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ROBERT R. MILL fls MICHAEL MÖLLER SHEILA M. GLIDEWELL DIANE MASSON BRIAN WILLIAMSON 《Botanical journal of the Linnean Society. Linnean Society of London》2004,145(3):295-316
Fertile complexes (individual reproductive units of ovulate cones) of three Prumnopitys species and Afrocarpus falcatus (Podocarpaceae) were subjected to histological examination and non-destructive NMR imaging. The latter technique allowed the display, frame-by-frame analysis and electronic 'dissection' of internal structures such as the number and courses of vascular traces and resin canals and their morphology. Characters of these internal structures distinguished all three Prumnopitys species from each other and thus were shown to be taxonomically diagnostic. Fertile complexes of Prumnopitys andina and P. taxifolia were most similar, possessing simple vascular traces and few unbranched resin canals. Those of P. ferruginea were very different and possessed an interconnected network of resin ducts within the sarcotesta. These findings are congruent with relationships inferred from molecular phylogenetic studies, in which two subclades were recovered within Prumnopitys . The anatomy of the female fertile complexes of Afrocarpus falcatus was very distinct from all Prumnopitys species analysed. Its most distinctive feature was the existence of a complex network of radial vascular strands originating from within the outer layers of the sarcotesta and penetrating the inner layers of the fertile complex. The surface texture and morphology of the sclerotesta of the seed was also unique to each species. © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society , 2004, 145 , 295–316. 相似文献
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Localization of acid phosphatases (phosphomonoesterases II EC3.1.3.2
[EC]
) was studied in the secretory cells of stalked glandtissue of Drosera rotundifolia L. using a modified Gomori procedurewith p-nitrophenol phosphate (pNP) as substrate. In unstimulatedand 24 h stimulated tissue, some acid phosphatase activity waslocalized in vacuoles, cell wall regions and cuticular poresof only a few cells. Following stimulation for either 48, 72or 96 h, acid phosphatase activity was additionally observedin most gland cells within the nuclear envelope, endoplasmicreticulum and dictyosome cisternae and their associated vesicles,suggesting a de novo synthesis of acid phosphatases. Acid phosphatase, cytochemistry, Drosera rotundifolia, secretory cells 相似文献
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ALICE BENZECRY SHEILA D. BRACK-HANES fls 《Botanical journal of the Linnean Society. Linnean Society of London》2008,157(1):19-30
Middle Eocene seagrass compressions occur in the Avon Park Limestone Formation near Gulf Hammock on Florida's west coast. One group of specimens resembles two seagrass species of the hydrocharitaceans, Thalassia and Enhalus , that are living today in tropical and subtropical shallow marine environments. The Eocene plant has a dimorphic rhizome system consisting of a creeping, monopodial, plagiotropic rhizome with small roots and orthotropic laterals (short shoots) that occur in pairs every three to five nodes. Laterals bifurcate and produce glabrous eligulate leaves in an alternate and distichous arrangement. Foliage leaves have fibrous basal sheaths, blades with parallel venation, perpendicular and oblique cross veins, prominent midrib, and smooth, entire margins. Throughout the plant are numerous brown-coloured tanniferous dots and deposits of small calcium oxalate crystals. Based on features of these non-reproductive structures, the Florida Eocene seagrass is recognized as a new genus and species Thalassites parkavonensis in the Hydrocharitaceae. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society , 2008, 157 , 19–30. 相似文献
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SHEILA S. ANDERSON 《Mammal Review》1978,8(1-2):43-46
While some activity patterns in seals have been related to tidal rhythms, little work was done on diurnal rhythms until the recent development of image intensifying devices which facilitate night viewing. Individual bulls were studied over several 24-hour periods and the frequency of behavioural items was recorded during 10-min periods each hour. No significant differences were recorded between day and night activity levels, except in the frequency of 'Looks', nor was there any relationship between activity and tide state. The thesis that optimization of time spent ashore (and therefore 'at risk' both ecologically and energetically) is achieved by maintaining a constant level of activity through the 24-hour period is discussed. It is concluded that night time activity of Grey seal bulls can be inferred from observations made in daylight hours. 相似文献
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BOLLENBACHER WALTER E.; GRAY ROSEMARY S.; MUEHLEISEN DAVID P.; REGAN SHEILA A.; WESTBROOK ANNE L. 《Integrative and comparative biology》1993,33(3):316-323
SYNOPSIS. The prothoracicotropic hormone and the cerebral peptidergicneurons that produce it have traditionally been thought to havethe singular function of acting as a primary effector of insectpostembryonic development. Recent investigations of this neuroendocrineaxis in the tobacco hornworm, Manduca sexta, are leading toa new view that these peptidergic neurons and their peptidephenotypes may be multifunctional. They may act in differentways depending upon the animal's developmental stage and siteof phenotype release. The possibility for this functional diversityof the prothoracicotropic hormone is possibly even greater dueto multiple neuronal sites of peptide expression within thecentral nervous system. Similarly, the L-NSC III may have morefunctions due to the expression of multiple peptide phenotypes.The data, thus far, have not enabled us to identify additionalphysiological roles for the peptide, but they have providedinsight into the experimental approaches that might be effectivein resolving these functions. 相似文献
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Effect of Ethanol, Methanol and Acetone on Rooting Etiolated Cuttings of Vigna radiata in Presence of Sucrose and Auxin 总被引:1,自引:0,他引:1
Root formation on etiolated hypocotyl cuttings of Vigna radiataL. is greatly enhanced in the presence of ethanol, methanoland acctone. Low concentrations of solvents plus sucrose slightlypromoted the formation of roots. Vigna radiata, alcohol, rooting, auxin 相似文献