ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1923.tb05664.x

出版商:Blackwell Publishing Ltd    

年代:1923

数据来源: WILEY

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1923.tb05665.x

出版商:Blackwell Publishing Ltd    

年代:1923

数据来源: WILEY

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1923.tb05666.x

出版商:Blackwell Publishing Ltd    

年代:1923

数据来源: WILEY

摘要:

Summary.The “streak” disease of beans (Chocolate Spot Disease) is caused byB. lathyri.Moist and warm conditions are responsible for the appearance of the disease in epidemic form.The disease is spread by wind, black fly, and the bean beetle.Methods of control are sugges

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1923.tb05667.x

出版商:Blackwell Publishing Ltd    

年代:1923

数据来源: WILEY

摘要:

Summary.1Serum agglutination has been used in order to determine possible relationship withBacillus lathyriof certain yellow organisms which occur in the tissues of plants infected by that organism.2One of these gave all the reactions ofPseudomonas Phaseoli.3Pseudomonas PhaseoliandBacillus lathyrigave distinct cultural characters, and these were retained even after the two organisms had been “trained” by ten transfers through the same medium.4The two organisms seem to be susceptible to group agglutination,Bacillus lathyribeing agglutinated with the serum ofPseudomonas Phaseoli.5Intermediate forms between these two organisms are found which agglutinate equally with the sera of both species.6The suggestion is made that one species may have arisen in the tissues of the plant as a mutant from the other.7Aplanobacter dissimulans, another organism often associated withBacillus lathyri, appears to bear no sort of relationship with the latter.8Aplanobacter michiganensefailed to produce an agglutinating serum on inoculation into a rab

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1923.tb05668.x

出版商:Blackwell Publishing Ltd    

年代:1923

数据来源: WILEY

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1923.tb05669.x

出版商:Blackwell Publishing Ltd    

年代:1923

数据来源: WILEY

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1923.tb05670.x

出版商:Blackwell Publishing Ltd    

年代:1923

数据来源: WILEY

摘要:

Summary.1Field experiments, especially in America, nave indicated that, with annual plants at least, better crops are usually obtained by the use of heavy seed in preference to light, whether equal numbers of bushels or equal numbers of seeds are sown per acre.2Water culture experiments with peas and barley have shown that there is a steady and considerable rise in the dry weight of the plants as the initial weight of the seed increases. This occurs both with a limited and abundant food supply.3The efficiency index (rate per cent, increase per day) falls gradually as the weight of the seed rises. With prolonged periods of growth this tends ultimately to counterbalance the initial advantage gained by plants from the heavier seeds, but with annual crops as cereals, peas, etc. harvesting occurs before this equilibrium is reached, leaving the advantage with the heavier seeds.4The relative development of shoot and root is to some extent influenced by the initial weight of the seed, but may vary with the species and with the amount of available food.5The results lend support to the growing agricultural practice of advocating the use of large heavy seed, especially with annual crops. The advantage in the case of perennials would appear to be less, if any, but this has not been determined by laboratory experiments.

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1923.tb05671.x

出版商:Blackwell Publishing Ltd    

年代:1923

数据来源: WILEY

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1923.tb05672.x

出版商:Blackwell Publishing Ltd    

年代:1923

数据来源: WILEY

摘要:

Summary.1Diaporthe perniciosa, first isolated by Marchal from rots in stored fruits, has proved to be parasitic and one of the causes of “die back” in stone fruit trees.2The various strains ofD. perniciosaisolated from “die back” on peach and different varieties of plums have proved to be parasitic, morphologically identical, and cause definite wilt and “die back” on peach, plum, apricot and nectarine. Cross inoculations of the same organisms on two year old wood of Prince of Wales plum have so far not brought about typical symptoms of “die back,” but considerable disturbance, accompanied by gumming, has occurred at the points of inoculation. A strain obtained from apricot, which shows morphological differences, has also been proved to be capable of causing “die back” on peach and apricot. All the controls remained healthy.3The progress ofD. perniciosain the host tissue is slow; infection occurs a considerable time, in some cases years, before any external symptoms appear. The mycelium permeates the internal tissues more especially the medullary rays, cortical tissues, phloem cambium, and vessels.4D. perniciosahas a pycnidial orPhomopsisstage with “a” and “b” spores, and a perithecial orValsastage with numerous eight‐spored asci. The pycnospores emerge as whitish tendrils or globules through numerous lenticel‐like slits in the bark; the perithecial necks are long and protrude mostly through the same slits as the tendrils, and the ascospores are given off either through the ostiolum at the tip of the neck of the perithecium, or may burst through any part of the neck.5The external symptoms are sunken areas and longitudinal slits in the bark; elongated strands of numerous lenticel‐like transverse slits through which tendrils and perithecial necks emerge; rapid wilt and browning of the trees in summer, or premature yellowing and fall of the leaves in the autumn.6The internal tissues are discoloured and secondary thickening arrested.7The pycnidial stage occurs on living or more or less moribund bark, the perithecial stage on the parts which are dead.8D. perniciosashows a certain degree of polymorphism on the host plant; on artificial media this polymorphism is much more marked.9ThePhomopsisstage ofD. perniciosagrows and sporulates well on artificial media, but perithecia develop sparingly in cultures from pycnospores.10Cultures of mass infections of ascospores ofD. perniciosahave given rise in some cases to thePhomopsisstage with “a” and “b” spores; in others no “b” spores could be found. Mono‐ascospore cultures develop the pycnidial stage very sparingly, and no “b” spores have been observed in any of the cultures. Large numbers of perithecia

ISSN:0003-4746    

DOI:10.1111/j.1744-7348.1923.tb05673.x

出版商:Blackwell Publishing Ltd    

年代:1923

数据来源: WILEY