摘要:

Books reviewed in this article:BIOCHEMISTRY AND PHYSIOLOGY OF PLANT HORMONES. BY T. C. MOORESTRESS PHYSIOLOGY IN CROP PLANTS. Edited by H. MUSSELL&R. C. STAPLESCYCLIN PHENOMENA IN MARINE PLANTS AND ANIMALS, Edited by E. NAYLOR&R. G. HARTNOLLTHE LIFE OF THE GREEN PLANT. By A. W. GALSTON, P.J. DAVIES&R. L. SATTERKNOTT'S HANDBOOK FOR VEGETABLE GROWERS. 2nd Edition, by OSCARA. LORENZ&DONALDN. MAYNARDBIOGENESIS AND FUNCTION OF PLANT LIPIDS. Edited by P. MAZLIAK, P. BENVENISTE, G. COSTES&R. DOUCESPOTASSIUM RESEARCH—REVIEW&TRENDS. Proceedings of the 11th Congress of the International Potash Institute, Bern, Switzerla

ISSN:0140-7791    

DOI:10.1111/1365-3040.ep11610773

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

ISSN:0140-7791    

DOI:10.1111/1365-3040.ep11610780

出版商:Blackwell Publishing    

年代:1981

数据来源: WILEY

ISSN:0140-7791    

DOI:10.1111/1365-3040.ep11610785

出版商:Blackwell Publishing    

年代:1981

数据来源: WILEY

ISSN:0140-7791    

DOI:10.1111/1365-3040.ep11610892

出版商:Blackwell Publishing    

年代:1981

数据来源: WILEY

ISSN:0140-7791    

DOI:10.1111/1365-3040.ep11610895

出版商:Blackwell Publishing    

年代:1981

数据来源: WILEY

摘要:

Abstract.According to the multiphasic concept uptake isotherms consist of a number of successive Michaelis‐Menten phases separated by discontinuous transitions. In this paper evidence is provided that the concept is most probably due to an erroneous interpretation of continuous uptake isotherms that yield non‐linear, concave downward Lineweaver‐Burk plots. With reference to the isotherm of sulphate uptake in barley roots (Nissen, 1971) uptake isotherms were simulated in which the uptake rates, computed from the sum of two Michaelis‐Menten terms and a linear term, contained a 4% (or 5%) random error. The same arguments that have been adduced in support of the multiphasic concept would also lead to a multiphasic interpretation of the simulated isotherms. The conclusions concerning a multiplicity of transition points and the multiphasic concept follow from the particular form of statistical test that had been applied rather than from the set of data itself. Characteristics that have been noted in multiphasic uptake appear to follow simply from the multiphasic interpretation of uptake isotherms that yield non‐linear, concave downward Lineweaver

ISSN:0140-7791    

DOI:10.1111/1365-3040.ep11610902

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

Abstract.The phototropic and the geotropic sensitivities of cress hypocotyls differed in etiolated and in green seedlings. In etiolated seedlings, phototropism was poorly developed and geotropism seemed to be the dominant orientation mechanism. In green seedlings, although geotropic sensitivity was slightly greater, phototropic responses were markedly enhanced, such that photo‐signals could over‐ride, or even reverse, geocurvature. The ‘de‐etiolation’ light pretreatments required to bring about these changes in the photo‐and geo‐systems were different. The slight enhancement of geocurvature could be achieved by short‐term exposure to red light and was reversed by far‐red irradiation. The marked stimulation of photocurvature required extensive irradiat

ISSN:0140-7791    

DOI:10.1111/1365-3040.ep11610972

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

Abstract.Despite intensive research effort, the role of growth substances in the life of the intact growing plant is far from clear. Two reasons are suggested which may account for the lack of progress. The first is the failure to recognize the unique aspects of plant development. These which are expressed by the regenerative, organizational and developmental plasticity of the meristem probably result from the possession of growth substances. The second is the concept of growth substances as hormones. This represents the main conceptual thrust of research and is considered critically, starting with the historical system, the coleoptile and dealing with other major growth substance systems in turn. It is concluded that a hormonal concept which includes control by changes in growth substance concentration fails to explain the developmental phenomena under examination. A role for growth substances as integrating agents is suggested and the notion of quantitative tissue sensitivity variation is developed to explain the major growth patterns of developing shoots.

ISSN:0140-7791    

DOI:10.1111/1365-3040.ep11610983

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

Abstract.Germination responses of redroot pigweed (Amaranthus retroflexusL.) seeds to ethylene were determined at 25, 30, 35, or 40° C after preincubation at various temperatures (15–35° C) for different periods (0.5–32 d). After 7 d preincubation, seeds showed a log‐linear germination response to ethylene concentration in most of the temperature treatments. Sensitivity to ethylene increased with longer preincubation; response thresholds of 0.03−0.09 cm3m−3were observed after 32 d, compared to 0.18−1.6 cm3m−3after 7 d of preincubation. Preincubation at 15 or 20° C generally enhanced germinability, whereas 25 or 30° C produced secondary dormancy, which was readily broken with ethylene. Temperature during preincubation also significantly influenced the slope of the dose‐response curve. The responses of preincubated redroot pigweed seeds to ethylene suggested that, in the field, seeds would probably not lose their sensitivity to this gas during prolo

ISSN:0140-7791    

DOI:10.1111/1365-3040.ep11610993

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

Abstract.The effects of diurnally alternating temperatures and of prolonged burial in the soil on germination response of redroot pigweed (Amaranthus retroflexusL.) seeds to ethylene were investigated. Percentage germination in a 12 h/12 h, 23° C/35° C temperature regime roughly equalled that observed at constant 35° C, and greatly exceeded that observed at 30°C. Preincubation for 61 d in alternating temperatures, which were gradually increased to simulate soil warming in spring, caused little germination in the absence of ethylene, but considerably enhanced sensitivity to ethylene. Seeds kept in soil in the same temperature regime failed to show the response to ethylene, and the soil itself removed ethylene from the soil atmosphere.After burial in a field plot either over winter or during the summer, seeds had a very low ethylene response threshold (0.01−0.05 cm3m−3) and strong response to ethylene (70–95% germination at 51 cm3m−3compared to 1–20% without ethylene). Germinability of seeds buried overwinter declined between 10 May (85%) and 24 May (7%), and 90% of those recovered on or after 24 May had a visible rupture in the seed coat. Apparently, germination had begun during burial, but was arrested by unknown causes in an early phase and was followed by seed deterioration.Although the role of ethylene in germination of buried seeds remains uncertain, the greatly enhanced sensitivity to ethylene observed in pigweed seeds after burial deserves further

ISSN:0140-7791    

DOI:10.1111/1365-3040.ep11611005

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY