bluuebunny/crossref_metadata_2025_split huggingface dataset:
A growth study of sugar beet treated with gibberellic acid and (2‐chloroethyl)trimethylammonium chloride (CCC)
Authors: HUMPHRIES E. C. , FRENCH S. A. W. 
Published: February 2008

SUMMARYGibberellic acid sprayed on sugar‐beet plants decreased leaf production, whereas (2‐chloroethyl)trimethylammonium chloride (CCC) applied to the soil increased it. These changes were associated with a change in shape of the growing point; GA elongated it and CCC flattened it. Leaf area per plant increased to a maximum of about 28 dm. at the end of June; CCC consistently decreased it, but GA had no effect although the plant had fewer leaves than the controls. GA increased petiole length in the first part of the season but later diminished it. Petiole length increased with amount of GA applied. CCC had the opposite effect, decreasing petiole length at the beginning of the season and afterwards increasing it.Total dry matter of plants treated with GA was significantly increased at harvests 3 weeks and 8 weeks after initial application. CCC‐treated plants had less dry matter throughout. GA increased crown dry weight and the effect increased with the amount applied. Neither GA nor CCC significantly influenced the weight of storage root. Plants overwintered in an unheated glasshouse continued to increase in dry matter; GA increased the weight of flowering stems but CCC had no effect.From observations on individual leaves mean leaf area growth curves for successive groups of five leaves were constructed. Gibberellic acid increased both areas and longevity of leaves 8 to 17 and GA‐treated plants had the same dry weight as controls in spite of fewer leaves, because leaf area duration was increased. This study emphasizes that different leaves contribute very differently to the total dry matter of the plant. Each of leaves 8–17 had an average duration of 22 dm.2‐weeks and together they produced about two‐thirds of the final dry matter in autumn. CCC decreased leaf area duration and dry matter. None of the treatments changed net assimilation rate (E). In previous experiments with mustard plants CCC decreased E, either through a direct inhibitory effect of CCC on photosynthesis or through decrease in photosynthesis because the dwarfed stem in the treated mustard provided only a small sink for photosynthates. In sugar beet CCC does not affect E, possibly because the root provides a large sink.The differences between sugar beet and potato in development of leaf area and production of dry matter are discussed and the importance of leaf area duration emphasized.GA affects sugar beet and potato differently. It hastens leaf senescence in potato but delays it in sugar beet. GA may prolong the life of sugar‐beet leaves because by making them fewer it decreases competition between them. Gibberellic acid causes a transient increase in leaf growth and dry‐matter production both in sugar beet and potato.
Powdery mildew of tobacco (Erysiphe cichoracearum DC.)
Authors: COLE J. S. 
Published: February 2008

SUMMARYPercentage germination, and growth of hyphae from single conidia of Erysiphe cichoracearum DC., were measured on leaf discs from topped and intact tobacco plants, grown in aerated nutrient solutions consisting of basal medium plus large or small amounts of potassium. The effect of supplying sodium was also studied. Discs were incubated on water and on 10% sucrose solution. Changes in free amino nitrogen and carbohydrate in comparable uninfected leaf discs, before and after incubation, were also measured.Potassium deficiency resulted in more free amino nitrogen and soluble carbohydrate and less insoluble carbohydrate, per cm.2 of leaf. Spore germination was not greatly affected by treatments, though it was usually less on discs from potassium‐deficient leaves. The pathogen grew slower on potassium‐deficient leaf discs, whether they were incubated on water or on sucrose.Incubating discs from some leaves on sucrose, compared with water, gave greatly increased sugar content and less fungal growth; discs from other leaves had a much smaller increase in sugar, and hyphal length was similar to that on discs incubated on water.Sodium, when potassium was scarce, increased potassium deficiency symptoms, free amino nitrogen and sugar content, and resistance to powdery mildew.
Studies on the fungitoxicity of captan
Authors: RICHMOND D. V. , SOMERS E. 
Published: February 2008

SUMMARYThe uptake of captan from aqueous solution by conidia of Neurospora crassa can be markedly reduced by pretreatment of the cells with thiol reagents such as iodoacetic acid (IOA). The nature of this reaction has been investigated and it is shown that IOA largely reacts with the soluble thiol pool of the spores. Captan, however, reacts with both soluble and insoluble thiols and it is suggested that whilst the former is a detoxication process the latter may provide the key to its toxic action.Using glutathione as a model soluble thiol the molar ratio and pH dependence of the captan detoxication process has been determined and compared with the cellular reactions. Assay of 35S‐labelled captan has shown that captan is almost completely decomposed by the spores and that one‐third of the accumulated captan is converted to sulphur compounds fixed to insoluble cell entities.
Studies on photosynthesis in the ear of wheat
Authors: LUPTON F. G. H. , ALI MOHAMED A. M. 
Published: February 2008

SUMMARYEstimates of varietal differences in photosynthesis by ears of wheat, obtained by shading ears or stems, are compared with estimates obtained from a technique involving removal of spikelets at anthesis. The results obtained by different techniques and in different seasons differed widely.
The effects of nitrogen, phosphorus, potassium and magnesium on the growth of tulips during the second season of treatment and on the chemical composition of the bulbs
Authors: CHEAL W. F. , WINSOR G. W. 
Published: February 2008

SUMMARYIn factorial nutrition treatments, for a second season, with three rates of nitrogen, phosphorus and potassium, and some additional treatments with magnesium, on two bulb sizes of Golden Harvest and Elmus tulip, the effect of nitrogen was again found to be dominant. Nitrogen deficiency decreased bulb yields, leaf area, stem length (with one exception) and flower size; it also retarded flowering: the majority of small nitrogen‐deficient bulbs produced only single leaves.Deficiencies of phosphorus, potassium and magnesium had more marked effects than in the first season of treatment and generally reduced bulb yields and leaf area; in some instances stem length and flower size were also reduced. High phosphorus advanced the flowering of Elmus bulbs.The relationships between nutrition and mineral composition of the bulbs showed consistent trends determined by rates and duration of treatments, planting size and variety.
Studies on plant growth‐regulating substances: XXI. The release of pectic substances from wheat coleoptile tissue incubated with solutions of ethylenediamin etetraacetic acid
Authors: TAYLOR H. F. , WAIN R. L. 
Published: February 2008

SUMMARYThe effect on excised wheat coleoptiles of solutions of ethylenediaminetetraacetic acid, at concentrations which produce a significant growth response in segments of this tissue, was investigated.The removal not only of calcium ions, but also of pectin, from coleoptiles by these solutions of the chelator was demonstrated and the implications of these findings are discussed. An increase in the plasticity of the cell walls is considered to arise from the removal of both of these constituents, and the small extension of the coleoptile segments to be a direct consequence of these changes.The concentration of EDTA required to give either the growth‐regulating response or to cause the loss of pectin and calcium was shown to approach that which also caused visible signs of toxicity, and this was taken as further support for the ‘subacute toxicity’ theory put forward earlier by Fawcett, Wain & Wightman.
The residual effect of previous nutritional treatments on the growth and composition of tulips supplied with complete nutrients in sand culture
Authors: CHEAL W. F. , WINSOR G. W. 
Published: February 2008

SUMMARYTulip bulbs produced in sand culture with three rates each of nitrogen, phosphorus and postassium in factorial combination were subsequently grown for one season with complete nutrients in order to study the residual effects of the previous treatments. The bulbs included the progeny of large (II cm). and small (7 cm.) Golden Harvest after one season of differential nutritional treatments and of large Golden Harvest (II cm). and Elmus (12 cm.) after tow such seasons.The early stages of growth, became less apparent by early March, but many of the bulbs previously deprived of nitrogen produced only single leaves and no flowers. The favourable effect of nitrogen on the weights of Golden Harvest bulbs was less marked at lifting than at planting time, but remained highly significant. The yield of Elmus bulbs showed particularly marked responses to both nitrogen and phosphorus. Other residual effects included decreased leaf area of bulbs previously deprived of nitrogen and phosphorus, and slightly earlier flowering with increasing levels of nitrogen.Growth in complete nutrient solution decreased the differences in amounts of major nutrients in the bulbs. The percentage of nitrogen in Golden Harvest bulbs, and of phosphorus and potassium in both varieties, nevertheless increased significantly with the levels of these nutrients in the previous seasons.
A field experiment in Ghana on the tolerance of cocoa seedlings to cocoa swollen‐shoot and cocoa mottle‐leaf viruses
Authors: GLENDINNING D. R. , LEGG J. T. , LOVI N. K. , MARTINSON VERONICA A. 
Published: February 2008

SUMMARYSeedings of Amelonado Cocoa and of two progenies obtained by crossing Iquitos (Upper Amazon) parents were infected with three strains of cocoa swollen‐shoot virus (CSSV) and with cocoa mottle‐leaf virus (CMLV). CSSV strain I A had the most severe effects on the growth and canopy condition of all varieties. All four virus isolates had more effect on the growth of Amelonado than on the Iquitos progenies, except that CSSV strain I W affected the growth of Amelonado and one of the Iquitos progenies equally, as did CMLV which caused the greatest decrease in the first crop of all varieties. The relative virulence of different CSSV strains in any one variety can be assessed from single criteria such as length of latent period or effect on growth; CMLV had a shorter latent period than CSSV Strain I A but less effect on growth.
The effect of soil insecticides on the predators and parasites of the cabbage root fly (Erioischia brassicae (Bouché)) and on the subsequent damage caused by the pest
Authors: COAKER T. H. 
Published: February 2008

SUMMARYField experiments on the effect of residues of aldrin and dieldrin in the soil on the beetle predators of the cabbage root fly, showed that populations of adult carabid and staphylinid predators were altered by aldrin/dieldrin residues at concentrations of 0.06 p.p.m. and above. The lower insecticidal concentrations were aged residues which had become intimately mixed with the soil. Although the residues reduced the numbers of trapped Aleochara spp., concentrations below 0.5 p.p.m. increased the numbers of Bembidion lampros, probably because their movement was stimulated by the insecticide. Harpalus spp. and Feronia spp. were unaffected by residues below the concentration toxic to cabbage root‐fly eggs and larvae. The reductions of the predators implied by the trapping records increased the survival of the cabbage root‐fly eggs and larvae, thus leading to augmented damage to cauliflowers, cabbage and Brussels sprouts, which resulted in reductions in yield of up to 70%.Larval and pupal parasitism by Aleochara spp. and Idiomorpha rapae were also reduced by the insecticide residues, although concentrations of 0.2 p.p.m. and above were required to decrease parasitism by I. rapae.
The control of Alternaria species on leaves of sugar beet infected with yellowing viruses
Authors: RUSSELL G. e. 
Published: February 2008

SUMMARYLeaves of virus‐free sugar‐beet plants rarely became infected with Alternaria spp. in two field experiments at Cambridge in 1965. Infection with beet yellows virus (BYV) increased susceptibility of plants to Alternaria only slightly but infection with beet mild yellowing virus (BMYV) increased it greatly. There was a close association between the severity of Alternaria symptoms, shown by different breeding lines and varieties of sugar beet, and the losses of sugar yield which they sustained after infection with BYV and BMYV. Many lines and varieties were resistant to Alternaria even when infected with BMYV and their resistance seemed to be inherited as a dominant character. Individual plants of any one line or variety differed greatly in resistance to Alternaria, suggesting that selection should improve the present level of resistance.Spraying the foliage of Alternaria‐susceptible varieties with fungicides had little effect on the severity of Alternaria symptoms or on sugar yield. This was probably because the wet summer of 1965 was ideal for the spread of Alternaria and because rain washed the fungicide deposits from the sprayed leaves.
Powdery mildew of tobacco (Erysiphe cichoracearum DC)
Authors: COLE J. S. 
Published: February 2008

SUMMARYA Hirst volumetric spore trap, at a height of 30 cm., was used to assess the diurnal distribution of Erysiphe conidia in the air in tobacco crops infected with E. cichoracearum in Rhodesia. Air temperature and humidity, and the length of time leaves were wet each day, were also recorded at the same height, amongst the plants. In four seasons, most conidia were caught between 13.00 and 15.00 hr.There were close positive correlations in 1962 between numbers of conidia per m.3 of air per hour and saturation deficit and air temperature during the same hours (10.00–18.00 hr.) Correlations of total Erysiphe conidia per day with temperature and humidity were very variable; temperature had no apparent effect during three seasons, but in one (1961)there was a highly significant positive correlation between numbers of conidia and the daily duration of temperatures > 25d̀ C. More conidia were also caught when the air was dry for long periods that season, though temperature probably had the greater effect. In 1962, more conidia were caught per day the longer the air was humid (s.D. 0–1 mb.) In 1961, the amount of rain per day had no apparent effect on numbers of conidia, but in 1962 more were caught the greater the daily rainfall. However, rain, which nearly always fell in the afternoon, also removed most conidia from the air that afternoon. Neither windspeed nor duration of leaf wetness appeared to affect spore dispersion.
Glasshouse experiments on apple scab
Authors: MOORE M. H. 
Published: February 2008

SUMMARYDilutions of various fungicides were compared on potted MM 109 clonal rootstocks in the glasshouse for protective (pre‐infection) and curative (post‐infection) activity against apple scab. The materials, as commercial preparations, included captan, copper (as ‘dry’ Bordeaux mixture), dichlofluanid, didecyldimethylammonium bromide (DDAB), dispersible sulphur, dithianon, dodine acetate, lime‐sulphur (LS), phenylmercury chloride (PMC), and thiram; they were assessed on the basis of percentage active ingredient in the dilutions.When acting at normal rates of use, many of the fungicides were much more effective protectively than curatively, but this contrast was less applicable to DDAB, dodine acetate, LS, and dichlofluanid. PMC, however, was an especially notable exception in proving curatively superior at unusually low rates. In addition, it was particularly active in vapour form, and was effectively translocated not only from one leaf surface to the other, but, especially at 0.005%, from sprayed to younger unsprayed leaves on the same shoots. Other standard fungicides showed little or no translocated activity, but isobutyl‐o‐coumarate was effective at the growing shoot‐tips in spring from a spray applied to the lower leaves.PMC reduced infection when applied once at any time during the scab‐incubation period, and especially 24 hr. after infection, when the control was almost complete. Longer intervals before spraying reduced the curative action, but not in proportion to the intervals; the infection pattern showed multi‐peak fungicidal activity and, after the later sprays, many lesions were practically infertile. The curative properties of PMC were matched by several other formulated phenylmercury salts compared at equivalent percentage mercury content, but the dimethyldithiocarbamate proved rather less effective. A preliminary attempt to supplement the curative properties of PMC with the protective properties of LS, by mixing these fungicides at low rates, showed evidence of fungicidal antagonism, and this needs further investigation.Several fungicides, notably the inorganic sulphurs, thiram, the phenylmercury compounds, dichlofluanid, and DDAB showed incidental activity against natural infection by powdery mildew.
The fungitoxicities of plant furocoumarins
Authors: MARTIN J. T. , BAKER E. A. , BYRDE R. J. W. 
Published: February 2008

SUMMARYA mixture of the furocoumarins pimpinellin, isopimpinellin, isobergapten and sphondin isolated from Heracleum sphondylium root was toxic to Gloeosporium limetticola, Botryis cinerea, Sclerotinia fructigena and Stereum purpureum at 200 p.p.m. or less in nutrient medium. The extractive of the leaves of plants that contain furocoumarins suppressed in vivo growth of G. limetticola and B. cinerea at concentrations lower than the contents of the extractive in the leaves. Furocoumarins may form an important class of natural defensive agents against fungi; this possibility is discussed.
Modification of growth habit of Majestic potato by growth regulators applied at different times
Authors: DYSON P. W. , HUMPHRIES E. C. 
Published: February 2008

SUMMARYThe effect of gibberellic acid, CCC (2‐chloroethyltrimethylammonium chloride) and B 9 (N‐dimethylaminosuccinamic acid) was studied on growth of potato plants in pots. Growth was analysed on four occasions and changes in habit defined in terms of internode lengths, leaf areas and growth of lateral branches.Soaking seed pieces for 1 hr. in GA solution caused six internodes to elongate greatly, an effect not prevented by CCC applied when the shoot emerged from the soil. The effects on internode extension were determined by the length of the interval between GA treatment and CCC treatment.Treatment at emergence with CCC shortened all internodes and more CCC applied 4 weeks later had no effect. Late application of CCC or B9 shortened the top two lateral branches, usually very long in untreated plants.The regulators affected leaf growth differently from internode growth: usually growth regulators had less effect on leaf growth.Effects on growth depended on when the regulators were applied. Treatment with GA alone inhibited bud development at higher nodes than in untreated plants; when followed by late treatment with CCC, lateral growth at higher nodes was also less. CCC retarded development of lateral branches especially when applied early. B9 had a similar effect to CCC applied late. When regulators retarded growth of lower laterals, upper laterals often grew more than in untreated plants. Treatments did not affect the number of leaves on the main stem at first but later GA hastened senescence. GA increased the number of leaves on lateral stems, and the effect was enhanced by CCC. CCC alone increased the number of first‐ and second‐order lateral leaves. GA lengthened and CCC shortened stolons. The effect of CCC persisted throughout the life of the plant. CCC or B 9 shortened stolons whenever applied. CCC hastened tuber initiation but slowed tuber growth.CCC at first retarded formation of lateral tubers but had no effect on the ultimate numbers of lateral and terminal tubers.The value of E (net assimilation rate) did not alter with time. CCC applied at emergence increased E, probably because it hastened tuber initiation and temporarily increased sink capacity. Although tubers formed earlier with CCC, their growth was slower and their demand for carbohydrate was also less. The increase in second‐order laterals in CCC‐treated plants indicates that they utilize carbohydrate that would normally go to tubers.This experiment also demonstrates that crowding leaves by shortening stems did not diminish E, possibly because another over‐riding process (bigger sinks) offsets the effect of shading.
Studies on plant growth‐regulating substances: Interactions between auxins and inactive analogues
Authors: GRIFFITHS J. , INTARAKOSIT P. , TAYLOR H. F. , WAIN R. L. 
Published: February 2008

SUMMARYThe growth‐regulating activities of four auxins were assessed in the wheat cylinder and pea segment tests, and the capacity of certain inactive analogues to act as auxin antagonists was examined. 2,4‐Dichlorophenylthioisobutyric acid was found to antagonize the auxin activity of 2,4‐dichlorophenylthioacetic acid and was more effective than the established antagonist α‐(i‐naphthylmethylsulphide)propionic acid in interaction experiments with 2,4‐D. Two auxins were studied with their respective sulphonamide analogues as antagonists and only slight reduction in growth‐regulating activity was observed. Interaction experiments with an auxin and its corresponding arsonic acid revealed no evidence of true competitive antagonism. The implications of these findings are discussed.
The effect of temperature upon intensity of colour in the coronas of cut blooms of narcissus var. Soleil d'Or
Authors: SMITH W. H. , PARKER J. C. 
Published: February 2008

SUMMARYCut blooms of narcissus Soleil d'Or were subjected to constant temperatures ranging from 1.2° C. to 18.3° C. both in darkness and under illumination. The rate of opening of successive florets, the rate and final degree of colour development of the corona and subsequent display life were observed.Opening was negligible at 1.2° C. and 38 days were taken to open to five florets at 4.5° C. Full opening occurred in 4 days at 15.6° C.The change of colour of the corona from yellow to orange was negligible at 15.6° C, but final intensity of orange colour increased with decreasing temperatures. Temperature affected colour development both of opened and unopened florets, and after treatment at low temperature colour continued to develop when the blooms were removed to 18.3° C. The period of low‐temperature treatment giving maximum colour development was 8 days.Artificial illumination of intensity 200 ft.‐candles had little effect at 18.3° C. but it increased orange colouring at the lower temperatures.Increased orange colour whether at intermediate or low temperature was shown to be associated with a slight increase in the concentration of the total carotenoids, but more especially with greatly increased content of β‐carotene which constituted approximately 10–20% of the total carotenoids.
The relationship between hypersensitive tissue and resistance in wheat seedlings infected with Puccinia graminis tritici
Authors: BROWN J. F. , SHIPTON W. A. , WHITE N. H. 
Published: February 2008

SUMMARYData obtained during the first 120 hr. of the infection process in several resistant and susceptible varieties of wheat infected with Puccinia graminis tritici did not show any consistent relationship between the growth of the rust colony and the rate of increase of host tissue showing hypersensitive necrosis. Furthermore, no apparent relationship existed between the area of the rust colony at any given time after inoculation, and the amount of hypersensitive necrotic tissue per unit area of the leaf colonized. Thus, it is suggested that hypersensitive necrosis of the host tissue is a consequence and not the cause of resistance of wheat to infection by P. graminis tritici.