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141.
Tansley Review No. 82 总被引:2,自引:1,他引:1
142.
SILVIA ARROYO 《Botanical journal of the Linnean Society. Linnean Society of London》1986,93(4):323-328
ARROYO, S., 1986. Leaf anatomy in the Tecophilaeaceae . Leaf anatomy of 12 species of the seven genera in the Tecophilaeaceae is described. Characters of taxonomic value within the family are the shape of epidermal cells, hairs and venation. Characters of diagnostic importance at the family level include the occurrence of raphide sacs in the mesophyll, the absence of vessels in the aerial part of the plant and the presence of anomocytic stomata. Leaf anatomy is of restricted value within the family but supports the retention of both Cyanastrum and Walleria within the Tecophilaeaceae. 相似文献
143.
Rapid Osmotic Adjustment in Detached Wheat Leaves 总被引:2,自引:0,他引:2
Osmotic adjustment is induced in detached wheat leaves by rapiddrying to a relative water content below 0·65, followedby re-saturation. Quantitatively, the response to this treatmentis comparable to the maximum of adjustment obtained with pottedplants at the same developmental stage. Low temperatures duringdrying and re-saturation of the leaves reduce the adjustmentresponse. We conclude that drought stress serves as a triggeronly, while the metabolic events lowering the osmotic potentialare favoured by high or intermediate water contents. Triticum durum L., durum wheat, rapid dehydration, osmotic adjustment, pressure-volume curves 相似文献
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Abstract. The aim of this study was to characterize the vibratory signals produced by the parasitoid Sympiesis sericeicornis Nees (Hymenoptera: Eulophidae) while foraging on apple leaves infested by one of its hosts, the spotted tentiform leafminer Phyllonorycter malella (Ger.) (Lepidoptera: Gracillariidae).This leafminer changes its behaviour as a function of the parasitoid's behaviour to escape parasitization.We propose that the leafminer uses vibrations triggered by the parasitoid to detect the presence of its enemy.We measured vibrations produced by a foraging parasitoid on a mine with a laser vibrometer.By recording concurrently the behaviour of the parasitoid on video, vibrations could be assigned to particular behaviours.Subsequently, vibrations were characterized by their dominant frequencies and intensities.The behaviours Landing and Take-off both produced strong impact-like vibrations characterized by an initial irregular phase during which frequencies up to 25 kHz occurred followed by a slow decaying regular phase.Vibrations elicited by Moving, Standing and Probing showed no clear temporal pattern.During Probing , dominant frequencies of up to 5.6 kHz were observed frequently at intensities well above the background noise (>10 dB).During Moving and Standing , vibrations were more scarce and of lower frequencies and intensities.Due to their impact-like nature, vibrations produced by Landing and Take-off are probably not specific to the parasitoid.Vibrations produced by Moving and Standing are difficult to detect and not reliable because of their non-specificity.Therefore, only Probing provides a reliable and detectable source of information for the host.The vibrations elicited during Probing could account for the evasive behaviour that is observed in this and other leafminers. 相似文献
146.
Abstract: Fossil woods are described and assigned to Cuyoxylon multipunctatus gen. et sp. nov. The woods were deposited in shales from an interglacial period, and are the first to be described in detail from the Carboniferous glaciation of western Gondwana. They have the primitive characters of Early Carboniferous woods, such as mesarch protoxylem and numerous contiguous pits in an alternate arrangement. They are the oldest fossil woods to have been described from South America. The growth ring characteristics are consistent with a seasonal cool climate. 相似文献
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LUCIO BOTTE SILVIA SCIPPA MARIO DE VINCENTIIS 《Development, growth & differentiation》1979,21(5):483-491
The content of some transitional metals (Ti, V, Cr. Mn. Fe, Cu) in the ovary of Ascidia malaca and Ciona intestinalis and in the gonads of Polycarpa gracilis has been reported. The metals were localized histospectrographically and ultrastructurally. In the ovaries of C. intestinalis . the quantitative analysis shows a variable content of metals related to the ovary maturative cycle. The iron is localized in the electron dense cytoplasmic granules of A. malaca oocytcs and in the cytoplasmic dense formation of P. gracilis test cells. Cl, S, Si and P are present in the test, follicles and inierovarian cells of all examined species.
The results are discussed in relation to the zoological position of these species. The presence of metals and Ascidiacee phylogenesis might be correlated. 相似文献
The results are discussed in relation to the zoological position of these species. The presence of metals and Ascidiacee phylogenesis might be correlated. 相似文献