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Donald H. Les - One of the best experts on this subject based on the ideXlab platform.
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Ceratophyllum platyacanthum subsp. oryzetorum (Kom.) Les (Ceratophyllaceae): an addition to the flora of India from Kashmir Himalaya
Check List, 2015Co-Authors: Aijaz Hassan Ganie, Zaffar Ahmad Reshi, Bilal A. Tali, Anzar A. Khuroo, Donald H. LesAbstract:Ceratophyllum platyacanthum Cham. subsp. oryzetorum (Kom.) Les (Ceratophyllaceae) is recorded for the first time from Kashmir Himalaya and India. The species differs from its closely related taxon, Ceratophyllum demersum, in having smaller leaves and the fruit with a facial spine. A comparison between Ceratophyllum demersum and C. platyacanthum subsp. oryzetorum , and the taxonomic description, photographs and distribution map are provided to facilitate its field identification in the region.
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Ceratophyllum platyacanthum subsp. oryzetorum (Kom.) Les (Ceratophyllaceae): an addition to the flora of India from
2015Co-Authors: Kashmir Himalaya, Zaffar Ahmad Reshi, Aijaz Hassan Ganie, Bilal A. Tali, Anzar A. Khuroo, Donald H. LesAbstract:Ceratophyllum platyacanthum Cham. subsp. oryzetorum (Kom.) Les (Ceratophyllaceae) is recorded for the first time from Kashmir Himalaya and India. The species differs from its closely related taxon, Ceratophyllum demersum, in having smaller leaves and the fruit with a facial spine. A comparison between Ceratophyllum demersum and C. platyacanthum subsp. oryzetorum, and the taxonomic description, photographs and distribution map are provided to facilitate its field identification in the region.
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Fossil Ceratophyllum (Ceratophyllaceae) from the tertiary of North America
American Journal of Botany, 1990Co-Authors: Patrick S. Herendeen, Donald H. Les, David L. DilcherAbstract:Fossil fruits and a vegetative axis assignable to the extant genus Ceratophyllum are described from four North American Tertiary localities. Fossil fruits assignable to the extant species C. muricatum and C. echinatum are reported from the Eocene Green River and Claiborne formations, and the Miocene Esmerelda Formation, respectively. An extinct species, C. furcatispinum, is described from the Paleocene Fort Union Formation and represents the oldest published report of Ceratophyllum in the fossil record. The existence of extant angiosperm species in the Eocene is very unusual and may be attributable in this case to slow evolutionary rates and unusual evolutionary properties associated with hydrophily in the genus Ceratophyllum. Ceratophyllum is a submersed monoecious freshwater aquatic angiosperm with underwater pollination (hydrophily) and distinctive, often spiny fruits. One might expect such taxa to have an abundant fossil record, and in this paper we describe and illustrate fossil vegetative and reproductive Ceratophyllum specimens from four localities ranging in age from Paleocene to Upper Miocene. These specimens expand the known geological history of the group (Les, 1 988a) and provide an opportunity to evaluate the suggestion that slow rates of evolution and low diversity are consequences of hydrophilous pollination in perennial aquatic genera (Les, 1988c). Inefficient pollen transfer, reduced sexuality, widespread clonal growth and diminished seed production have been suggested as causal factors to explain the low species diversity in many hydrophilous genera (Les, 1988c). Hydrophily occurs in a phylogenetically heterogeneous group consisting of seven families and 18 genera, 16 of which consist of fewer than ten species (Les, 1 988c). The Ceratophyllaceae have been suggested to be a living representative of some of the oldest flowering plants (Les, 1988a). Therefore, the 1 Received for publication 16 December 1988; revision accepted 13 June 1989. We wish to thank Steven Manchester for photographing fossil specimens at the U.S. National Museum and for providing the Green River fossil fruits. We thank Lance Grande for providing access to the Green River fossil fish material. Figure 21 was prepared by the Cartographic Services Laboratory of the University of Wisconsin-Milwaukee. We thank Peter Crane for helpful comments and suggestions on an earlier draft of this paper. This work was supported in part by a National Science Foundation Grant BSR 8516657 to DLD and Indiana Academy of Science Grant to PSH. fossil history of Ceratophyllum is of interest particularly because it should allow for an evaluation of some of the hypotheses concerning diversity and rates of evolution in hydrophilous taxa (Les, 1988c). The Ceratophyllaceae have been reported previously in the paleobotanical literature. The extinct genus Ceratostratiotes Gregor from the Miocene of Europe has been suggested to have taxonomic affinities to Ceratophyllum. It is treated as a separate extinct genus in the Ceratophyllaceae because of differences from Ceratophyllurn in placentation, fruit wall ornamentation and symmetry (Buiz:ek, 1982; Les, 1988a). In addition to the reports of fossil Ceratophyllum speciescitedin Les (1 988a), several other reports are in the literature. Ceratophyllum miodemersum Hu and Chaney was reported from the Miocene of Shantung Province, China (Hu and Chaney, 1940). The fossil vegetative axes have whorled leaves which appear to be at least twice dichotomously divided. Reports of fossil material of twelve Ceratophyllum species, several of which were originally described in a number of different papers, are summarized by Dorofeev (1974). However, the report of C. praedemersum Ashlee (Ashlee, 1932; Brown, 1937) is erroneous. The axis illustrated by these authors is perhaps an immature platanoid inflorescence, not a vegetative shoot of Ceratophyllum. The Ceratophyllaceae appear to have been relatively diverse in the past. Thus the paleobotanical record provides an understanding of the extent of past morphological diversity as compared to that observed in extant Ceratophyllum species. Historically, taxonomic studies of Cerato-
G. Moya - One of the best experts on this subject based on the ideXlab platform.
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Submerged vascular plants and water chemistry in the coastal marsh Albufera de Mallorca (Balearic Islands)
Hydrobiologia, 1993Co-Authors: A. Martinez-taberner, G. MoyaAbstract:Ten species of aquatic macrophytes have been analyzed for seven environmental variables by means of a significance test. A synthetic view has been obtained through a cluster analysis for species and a principal component analysis for 17 variables which form the multidimensional space where we project the species habitats. Myriophyllum spicatum L., Najas marina L., Potamogeton crispus L., Potamogeton pectinatus L. and Zannichellia pedunculata Reichenb. are widely distributed in the Albufera . Ceratophyllum submersum L. and Ruppia maritima L. var. brevirostris Ag. are considered stenoic. The tolerance of Ceratophyllum submersum to salts is significantly low and that of Ruppia cirrhosa (Petagna) Grande and Ruppia maritima var. brevirostris significantly high. Ceratophyllum submersum has a significantly negative distribution with regard to chlorophyll a and phosphate concentrations. Ceratophyllum demersum L. and C. submersum primarily occur in nitrate-rich waters whereas Ruppia cirrhosa primarily occurs in low nitrate waters.
Virginia Reid - One of the best experts on this subject based on the ideXlab platform.
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patterns of aquatic weed regrowth following mechanical harvesting in new zealand hydro lakes
Hydrobiologia, 1996Co-Authors: Clive Howardwilliams, Annemaree Schwarz, Virginia ReidAbstract:Mechanical harvesting is used to control submerged aquatic weeds in parts of the hydro-lakes in New Zealand’s North Island. Problem species are Egeria densa and Lagarosiphon major (Hydrocharitaceae), and Ceratophyllum demersum. Experiments were conducted in two contrasting hydro-lakes. Lake Aratiatia; clear water (K o 0.2 m−1) and a low residence time ( 5 days). Growth rates were measured underwater in harvested and control (unharvested) plots. Regrowth of C. demersum was dependent on the prior establishment of the rooted Hydrocharitaceae. Regrowth of the Hydrocharitaceae was inhibited where significant water movement occurred. Regrowth declined after 3 six-monthly harvests allowing the establishment of low growing native Nitella spp. beds in the smaller clear water lake. In Lake Ohakuri there was a change in species dominance from Ceratophyllum to Elodea canadensis in shallow (1-2 m) water. No change in species dominance was observed in deeper (<2 m) water and native species were not able to re-establish. The recommended cutting frequency for management of surface weed growths was only once per year in Lake Aratiatia, but twice per year in Lake Ohakuri.
Josef Hedbavny - One of the best experts on this subject based on the ideXlab platform.
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comparison of vascular and non vascular aquatic plant as indicators of cadmium toxicity
Chemosphere, 2017Co-Authors: Jozef Kovacik, Petr Babula, Josef HedbavnyAbstract:Antioxidative and microscopic responses in non-vascular (moss Taxiphyllum barbieri) and vascular (Ceratophyllum demersum) aquatic plants exposed to short-term (24 h) cadmium (Cd) excess (10 and 100 μM) were compared. Ceratophyllum considerably accumulated Cd but less pronounced symptoms of oxidative stress were detected by confocal microscopy (at the level of general ROS, hydrogen peroxide, hydroxyl radical/peroxynitrite and superoxide) that could be related to enhanced activities of antioxidative enzymes (SOD, CAT, APX). Amounts of ascorbic acid and non-protein thiols were higher in Ceratophyllum than in Taxiphyllum and increased with increasing Cd dose, which may help to better regulate circulation of free metal ions in Ceratophyllum mainly. Besides, it was observed that citric acid increased in Ceratophyllum while malic acid in Taxiphyllum in response to Cd which may also contribute to Cd chelation. Our data indicate that Ceratophyllum is a suitable species for Cd bioaccumulation while Taxiphyllum is more sensitive to Cd excess and thus suitable as indicator species. It was also proven that sensitive microscopic techniques allow the visualization of Cd-induced changes in aquatic plants even after short-term exposure when no morphological signs of damage are visible.
Petr Babula - One of the best experts on this subject based on the ideXlab platform.
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comparison of vascular and non vascular aquatic plant as indicators of cadmium toxicity
Chemosphere, 2017Co-Authors: Jozef Kovacik, Petr Babula, Josef HedbavnyAbstract:Antioxidative and microscopic responses in non-vascular (moss Taxiphyllum barbieri) and vascular (Ceratophyllum demersum) aquatic plants exposed to short-term (24 h) cadmium (Cd) excess (10 and 100 μM) were compared. Ceratophyllum considerably accumulated Cd but less pronounced symptoms of oxidative stress were detected by confocal microscopy (at the level of general ROS, hydrogen peroxide, hydroxyl radical/peroxynitrite and superoxide) that could be related to enhanced activities of antioxidative enzymes (SOD, CAT, APX). Amounts of ascorbic acid and non-protein thiols were higher in Ceratophyllum than in Taxiphyllum and increased with increasing Cd dose, which may help to better regulate circulation of free metal ions in Ceratophyllum mainly. Besides, it was observed that citric acid increased in Ceratophyllum while malic acid in Taxiphyllum in response to Cd which may also contribute to Cd chelation. Our data indicate that Ceratophyllum is a suitable species for Cd bioaccumulation while Taxiphyllum is more sensitive to Cd excess and thus suitable as indicator species. It was also proven that sensitive microscopic techniques allow the visualization of Cd-induced changes in aquatic plants even after short-term exposure when no morphological signs of damage are visible.