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Hilton, J. R. and Thomas, J. A. 1987. Changes in respiratorypotential of dormant and non-dormant Galium aparine L. (cleavers)seeds during dry storage.J. exp. Bot. 38: 14841490. Pre-germinative rates of O2 uptake of two collections of Galiumaparine L. seed were compared throughout a 9 month period ofdry storage at 4 °C, 23 °C and at ambient (frost-protected)temperatures. Uptake of O2 by the dormant seeds was generallyhigher than that of the less dormant seeds except when freshly-harvested.Moreover, changes in the O2 consumption of seeds stored at ambienttemperatures could be associated with periods of germinationand seedling emergence in the field. The results are discussedin relation to changes in respiratory metabolism during dormancybreakage. 相似文献
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XIAO-YUAN HE SHI-JUN WANG JASON HILTON fls YI-LONG ZHOU 《Botanical journal of the Linnean Society. Linnean Society of London》2006,151(2):279-288
Several isolated marattialean synangia and sporangia are reported from coal balls collected from Coal Seam No.1 (C605) in the uppermost Permian Wangjiazhai Formation in Guizhou Province, south-western China. The synangia are radially symmetrical with diameters between 0.8 and 1.2 mm and are 1.7 mm long, consisting of 3–4 elongate sporangia that are fused basally, free distally and possess a pointed apex. The outer-facing sporangial wall is 4–5 cells thick and conspicuously differentiated. Spores are trilete, have a granular ornamentation and are nearly round equatorially with a diameter of 55–60 µm. Comparisons with other anatomically preserved Palaeozoic marattialean synangia from the Euramerican and Cathaysian floras permit their assignment to the genus of Scolecopteris (Zenker) Millay. In this species the thick, outer-facing sporangial walls and large trilete spores are features consistent with those of the Oliveri Group within Scolecopteris , a group that has previously been considered primitive within this genus. Distinctions from all other previously recognized species within the Oliveri Group lead to the creation of a new species, S. guizhouensis sp. nov. This species is the youngest of the reported species of Scolecopteris recognized from the Euramerican and Cathaysian floras, and provides important evidence on the organization of marattialean ferns from the Upper Permian strata of south China. © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 151 , 279–288. 相似文献
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The influence of light and potassium nitrate on the dormancyand germination of Avena fatua L. seed stored buried under naturalconditions was studied over a 13 month period. Natural emergenceof seedlings from buried seed in relation to rainfall and temperatureregimes and fluctuation was also monitored. The present findingsshow that potassium nitrate is stimulatory to germination onlyin the light and, further, that seeds from two positions inthe spikelet respond differently. Key words: Dormancy, Light, Nitrate 相似文献
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JEAN GALTIER SHI-JUN WANG CHENG-SEN LI JASON HILTON † 《Botanical journal of the Linnean Society. Linnean Society of London》2001,137(4):429-442
Recent investigation on the Cathaysian flora of the Lower Permian Taiyuan Formation in Hebei Province, North China has led to the discovery of a new type of fern, Rastropteris pingquanensis gen. et sp. nov. Preserved as a permineralization, the stem, with a mantle of petiole bases and roots, shows a unique combination of anatomical characters. The vascular strand consists of a solid protostele with uniformly elongated tracheids and mesarch maturation of the xylem. In transverse section, the configuration of leaf trace xylem changes from reniform endarch to a tangentially elongated strand adaxially recurved at each end with several adaxial ridges. Stem and petiole cortex contains abundant sclerotic tissue with an interstitial tissue developed within the mantle of petiole bases and roots. A reinvestigation of Grammatopteris rigollotii , from the Permian of France, the type species of the genus allows interpretation of the latter as closer to Rastropteris than any other fern. Both taxa are provisionally reported to an incertae sedis group of filicalean ferns possibly involved in the origin of Osmundaceae. 相似文献