentrations are seldom met with in plant tissues except in the case of acid fruits. The acidity of the cell sap has been determined by several investigators by the hydrogen electrode method; Clevenger(8) found that it varied from pH 4.33 for Buckwheat seedlings to pH 6.40 for Soy bean leaves. The values obtained by Hoagland(ii) for barley tops, by Phillips (17) for Indian Corn and Vicia faba, and by Wagner (21) by means of an indicator method for Sinapis alba, Brassica oleofera, Solanum tuberosum and Sempervivum Hausmanni all lie between pH 4.9 and pH 6.2. The cell sap used in these experiments was generally obtained by pressure of the tissues after grinding with sand; treatment of sections of fresh tissues with methyl red indicates that the acidity of the protoplasm itself is somewhat higher than that of the cell sap, whilst Atkins (1) found that the liquid centrif uged from the tracheae of Acer pseudoplatanus was neutral to litmus. Priestley (18) too remarks with respect to the sap collected from a bleeding vine stem, that, “tested with the usual series of indicators, the pH values of the sap in the vines was practically that of true neutrality.”
THE CROWN‐GALL DISEASE OF NURSERY STOCKS
Authors: WORMALD H. , GRUBB N. H. 
Published: February 2008

Summary.An account is given of the galls (“crown‐gall”) found on layered apple stocks and on seedling apple trees raised at the East Mailing Fruit Research Station.On the layered stocks the galls arise most frequently at the .base of the stocks, i.e. at the wound caused when removing the stock from the parent stool, but they may also occur on other parts of the stem below ground, and on the roots.Observations extending over several years lead to the conclusion that, although galls have been found on every variety of layered apple stocks so far propagated at East Malling, some varieties are far more susceptible to crown‐gall than others.Evidence has been obtained that the susceptibility of the stock is to some extent influenced by the variety of scion grafted on it.No difference in vigour could be detected on the subsequent general growth of trees planted up with, or without, galls.
THE APPLE BUD WEEVIL, ANTHONOMUS CINCTUS, KOLL.
Authors: PETHERBRIDGE F. R. , COWLAND J. W. 
Published: February 2008

Summary. Anthonomus cinctus is widely distributed on the Continent and occasionally, in certain districts, does serious damage to pear buds, and now and then is found injuring apples. In this country it is not yet recorded on pears, but was found killing apple buds at Wisbech, in 1921, and near Cambridge, in 1922. Adults have also been found in Kent.The eggs are laid in apple buds (usually fruit buds) in the autumn, one egg only in each bud. The larva hatches at the end of February and eats out the succulent portion of the bud. It pupates in May and changes to the weevil stage in June. The weevils puncture the leaf stalks, buds and succulent portion of the shoots.A description of the various stages is given.A comparison is made between this species and those closely allied.Near Cambridge Pimpla pomorum killed most of the larvae and pupae left on the trees after collecting.
FURTHER EXPERIMENTS IN THE CONTROL OF CERTAIN MAGGOTS ATTACKJNG THE ROOTS OF VEGETABLES
Authors: SMITH KENNETH M. 
Published: February 2008

SUMMARY.Experiments dealing with four species of root feeding maggots are described. The insects concerned are: Hylemyia antiqua, the onion fly; Psila rosae, the carrot fly; Chortophila brassicae, the cabbage root fly; and Ceuthorrhynchus pleurostigma, the turnip gall weevil.Control experiments on the first two have been carried on since 1920. A list of all the chemicals used in these trials is given.As a result of the 1924 experiments the following are recommended for use against onion fly: (a) nicotine sulphate dust, in a 5 per cent. mixture with precipitated chalk; (b) chlor‐cresylic acid, in a 1 per cent, mixture with precipitated chalk.After three seasons' trials creosote is not considered an efficient remedy for onion fly.For carrot fly: (a) nicotine sulphate dust in a 6 per cent. mixture; and (b) creosote, in a 1 per cent. mixture, both in chalk, gave promising results in the 1924 trials.Of chemicals wed in field trials against the cabbage root maggot the most successful were: (a) chlor‐cresylic acid, (b) green tar oil, (c) creosote. Anthracene oil and nicotine sulphate also gave fair results.A number of pot experiments, designed to test the efficacy of corrosive sublimate as a control for cabbage root maggot, were carried out. Results do not appear to justify the use of this substance as a remedy, but further trial is necessary.400 cabbages, 200 galled by the larvae of the turnip gall weevil and 200 healthy, were grown under test conditions in order to ascertain the effect of these galls upon the health of the plant. The results of this experiment indicate that firstly the galls are attractive to slugs and secondly that the critical time in the life of a galled cabbage is the seedling stage, but that given good cultural conditions at the time of setting out, the cabbage will flourish normally.
A DISEASE OF WILD WHITE CLOVER CAUSED BY THE EELWORM, TYLENCHUS DIPSACI (KÜHN) BASTIAN
Authors: WARE W. M. 
Published: February 2008

SUMMARY.A disease of white clover, due to the eelworm, Tylenchus dipsaci, has been found to cause serious harm. This and other diseases are thought to be partly responsible for the lack of permanence sometimes ascribed to strains of white clover. In tests of the susceptibility shown by various clovers to the attacks of the eelworm from wild white clover, remarkable resistance was shown by red clovers and the maximum susceptibility by cultivated white clovers. The suggestion is made that in future tests of the relative susceptibility of various plants to attack by this parasite, the former hosts of the eelworm should be taken into account.A grant in aid of this and other work in connection with wild white clover was made by the Ministry of Agriculture.Thanks are due also to Mr Harald Faber, Agricultural Commissioner to the Danish Government, to Messrs Donaldson & Co., and to Messrs Gartons Ltd. for kindly supplying many of the seeds used.
REVERSION DISEASE OF BLACK CURRANTS: MEANS OF INFECTION
Authors: LEES A. H. 
Published: February 2008

SUMMARY.

This paper is a continuation of previous work on Reversion Disease of Black Currants, and deals more especially with the possible means of infection.
Evidence is put forward showing that the disease can be propagated by contact of diseased material with healthy, either by grafting or by pruning with a contaminated pruning tool.
The disease, after it has attained entry, is propagated slowly downwards.
The rate at which it travels appears to depend on the intensity of the original infection, and there is some evidence to show that the intensity of the resulting disease is also similarly dependent.
Propagation can be independent of Black currant mite, Eriophyes ribis.
There is no evidence of occurrence of the disease solely on the ground of proximity of healthy and infected plants.
There is some evidence in support of the possibility of a pest carrier.
STUDIES ON THE SEX‐RATIO AND RELATED PHENOMENA: 6. THE EFFECT OF POLYGYNY.
Authors: PARKES A. S. 
Published: February 2008

SUMMARY.(1) The evidence relating to the effect of polygyny on the sex‐ratio in man is conflicting, but the result, if any, appears to be a rise in the proportion of males.(2) In horses Düsing has shown that the proportion of males rises with increased stud work.(3) The experimental work on mice described in this paper shows that in this mammal a rise in the pescentage of males follows polygynous mating, and therefore supports Düsing's results.
STUDIES ON CONTACT INSECTICIDES: PART III. A QUANTITATIVE EXAMINATION OF THE INSECTICIDAL ACTION OF TKE CHLOR‐, NITRO‐ AND HYDROXYL DERIVATIVES OF BENZENE AND NAPHTHALENE
Authors: TATTERSFIELD F. , GIMINGHAM C. T. , MORRIS H. M. 
Published: February 2008

SUMMARY.1. The toxicities of a number of chlor‐, nitro‐ and hydroxyl‐derivatives of aromatic hydrocarbons to Aphis rumicis L. (adults) and to Selenia tetralunaria Hufn. (eggs) have been determined.2. The order of toxicity to the aphides of the hydrocarbons and their chlor‐ and nitro‐derivatives is benzene < toluene < sylene < monochlor‐benzene < p‐dichlor‐benzene < o‐dichlor‐benzene < trichlor‐benzene < nitro‐benzene < m‐dinitro‐henzene. The mono‐chlor‐nitro‐benzenes have about the same toxicity as nitro‐benzene; l‐chlor‐2: 4–dinitro‐benzene is slightly less toxic than m‐dinitro‐benzene.3. Phenol and the three isomeric cresols are toxic to aphides only at high concentrations. The mono‐nitro‐phenols and cresols are all mare toxic than the parent substances, the order of toxicity of the phenol being o‐nitro‐phenol < m‐nitro‐phenol and p‐nitro‐phenol < 2: 4–dinitro‐phenol > trinitro‐phenol; and the same order applies to the cresols and their corresponding derivatives.4. α‐chlor‐naphthalene proved to be the most toxic of the naphthalene‐derivatives tested.5. With few exceptions, the relative toxicities of the various compounds to the insect eggs are approximately in the same order as to the aphides. The nitro‐derivatives of phenol and the cresols were specially studied and it was shown that, as in the case of aphides, the dinitro‐compounds are more toxic to eggs than either the mono‐ or the tri‐nitrocompounds.6. 3:5–dinitro‐o‐cresol is shown to have a toxicity both to adults of Aphis rumicis and to eggs of Selenia tetralunaria which is of the same order as that of nicotine.7. Some of the compounds tested may prove to be of value as winter spray fluids for trees in a dormant condition although injurious to foliage, and experiments on a practical scale are in hand.8. A consideration of the results as a whole leads to the conclusion that no simple generalisation as to the correlation of toxicity with any one chemical or physical property is possible in the present stage of our knowledge. It is probable that the nature of the toxic activity depends on chemical constitution whereas intensity of activity is determined by one or more physical properties.
STUDIES ON OSCINELLA FRIT, LINN.: A PRELIMINARY INVESTIGATION OF THE EXTENT OF THE RECOVERY POWER OF OATS WHEN SUBJECT TO INJURY.
Authors: CUNLIFFE NORMAN 
Published: February 2008

SUMMARY.In the summer of 1924 an investigation of the extent of the recovery power of oats after injury approximately similar to that caused by Oscinella frit Linn. was conducted under experimental conditions. The larval attack in spring was simulated by killing the growing points of the stems [(1) main stem only and (2) main stem plus first two tillers] and growth records were obtained after a limited period of time. The varieties of spring oat, Scotch Potato and Sir Douglas Haig were used, being prolific and poor tillerers respectively. The oats were sown on April 13th, were above ground on April 26th, treated (1) May 27th and (2) June 6th, the crop being harvested during the third week in August.1. Undamaged Haig plants produced a less number of panicles than undamaged Potato plants by 21 per cent. With Potato, loss of main stem alone and loss of the first three shoots caused a reduction of about 40 per cent. in panicle production, With Haig, recovery after subjection to the first type of damage was almost complete, and as good as that exhibited by Potato after the second type of damage.2. With regard to height of fruiting stem, a reduction of about 20 per cent. was observed after the more severe treatment with both varieties.3. Spikeleh production varied greatly with variety, Potato carrying twice as many spikelets per fruiting stem as Haig. Tillers produced after the loss of the main stem carried no more spikelets than the normal tillers, i.e. about 30 per cent. less than the mean of the stems of the control plants. Tillers formed after the loss of three stems exhibited a reduction of 50 per cent. in spikelet production.4. Yield of grain was not recovered by Potato after loss of the main stem (reduction 60 per cent. by weight), whereas Haig to a great extent recovered its yield. Loss of the first three stems caused a reduction of 80 per cent. in both cases, the additional reductions not however being significant in these experiments. Owing to the production of a greater number of seed, however, Potato yielded almost as well after losing its main stem as Haig did when undamaged. The variations in yield of straw were of the same order as those observed for yield of grain.5. Recovery power after injury would appear to be much more marked with Haig than with Potato, and cannot necessarily be forecasted from a knowledge of tillering capacity. Under field conditions, where capability of covering the ground after losses may be comparatively small, as in the case of a weak tillering variety (although poor initial tillering capacity may be compensated for by an increased population), an oat like Potato might give a better yield of produce than one like Haig, even although Haig may exhibit greater recuperative powers than Potato. This problem is of course intimately related to the general problem of yield, which itself still awaits solution.
STUDIES IN CACAO
Authors: BGRLBND S. C. 
Published: February 2008

SUMMARY

Previous investigations on the pollination of cacao are reviewed. It is pointed out that the consensus of opinion is in favour of the pollinating agent being small insects, either thrips, aphides or ants.
Direct proof of natural crossing was obtained by examination of flowers on a male sterile tree, in which 9 per cent. of the flowers were found to be pollinated.
Daily examination of flowers artificially pollinated, flowers attended by ants and aphides, and flowers with no attendant insects, indicated that the majority of cacao flowers are never pollinated under Trinidad conditions. Adequate pollination took place in 35 per cent. of flowers attended by ants and aphides, and is only 6 per cent of the controls. It is concluded that ants and aphides are the chief pollinating agents in the field under examination.
Elimination of crawling insects demonstrated the presence of another pollinating agent, probably a night flying insect which pollinated about 1 per cent. of flowers.