摘要:

Summary.Studies on clones ofcynodon dactylon(L.) Pers. have revealed the existence of four biotypes of this species. The sole use of morphological characters to classify them was found unsatisfactory and other definite diagnostic characters have been introduced comprising hair group characteristics and leaf and stolon epidermal structures. Cytotogical studies showed that the biotypes differ in their chromosome number; tetraploid and triploid races have been distinguished. Phasic growth investigations have pointed out that thr biotypes have a similar growth behaviour but that the tetraploids are more vigorous plants than the triploids. Studies on the seasonal variation in available carbohydrates in rhizomes and roots have established that the seasonal trend of this reserve substance in these organs is related to rhizome growth.Recherches sur des biotypes deCynodon dactylon (L.) Pers.

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1962.tb00177.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

Summary.Observations have been made on the effects of maleic hydrazide (MH) and 2,4‐dichlorophenoxyacetic acid (2,4‐D), used singly or as a combined spray, on the vegetation of roadside verges, over a period of 3‐4 years (1958‐61). Each year, replicate plots were sprayed in spring, and assessments of growth and floristic composition of the vegetation, which was dominated by grasses, were usually made on three occasions. Treatment with MH, used singly, resulted in a general suppression of growth and flowering, particularly of the grasses. Well‐marked changes in the composition of the sward were attributable to MH, notably the decline of tufted forms, e.g.Arrhenatherum elatius, Dactylis glomerata, and the rise to dominance of the rhizomatous grasses. These changes were associated with a progressive increase of some dicotyledonous plants, although this was effectively prevented by the combined spray of MH and 2,4‐D. Two of the commonest weeds,Anthriscus sylvestrisandHeracleum sphondylium, were almost eliminated from plots treated with this combined spray for 3 successive years; a low sward, fairly free from dicotyledons and dominated byPoarather thanFestuca, usually resulted. Treatment with 2,4‐D alone, had relatively little effect on growth, flowering and proportion of the different grasses, but there was a reduction in the weed population.Les effets de l'hydrazide maléique et de l'acide 2,4‐dichlorophénoxyacétique sur la végetation

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1962.tb00178.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

Summary.The breakdown of amitrole has been studied on different soil types and at two temperatures. It is shown by use of soil sterilization and of microbiological toxicants, that amitrole is broken down microbiologically. Increase in soil organic matter and in temperature up to 30° C both increase the rapidity of breakdown.Premières observations sur la décomposition du 3‐amino‐1,2,4‐triazole da

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1962.tb00179.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

Summary.The translocation of14C‐labelled herbieides in field bracken has been sludied in some preliminary experiments by means of autoradiography. A detailed account is given of the methods employed. It is shown that when 2,4‐D is applied to fronds at different stages of development movement of the tracer into the rhizome is considerably greater from parts of the frond which are still immature. Trasnslocation within the frond is predominantly basipetal at all stages of development; within the rhizome the direction of movement appears to be determined primarily by the nature of the vascular connections with the treated pinna.In a comparison between the translocation of 2,4‐D, 4‐CPA and dalapon no difference was apparent after 24 hours, but when the treatment period was extended to 96 hours there was evidence that 4‐CPA bad been translocated in a considerably greater amount than either of the other two herbicides.Rechrches iréliminaires sur la migration des herbieides marqués am14C dans la fougrère algle(Pteridi

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1962.tb00180.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

Summary.A method for the bioassay of chlorpropham in soil from field plots is described which involves the preparation of mixtures of treated soil with untreated soil and the determination of the dilution required to produce 50% inhibition of primary root growth in buckwheat (Fagopyrum esculentumMoench). Using this method, it was found that the period required for 90% disappearance of chlorpropham from a sandy foam ranged from 3 to 14 weeks, according to the prevailing temperature and soil moisture conditions. When applications of 1 and 2 lb/ac were compared, the percentages of chlorpropham remaining at any one time were similar.Dosage biologique du chlorpropham dans le sol

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1962.tb00181.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1962.tb00182.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1962.tb00183.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1962.tb00184.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY