The effect of Brevicoryne brassicae on leaf area, dry matter distribution and amino acids of the Brussels sprout plant

1990 ◽  
Vol 116 (2) ◽  
pp. 199-204
Author(s):  
H. F. VAN EMDEN
1983 ◽  
Vol 61 (8) ◽  
pp. 2186-2194 ◽  
Author(s):  
Roy Turkington

Replicates of two genotypes of Trifolium repens L., collected from a Poa pratensis dominated sward and a Dactylis glomerata dominated sward, respectively, were grown in swards composed of various proportions of P. pratensis and D. glomerata. These swards represented a range of environments of neighbours; an increasing proportion of P. pratensis was considered as an increasingly alien environment for individuals of T. repens collected from the D. glomerata dominated site, and vice-versa for the individuals from the P. pratensis dominated site. The individuals of T. repens were harvested on five occasions over a period of 27 months. Both genotypes responded to increasingly alien environments by producing more inflorescences and by distributing proportionately more dry matter to inflorescence production. Some evidence is also presented which suggests that allocation to stolons and inflorescences are alternatives and the balance of the trade off is dependent on the advantages of possibly producing new, better adapted offspring from seed, against the chances of a wandering stolon encountering a less hostile environment. Results are discussed in the context of environmental alienness, a major source of which is the different relative proportions of neighbours. The various genotypes of organisms which a relatively mobile plant species encounters are a major source of this environmental, or biotic, alienness.


1971 ◽  
Vol 49 (3) ◽  
pp. 353-358 ◽  
Author(s):  
Klaus Steinbeck

Four random clones of American sycamore supplied with four concentrations of Hoagland's solution differed in their response to and interacted with treatment as far as height and diameter growth and total dry matter production in the first growing season were concerned. Varying nutrient intensity did not affect the time of the seasonal peak of height and diameter growth; better growth was maintained subsequent to the seasonal peak at the higher concentrations, however. The proportions of the trees in terms of dry-matter distribution and branching characteristics changed with nutrient concentration.


1967 ◽  
Vol 45 (11) ◽  
pp. 2063-2072 ◽  
Author(s):  
Holger Brix

Seedlings of Douglas fir (Pseudotsuga menziesii (Mirb.) Franco) were grown in growth chambers under all combinations of three temperatures (13, 18, and 24 °C) and three light intensities (450, 1000, and 1800 ft-c). Dry matter production of leaves, stem, and roots was determined at 65 and 100 days after germination. The leaf area produced per unit of leaf dry weight and the dry matter distribution to the plant organs was measured. Net assimilation rates between the ages of 65 and 100 days were calculated. Rates of photosynthesis per unit of leaf were determined at different light intensities and temperatures, and rates of respiration of plant top and of roots were found for different temperatures.Increasing light intensity affected dry matter production in two opposing ways: (i) it increased the rate of photosynthesis per unit leaf area, and (ii) it decreased the leaf area added per unit of dry matter produced. A pronounced increase in growth with increase in temperature from 13 to 18 °C was a result of a temperature influence on production of leaf area rather than the effect of photosynthesis per unit of leaf. Net assimilation rates decreased with increase in temperature at all light intensities.


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