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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    European journal of applied physiology 49 (1982), S. 277-286 
    ISSN: 1439-6327
    Keywords: Age changes ; Metabolic transients ; Respiratory transients ; Heart rate transients ; Mechanical efficiency ; Gas exchange ; Dynamics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Five older men (aged 60–69 yr) and five young men (aged 21–29 yr) with approximately equal levels of age-corrected $$\dot VO_2$$ max were compared with respect to oxygen kinetics at equal absolute workloads (100 watts) and at equal relative workloads (45% $$\dot VO_2$$ max) on a cycle ergometer. At 45% $$\dot VO_2$$ max, half times for $$\dot VO_2$$ response to instantaneous transition from unloaded pedalling were 30.0 s and 27.4 s for old and young respectively (t=0.260,p〈0.80). No significant differences were found in the $$\dot V_E$$ response and by inference none existed in O2 extraction. Mean half times for heart rate responses at a workload of 100 W were 24.2 s and 20.6 s for old and young groups respectively (t=0.722,p〈0.49). Mechanical efficiency estimated from steady state data at 100 W was 19.8% and 20.5% for old and young groups respectively (t=0.574). The close similarity in responses to submaximal work in old and young subjects of equivalent fitness suggests caution in the interpretation of agewise decrements observed in physiological variables which may be sensitive to physical fitness status.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Plant and soil 56 (1980), S. 3-16 
    ISSN: 1573-5036
    Keywords: Beans ; Leaf extension rate ; Salt tolerance ; Soil water osmotic potential ; Transpiration rate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Bean plants (Kora cv) were grown in potted soil artificially salinized by adding NaCl and CaCl2 to the irrigation water to obtain an electrical conductivity of the soil saturation extract (ECe) thirty days after emergence of 0.1, 0.3, 0.5 and 0.7 S/m at 25°C and a sodium adsorption ratio (SAR) of 4 (mmol/l)2. Thereafter, plants were irrigated when soil water matric potential (ΨM) was in the range of −20 to −30 kPa (wet treatment) and when ΨM was in the range of −40 to −60 kPa (dry treatment). Transpiration rates (Tr) and leaf extension rates (LER) per plant or per unit of leaf area were decreased by increasing soil salinity and by decreasing soil moisture. However, a given decrement of ΨM produced a considerable larger decrement in Tr of LER than an equivalent decrement of soil water osmotic potential (Ψ0). Absolute yields of green pods under wet treatments were from twice to one and a half time as large under the wet than under the dry treatment at equivalent values of Ψ0. Relative yields were reduced by 25% when ECe were about 0.5 S/m and 0.7 S/m in the dry and wet treatment respectively. Salt tolerance data of crops may not have a quantitative interest when soil irrigation regimes under which they were obtained are not specified.
    Type of Medium: Electronic Resource
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