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991.
Fodor F Gáspár L Morales F Gogorcena Y Lucena JJ Cseh E Kröpfl K Abadía J Sárvári E 《Tree physiology》2005,25(9):1173-1180
Effects of 10 microM cadmium (supplied as Cd nitrate) on the utilization and allocation of iron (Fe) were investigated in poplar (Populus alba L.) plants grown in nutrient solution with Fe(III)-EDTA or Fe(III)-citrate as the Fe source. The effects of Cd were also compared with those of Fe deprivation. The accumulation of Fe in roots was 10-fold higher in plants grown with Fe-citrate than with Fe-EDTA. Cadmium decreased leaf chlorophyll concentrations and photosynthetic rates, and these decreases were more marked in plants grown with Fe-citrate than with Fe-EDTA. In both Fe treatments, addition of Cd caused large increases in root and shoot apoplasmic and non-apoplasmic Cd contents and increases in root Fe content; however, Cd decreased shoot Fe content, especially in plants grown with Fe-citrate. New leaves of plants grown with Fe-citrate had small cellular (non-apoplasmic) Fe pools, whereas these pools were large in new leaves of plants grown with Fe-EDTA. Non-apoplasmic Cd pools in new leaves were smaller in plants grown with Fe-citrate than with Fe-EDTA, indicating that inactivation of non-apoplasmic Cd pools is facilitated more by Fe-EDTA than by Fe-citrate. In the presence of Cd, Fe-EDTA was also superior to Fe-citrate in maintaining an adequate Fe supply to poplar shoots. Differences in plant responses to Fe-EDTA and Fe-citrate may reflect differences in long-distance transport of Fe rather than in acquisition of Fe by roots. 相似文献
992.
Fredrik?SchlyterEmail author Elisabeth?Marling Jan?L?fqvist 《Journal of pest science》2004,77(4):191-195
A micro-feeding assay was developed for testing small amounts of synthetics and extracts as antifeedants for Hylobius pine weevils. We devised a simple setup consisting of 5×5-mm pieces of thin layer chromatography cellulose plates used in pairs for a bioassay involving choice. After application of 1.5 l solutions and evaporation of the solvent, each plate received a 5 l aliquot of 1 M sucrose as a feeding stimulant. The test period was 4 h at 25 °C with 6 days of starvation before the test, compared to just the 1 day sufficient for twig tests. Deprivation of water for 1 day at 65% RH before the test was critical because it increased feeding but not mortality. The combination of starvation and thirst reduced the relative variance (coefficient of variation) to below 50%. There was a good correlation of antifeedant activity in the microassay with the activity in a standard twig test. The microassay needs only several mg for a test series, whereas the twig test needs grams. 相似文献
993.
A modified rate equation, in which the diffusion of reagent was taken into consideration, was proposed and applied to results reported previously for the acetylation of wood. The equation was fitted more successfully to the prolonged as well as the early stage of the reaction than a common first-order rate equation. Although the conclusions were virtually unchanged, the reliability was enhanced because reaction parameters such as the rate constant, ultimate extent of the reaction, and activation energy calculated for the modified equation were based on much more data than those reported previously. The equation proposed here may be applicable not only to acetylation but to other chemical modifications of cellulosic materials in heterogeneous systems. 相似文献
994.
K. Samšinák 《Journal of pest science》1981,54(8):120-122
Outbreaks of some Arthropoda species in buildings of Praha are reviewed.Cylindroiolus teutonicus (Myriap., Chilopoda) leaved grassland around and entered cellars and rooms of dwelling houses. Here they died quickly in consequence of dryness. Several observations showed that Anobiidae (Anobium punctatum) living in wooden sculptures died within short after coming into central heated rooms.Lepisma saccharina damaged textil goods in a nursery school. The miteTyrophagus putrescentiae, unknown from field hitherto was often found in spider (Meta menardi) cocoons in caves and cracks of rocks. 相似文献
995.
To determine the effect of shade on morphology, growth and biomass allocation in Picea sitchensis, Larix × eurolepis and Thuja plicata, seedlings were grown in the open or under shadehouses providing 25%, 50% and 75% reductions of full-light for two growing
seasons. For most of the characteristics assessed there was no significant interaction between species and shade indicating
that the morphological responses to changing shade treatments were not species-dependent. After two growing seasons the mean
height increment for the three species was significantly greater in 25% (76.1 cm) and 50% shade (74.9 cm) than in the open
(69.5 cm). Root collar diameter increment, shoot, root and total biomass declined significantly with increasing shade while
the opposite was true for the height:diameter ratio. In both western red cedar and hybrid larch the shoot:root ratio was significantly
greater in the shade while in Sitka spruce this characteristic was not influenced by shade. While all species had significantly
greater specific shoot areas in 75% shade than in 0% shade, this trend was particularly pronounced in hybrid larch. In hybrid
larch and western red cedar, the normalised specific projected shoot area increased significantly with increasing shade. The
opposite trend was observed for Sitka spruce. We conclude that in the main the species studied demonstrated similar shade
acclimation responses despite their reported differences in shade tolerance. 相似文献
996.
997.
The aqueous extracts of Datura fastuosa leaves and seeds were evaluated for the analgesic effect on acetic acid-induced writhing and hot plate reaction in mice. According to the results, D. fastuosa leaves and seeds extracts at oral doses of 400 and 800 mg/kg are effective as analgesic. The analgesic activity of leaf extract is reduced by naloxone but not that of seed extract. 相似文献
998.
In the Bavarian Forest national park, the spruce bark beetle Ips typographus (Col., Scolytidae) has caused an uncontrolled mass propagation for more than 10 years. To find out if the population of parasitoid species, which can develop in an uncontrolled natural forest, is able to restrict spruce bark beetle gradation, we investigated the parasitoid fauna, their abundance and frequency in the central part of the park (no control), in the protection area and the enlargement area of the park and in a productive forest where the spruce bark beetle is strictly controlled. In 2002 and 2003, the species Coeloides bostrichorum, Roptrocerus xylophagorum/mirus, Rhopalicus tutela, Tomicobia seitneri and Dendrosoter eupterus were identified. C. bostrichorum was the most numerous species before Roptrocerus sp. and Rh. tutela. T. seitneri and D. eupterus were not as numerous. The order of frequency differed. Roptrocerus sp. was the most frequent parasitoid wasp in both years, and Rh. tutela and even T. seitneri were more frequent than C. bostrichorum. C. bostrichorum and Rh. tutela were found to be protandrous, whereas Roptrocerus sp. males and females had different sequences of appearance in different forest types. The average percentages of parasitism increased with time of exposure and was highest in the second generation. We found astonishingly high parasitization rates at sites where attacked trees are regularly removed. 相似文献
999.
Akio?InoueEmail author Marie?Miyake Tomohiro?Nishizono 《Journal of Forest Research》2004,9(4):319-324
An allometric model that explains the mechanism of the difference in the slope of the Reineke equation (A) among species was proposed based on the allometric relationships of mean tree height (H) to quadratic mean diameter D (H ∝ D
θ
) and stand density N (H ∝ N
δ
), i.e., A = θ/δ. The proposed model was fitted to Japanese cypress (Chamaecyparis obtusa Endl.) and red pine (Pinus densiflora) stands. The allometric exponents θ and δ were, respectively, 0.8995 and −0.5000 for cypress and 0.8612 and −0.6619 for pine. The difference between cypress and pine
was significant for δ but not for θ. Inserting the exponents into the model resulted in predicted slopes of −1.7991 for cypress and −1.3011 for pine. The difference
in the slope of the Reineke equation between the two species was produced by characteristics related to the tree crown, rather
than characteristics related to stem slenderness. The proposed model enables us to estimate the slope of the Reineke equation
from commonly measured stand attributes, such as mean tree height and quadratic mean diameter. Therefore, the proposed model
is expected to be practical and convenient for estimating the slope of the Reineke equation and for explaining the mechanism
of its variation among species. The model should be also accepted as a generalized model of the stand density versus quadratic
mean diameter relationship, whereas the original Reineke equation should be seen as a specific case of this model. 相似文献
1000.
Koji?YoshidaEmail author Ryota?Shibasaki Chika?Takami Chisato?Takenaka Kazukiyo?Yamamoto Takafumi?Tezuka 《Journal of Forest Research》2004,9(3):195-203
In order to clarify the chronic influence of acid fog on the gas exchange rates of momi fir (Abies firma Sieb. et Zucc.) trees, we exposed them to simulated acid fog (pH 3) for 3 years. The composition of the acid fog was similar to that observed in a region where momi fir trees have been declining, and it contained organic acids. We then treated the firs with various additional stresses, such as drought, low temperature, fine root cutting, ozone exposure, soil acidification, nitrogen load, and rhizosphere aluminum stress. Under chronic exposure to acid fog, the momi fir seedlings exhibited a pattern of stomatal behavior whereby they excessively opened in summer and closed in winter. Furthermore, the stomata of these seedlings tended to open during drought stress, and their needles were visibly injured after ozone exposure. The net photosynthesis rates of the seedlings exposed to acid fog were regulated by their stomatal aperture, rather than directly by acid fog. These results suggest that acid fog exposure disturbs the control of stomatal function in the momi fir seedlings. In addition, we found that chronic acid fog exposure suppressed the decrease in net photosynthesis rate, due to its nitrogen load. 相似文献