摘要:

AbstractAn experiment was conducted using a greenhouse hydroponics system to investigate the influence of N nutrition on leaf growth and chlorophyll content in oilseed rape (Brassica napusL.) during both vegetative and generative growth. Plants were treated continuously with one of three levels of N supply (30, 100 or 170ppm N). Leaf expansion in terms of lamina area of individual leaves and leaf area per plant, and chlorophyll content of leaves during both growth phases were increased significantly by N supply up to 100 ppm N, which was found to be the optimum level for oilseed rape. N supply of 30 ppm N resulted in N stress while 170 ppm N represents an excessive supply. N supply of 100 ppm N enhanced leaf expansion during H–6 weeks after transplanting by 88–260 % over that of 30 ppm N. Lamina areas of younger leaves responded to N nutrition better than did those of older leaves. Leaf area per plant increased 155–194 % due to increasing N supply but leaf number was increased less remarkably (by 25–44 %). N supply enhanced the contents of leaf chlorophylla, chlorophyllb, and total chlorophyll but had very little influence on chlorophylla/bratios; except that increasing N supply tended to reduce these ratios. Results suggest that variation in leaf chlorophyll content of rape plants in response to N nutrition is a function of leaf age and position. The significance of these results in terms of certain physiological implications for the rape plant is di

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1989.tb00740.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractImpact of crop rotation, fertilizer treatments, and herbicidal applications on the long term maintenance of soil fertilityVI. Examination of progressive differences regarding chemical and physical factors of the yield potential of a soil conducted over the period 1973 through to 1983In order to investigate the influence of different crop management practices such as crop rotation, fertilizer treatments, and herbicide applications on the yield potential of a soil, the Crop Science Department of the Swiss Federal Institute of Technology (ETH Zürich) conducted a long term field experiment commencing 1973. The experimental location was at the Swiss Federal Research Station for Farm Management and Agricultural Engineering at Tänikon/TG (northeastern Switzerland).Over ten years of research it was found that chemical and physical soil properties had, in general, been only marginally affected by the different experimental treatments. However, consistent studies have shown that certain trends regarding specific factors of greater importance have emerged, which were not observed during the first five year period. Should they persist, the yield potential of the soil could be substantially affected in the long run.Soil reaction, organic carbon content, cation exchange capacity, and aggregate stability have proven to be relatively stable values. Changes of greater significance were evidenced regarding the character of the air‐water regime, a factor of particular importance for this site. Obviously, crop rotation had a marked impact on soil compaction. Therefore under local research conditions, the yield potential of the soil will, in the short term, be most likely endangered by structural soil chan

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1989.tb00741.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractLegumes are an important component of the dietary pattern of the developing world. Thus optimal yields are a vital factor in agricultural production in these countries. Seed characters affect plant growth and yields of grain legumes. Due to the lack of similar studies inPhaseolus vulgaris(Frenchbeans), a study was carried out to determine the effect of seed characters on the growth cycle of frenchbean plants. Seed size was primarily determined by the size and weight of cotyledons and seed coat, as embryo size was similar in all seed classes. Seed size had no effect on seed viability, although larger seeds germinated earlier. There was a positive relationship between seed size and plant growth characters. Larger seeds developed plants with better growth and yield component parameters, resulting in higher yields. The importance of determining seed size in frenchbeans is presented.

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1989.tb00742.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractTreating grains and roots of wheat seedlings with supernatants of different aged cultures ofStreptomyces atroolivaceusstimulated plant growth. The treatment resulted in increased shoot elongation, shoot fresh and dry weights, and root fresh and dry weights but suppressed the depth of the root system. The supernatants resulted in increased shoot DNA but not root DNA. Shoot and root contents of RNA and protein were also enhanced. Effects probably caused by activity of plant growth regulators.

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1989.tb00743.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractThe effect of water stress and its subsequent recovery on the photosynthesis, productivity and water status, was examined in three mungbean varieties (Vigna radiataL. Wilczek) i.e.PS 16, P 105 and Pusa Baisakhi.The varietyP 105was found relatively less susceptible to water stress compared to high susceptibility inPusa BaisakhiandPS 16.The adverse effect of stress was comparatively higher at the post‐flowering and pod development stages. It was observed that varietyP 105had inherently maintained higher water status by retaining higher water potential and water content under water stress condition, thereby effectively reducing the water loss. The higher transpiration rate in this variety regulates the flow of water within the plant. This type of regulation of water flow and maintenance of high water status inP 105helped to resist the adverse effect of water stress on photosynthesis and productivity. Such adaptation mechanism was not observed in varietiesPS 16andPusa Baisakhi.The recover) mechanism was, however, operated efficiently in susceptible varietiesPS 16andPusa Baisakhiparticularly for recouping the vegetative growth, but its effect could not be retained for reproductive characters, wherein also varietyP 105due to its efficient partitioning system yielded better than other cultivar

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1989.tb00744.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractComparison of methods to determine the root length density of cropsIn this paper, in a first step a comparison of the soil core or monolith method with the profile wall method was undertaken with data obtained for sugar beets.Results show that differences between both methods, expressed as a factor, decline destinctly during the vegetation period. This means that the calibration of the profile wall method with the help of a time independent, average factor cannot be recommended.In a second step, we compared the monolith method with a new procedure to estimate root growth.Results for a soil derived from loess show that values measured and estimated correspond very well, while for a sandy soil, there was only a satisfactory correspondence.The comparison led to the conclusion, that in field work the monolith method should be preferred to the profile wall method, and the root growth estimation procedure is available alternative to determine the root length density of cereals.

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1989.tb00745.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractLeaf area development, biomass production and yield of four spring barley varieties grown in a Mediterranean environment (southern Spain) in response to an early application of foliar sulphur or etephon have been studied. Both sulphur and etephon produced similar results compared to the control. Thus, whereas the maximum leaf area index on untreated plots was reached at the beginning of shooting, the growth of foliar area in the treated ones was extended until anthesis and its decline during maturity was similarly retarded. This led to a significant improvement in the biomass at anthesis (which was closely correlated with grain yield) as well as in the leaf area duration during grain filling. These effects were principally due to variations in the number of leaves per plant, caused by a higher tiller production in the treated plants and not by an increase in the number of leaves per tiller or by leaf size.An application of sulphur or etephon at tillering increases grain yield by raising both the number of ears per plant and per plot, without modifying the number of grains per ear or 1000‐grain weight. The similarity between the effects of sulphur and etephon may be due to the fact that sulphur absorbed by the leaves results in an increase in methyonine, the biological precursor or ethylene. The positive correlation between biomass at anthesis and number of ears over grain yield suggests that sink capacity and source activity are closely related and both simultaneously limited by the environmen

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1989.tb00746.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

AbstractTwelve varieties of Oat (Avena sativaL.) were screened for relative drought tolerance based on the magnitude of chlorophyll stability index (CSI), relative water content (RWC) and free proline accumulation.IGFR1‐2670, IGFRI‐3021, IGFRI‐2688andIGO‐8showed a lower magnitude of CSI under stress condition in comparison to other tested varieties whereas the values of RWC and tree proline accumulation were higher. Based on the observations of this study it is concluded that, of the varieties tested,IGFRI‐2670, 3021 2688andIGO‐8are relatively more drought tolerant than the other genotypes tested. A close agreement was also noticed amongst the trends of CSI and proline accumulation, and per cent reduction in yield in rainfed over irrigated

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1989.tb00747.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Books Reviewed in this Article:Hunte, W., und K. Grabbe, Champignonanbau.8., völlig neubearbeitere Aufl. von K. Grabbe.Pais, M. Salomé S., F. Mavituna, and J. M. Novais (eds.): Plant cell biotechnology.Döbereiner, J., and F. O. Pedrosa, Nitrogen‐fixing Bacteria in Nonleguminous Crop Pl

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1989.tb00748.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1989.tb00749.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY