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81.
Abstract: We examined beliefs of landowners who hunt and do not hunt regarding chronic wasting disease (CWD) and its management. We mailed surveys to a random sample of 973 Wisconsin, USA, landowners living in the CWD southwest disease eradication zone. Of 613 respondents, 360 (59%) were hunters and 253 (41%) were not hunters. We created multiple item indices to measure respondent beliefs about effects of CWD and its management. Hunters and nonhunters differed on 5 of 6 belief indices. Both groups were, on average, relatively neutral in their trust of the Wisconsin Department of Natural Resources but landowners who did not hunt reported slightly higher trust. Both groups were neutral or slightly agreed that CWD should be managed and they were concerned about deer (Odocoileus spp.) health and the safety of eating venison. Landowners who did not hunt were more likely than those who hunted to agree with these issues but effect sizes indicated these differences were minimal. Landowners who hunted were more concerned than nonhunters about effects of CWD on deer hunting. Cluster analyses indicated most nonhunting landowners were neutral or not concerned about CWD and its management, whereas most hunting landowners were concerned. Our results suggest that managers should use communication campaigns to increase awareness and mitigate concerns about CWD, increase trust and input related to the disease, and inform publics about CWD management strategies.  相似文献   
82.
More than 15,000 lizards from South Georgia were examined over a period of 16 years. Five percent of Sceloporus undulatus and 36% of Anolis carolinensis were found to harbor Plasmodium floridense. Development of 28 natural new infections was followed in detail as soon as they became patent and comparisons in the 2 host species made of intensity and duration of infections and of merozoite means during the periods of acute rise and decline. During the acute rise, the merozoite mean in Sceloporus was 10.6 ± 0.11 (8,495 segmenters counted), compared with 13.44 ± 0.15 in Anolis (3,805 counted); during the decline, the merozoite means were 8.55 ± 0.13 (3,305 counted) and 10.28 ± 0.09 (6,772 counted), respectively. It took an average of 150 (100–253) days for the infection to run its course in Sceloporus, compared with the average of 71 (60–90) days in Anolis; the peak of parasitemia in Sceloporus was 11,600 parasites/10,000 red cells, compared with 1,600 in Anolis. Both lizard genera produced 5–10% gametocytes.  相似文献   
83.
84.
1. New logical and analytical frameworks for studying functional traits have led to major advances in plant and freshwater ecology at local and global scales. The ecological and taxonomic diversity of terrestrial adult beetles (Coleoptera) means that functional trait approaches should have considerable power to illuminate the function not only of these animals but also of the ecosystems in which they occur. 2. Even though the functional trait concept is not new in ecology, it is still plagued with inconsistencies in methodology and terminology. Plant‐based studies have shown that an integrated and relatively consistent functional trait approach facilitates comparisons between studies, and allows the full utility and predictive capacity of trait‐based approaches to be realised. 3. This review outlines a logical framework for adult beetle functional trait studies using uniform terminology and methodology similar to those used by plant ecologists. Beetle life‐history and ecomorphological trait studies are synthesised and it is shown that a combination of both is analogous to the functional trait approach. A general functional trait list for beetles and potential functional links is outlined, as are potential analysis approaches. A consistent functional trait approach, coupled with advances in molecular techniques, has the capability to provide deeper insights into beetle community assembly and how beetles impact ecosystems and will enable worldwide comparisons and predictions to be made.  相似文献   
85.
Although central to understanding life‐history evolution, the relationship between lifetime reproductive success and longevity remains uncertain in many organisms. In social insects, no studies have reported estimates of queens’ lifetime reproductive success and longevity within populations, despite the importance of understanding how sociality and associated within‐group conflict affect life‐history traits. To address this issue, we studied two samples of colonies of the annual bumblebee, Bombus terrestris audax, reared from wild‐caught queens from a single population. In both samples, queens’ lifetime reproductive success, measured as either queens’ inclusive fitness or as total biomass of queen‐produced sexuals (new queens and males), was significantly positively associated with queen longevity, measured from the day the first worker was produced. We suggest that a positive relationship between reproductive success and longevity was inherited from nonsocial ancestors showing parental care and maintained, at least in part, because the presence of workers buffers queens against extrinsic mortality.  相似文献   
86.
Efficient conduction of water inside leaves is essential for leaf function, yet the hydraulic-mediated impact of drought on gas exchange remains poorly understood. Here we examine the decline and subsequent recovery of leaf water potential ( Ψ leaf), leaf hydraulic conductance ( K leaf), and midday transpiration ( E ) in four temperate woody species exposed to controlled drought conditions ranging from mild to lethal. During drought the vulnerability of K leaf to declining Ψ leaf varied greatly among the species sampled. Following drought, plants were rewatered and the rate of E and K leaf recovery was found to be strongly dependent on the severity of the drought imposed. Gas exchange recovery was strongly correlated with the relatively slow recovery of K leaf for three of the four species, indicating conformity to a hydraulic-stomatal limitation model of plant recovery. However, there was also a shift in the sensitivity of stomata to Ψ leaf suggesting that the plant hormone abscisic acid may be involved in limiting the rate of stomatal reopening. The level of drought tolerance varied among the four species and was correlated with leaf hydraulic vulnerability. These results suggest that species-specific variation in hydraulic properties plays a fundamental role in steering the dynamic response of plants during recovery.  相似文献   
87.
Thermal and Water Relations of Roots of Desert Succulents   总被引:6,自引:0,他引:6  
Two succulent perennials from the Sonoran Desert, Agave desertiEngelm. and Ferocactus acanthodes (Lem.) Britton and Rose, loselittle water through their roots during drought, yet respondrapidly to light rainfall. Their roots tend to be shallow, althoughabsent from the upper 20 mm or so of the soil. During 12–15d after a rainfall, new root production increased total rootlength by 47 per cent to 740 m for A. deserti and by 27 percent to 230 m for F. acanthodes; root dry weight then averagedonly 15 per cent of shoot dry weight. The annual carbon allocatedto dry weight of new roots required 11 per cent of shoot carbondioxide uptake for A. deserti and 19 per cent for F. acanthodes.Elongation of new roots was greatest near a soil temperatureof 30°C, and lethal temperature extremes (causing a 50 percent decrease in root parenchyma cells taking up stain) were56°C and -7°C. Soil temperatures annually exceeded themeasured tolerance to high temperature at depths less than 20mm, probably explaining the lack of roots in this zone. Attached roots immersed in solutions with osmotic potentialsabove -2·6 MPa could produce new lateral roots, with50 per cent of maximum elongation occurring near -1·4MPa for both species. Non-droughted roots lost water when immersedin solutions with osmotic potentials below -0·8 MPa,and root hydraulic conductance decreased markedly below about-1·2 MPa. Pressure-volume curves indicated that, fora given change in water potential, non-droughted roots lostthree to five times more water than droughted roots, non-droughtedleaves, or non-droughted stems. Hence, such roots, which couldbe produced in response to a rainfall, will lose the most tissuewater with the onset of drought, the resulting shrinkage beingaccompanied by reduced root hydraulic conductance, less contactwith drying soil, and less water loss from the plant to thesoil. Agave deserti, Ferocactus acanthodes, roots, soil, temperature, water stress, drought, Crassulacean acid metabolism, succulents  相似文献   
88.
Davies, E. C, Jordan, B. R., Partis, M. D. and Chow, W. S. 1987.Immunochemical investigation of thylakoid coupling factor proteinduring photosynthetic acclimation to irradiance.—J. exp.Bot. 38: 1517—1527 A double antibody sandwich enzyme-linked immunosorbent assay(ELISA) has been used to determine the amount of coupling factorprotein (CF1 present on thylakoid membranes isolated from lettuceleaves. Thylakoid CF1 was purified from lettuce chloroplastsand used to raise antibodies. After purification of the IgGits specificity to CF1 was examined by Ouchterlony double diffusion,Western blotting and control ELISA experiments. The specificityof the response for CF1 was confirmed and the ELISA found togive a log-linear measurement of purified CF1 concentrationswithin a range of 10 µg cm3 to 25 ng cm 3. The ELISA wasthen used to determine the level of CF1 protein associated withthe thylakoid membrane. Comparable values were obtained forCF1 levels, either assayed directly on the thylakoid or afterrelease from the membrane by chloroform treatment. Determinationof CF1 protein content on thylakoids isolated from lettuce grownat different irradiances showed that the amount of CF1 proteinper chlorophyll and chloroplast increased with increased lrradiance.In addition, the changes in CF1 protein as determined by ELISAare reflected in changes that have been found in enzymic activityunder these same light environments. The implications for thephotoregulation of CF1 are discussed.  相似文献   
89.
The nucleus and nucleolus have been examined by phase contrastmicroscopy of isolated fixed nuclei from synchronously dividingcells of Helianthus tuberosus L. tuber explants grown in nutrientmedium on filter paper. The volumes of nuclei and nucleoli werecomputed from their areas and perimeters obtained by digitizingimages projected from film. The nuclei did not show a pattern of growth related to the Sphase but enlarged at times of both de-differentiation and differentiation.There was also rapid post-mitotic nuclear enlargement. The sizeattained by nuclei in the three successive divisions followingcell activation decreased progressively, but started to riseagain at the time of cell differentiation. The changes are discussed in relation to nuclear size regulation,the nuclear matrix and hypotheses relating nuclear growth toDNA, protein and water in the processes of de-differentiation,mitosis and differentiation. Nucleoli showed a clear fusion and growth cycle. The patternof fusion can be used to identify the position of a sample ofcells, though not any particular cell, within the cycle. Nucleolargrowth was different in the succeeding cell cycles that wereinduced in the de-differentiating tissue. Nucleolar enlargementwas slow in the first cycle and continued until mitosis. Therewas rapid nucleolar growth in the second cycle and none in latercycles until the time of cell differentiation. Nucleolar changes are discussed in relation to rRNA gene dosage,replication and polymerase availability. Helianthus tuberosus L. Jerusalem artichoke, isolated-nuclei, tissue culture, cell cycle, nucleolar cycle  相似文献   
90.
When young tomato plants grown in high light (400 µmolquanta m–2s–1 PAR) were transferred to low light(100 µmol quanta m–2s–1 PAR), non-cyclic electrontransport capacity was decreased and the rate of dark re-oxidationof Q, the first quinone electron acceptor of photosystemII, was decreased within 1–2 d. In contrast, the amountof coupling factor CF1, assayed by its ATPase activity, decreasedmore gradually over several days. The total chlorophyll contentper unit leaf area remained relatively constant, although thechlorophyll a/chlorophyll b ratio declined. When young tomato plants grown in low light were transferredto high light, the ATPase activity of isolated thylakoids increasedmarkedly within 1 d of transfer. This increase occurred morerapidly than changes in chlorophyll content per leaf area. Inaddition, in vivo chlorophyll fluorescence induction curvesindicate that forward electron transfer from Q occurredmore readily. The functional implications of these changes arediscussed. Key words: Tomato, leaves, light intensity, thylakoid membrane  相似文献   
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