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71.
Gérald Chouinard Charles Vincent Stuart B. Hill Bernard Panneton 《Journal of Insect Behavior》1992,5(3):385-394
From 12 to 19 May 1987, during Morspur apple bloom, 21 radioactively labeled (65
Zn) adult plum curculios, Conotrachelus nenuphar (Herbst), were released within a field cage containing four dwarf apple trees and located three times a day. A technique was developed for quickly obtaining (x, y, z)coordinates of location for adults foraging within apple trees. Cyclic patterns of behavior were detected using spectral analysis procedures. Over 70% of plum curculios exhibited diel periodicity with respect to activity and rate of movement, 36% exhibited such periodicity with respect to presence in the trees, and 27% with respect to movements from the center to the periphery of the canopy. Presence in fruit clusters, height in the trees, and movements along east-west and north-south axes showed little or no periodicity. Factors triggering cyclic behavior and practical implications of the results are discussed. 相似文献
72.
Toshiyuki Sato 《Ecological Research》1992,7(1):1-7
Gametophyte populations inAthyrium brevifrons were analysed with respect to population size and surviving area (%) of individual thalli in a transplant garden at Sapporo
during 5–26 April 1983, to study the safe-microsite for gametophyte establishment in nature. Spores dispersed in August 1982
germinated and grew into thalli of various widths (<10 mm); 10.3% of the thalli matured by early October 1982. Maturation
was attained by gametophytes of width 4–7 mm. The number of gametophytes gradually decreased with increasing width. By April
1983, 20.5% of total gametophytes were mature with a mode of 5–6 mm in width. The relative number of gametophytes with surviving
area of 2–20% increased and that of 85–100% decreased in accordance with collection days delayed until after snow-melt. Surviving
area (%) on gametophyte of all widths decreased with decreasing soil moisture contents. In particular, immature gametophytes
of 2–4 mm width showed a significant correlation (P<0.01) between soil moisture content and relative number of gametophytes with 0–20% surviving area and mean surviving area
(%) of every width of thalli. The spring desiccation might be a factor that reduces or limits gametophyte populations in nature. 相似文献
73.
Martin W. Ganal Meredith W. Bonierbale Marion S. Roeder William D. Park Steven D. Tanksley 《Molecular & general genetics : MGG》1991,225(3):501-509
Summary Genes for the major storage protein of potato, patatin, have been mapped genetically and physically in both the potato and tomato genomes. In potato, all patatin genes detected by the cDNA clone pGM01 map to a single locus at the end of the long arm of chromosome 8. By means of pulsed field gel electrophoresis (PFGE) it was possible further to delimit this locus, containing 10–15 copies of the gene, to a maximum size of 1.4 million base pairs. Hybridizations with class-specific clones suggest that the locus is at least partially divided into domains containing the two major types of patatin genes, class I and II. In tomato, patatin-homologous sequences were found to reside at the orthologous locus at the end of chromosome 8. The approximately three copies in tomato were localized by PFGE to a single fragment of 300 kilobases. Whereas the class II-specific 5 promoter sequences reside in tomato at the same locus as the coding sequences, the single class I-specific copy of the 5 promoter sequences was localized on chromosome 3 with no coding sequence attached to it. A clone from this chromosome 3 locus of tomato was isolated and by restriction fragment length polymorphism mapping it could be further shown that a similar class I-specific sequence also exists on chromosome 3 of potato. As in tomato, this copy on chromosome 3 is not linked to a coding sequence for patatin. The results are discussed with respect to genome evolution and PFGE analysis of complex gene families. 相似文献
74.
Dicotyledonous plants subjected to Fe-deficiency stress can decrease pH in the rhizosphere by proton excretion and reduce ferric iron by an activated reduction system in the plasma membranes of the root or by reductants released from the roots. The efficiency by which these plants take up Fe may strongly depend on their cation-anion balance. This study presents results of two experiments conducted to evaluate the effect of K, growth stage and cultivar on ionic balance and Fe acquisition of peanut (Arachis hypogaea L.) plants.Potassium applications to the high calcareous soil (30.3% CaCO3) favoured proton release, but did not ameliorate plant Fe acquisition. At the earliest stages of plant growth, anion uptake exceeded cation uptake due to intensive N uptake. With time, a shift in the ionic balance was observed as a result of predominant cation uptake. It appears that the relationship between H/OH-ion release and Fe nutrition of peanut plants is actually a complex phenomenon under soil conditions and depends on some soil parameters, such as CaCO3 content. Even by enhanced H-ion release Fe nutrition of plants can be impaired if soil CaCO3 is too high. 相似文献
75.
Silicon accumulation and water uptake by wheat 总被引:2,自引:0,他引:2
Silicon (Si) content in cereal plants and soil-Si solubility may be used to estimate transpiration, assuming passive Si uptake. The hypothesis for passive-Si uptake by the transpiration stream was tested in wheat (Triticum aestivum cv. Stephens) grown on the irrigated Portneuf silt loam soil (Durixerollic calciorthid) near Twin Falls, Idaho. Treatments consisted of 5 levels of plant-available soil water ranging from 244 to 776 mm provided primarily by a line-source sprinkler irrigation system. Evapotranspiration was determined by the water-balance method and water uptake was calculated from evapotranspiration, shading, and duration of wet-surface soil. Water extraction occurred from the 0 to 150-cm zone in which equilibrium Si solubility (20°C) was 15 mg Si L–1 in the Ap and Bk (0–58 cm depth) and 23 mg Si L–1 in the Bkq (58–165 cm depth).At plant maturity, total Si uptake ranged from 10 to 32 g m–2, above-ground dry matter from 1200 to 2100 g m–2 and transpiration from 227 to 546 kg m–2. Silicon uptake was correlated with transpiration (Siup=–07+06T, r2=0.85) and dry matter yield with evapotranspiration (Y=119+303ET, r2=0.96). Actual Si uptake was 2.4 to 4.7 times that accounted for by passive uptake, supporting designation of wheat as a Si accumulator. The ratio of Si uptake to water uptake increased with soil moisture. The confirmation of active Si uptake precludes using Si uptake to estimate water use by wheat. 相似文献
76.
Air dry soil samples stored at room temperature for more than one and a half years, were used as inocula for actinorhizal plants. Seedlings of Colletia paradoxa, Discaria americana, D. articulata and D. trinervis (Rhamnaceae) cultivated in nitrogen-free nutrient solution, were inoculated by adding dry soil to the solution. All the soil samples tested were able to induce nodulation, showing the presence of infective propagules of Frankia. Healthy growth of nodulated plants suggested the occurrence of nitrogen fixation. 相似文献
77.
An inflatable minirhizotron system for root observations with improved soil/tube contact 总被引:3,自引:1,他引:2
Commonly used minirhizotrons consisting of a transparent tube inserted into the soil seldom attain good contact between the tube and the soil, which leads to root growth occurring in a gap rather than in the soil. A new system is described involving an inflatable flexible rubber wall, made from a modified motorcycle tube. Pressure ensures a proper tube/soil contact so that the environmental circumstances for root growth along the tube more closely correspond to those in the undisturbed soil. Before the endoscope slide is introduced into the minirhizotron for taking pictures, the inflatable tube is removed, so that there is no-often opaque-wall between the endoscope and the roots. This improves the picture quality and facilitates the analysis of root images. 相似文献
78.
CO2 exchange between the atmosphere and soil algal crusts of the Trachypogon savannas of the Orinoco Llanos has been analyzed
using an open gas exchange system. These savannas encompass a wide range of physiognomic types, from herbaceous communities
to savanna woodlands. A maximum CO2 flux of 0.207 mg m-2 s-1 was measured in the crusts of the Guanipa savannas, while in the other examined crusts (0.035–0.105 mg m-2 s-1) the flux was similar to values reported for terrestrial algae. The CO2 flux data were statistically fitted to the photosynthetically active radiation by a logarithmic relationship, and the photosynthetic
efficiencies of the crusts were compared. The activation energy calculated for the CO2 fixation indicates that limitations by diffusion and photochemical processes were excluded in the Guanipa crusts (above 12
kcal mole-1), whereas they were evident in the other crust studied. An optimum CO2 incorporation as a function of the crust water potential was established and carbon gain strategies were proposed on the
basis of the results and characteristics of the habitats. 相似文献
79.
Evaluation of the leaf juice of some higher plants for their toxicity against soil borne pathogens 总被引:1,自引:0,他引:1
Out of the leaf juices of eighteen plant species screened, only Eupatorium cannabinum exhibited complete toxicity against Pythium debaryanum, Fusarium oxysporum, Rhizoctonia solani and Sclerotium rolfsii. Shade drying of the leaves had no adverse effect, while oven drying produced an adverse effect on the fungitoxicity of the
leaves of E. cannabinum. The crude leaf juice of E. cannabinum successfully inhibited damping-off (Fusarium oxysporum) infection of Pisum sativum seedlings. 相似文献
80.
The effects of inoculum level and lime-pelleting were studied in an acid soil with respect to the nodulation and growth of
lucerne (Medicago sativa cv Resis) and the population dynamics of Rhizobium meliloti. In small root-boxes (rhizotrons), the in-situ survival of inoculated rhizobia was studied in the micro-environment around the seed for a period of 12 days after sowing.
During the initial 24 hours, a strong increase in rhizobial numbers was measured, concomitantly with the development of roots.
As a result of lime-pelleting, rhizobial numbers were higher only at 3 days after sowing (P<0.05). Later, this difference diminished steadily. Addition of lime did not increase the adhesion of the rhizobia to the
seedling tap root.
Plant responses to inoculation were studied in pots. To obtain optimal nodulation, the soil had to be neutralized around the
seed with lime and at least 105 cells of R. meliloti were required. With more than 105 rhizobia per seed, lime-pelleting increased the number of crown-nodulated seedlings from 24% to 77%. Higher numbers of rhizobia
could not compensate the effect of lime. A strong correlation was found between crown nodulation, nitrogen content and dry
weight of the shoots. 相似文献