Variation in the senescence of carnation (Dianthus caryophyllus L.) cultivars. I. Comparison of flower life, respiration and ethylene biosynthesis.
Wu, M. J.; Doorn, W. G. van; Reid, M. S.;
Scientia Horticulturae Year: 1991 Vol: 48 Issue: 1-2 Pages: 99-107 Ref: 21 ref.
1991
บทคัดย่อ
A life table study was conducted of injury and mortality of Douglas fir [Pseudotsuga menziesii] seedlings in 44 plantations on public and private lands in Humboldt and Del Norte Counties, California. The areas were planted in late autumn 1983 or early spring 1984. Field examinations were made 3 times each year in 1984, 1985 and 1986. Dead and dying seedlings were lifted and examined in the laboratory. Real mortality (the number of seedlings found dead at each examination time as a percentage of the number planted minus missing seedlings) and apparent mortality (the number of dead seedlings found at each examination time as a percentage of the number alive at the beginning of that time interval) were recorded in life table format for the 9 time intervals (3 in each year). Seedling real mortality per time interval in the different ownerships varied from 0 to 35.0%, and totalled 14.0 to 70.7% for the three years. Highest mean mortality occurred from late spring to autumn in the first year. Trend an alyses, using a curvilinear regression model, showed significant differences in rates of mortality among ownerships. The performance of containerized and bare root seedlings was similar. Conclusions from the life table analyses, using a two-step modelling process, are presented. Variations and covariations in mortality associated with intervals 2 and 3 were most important in determining total variation in survival in the 3-year period; intervals 1, 4, 7 and 9 were also critical in some cases. Planting- and weather-related factors were most important in intervals 1-4; disease, insects and vertebrates (alone and jointly) were more important in the second and third years. Substantial covariations in mortality among the time intervals indicated carryover effects; covariations among certain categories of causal factors indicated strong positive or negative interactions that either added to or dampened the direct effects of these factors.