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101.
102.
GAD PERRY GORDON RODDA THOMAS FRITTS & THOMAS SHARP 《Global Ecology and Biogeography》1998,7(5):353-365
We sampled the lizard fauna of twenty-two small islets fringing the Pacific island of Guam and used these data to shed light on the processes responsible for present-day diversity. Habitat diversity, measured by islet area and vegetation complexity, was significantly correlated with the number of species found on an islet. However, islet distance and elevation were not significant predictors of diversity. Distribution patterns were slightly different for the two major families in our sample, Scincidae and Gekkonidae: skinks needed larger islets to maintain a population than did geckos. Presence/absence patterns were highly and significantly nested, and population density was correlated with the number of islets on which a species was found. An area cladogram was poorly supported and showed no faunal similarity between nearby islands. These patterns indicate that extinctions on most islets were due mostly to non-catastrophic, long-acting biological causes. The presence on the islets of species extirpated on Guam and the lack of significant nestedness on islands with greater maximum elevation highlight the impact that predators (primarily brown treesnakes) can have. Our findings also show that small reserves will not suffice to protect endangered lizard faunas, and that the islets may serve as a short-term repository of such species until snake-free areas can be established on Guam 相似文献
103.
The design of a simple instrument to monitor leaf expansionin grasses is described. The instrument was used to comparethe effects of water stress on leaf extension of two cultivarsof maize and sorghum. The effect of withholding water for 3days was an appreciable reduction in the rate of leaf expansionin both plants, particularly during the light period. In well-wateredplants of both species, leaf extension continued at a steadyrate even when leaf turgor fell to around 0.1 MPa. In water-stressedmaize plants, leaf turgor during the light period fell to zeroand leaf growth ceased. When turgor was restored, followingstomatal closure, leaf extension resumed at a slow rate. Inunwatered sorghum plants, leaf turgor remained at a value greaterthan 0.1 MPa but the rate of leaf extension was significantlyreduced. The reduction in leaf turgor in the unwanted plantsresulted partly from an increase in solute potential. Zea mays L, maize, Sorghum bicolor L, leaf expansion, leaf turgor, water stress 相似文献
104.
The anatomy and ultrastructure of stigmas in 37 species of 13genera of Commelinaceae are described. The stigmas are papillate,papillae forming a dense fringe of cells around the mouth ofthe stylar canal in most species. The papillar cell wall iscovered by an unstructured cuticle of variable thickness andis of variable thickness because of small wall ingrowths. Thecuticle and the external surface of the papillar cell wall arevariably disrupted, particularly in the mid and basal regionsof the cell. This was not found in species of the genus Aploleiaor Callisia. The cell cytoplasm possesses all major organellesexcept chloroplasts and each cell is vacuolate. In all species except Aploleia mulitiflora the style comprisesan epidermis, a cortex and a hollow, tripartite canal whichis continuous into the ovary cavity. The three vascular strandsare positioned at the apex of each canal lobe. The canal cellsare elongate and tabular and the wall abutting the canal hasingrowths. The style in Aploleia is solid and the transmittingtissue comprises cells whose walls are electron opaque. Thecytoplasms of both types of cell are similar in content althoughthere is a single, large vacuole in canal cells and many smallvacuoles in transmitting tissue. The morphology, position and histochemistry of stigmatic andstylar exudate was similar in all wet stigmas.Most of the exudate originates from the stylar canal althoughsignificant contributions are made by the papillae in stigmasof Coleotrype, Dichorisandra and Thyrsanthemum. There is no apparent relationship between stigma structure andthe presence of self-incompatibility. Stigma papillae, stylar canal, transmitting tissue, Commelinaceae 相似文献
105.
106.
An indirect procedure for the estimation of assimilation efficiency of aquatic insects 总被引:1,自引:0,他引:1
SUMMARY. 1. From forty-five values reported for twenty species of aquatic insect species, it was found that the nitrogen content (N) of the food was significantly and positively correlated (r=0.97. P<0.001) with assimilation efficiency (Ase).
2. Therefore, the Ase of aquatic insects can be predieted, if the nitrogen content of the food is known, using the equation: Ase (%)=9.29+8.82N. 相似文献
2. Therefore, the Ase of aquatic insects can be predieted, if the nitrogen content of the food is known, using the equation: Ase (%)=9.29+8.82N. 相似文献
107.
The first successful cryopreservation of Ochromonas danica and Ochromonas malhamensis is reported. The freezing method was consistently reproducible for the former, but not for the latter. Ochromonas danica cultures established from frozen material still could be used as test organisms for assay of thiamin. This is the first report of a protozoon retaining its assay property after being frozen to -196 C. 相似文献
108.
Dephosphorylation of adenosine triphosphate by concentrates of the virus of avian erythromyeloblastic leucosis 总被引:4,自引:0,他引:4
109.
MARIAN PONCE CARLOS INFANTE ANIELA CRESPO EUGENIA ZUASTI LAURA PREZ VICTORIA FUNES GAETANO CATANESE SALVADOR CRDENAS MANUEL MANCHADO 《Molecular ecology resources》2006,6(2):527-529
The redbanded seabream Pagrus auriga (Teleostei, Sparidae) is a species of a high commercial value in Spain. There is currently little information available about the genetic characteristics of both wild and cultured populations. In this survey, we have developed eight polymorphic microsatellites for the redbanded seabream using an enriched genome library protocol. All of them were polymorphic in the 64 individuals tested, 22 of which were wild specimens, and 42 were individuals from a captive reproductive broodstock. These markers can potentially be useful tools for use in population genetic studies. 相似文献
110.