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Rainer Butzmann - One of the best experts on this subject based on the ideXlab platform.
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Permian ginkgophyte fossils from the Dolomites resemble extant O-ha-tsuki aberrant leaf-like fructifications of Ginkgo biloba L
BMC Evolutionary Biology, 2010Co-Authors: Thilo C. Fischer, Barbara Meller, Evelyn Kustatscher, Rainer ButzmannAbstract:Background Structural elucidation and analysis of fructifications of plants is fundamental for understanding their evolution. In case of Ginkgo biloba, attention was drawn by Fujii in 1896 to aberrant fructifications of Ginkgo biloba whose seeds are attached to leaves, called O-ha-tsuki in Japan. This well-known phenomenon was now interpreted by Fujii as being homologous to ancestral Sporophylls. The common fructification of Ginkgo biloba consists of 1-2 (rarely more) ovules on a dichotomously divided stalk, the ovules on top of short stalklets, with collars supporting the ovules. There is essentially no disagreement that either the whole stalk with its stalklets, collars and ovules is homologous to a Sporophyll, or, alternatively, just one stalklet, collar and ovule each correspond to a Sporophyll. For the transition of an ancestral Sporophyll resembling extant O-ha-tsuki aberrant leaves into the common fructification with stalklet/collar/ovule, evolutionary reduction of the leaf lamina of such ancestral Sporophylls has to be assumed. Furthermore, such ancestral Sporophylls would be expected in the fossil record of ginkgophytes.
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Permian ginkgophyte fossils from the Dolomites resemble extant O-ha-tsuki aberrant leaf-like fructifications of Ginkgo biloba L
BMC Evolutionary Biology, 2010Co-Authors: Thilo C. Fischer, Barbara Meller, Evelyn Kustatscher, Rainer ButzmannAbstract:Background Structural elucidation and analysis of fructifications of plants is fundamental for understanding their evolution. In case of Ginkgo biloba , attention was drawn by Fujii in 1896 to aberrant fructifications of Ginkgo biloba whose seeds are attached to leaves, called O-ha-tsuki in Japan. This well-known phenomenon was now interpreted by Fujii as being homologous to ancestral Sporophylls. The common fructification of Ginkgo biloba consists of 1-2 (rarely more) ovules on a dichotomously divided stalk, the ovules on top of short stalklets, with collars supporting the ovules. There is essentially no disagreement that either the whole stalk with its stalklets, collars and ovules is homologous to a Sporophyll, or, alternatively, just one stalklet, collar and ovule each correspond to a Sporophyll. For the transition of an ancestral Sporophyll resembling extant O-ha-tsuki aberrant leaves into the common fructification with stalklet/collar/ovule, evolutionary reduction of the leaf lamina of such ancestral Sporophylls has to be assumed. Furthermore, such ancestral Sporophylls would be expected in the fossil record of ginkgophytes. Results From the Upper Permian of the Bletterbach gorge (Dolomites, South Tyrol, Italy) ginkgophyte leaves of the genus Sphenobaiera were discovered. Among several specimens, one shows putatively attached seeds, while other specimens, depending on their state of preservation, show seeds in positions strongly suggesting such attachment. Morphology and results of a cuticular analysis are in agreement with an affiliation of the fossil to the ginkgophytes and the cuticle of the seed is comparable to that of Triassic and Jurassic ones and to those of extant Ginkgo biloba . The Sphenobaiera leaves with putatively attached seeds closely resemble seed-bearing O-ha-tsuki leaves of extant Ginkgo biloba . This leads to the hypothesis that, at least for some groups of ginkgophytes represented by extant Ginkgo biloba , such Sporophylls represent the ancestral state of fructifications. Conclusions Some evidence is provided for the existence of ancestral laminar ginkgophyte Sporophylls. Homology of the newly found fossil ginkgophyte fructifications with the aberrant O-ha-tsuki fructifications of Ginkgo biloba is proposed. This would support the interpretation of the apical part of the common Ginkgo biloba fructification (stalklet/collar/ovule) as a Sporophyll with reduced leaf lamina.
C. S. Park - One of the best experts on this subject based on the ideXlab platform.
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Development and cultivation of F_2 hybrid between Undariopsis peterseniana and Undaria pinnatifida for abalone feed and commercial mariculture in Korea
Journal of Applied Phycology, 2014Co-Authors: E. K. Hwang, I. K. Hwang, E. J. Park, Y. G. Gong, C. S. ParkAbstract:The kelp Undariopsis peterseniana (Kjellman) Miyabe et Okamura is warm water tolerant and consequently there is currently considerable interest in developing commercial cultivation techniques for this species in Korea. Undaria is an important species for both the abalone industry and for commercial seaweed mariculture. In an attempt to extend the culture period of Undaria we bred and cultured hybrid kelp that is a cross between free-living gametophytes of U . peterseniana and Undariopsis pinnatifida . The morphological characteristics of the F_1 hybrid sporophytes were intermediate between those of the parent plants having shallow pinnated blades and forming both sorus and Sporophyll. A F_2 generation was produced by isolating zoospores from sorus and Sporophyll separately from a F_1 hybrid thallus. Using free-living gametophyte seeding and standard on-growing techniques, F_0 (female U . pinnatifida and male U . peterseniana ), F_1, and F_2 gametophytes were cultured from December 2011 to May 2013. The morphological differences between the F_1 and F_2 generations were assessed. The F_2 hybrids were found to have longer pinnate blades and narrower midribs than the F_1 hybrid and only formed Sporophylls. Growth and morphology of F_2 hybrids originating from the Sporophyll or sorus of the F_1 hybrids were not morphologically different from each other. Both of the F_2 hybrids exhibited late maturation, with the early stages of Sporophylls appearing in April. This late maturation of F_2 hybrids is beneficial in the development of hybrid strains that extend the period of availability of Undaria for abalone feed and cultivation in Korea.
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Development and cultivation of F2 hybrid between Undariopsis peterseniana and Undaria pinnatifida for abalone feed and commercial mariculture in Korea
Journal of Applied Phycology, 2013Co-Authors: E. K. Hwang, I. K. Hwang, E. J. Park, Y. G. Gong, C. S. ParkAbstract:The kelp Undariopsis peterseniana (Kjellman) Miyabe et Okamura is warm water tolerant and consequently there is currently considerable interest in developing commercial cultivation techniques for this species in Korea. Undaria is an important species for both the abalone industry and for commercial seaweed mariculture. In an attempt to extend the culture period of Undaria we bred and cultured hybrid kelp that is a cross between free-living gametophytes of U. peterseniana and Undariopsis pinnatifida. The morphological characteristics of the F1 hybrid sporophytes were intermediate between those of the parent plants having shallow pinnated blades and forming both sorus and Sporophyll. A F2 generation was produced by isolating zoospores from sorus and Sporophyll separately from a F1 hybrid thallus. Using free-living gametophyte seeding and standard on-growing techniques, F0 (female U. pinnatifida and male U. peterseniana), F1, and F2 gametophytes were cultured from December 2011 to May 2013. The morphological differences between the F1 and F2 generations were assessed. The F2 hybrids were found to have longer pinnate blades and narrower midribs than the F1 hybrid and only formed Sporophylls. Growth and morphology of F2 hybrids originating from the Sporophyll or sorus of the F1 hybrids were not morphologically different from each other. Both of the F2 hybrids exhibited late maturation, with the early stages of Sporophylls appearing in April. This late maturation of F2 hybrids is beneficial in the development of hybrid strains that extend the period of availability of Undaria for abalone feed and cultivation in Korea.
Evelyn Kustatscher - One of the best experts on this subject based on the ideXlab platform.
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Sporophyll organization in the Triassic isoetalean lycopsid Lepacyclotes (formerly Annalepis) zeilleri from Germany
Paläontologische Zeitschrift, 2015Co-Authors: Evelyn Kustatscher, Hubert Donà, Michael KringsAbstract:Annalepis zeilleri is one of the most frequently recorded Middle Triassic lycopsid fossils in central Europe and China. The taxon includes tongue-shaped Sporophylls with a blunt to mucronate apex and an adaxial sporangium. However, little is known about the arrangement of the Sporophylls and the morphology of the plant that produced them. Specimens from the Middle Triassic of Germany consist of wide axes in cross section surrounded by tightly clustered A. zeilleri Sporophylls. This suggests that the Sporophylls were produced in a strobilus or in intercalary fertile zones along an axis. Moreover, the fossils correspond in structure to certain other Triassic lycopsid remains that are described as Lepacyclotes circularis and L. bechstaedtii ; they thus strengthen the concept that Annalepis and Lepacyclotes are congeneric. Since Lepacyclotes has priority over Annalepis , Lepacyclotes zeilleri is the correct name for the taxon. Annalepis zeilleri ist eines der häufigsten Lycopsidenfossilien der mittleren Trias in Zentraleuropa und China. Das Taxon wird verwendet für zungenförmige Sporophylle mit stumpfem oder leicht stachelspitzigem Apex und adaxialem Sporangium. Wenig ist bekannt über die Anordnung der Sporophylle und die Morphologie der sie produzierenden Pflanze. Neue Fossilien aus der mittleren Trias von Deutschland zeigen relativ dicke Achsen im Querschnitt, welche von dicht stehenden A. zeilleri Sporophyllen umgeben sind. Die Stücke deuten darauf hin, dass die Sporophylle entweder in kompakten endständigen Strobili oder in interkalaren fertilen Zonen entlang der Achse produziert wurden. Darüber hinaus erinnern die Fossilien stark an die als Lepacyclotes circularis und L. bechstaedtii beschriebenen triassischen Lycopsiden, und bekräftigen dadurch die Ansicht, dass Annalepis und Lepacyclotes kongenerisch sind. Da Lepacyclotes über Annalepis Prioriträt hat, ist Lepacyclotes zeilleri der korrekte Name für die Art.
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Sporophyll organization in the Triassic isoetalean lycopsid Lepacyclotes (formerly Annalepis) zeilleri from Germany
Paläontologische Zeitschrift, 2014Co-Authors: Evelyn Kustatscher, Hubert Donà, Michael KringsAbstract:Annalepis zeilleri is one of the most frequently recorded Middle Triassic lycopsid fossils in central Europe and China. The taxon includes tongue-shaped Sporophylls with a blunt to mucronate apex and an adaxial sporangium. However, little is known about the arrangement of the Sporophylls and the morphology of the plant that produced them. Specimens from the Middle Triassic of Germany consist of wide axes in cross section surrounded by tightly clustered A. zeilleri Sporophylls. This suggests that the Sporophylls were produced in a strobilus or in intercalary fertile zones along an axis. Moreover, the fossils correspond in structure to certain other Triassic lycopsid remains that are described as Lepacyclotes circularis and L. bechstaedtii; they thus strengthen the concept that Annalepis and Lepacyclotes are congeneric. Since Lepacyclotes has priority over Annalepis, Lepacyclotes zeilleri is the correct name for the taxon.
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Permian ginkgophyte fossils from the Dolomites resemble extant O-ha-tsuki aberrant leaf-like fructifications of Ginkgo biloba L
BMC Evolutionary Biology, 2010Co-Authors: Thilo C. Fischer, Barbara Meller, Evelyn Kustatscher, Rainer ButzmannAbstract:Background Structural elucidation and analysis of fructifications of plants is fundamental for understanding their evolution. In case of Ginkgo biloba, attention was drawn by Fujii in 1896 to aberrant fructifications of Ginkgo biloba whose seeds are attached to leaves, called O-ha-tsuki in Japan. This well-known phenomenon was now interpreted by Fujii as being homologous to ancestral Sporophylls. The common fructification of Ginkgo biloba consists of 1-2 (rarely more) ovules on a dichotomously divided stalk, the ovules on top of short stalklets, with collars supporting the ovules. There is essentially no disagreement that either the whole stalk with its stalklets, collars and ovules is homologous to a Sporophyll, or, alternatively, just one stalklet, collar and ovule each correspond to a Sporophyll. For the transition of an ancestral Sporophyll resembling extant O-ha-tsuki aberrant leaves into the common fructification with stalklet/collar/ovule, evolutionary reduction of the leaf lamina of such ancestral Sporophylls has to be assumed. Furthermore, such ancestral Sporophylls would be expected in the fossil record of ginkgophytes.
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Permian ginkgophyte fossils from the Dolomites resemble extant O-ha-tsuki aberrant leaf-like fructifications of Ginkgo biloba L
BMC Evolutionary Biology, 2010Co-Authors: Thilo C. Fischer, Barbara Meller, Evelyn Kustatscher, Rainer ButzmannAbstract:Background Structural elucidation and analysis of fructifications of plants is fundamental for understanding their evolution. In case of Ginkgo biloba , attention was drawn by Fujii in 1896 to aberrant fructifications of Ginkgo biloba whose seeds are attached to leaves, called O-ha-tsuki in Japan. This well-known phenomenon was now interpreted by Fujii as being homologous to ancestral Sporophylls. The common fructification of Ginkgo biloba consists of 1-2 (rarely more) ovules on a dichotomously divided stalk, the ovules on top of short stalklets, with collars supporting the ovules. There is essentially no disagreement that either the whole stalk with its stalklets, collars and ovules is homologous to a Sporophyll, or, alternatively, just one stalklet, collar and ovule each correspond to a Sporophyll. For the transition of an ancestral Sporophyll resembling extant O-ha-tsuki aberrant leaves into the common fructification with stalklet/collar/ovule, evolutionary reduction of the leaf lamina of such ancestral Sporophylls has to be assumed. Furthermore, such ancestral Sporophylls would be expected in the fossil record of ginkgophytes. Results From the Upper Permian of the Bletterbach gorge (Dolomites, South Tyrol, Italy) ginkgophyte leaves of the genus Sphenobaiera were discovered. Among several specimens, one shows putatively attached seeds, while other specimens, depending on their state of preservation, show seeds in positions strongly suggesting such attachment. Morphology and results of a cuticular analysis are in agreement with an affiliation of the fossil to the ginkgophytes and the cuticle of the seed is comparable to that of Triassic and Jurassic ones and to those of extant Ginkgo biloba . The Sphenobaiera leaves with putatively attached seeds closely resemble seed-bearing O-ha-tsuki leaves of extant Ginkgo biloba . This leads to the hypothesis that, at least for some groups of ginkgophytes represented by extant Ginkgo biloba , such Sporophylls represent the ancestral state of fructifications. Conclusions Some evidence is provided for the existence of ancestral laminar ginkgophyte Sporophylls. Homology of the newly found fossil ginkgophyte fructifications with the aberrant O-ha-tsuki fructifications of Ginkgo biloba is proposed. This would support the interpretation of the apical part of the common Ginkgo biloba fructification (stalklet/collar/ovule) as a Sporophyll with reduced leaf lamina.
Yukio Agatsuma - One of the best experts on this subject based on the ideXlab platform.
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Sporophyll of Undaria pinnatifida: a potential feed for the production of high-quality gonads in the sea urchin Mesocentrotus nudus (A. Agassiz, 1864)
Journal of Applied Phycology, 2020Co-Authors: Satomi Takagi, Yuko Murata, Eri Inomata, Yukio AgatsumaAbstract:Previous study has shown that feeding fresh Saccharina japonica kelp at the late sporophyte stage to Mesocentrotus nudus from a barren can improve the gonad quality of the sea urchin. In particular, the basal frond portion of S . japonica , which accumulates amino acids during maturation, greatly enhances the sweet and umami taste of the gonads. In the kelp Undaria pinnatifida , resources are accumulated in the blade for growth, then translocated to the Sporophyll for maturation at the late sporophyte stage. In this study, we demonstrate the effects of feeding U . pinnatifida Sporophyll to M . nudus from a barren from May to July on gonad quality (size, color ( L*a*b* ), and taste (free amino acids)) compared with the effects of feeding the U . pinnatifida midrib (negative control) and the basal frond portion of S . japonica (positive control). Feeding M . nudus the U. pinnatifida Sporophyll, which has high protein, carbohydrate, and total and free alanine contents, improved M . nudus gonad size and color and increased alanine content and decreased arginine content in the gonad, similar to the results of feeding M . nudus the basal frond portion of S . japonica . The Sporophyll increased free glutamic acid and decreased bitter-tasting amino acid contents in the gonads of sea urchins, indicating that feeding of the Sporophyll improved the gonad taste more than feeding of the basal frond portion of S . japonica . This study first indicated that the Sporophyll of U . pinnatifida is a high potential feed to improve gonad taste of M . nudus . The appropriate feeding period in which gonad quality can be improved must be confirmed in order to shorten the duration of M . nudus culture.
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Feeding the Sporophyll of Undaria pinnatifida kelp shortens the culture duration for the production of high-quality gonads of Mesocentrotus nudus sea urchins from a barren
Aquaculture, 2020Co-Authors: Satomi Takagi, Yuko Murata, Yukio AgatsumaAbstract:Abstract Our past studies revealed that feeding the basal frond portion of fresh Saccharina japonica kelp (BS) and the Sporophyll of fresh Undaria pinnatifida (SU) during May–July for 2 months can effectively improve the gonad quality of Mesocentrotus nudus from a barren. In the present study, M. nudus were collected from a barren and fed BS, SU or no food during May–July. We investigated the temporal changes in gonad size, color and texture and the contents of free amino acids in the gonads of M. nudus every 3 weeks during May–July to identify the appropriate culturing duration. The protein, carbohydrate, and total and free amino acid contents in each kelp thallus portion were examined at each time point. The gonad quality of sea urchins fed each portion for 9 weeks was evaluated by the chefs of sushi restaurants with three or two Michelin stars in Tokyo with a sensory test. The results of the sensory test indicated that the gonads of sea urchins fed BS or SU are of high quality, the same as those served in the sushi restaurants. Feeding the sea urchins BS improved gonad hardness in 3 weeks, gonad bitterness in 6 weeks, and gonad size, color and sweetness in 9 weeks. Feeding SU improved gonad hardness and taste in 3 weeks and gonad size and color in 6 weeks. These results indicate that the use of the Sporophyll enables the culture duration to shorten to 6 weeks for the production of high-quality gonads. The sweet-tasting alanine contents in the gonads of sea urchins fed BS and SU increased, coinciding with the high glutamic acid content in BS and high alanine content in SU. As nutrients in the frond of U. pinnatifida are translocated and accumulate in the Sporophyll from March and May, hastening the start of U. pinnatifida Sporophyll feeding would further shorten the culture duration.
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Effect of nitrate fertilization of gametophytes of the kelp Undaria pinnatifida on growth and maturation of the sporophytes cultivated in Matsushima Bay, northern Honshu, Japan
Aquaculture International, 2013Co-Authors: Yukio Agatsuma, Kazuya TaniguchiAbstract:In northern Japan, the early production of high-quality specimens of kelps Undaria pinnatifida prior to the outbreak of pinhole disease is needed. To address this need, we tested the effect of nitrate fertilization of gametophytes on the growth and maturation of sporophytes using experimental and control gametophytes derived from sporophytes cultivated in Matsushima Bay, northern Honshu, Japan. From mid-August to October 2008, experimental gametophytes were cultured on a rope indoors at a nitrate concentration of 1 mg/L at the optimal seawater temperature of 20 °C, whereas control gametophytes were cultured without the addition of nitrate in normal seawater at an average temperature of 23.5 °C during this period in the past 30 years. Next, the seedlings were cultivated in Matsushima Bay until March 2009. For the experimental kelps, the total length, stipe length, stipe width, Sporophyll length, Sporophyll width, and dry weight of the blade, midrib, and Sporophyll increased significantly from December to January compared to those of control kelps. Matured Sporophylls of the experimental kelps were more than those of the control kelps from early December to late January. Significant higher photosynthesis occurred at seawater temperatures of 10 and 15 °C, as well as higher uptake rates of NO_3–N of the experimental kelps in December and January. These results show that nitrate fertilization of the gametophytes makes it possible to harvest the high-priced blade, midrib, and Sporophyll in January, which is earlier than the traditional harvest date.
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compensatory abilities depending on seasonal timing of thallus excision of the kelp undaria pinnatifida cultivated in matsushima bay northern japan
Journal of Applied Phycology, 2013Co-Authors: Hikaru Endo, Kazuya Taniguchi, Makoto Yamana, Yukio AgatsumaAbstract:Improved cultivation technology for the kelp Undaria pinnatifida is greatly needed to increase production to meet increasing commercial demand. A previous cultivation trial indicated that the crop yield of U. pinnatifida sporophytes could be increased greatly by thallus excision in late February due to compensatory growth of the remaining tissues. To develop this potential new cultivation technology, it is essential to identify the time period during which this kelp can compensate and its physiological responses to thallus excision. In this study, U. pinnatifida sporophytes were excised at about 30 cm above the meristem at the beginning of January, February, March, and April, respectively. Morphological features, photosynthesis, nutrient uptake, and carbon and nitrogen contents of excised kelps were measured and compared with these parameters in control kelps grown without excision. Both experimental and control kelps were farmed together in Matsushima Bay, northern Japan. The kelps excised in January and February showed significant increases in the lengths and dry weights of the blade, photosynthetic rates, nutrient uptake rates, and carbon and nitrogen contents compared with the control kelps, and the growth phase was prolonged for at least 1 month. No significant increases were found in dry weights and carbon and nitrogen contents of Sporophylls until early April, which indicated that the maturation period was delayed. At the end of this experiment, the nitrogen contents of Sporophyll tissues formed after excisions were significantly lower than those of tissues formed before excisions. In contrast, the kelps excised in March and April showed no significant increases in morphological and physiological parameters compared with control kelps. These results suggest that U. pinnatifida sporophytes exhibited great compensation when excisions were conducted during the growing phase in January and February but not in March and April when the maturation phase had started. The regulation of resource allocation to growth and maturation after thallus excisions in January and February likely results in prolongation of the growth phase and maturation phase in excised kelps.
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Dietary effect of the boiled stipe of brown alga Undaria pinnatifida on the growth and gonadal enhancement of the sea urchin Strongylocentrotus nudus
Fisheries Science, 2002Co-Authors: Yukio Agatsuma, Yuka Yamada, Kazuya TaniguchiAbstract:: In Miyagi Prefecture, the cultured brown alga Wakame (Undaria pinnatifida) is boiled and then salted for human consumption. The stipes are discarded. To explore a use for the discarded stipes, we studied their dietary value on the growth of the juvenile sea urchin Strongylocentrotus nudus and the gonadal enhancement of adults and compared them with that of fresh stipes, blades and Sporophyll in the rearing experiment. Rapid growth in juveniles was most effectively promoted by the intake of fresh blades, with consumption of boiled stipes being next in value. The intake of boiled and salted stipe was higher than fresh stipe and Sporophylls; however, Sporophylls promoted the best gonadal enhancement in adults. Despite the low carbohydrate and crude protein content in boiled stipe, we estimated that boiled stipe could enhance the gonadal index by as much as 18%, the minimum level for market, after 5 months of feeding. The results suggest that boiled stipe would be an effective deterrent to the grazing intensity of the wild sea urchin within coralline flats where marine afforestation is being attempted.
Qi Wang - One of the best experts on this subject based on the ideXlab platform.
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Yuguangia ordinata gen. et sp. nov., a New Lycopsid from the Middle Devonian (Late Givetian) of Yunnan, China, and Its Phylogenetic Implications
International Journal of Plant Sciences, 2007Co-Authors: Qi WangAbstract:A new heterosporous and ligulate lycopsid, Yuguangia ordinata gen. et sp. nov., is described from the Haikou Formation (late Givetian) of Yunnan Province, southwestern China. Its slender stems branch isotomously. Vegetative leaves are arranged in pseudowhorls. Compact bisporangiate strobili terminate distal branches and have megasporangia located proximally and microsporangia distally. Sporophylls are differentiated into horizontal pedicel, upturned lamina, and downward “heel,” and they are pseudowhorlly arranged, with about eight per gyre. Each Sporophyll bears adaxially one mega‐ or microsporangium. Megasporangia and microsporangia are obovoid, round to elliptical in shape. Each megasporangium contains four or more Trileites‐type megaspores. Microspores are comparable, to some extent, to those of the dispersed spore genus Acinosporites. A ligule is located at the distal end of the horizontal pedicel of a Sporophyll. Distal axes have an exarch primary xylem strand, phloem, and a two‐zoned cortex. This st...
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Yuguangia ordinata gen. et sp nov., a new lycopsid from the middle devonian (late givetian) of Yunnan, China, and its phylogenetic implications
international journal of plant sciences, 2007Co-Authors: Hao Shougang, Qi Wang, Xue Jinzhuang, Liu ZhenfengAbstract:A new heterosporous and ligulate lycopsid, Yuguangia ordinata gen. et sp. nov., is described from the Haikou Formation (late Givetian) of Yunnan Province, southwestern China. Its slender stems branch isotomously. Vegetative leaves are arranged in pseudowhorls. Compact bisporangiate strobili terminate distal branches and have megasporangia located proximally and microsporangia distally. Sporophylls are differentiated into horizontal pedicel, upturned lamina, and downward 'heel," and they are pseudowhorlly arranged, with about eight per gyre. Each Sporophyll bears adaxially one mega- or microsporangium. Megasporangia and microsporangia are obovoid, round to elliptical in shape. Each megasporangium contains four or more Trileites-type megaspores. Microspores are comparable, to some extent, to those of the dispersed spore genus Acinosporites. A ligule is located at the distal end of the horizontal pedicel of a Sporophyll. Distal axes have an exarch primary xylem strand, phloem, and a two-zoned cortex. This study provides a new temporal framework for ligule acquisition and early diversification of heterosporous lycopsid lineages and implies that homosporous, ligulate lycopsid lineages (i.e., Leclercqia of Protolepidodendrales) and heterosporous, ligulate lycopsid lineages (i.e., Selaginellales and Isoetales) had diverged by the late Middle Devonian.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000249331500006&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Plant SciencesSCI(E)10ARTICLE81161-117516
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A new species of Lepidostrobus from the Upper Devonian of Xinjiang, China and its bearing on the phylogenetic significance of the order Isoëtales
Botanical Journal of the Linnean Society, 2003Co-Authors: Qi Wang, Bao-yin Geng, Cheng-sen Li, Shya ChitaleyAbstract:Lepidostrobus xinjiangensis sp. nov. is described from Upper Devonian rocks of the eastern Junggar Basin, Xinjiang, north-west China. It provides new insights into the reproductive diversification and phylogenetic relationships of lycopsids in the Late Devonian. The strobilus shares more characteristics with arborescent lycopsids than any herbaceous forms, and falls within the diagnosis of Lepidostrobus. Each Sporophyll consists of a deltoid pedicel and a triangular lamina. Sporophylls are horizontally inserted into the strobilus axis in low spirals. The pedicel, with lateral alations and an abaxial keel, extends distally into the upturned lamina and downturned heel, producing a peltate appearance. A single sporangium with terminal longitudinal dehiscence is a radially elongate, dorsiventrally flattened ovoid and is attached along its length to the adaxial surface of the pedicel. A column-like subarchesporial pad is found in the sporangium. A possible ligule occurs on the adaxial surface of the pedicel distal to the sporangium. The strobilus is microsporangiate, containing Lycospora-type spores with granulate ornamentation and an equatorial flange. Based on this new species, the reproductive diversification and evolutionary pattern in arborescent lycopsids from the Devonian through the Carboniferous are discussed in a phylogenetic framework. We suggest that the reproductive strategies represented by bisporangiate- and monosporangiate-strobili had proliferated by the Late Devonian, which implies that phylogenetically advanced arborescent lycopsids bearing Lepidostrobus strobili had an earlier origin than previously thought. © 2003 The Linnean Society of London, Botanical Journal of the Linnean Society, 2003, 143, 55−67.