bluuebunny/crossref_metadata_2025_split huggingface dataset:
Water loss from cut grass with special reference to hay‐making
Authors: LESHEM Y. , THAINE R. , HARRIS C. E. , CANAWAY R. J. 
Published: February 2008

SUMMARYWater loss from cut grass was studied to determine factors limiting the drying process.An apparatus, used to measure water loss at 28±1°C from blotting paper and from leaves and stem internodes of cocksfoot, consisted of four channels in which air speed was controlled at 25–80 cm s‐1 and relative humidity at 7–68%.The maximum rate of water loss from wet blotting paper was 10500 mg water dm‐2 h‐1 but from leaves and stem internodes supplied with water it was less than 250 mg dm‐2 h‐1. The rate of loss from both plant specimens and blotting paper was linearly related to the vapour pressure differences between the specimen and the surrounding air but was not increased when air speed was changed from 40 to 80 cm s‐1. Grass specimens supplied with water had lower rates of water loss than wet blotting paper because of tissue resistances which were calculated for (a) untreated leaf and stem specimens, (b) rubbed leaves, (c) cut leaves, (d) leaves exposed to steam for 60 s. Treatments (b)‐(d) greatly reduced tissue resistances.The rates of drying of leaves and stem internodes not supplied with water changed only slightly in response to faster air speeds but were significantly increased by treatments (b), (c), (cs) (split stems), (d) and (e) (exposure to petroleum vapour for 60 s). The most effective treatments trebled the drying rates of leaves and increased the drying rates of stem internodes by 10 times. Reductions in relative humidity had little effect on drying rate following treatments (a), (b), (c) and (d), but when treatments (cs) and (e) were given, additional significant increases in drying rates were obtained when the relative humidity was reduced.Grass specimens given the most effective treatments and dried under the most favourable conditions did not utilize the full drying capacity of the environment, for the rates of water loss from these specimens were at least three times lower than those from wet blotting paper. The results indicate that high rates of drying could be achieved at 28 oC or similar temperatures if practical treatments were developed to remove or greatly reduce the high resistance to water loss in cut grass.
Dilemmas in conservation for applied biologists
Authors: GUNN D. L. 
Published: February 2008

SUMMARYPrevention of the use of DDT has been made the target of a powerful propaganda drive in certain prosperous countries because, it is stated, DDT is a danger to man and harms wild life. On the other hand, DDT is by far the most economical, effective and safe insecticide for many uses, particularly for protecting men from certain insect‐borne diseases and for enabling cotton to be grown in poor countries. Some risks can be reduced by eliminating those uses of DDT for which adequately safe, economical and effective substitutes exist, whether chemical or not; other risks can be reduced in other ways. The known risks to men are trivial, except when DDT concentrate is deliberately drunk, and the scare is made up of unknown risks ‐which could equally exist with any object or material, new or old. Risks to wild life have been greatly exaggerated and scares depending on falsehoods have become current. The postulated threat of progressive accumulation of DDT along a long food chain is not adequately supported by evidence, much of which has been misinterpreted.Thus the main dilemma is how to balance the great and undoubted benefits of DDT to millions of men, women and children against harm to wild life, sometimes genuine and remediable and sometimes dubious.People who campaign for banning have possibly failed to recognize this dilemma. On the other hand, they may have made a deliberate choice in favour of wild life. In that case, to be logical, they should also oppose all other means of preventing premature death of other people, which they might justify as a means of postponing over‐population. The use or abuse of DDT is a minor component in the rise of the worl's population.
A world‐wide survey of the microflora of Dactylis glomerata seed*
Authors: TULLOCH MARGARET , LEACH C. M. 
Published: February 2008

SUMMARYThe fungal microflora of orchard (cock's‐foot) grass seed(Dactylis glomerataL.) was determined for 140 samples obtained from thirteen countries. The microflora was assessed by visual examination of dry seed (20–50 x), by microscopic examination of centrifuged seed washings and by incubating seed on 2 % malt extract agar (MA) under a 10‐day regime of diurnal cycling of temperature (23‐9oC/i8‐3oC) and near‐ultraviolet radiation (12 h NUV/ 12 h dark). More than twenty‐five species of potentially pathogenic fungi and forty species of saprophytes were detected. The pathogens included anAscochytasp.,Botrytis cinerea, nine species ofDrechsleraincludingD. dactylitis(infested 23% of seed lots) andD. Useptatum(10% of seed lots), five speciesoiFusariumincludingF. avenaceum(5 % of seed lots),Lep‐tosphaeriasp.,Phleosporasp.,Phomasp.,Phomopsissp.,Pyrenochaetasp.,Rhizoctoniasp.,Rhynchophomasp.,Septoriasp. andStagonosporasp. Many more fungi were identified from seed plated on MA and exposed to NUV than by examination of seed washings or visual examination of dry seed. Several of the fungi that were detected are known to produce mycotoxins.
The transmission of cocksfoot mottle and phleum mottle viruses by Oulema melanopa and O. lichenis.
Authors: A'BROOK JOHN , BENIGNO D. A. 
Published: February 2008

SUMMARY Oulema melanopa and O. lichenis both transmit cocksfoot mottle and phleum mottle viruses with similar efficiencies. The viruses were serologically dissimilar and did not cross‐protect against each other in barley. Both viruses were acquired after a few minutes feeding, but longer acquisition feeding periods increased both the efficiency of transmission and persistence in the vectors. Acquisition of either virus increased vector mortality whilst acquisition of both together did not. When both viruses were ingested, only one was transmitted. Each virus could be recovered from haemolymph and faeces, but regurgitation was not observed and could only be induced with the greatest difficulty. The results suggest possible circulative transmission of some beetle‐borne viruses.
The isolation and identification of parsley viruses occurring in Britain*
Authors: FROWD J. A. , TOMLINSON J. A. 
Published: February 2008

SUMMARYSevere stunting of parsley plants, with leaf chlorosis and reddening was reported from four localities in Britain in 1968‐70. Affected plants were collected from thirteen sites in Bedfordshire, Buckinghamshire, Cheshire and Bristol, and five viruses (designated PV1‐PV5) were isolated from them. The viruses were distinguished by electron microscopy, host range and type of aphid transmission.From diagnostic reactions in a range of host species and its transmission by Cavariella aegopodii Scop., the most frequently isolated virus (PV4) and the principal cause of the parsley disease was identified as carrot mottle virus (CMotV).The other four viruses were infrequently isolated. PV1, PV2 and PV3 were transmitted in the non‐persistent manner by Myzus persicae Sulz. Each was purified and identified serologically as western celery mosaic virus, cucumber mosaic virus and broad bean wilt respectively. PV5 was not fully identified, but was transmitted by C. aegopodii in the presence of CMotV and had particles ca. 500 nm in length. Each of these viruses was re‐transmitted to parsley, but induced slight symptoms or none.
Bacterial canker of poplar
Authors: BURDEKIN D. A. 
Published: February 2008

SUMMARYBacterial canker is a serious disease of poplar and it is important for commercial planting to select those clones of poplar which show resistance to the disease. In inoculation tests, natural bacterial slime and a pure bacterial suspension gave similar extent of invasion. A study of the life‐cycle of the disease indicated the presence of inoculum and of potential infection courts throughout the growing season. It is suggested that the susceptibility of a poplar clone should be determined by assessment of both artificial inoculations and natural infection.
Uptake and distribution of the growth retardant, aminozide, in relation to control of latera shoot elongation in Chrysanthemum morifolium
Authors: DICKS J. W. 
Published: February 2008

SUMMARYThe uptake, stability and redistribution of the plant growth retardant, aminozide, in ‘pinched’ plants of Chrysanthemum morifolium Ramat. cv. Lemon Princess Anne were examined in relation to control of lateral shoot elongation.Foliar uptake was most rapid over the first few hours, and was almost complete within 72 h. More of the available aminozide was taken up by the young lateral shoots than by older foliage on the main stem. The aminozide content of entire plants generally remained constant over several weeks, indicating that the compound was relatively stable within the plant.The time scale and pattern of redistribution of foliar‐ and root‐applied aminozide suggests that the compound may be translocated in both phloem and xylem. Spray application to young lateral shoots was as effective in controlling their elongation as application to all aerial organs. Basipetal transport of aminozide from lateral shoots was slight. The results are discussed in relation to the site of action of the compound and to its application in commercial practice.
Germination of sclerotia of Botrytis tulipae, the cause of tulip fire
Authors: COLEY‐SMITH J. R. , JAVED Z. U. R. 
Published: February 2008

SUMMARYSclerotia of Botrytis tulipae (Lib) Lind. buried in field soil germinated mainly in winter and early spring to produce conidiophores and conidia and then decayed. Except when buried very late in the year sclerotia germinated and decayed in the season following burial.In the laboratory, sclerotia from pure culture germinated in two ways. On sterile water‐agar they formed colourless mycelium but no conidiophores; the rate of germination was greatest at 25 d̀C. On unsterile filter paper and on soil they produced mainly conidiophores and conidia; the rate of germination was greatest at 5 d̀C and was enhanced by previous cold treatment. It was unaffected by soil‐moisture or pH.Primary infections of tulips arose from sclerotia placed in the soil but only when they were close to the shoot tip or developing stem. It is suggested that, because of their limited survival, soil‐borne sclerotia are of importance only when tulips are planted in annual succession.
The purification and some properties of cocoa necrosis virus, a serotype of tomato black ring virus
Authors: KENTEN R. H. 
Published: February 2008

SUMMARYCocoa necrosis virus (CNV) was transmitted by sap inoculation to twelve of twenty‐one species tested. It was propagated and assayed in Phaseolus vulgaris. Sap from P. vulgaris was infective after dilution to 10‐3but not 10‐4, after 10 min at 60 d̀C but not 65 d̀C, and after 4 but not 7 days at 20–24 d̀C. Lyophilized sap from P. vulgaris was infective after 2 years in vacuo.Virus was prepared by extracting infected leaves of P. vulgaris with 0.1 M phosphate (pH 7.5) containing 0.05 M ethylene diamine tetra‐acetate and 0.02 M thioglycollate. After clarification with n‐butanol, virus was purified by precipitation with polyethylene glycol and several cycles of differential centrifugation. Such preparations were very infective and contained numerous particles, 24–26 nm in diameter with a hexagonal profile, which sedimented as two components with sedimentation coefficients (Sd̀20,w) of 101 S and 129 S. The absorption spectra of both components with maximum and minimum absorption at 259 and 240 nm respectively were typical of nucleoproteins (101 S component, A 260/280 = 1.63; A 260/240 = 1.40:129 S component, A260/280 = 1.78; A260/240 = 1.58) and indicated nucleic acid contents of ca. 35% for the 129 S component and ca. 20% for the 101 S component; values calculated from the sedimentation coefficients were 41 and 30% respectively. Only the 129 S component seemed to be infective and was not more so when mixed with 101 S component. Both components contained a single protein subunit weighing ca. 60000 daltons.Under certain conditions sap fractionated without butanol gave virus preparations containing empty protein shells (54 S) and small spherical particles (20–30 S) ca. 12 nm diameter.CNV is a serotype of tomato blackring virus and is distantly related to Hungarian chrome mosaic virus.The cryptogram of CNV is */*:*/(35–41):S/S:S/*.
Black leaf streak of bananas in Fiji
Authors: FIRMAN I. D. 
Published: February 2008

SUMMARYBlack leaf streak of bananas, caused by Mycosphaerella sp., prevented fruit of export quality forming and bunches maturing. Some infected leaves lived less than 50 days and were seldom retained until harvest. Maneb or benomyl applied in oil/water emulsions gave good control and benomyl was so effective that plants had ten leaves at harvest and some leaves survived for 245 days. Plants sprayed with maneb or benomyl flowered I month early. No benomyl residues were detected in the fruit exported to New Zealand.The control of black leaf streak by sprays containing oil has caused other leaf diseases to become more prevalent and the ensuing complex disease situation is discussed.
Purification and properties of elderberry latent virus, one of four sap‐transmissible viruses obtained from American elder (Sambucus canadensis L.)
Authors: JONES A. T. 
Published: February 2008

SUMMARYCherry leaf roll, tomato black ring and two previously unrecorded viruses were transmitted to Chenopodium quinoa from Sambucus canadensis plants imported from the U.S.A. Of the two newly recognized viruses one, code‐named elderberry virus A, has filamentous particles about 650 times 15 nm; the other, named elderberry latent virus (ELV), was transmitted to several herbaceous species but remained symptomless in elder and most other hosts. In C. quinoa sap ELV lost infectivity after dilution to 10‐‐5 to 10‐‐6, 10 min at 85–90°C, and 7 days at 18°C. Infectivity of nucleic acid extracts was abolished by ribonuclease in 0.2 m sodium chloride. ELV was purified from C. quinoa leaf extracts that were clarified with chloroform, by precipitation at pH 5 and differential centrifugation. Purified preparations contained numerous isometric particles c. 30 nm in diameter and a few particles c. 17 nm in diameter. In 0.06 M phosphate buffer ELV sedimented as a major 112 S (calculated for infinite dilution) component and a 48 S minor component. ELV showed no serological relationship to twenty‐seven other isometric plant viruses. Its present cryptogram is R/I: *I*:S/S:S/*.
The carbohydrate and water balance of beans (Vicia faba) attacked by broomrape (Orobanche crenata)
Authors: WHITNEY P. J. 
Published: February 2008

SUMMARY Orobanche crenata parasitizing beans maintained a slightly higher osmotic pressure than the bean roots, largely because of the higher concentration of sugars in the broomrape tissues. The sugar was withdrawn from the bean mainly as sucrose, which was hydrolysed to glucose and fructose by the Orobanche. These sugars were then rapidly translocated to the developing flower spike. As well as maintaining a high osmotic pressure this hydrolysis ensured a sucrose concentration gradient between host and parasite.In the field, bean plants showed wilt symptoms at about the time that the Orobanche flower spikes emerged. It was found that the higher the level of infection the lower was the water content of the host. This fall in water content was not due to increased water loss by the bean shoots and it seemed unlikely that it was due to water removal by the parasite.It was concluded that the death of the bean was due to desiccation brought about largely by the reduced ability of the carbohydrate‐starved roots to extract water from the soil.
Effect of awns and drought on the supply of photosynthate and its distribution within wheat ears
Authors: EVANS L. T. , BINGHAM J. , JACKSON P. , SUTHERLAND JENNIFER 
Published: February 2008

SUMMARYThe presence of awns doubled the net photosynthetic rate of wheat ears and also increased the proportion of 14CO2 assimilated by the ear that moved to the grain. The effect of water supply on photosynthesis and movement of assimilates was greater for leaves than ears, so that drought increased the proportion of assimilate contributed by ear photosynthesis to grain filling from 13% to 24% in the awnless ears, and from 34% to 43% in the awned ears. 14C assimilated by the ears was most important to the economy of the upper spikelets and to the distal florets in each spikelet, whereas flag leaf assimilate went mainly to the spikelets in the lower half of the ear, and to the proximal florets.Awns increased grain yield in the dry but not in the irrigated treatment, despite the large contribution of awned ears to grain filling. Either the supply of assimilate did not limit grain yield when water supply was not limiting, or there were compensating disadvantages to awns. However, they did not seem to have any adverse effect on the development of the upper florets, nor did they reduce grain number per ear.
Influence of temperature on hatching of winter eggs of fruit‐tree red spider mite, Panonychus ulmi (Koch)
Authors: CRANHAM J. E. 
Published: February 2008

SUMMARYThe effects of the duration and degree of chilling, and the temperature of incubation, on hatching of winter eggs of Panonychus ulmi (Koch) were investigated. For chilling, 0°C and 5°C were more effective than — 5° and 9°, and the limits for the reaction were close to — 10° and 15°. As the chilling period was increased from 60 to 200 days, the percentage hatch on incubation at 21° increased, and the mean incubation time and its variance decreased. Before the maximum effect of chilling was achieved, percentage hatch on incubation at 9° and 15° was higher than at 21°; 27° was lethal to most winter eggs though not to summer eggs. After chilling, the later stages of diapause development could occur at temperatures from 0° to 21°) i.e. above and below the threshold temperature for morphogenesis, 6–7° in both winter and summer eggs. Diapause development cannot, therefore, be a unitary process. The significance of the results is discussed in relation to forecasting the time of hatch in the field, and to the phenological aspects of hatching in the spring.
Observations on the effects of mildew, Erysiphe graminis, on growth of spring and winter barley
Authors: BROOKS D. H. 
Published: February 2008

SUMMARYIn field plots, early and severe attacks of powdery mildew on spring barley plants greatly reduced the vigour, decreased the amount of root, the number of ear‐bearing tillers and the grain size. In less severe, or later attacks, mildew mainly affected the grain size.On winter barley, where mildew attacked both in autumn and in spring, yield was decreased more than when only a spring attack occurred. The early attack retarded development of the root system, increased winter kill and decreased the number of ears reaching maturity.Because early mildew attack affects yield, it is not always possible to correlate yield loss with intensity of mildew at any one growth stage of the crop.
Verticillium wilt of cacao in Uganda: the relationship between Verticillium dahliae and cacao roots
Authors: EMECHEBE A. M. , LEAKEY C. L. A. , BANAGE W. B. 
Published: February 2008

SUMMARYIsolates of Verticillium dahliae Kleb. from wilted cacao (Theobroma cacao L.), cotton (Gossypium hirsutum L.), and okra (Abelmoschus esculentus Medik.) penetrated all regions of living cacao tap and lateral roots and progressed intracellularly from the epidermis to the xylem in 4–6 days. The hypocotyl and tissues of the unerupted lateral roots beneath the epidermis resisted invasion.Host reactions included browning of extensively colonized cells, alteration (with apparent granulation) of the cytoplasm, and accumulation of materials in the lumina of endodermal cells. Resistance in the hypocotyl was associated with occasional thickening of inner tangential walls of colonized epidermal cells.The fungus formed conidia, microsclerotia, and narrow and wide hyphae within root tissues. The narrow hyphae predominated at the front of mycelial invasion of tissues while the broad hyphae developed behind this front.Limited studies under non‐sterile conditions indicated that the apparent host‐parasite interactions were similar to those observed with sterile roots and cultures of V. dahliae.
Factors' governing ingestion by the earthworm Lumbricus terrestris (L.), with special reference to apple leaves
Authors: WRIGHT M. A. 
Published: February 2008

SUMMARYCaptive worms fed little on fresh apple leaves, but did so readily after the leaves had been leached in water. This was due to their being soft and easy to fragment and not to loss of unpalatable substances during the leaching process. A simple apparatus to measure leaf texture is described. Worm feeding rates were similar for leaves of similar texture but of different phenolic content. Filter paper was accepted as food. The addition of leaf leachates to filter paper disks increased feeding rates, so did added bacterial cells. The part played by leaf micro‐organisms in the nutrition of worms and their effect on leaf texture is discussed. Unsoftened leaf material was readily eaten provided it was small enough to be swallowed whole. Leaves from various aromatic plants were eaten by starved worms, but rejected by well‐fed ones. Starved worms given aromatic leaf material together with apple leaf preferred the latter. Various unusual materials were eaten, but polyester foam was accepted only when coated with bacterial cells. Responses to chemical as well as to tactile stimuli seem to be involved.
The infection and perennation of the bitter rot fungus, Gloeosporium album, on apple leaves
Authors: TAN A. M. , BURCHILL R. T. 
Published: February 2008

SUMMARYIn the period from late spring to leaf‐fall (May‐November) Gloeosporium album Osterw. was regularly isolated from leaves of the apple variety Cox's Orange Pippin affected by the disorder called ‘Cox‐spot’. The fungus grew epiphytically on healthy apple leaves, producing a network of mycelium which developed sporulating pustules when in contact with damaged or moribund tissues.Both the imperfect and perfect stages of the fungus were found on overwintered leaves; isolates from ascospores and conidia proved pathogenic on wood and fruit.
Effect of Ophiobolus graminis infection on the growth of wheat and barley
Authors: ASHER M. J. C. 
Published: February 2008

SUMMARYGlasshouse experiments are reported, in which the development of young wheat and barley plants was examined following inoculation with Ophiobolus graminis (Sacc.) Sacc. The dry weight, leaf area, tiller number and water content of the shoot were reduced by infection. Reductions were equally severe in wheat and barley. The seminal root system of both was severely attacked and its growth retarded. Inoculated plants, however, translocated a greater proportion of their total assimilates to the root system and produced more adventitious roots than healthy plants. As a result there was an increase in both the number and proportion of healthy roots on these plants following the initial infection of their root systems. This effect was more pronounced in barley than in wheat. It is suggested that this may in part account for the reported relative tolerance of barley to take‐all attack under field conditions.