摘要:

Summary1All available parts at all available stages of growth, of twenty‐two species of Papilionaceae have been examined microscopically for the presence of rotenoids: fourteen contain them, and Table V summarizes all the plant parts in which they occur.2The rotenoid content varies from mere traces in the seeds only of one species to appreciable quantities in nearly every organ of another species.3Seeds of twelve of the rotenoid‐containing species were available: all contained rotenoids. It appears to be the rule that if any species contains rotenoids in any tissue it will contain them in its seeds.4Roots of thirteen of the species were available: twelve contained rotenoids.5In general, rotenoid cells in the roots and stems are normal ones, but in all other tissues they are usually morphologically distinct, and frequently relatively very large.6Rotenoids occur in the seeds of species ofMillettiaandDerrisnot in cells but in iysigenous cavities.7In many species rotenoids are first detected in the cortex of the root opposite the protoxylem and primary medullary rays.8In general, the roots contain rotenoids in the xylem parenchyma, especially in the medullary rays, and in the cortex. In stems they occur mainly in the pith, when not lignified, and also in the phloem, especially in the rays, and in the cortex.9At nodes there is frequently an increase in the number of rotenoid cells, especially in the pith.10On germination, the seeds ofMunduleaandTephrosiaspecies at first produce new rotenoid cells, accompanied by an increase in total rotenoid content, in the growing radicle and in the cotyledons. Later, the rotenoids diminish to nil in the radicle and to between 45% and nil. for different species, in the cotyledons. WithMillettia.new rotenoid cavities are at first formed in the radicle, and later all rotenoids disappear from it: only a small reduction in the rotenoid content of the oetyledons, however, occurs. WithDerris, no new rotenoids are formed in the radicle: the amount in the cotyledons in one species diminished to 62 %.11Rotenoids in the plumules ofMillettiaandDerrisspecies disappear soon after germination.12Two instances only of lability of rotenoids have been proved: in the germinating seeds of all species, and in the lignifying pith of the stems of two species.13Derris ellipticaplants placed in the dark until dead show no reduction in the amount of rotenone per plant: indicating that the rotenone is not available as a food reserve.14The application of the sap fromDerrisroots and stems toDerriscuttings produces no increase in percentage rooting or in the speed of rooting.15The results suggest that rotenoids are of some direct use to the germinating seed and seedling, but that they are probably waste products in all other tiss

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1939.tb06993.x

出版商:Blackwell Publishing Ltd    

年代:1939

数据来源: WILEY

摘要:

Summary1The growing points of more than 100 plant species of diverse habit have been examined between 1937 and 1939, in order to find the exact times of flower initiation.2Types of organization for flowering may be classified into(a)direct‐flowering plants,(b)indirect‐flowering plants,(c)cumulative‐flowering plants and(d)climax flowering plants. Initiation of the flower in(a), (b)and(c)may either begin (i) during the period of maximum vegetative growth or (ii) when vegetative growth is at a minimum. In the latter class, any direct cause of flowering operated entirely or largely by external influences, such as those affecting the vigour of photosynthesis, would appear to be eliminated.3Abnormal flowering of some indirect‐flowering plants during the autumn of 1938 suggests that their physiological rest periods were concluded at that time. Their normal extension of dormancy until the following spring is probably a direct effect of winter climate.4Plant habit, as annual, biennial, perennial, does not appear to affect the time of flowering, unless associated with a store of food, but not all plants with stored food flower early.5A series of correlation diagrams of the two variables, temperature and time of flowering, has been prepared from the Royal Meteorological Society's phenological data. These suggest that temperaturesbeforethe initiation of flower bud formation, in addition to those at other periods of floral development, may affect the time of flowering. Some species appear to be hastened by higher temperatures than normal at this period, e.g. ivy, and yet other kinds by temperatures lower than normal, e.g. coltsfoot.6Flower emergence in thirteen wild plants is hastened by a temperature higher than that of normal climate for a period just before the time of

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1939.tb06994.x

出版商:Blackwell Publishing Ltd    

年代:1939

数据来源: WILEY

摘要:

SummaryTwo kinds of intracellular inclusions in solanaceous plants infected with severe etch virus are described. One occurs in the cytoplasm and is similar to the X‐bodies found in many other plant virus diseases. The other occurs only in the nuclei. These intranuclear inclusions appear to be crystalline, have the form of thin rectangular plates, and resemble the inclusions described in the polyhedral disease of silkworms more than any other type of previously recognized virus‐inclus

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1939.tb06995.x

出版商:Blackwell Publishing Ltd    

年代:1939

数据来源: WILEY

摘要:

SummaryA detailed study of the morphology and biology of all stages in the life cycle ofNotocelia uddmannianaL. has been made over a period of 2 1/2 years.This tortricid is a pest of loganberry in certain fruit‐growing areas.The widths of the head capsules in all larval instars have been measured and found to follow Dyar's Law.In the East Mailing district an ichneumonid,Omorgus mutabilisH.Gr., parasitizes 35–50 % of the larvae. A few specimens of an undescribed species ofApanteleshave been bred from larvae, and also a tachinid fly,Nenwrilla notabilisMg.Preliminary control measures have given poor resu

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1939.tb06996.x

出版商:Blackwell Publishing Ltd    

年代:1939

数据来源: WILEY

摘要:

SummaryContinued field observations on disease in rhubarb accompanied by infection byAnguillulina dipsaciare recorded. The symptoms, both in the foliage and in the root stock, are similar to those described for bacterial crown rot by Millard.In infection experiments using the rhubarb strain ofA. dipsacisymptoms of disease similar to those found in the field were reproduced in rhubarb seedlings and setts. The course of eelworm infection in the young leaves and in the crown in these experiments is recorded.Host transference experiments have shown that the rhubarb strain ofA. dipsaciis not rigidly restricted in its feeding habits for it is capable of producing persistent infection in oats, pea and chickweed. It is also capable of producing only temporary infection in cabbage and mangold. Infection is also recorded inRumexspp. but insufficient evidence is available as to its persistence on these hosts.Incidence ofA. dipsaciis recorded in rhubarb from Scotland and southern England in addition to Yorkshire.

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1939.tb06997.x

出版商:Blackwell Publishing Ltd    

年代:1939

数据来源: WILEY

摘要:

SummaryVarious textile fabrics were exposed to a wide range of climatic conditions.Those exposed to waterlogged conditions were destroyed rapidly. In the case of cellulose fabrics this destruction was due solely to bacteria, and not to fungi or actinomycetes. In the case of wool, the evidence of microbiological action was not conclusive.Cellulose, wool, silk and cellulose rayon fabrics disintegrated on exposure in microbiologically active soils. The destruction was due to microbiological action, the rate being governed by the moisture content of the soil and, to a lesser extent, by the temperature. Cellulose acetate rayon was completely resistant.Cellulose and wool fabrics exposed in the shade to very humid tropical conditions were damaged much less rapidly than in soil, although there was extensive “mildewing”.“With fabrics exposed for a year in the shade at stations with subtropical or temperate climates, and with a rainfall of about 30 in., the microbiological damage suffered was insufficient to affect the strength of the fabric, but there was much”mildewing“. No microbiological damage or”mildewing“was observed in shade‐exposed fabrics in arid climates where the annual rainfall did not exceed 9·5 in.Where fabrics were exposed to the action of sun as well as rain and wind, microbiological damage occurred when the moisture conditions were suitable for the growth of micro‐organisms. This damage was invariably less than that of fabrics exposed in the shade at the same station.Exposure of cellulose fabrics both in sun and shade caused a lowering in viscosity, whereas soil exposure, which causes more extensive microbiological destruction, did not affect the viscosity. All sun‐ and shade‐exposed samples showed a lowering inpH value during the first 3 months, but subsequent exposure caused little further change. Soil exposure caused practically no change.Inert substances such as glass, metals and rubber, when used as a covering for cellulosic fabrics, retard microbiological decay in soil and sea exposures. Some commercial protective substances owe their value to their shielding action. The parenchymatous and epidermal tissues surrounding the fibre bundles of jute exert no shielding effect. In a micro‐biologically active soil, flax, hemp and jute fabrics decay at approximately the same rate as cotton, which contains no protective tissue.A provisional technique is described by which the relative merits of “mildew”‘ protective treatments may be evaluated. The only treatment which has been found to give permanent protection in the case of cellulosic

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1939.tb06998.x

出版商:Blackwell Publishing Ltd    

年代:1939

数据来源: WILEY

摘要:

Summary1A survey of the natural and artificial habitats ofLumbricillus lineatusMull, shows a wide range and toleration of diverse chemical conditions.2The bacteria beds are described in relation to the needs of the worm.3An account is given of the life‐history of the worm including breeding season, copulation, cocoon deposition, development and hatching. The latter is given in detail since it is believed to be new. It demonstrates a use of the eversible pharyngeal plate. Experiments show that the hatching worms increase in size with an increase in quantity of food available within the cocoon in the form of undeveloped ova.4A short account of the parasites and possible predators is given.5Experiment shows that the worms migrate from low temperatures to higher, a reaction observed in the beds during cold weather.6Temperatures below 6°C. affect adversely: (a) cocoon deposition,(b)rate of development, (c) hatching. The beds, in contrast to natural habitats, rarely fall below 6°C. Egg sterility is increased at a temperature of 20°C.7The bacteria beds form an environment for this worm which includes all the main features of its natural habitats. The higher temperature in winter, the protection from desiccation and birds, and the scarcity of natural predators allow excessive multiplication of the worm. Further, certain factors in the beds, probably the peculiar chemical conditions, prevent colonization by other similar worms so that competition with other Oligochaetes is at a minimum. Thus, by virtue of its great degree of physiological adaptability, this worm is able to thrive in the bacteria beds to an extent not found in any natural hab

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1939.tb06999.x

出版商:Blackwell Publishing Ltd    

年代:1939

数据来源: WILEY

摘要:

Summary1A survey of various fruit‐producing areas in England showed that fruit and foliage were liable to be contaminated with ascospores ofByssochlamys fulva.Contamination was most pronounced on mummified plums and on certain fruit refuse.2The thermal death point of ascospores is about 96°C., but only a small proportion of spores show this maximum heat resistance. Conidia are killed by exposure to relatively low temperatures.3The reaction and the sucrose concentration of the heating medium, and the strain of the fungus, are factors influencing the heat resistance of ascospores.4Ascospores germinate slowly and irregularly, but their germination is stimulated by previous heating to about 70°C. Ascospore germination and mycelial growth take place at relatively high temperatures, in high sucrose concentrations, in acid media, and in very high concentrations of carbon dioxide.5Ascospores are relatively insensitive to antiseptics and to desiccation.6Growth is accompanied by the production of a pectin‐destroying enzyme.7The results of laboratory experiments were applied to canning experiments and good agreement was obtained. Natural contamination on fruits could be overcome in cans by heating the contents to 195°F.8The amount of mycelial growth developing in an infected can depends upon the size of head space and the storage tempe

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1939.tb07000.x

出版商:Blackwell Publishing Ltd    

年代:1939

数据来源: WILEY

摘要:

SUMMARY1Single spore cultures ofO. graminisSacc. produced ascospores on the host, confirming the conclusion of Davis (1925) that the fungus is homothallic.2Single spores removed from a Petri dish took several weeks to germinate, whereas the spores remaining in the dishes germinated within 24 hr.3It is suggested that a retardation of spore germination may have been due to dilution of some necessary chemical substance.4The significance of slow spore germination in relation to the results obtained by Garrett (1939) on infection of wheat seedlings by the ascospores ofO. graminisis discussed.

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1939.tb07001.x

出版商:Blackwell Publishing Ltd    

年代:1939

数据来源: WILEY

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1939.tb07002.x

出版商:Blackwell Publishing Ltd    

年代:1939

数据来源: WILEY