Sea buckthorn (Hippopha? rhamnoides L.) is a rich source of flavonols, especially isorhamnetin. Most prospective cohort studies have indicated some degree of inverse association between flavonoid intake and coronary heart disease. Animal and human studies suggest that sea buckthorn flavonoids may scavenge free radicals, lower blood viscosity, and enhance cardiac function. The effects of flavonol aglycones derived from sea buckthorn on the risk factors of cardiovascular disease as well as their absorption were studied in humans. The flavonols, ingested with oatmeal porridge, did not have a significant effect on the levels of oxidized low-density lipoprotein, C-reactive protein, and homocysteine, on the plasma antioxidant potential, or on the paraoxonase activity. Flavonols at two dosages in oatmeal porridge were rapidly absorbed, and a relatively small amount of sea buckthorn oil added to the porridge seemed to have increased the bioavailability of sea buckthorn flavonols consumed at the higher dose. 相似文献
In this study, the information needs of non-industrial private forest owners in Finland, after logging operations, were investigated. The study was carried out as an online survey in 2017. The survey was targeted at non-industrial private forest owners who had sold their timber during the previous 10 years (2008–2017) and whose email addresses were in the customer relationship management system of a large wood procurement company in Finland. A response link for the survey was successfully sent to 31,988 forest owners, of whom 3323 replied (response rate: 10.4%). The final study data included 3284 non-industrial private forest owners. The results of the study, which need to be interpreted cautiously due to the low response rate, showed that the forest owners want better-quality reporting after logging operations. Furthermore, the results suggested that gender, age, education, occupational status, place of living, size of, and access to, forest property, and length of, and objectives for, forest ownership have a significant effect on their information needs. Younger, highly-educated, female, urban-living and multi-objective forest owners with larger forest holdings and short forest ownership tenures desired more information. Particularly, the respondents conveyed that they would like more and better information about thinning harvesting result. The results also indicated that when different groups of forest owners call for certain information, there is a need for producing different types of reports after logging operations for different forest owner segments.
Finnish isolates of Beauveria bassiana (8 isolates), Metarhizium anisopliae (7), Tolypocladium sp. (2), Paecilomyces farinosus (2), P. fumosoroseus (1), Steinernema feltiae (3) and Bacillus thuringiensis ('Muscabac') were tested for efficacy against mixed populations of Delia radicum and D. floralis under field conditions in 1986–90. All pathogens were applied preventatively, the fungi as aqueous conidial or mycelial suspensions, dry conidia or dry mycelial powder. In only two of the nine experiments did B. bassiana or M. anisopliae give some control. In 1986, B. bassiana SF85–2 and Tolypocladium sp. SF85–4 (both at rate 1.2 x 109 conidia plant‐ 1), and ‘Muscabac’ (25 g 1?1, 1 dl plant?1) reduced the number of pupae by 80%, 60% and 50%, respectively, as compared with untreated and chemical (isophenphos) controls. In 1990, M. anisopliae SF86–39 at rate 1.6 x 109conidia plant?1 and 1.5 x 108 CFU plant?1 and S. feltiae SFS‐22 (35000 plant?1), increased the yield of cauliflower 2.2, 1.8, and 2.3‐fold, respectively, as compared with the untreated control, but these yields were only 19%, 15% and 19% of those of the chemical (diazinon) control. Paecilomyces isolates were ineffective in the 1986 experiment in which they were included. Our results suggest that it is difficult to find efficient control agents among the fungal and nematode species tested for use as biopesticides against cabbage root flies, but that the potential of M. anisopliae against these pests deserves further study. 相似文献
Two models of shoot photosynthesis, the needle surface element model (SEM) and needle volume element model (VEM), were tested against empirical data obtained from measurements of the photosynthetic response of twelve Scots pine (Pinus sylvestris L.) shoots in direct and diffuse radiation. The models assume that shoot photosynthesis is obtained as the integrated response of either all needle surface area elements (SEM) or all needle volume elements (VEM) of the shoot. The models differ in that needles are treated as optically black in SEM, whereas in VEM radiation penetrates into the needle. The photosynthetic response of a surface/volume element was described as a Blackman-type curve and the distributions of irradiance on the elements were derived by computer simulation, based on a model of shoot geometry. The parameters (initial slope and maximum rate) of the Blackman-curve of an element were estimated iteratively by the method of least squares, i.e., by minimizing the residual sum of squares of simulated and measured rates of shoot photosynthesis. The parameter estimation was done separately for direct and diffuse radiation, and the models were evaluated based on the notion that, for the "ideal" model, the estimated parameter values should be the same in direct and diffuse radiation. Both models produced shoot photosynthesis curves that agreed well with measurements, but there was a discrepancy in the estimated parameter values, indicating that differences in the photosynthetic response of shoots in direct and diffuse radiation could not be explained solely on the basis of the simulated irradiance distributions. The agreement was, however, much better for the volume element model, which accounts for penetration of radiation into the needles. 相似文献
Coniferous trees growing in the boreal and temperate zones have a clear annual cycle of photosynthetic activity. A recent study demonstrated that the seasonal variation in photosynthetic capacity of Scots pine (Pinus sylvestris L.) could be attributed mainly to the light response curve of photosynthesis. The magnitude of the light response curve varied over the season while its shape remained constant, indicating that the two physiological parameters quantifying the curve-the quantum yield per unit internal carbon dioxide concentration and the corresponding light-saturated rate-remained proportional to each other. We now show, through modeling studies, that the quantum yield (and hence the light-saturated rate) is related to the annual cycle of temperature through a delayed dynamic response. The proposed model was tested by comparing model results with intensive measurements of photosynthesis and driving variables made from April to October in three shoots of Scots pine growing near the northern timberline. Photosynthetic capacity showed considerable acclimation during the growing season. A single model describing photosynthetic capacity as a reversible, first-order delay process driven by temperature explained most of the variation in photosynthetic capacity during the year. The proposed model is simpler but no less accurate than previous models of the annual cycle of photosynthetic capacity. 相似文献
Microbial biomass C and N, and activities related to C and N cycles, were compared in needle and leaf litter, and in the uppermost 10 cm of soil under the litter layer in Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies L.) and silver birch (Betula pendula L.) stands, planted on originally similar field afforestation sites 23–24 years ago. The ground vegetation was differentiated under different tree species, consisting of grasses and herbs under birch and pine, and mosses or no vegetation with a thick layer of needles under spruce. The C:N ratio of the soils was 13–21 and the soil pHCaCl2 3.8–5.2. Both showed little variation under different tree species. Microbial biomass C and N, C mineralization, net ammonification, reduction) did not differ significantly in soil under different tree species either. Birch leaf litter had a higher pHCaCl2 (5.9) than spruce and pine needle litter (pH 5.0 and 4.8, respectively). The C:N ratio of spruce needles was 30, and was considerably higher in pine needles (69) and birch leaves (54). Birch leaves tended to have the highest microbial biomass C and C mineralization. Spruce needles appeared to have the highest microbial biomass N and net formation of mineral N, whereas formation of mineral N in pine needles and birch leaves was negligible. Microbial biomass C and N were of the same order of magnitude in the soil and litter samples but C mineralization was tenfold higher in the litter samples. 相似文献
Landscape classifications are increasingly being used in conservation planning and biodiversity management, although there is a dearth of studies actually showing concordant patterns between such classifications and biodiversity. We studied the utility of tributary and stream type classifications in accounting for the variability of invertebrate biodiversity in a boreal drainage system. We found that only weak, although significant, differences existed between the studied three tributaries and four stream types in macroinvertebrate assemblage structure, species distributions, and taxonomic richness. Further, the classification strengths, calculated as mean within-group-similarity minus mean between-group-similarity of assemblage structure, were rather low, suggesting that the a priori physical classifications did not effectively describe variability in macroinvertebrate assemblage structure. The low classification strengths likely resulted from the facts that: (i) most stream macroinvertebrate taxa show individualistic responses to environmental gradients; (ii) many taxa occur either across all stream types; or (iii) only sporadically in a given stream type; and (iv) only a few species show high fidelity to a given stream type. However, the significance of the differences in macroinvertebrate assemblage structure and taxonomic richness, as well as a bunch of effective indicator species for different stream types, suggest that such classifications could be used as a preliminary scheme for the conservation planning of running waters. This reasoning is also supported by the evidence from other studies that have found stream size and the distance to upstream lakes to shape considerably the biodiversity of various groups of stream organisms, although no single organism group is likely to show a perfect match with any classification scheme. 相似文献