Semi-aquatic Plant Research Articles

First report of an invading population of Colocasia esculenta (L.) Schott in the Iberian Peninsula

Colocasia esculenta, or taro, is an emergent aquatic and semi-aquatic plant, native to Asia, which is cultivated for its edible corm in several parts of the world. This species has colonized or invaded wetlands and rivers in different parts of the world (e.g., Southeast USA, Southwestern Australia, Southern Africa, etc.) thus suggesting that early detection of this species should be conducted. Here we present the first report of an invasive population of C. esculenta in the Iberian Peninsula (Southern Europe). Characteristics of the patches found that serve as an early diagnosis of the degree of invasion and the origin of introduction are given. The current population consists of a number of patches that are heterogeneously distributed along the stream (ca. 7 km). Monospecific Taro patches displace native species and provoke the narrowing of river sections, similar to rivers and wetlands in Australia or the United States where this species is considered an invasive plant. This new record also suggests the ability of this tropical species to withstand the long dry summers typical of the Mediterranean climate within permanent streams.

Reintroduction of Federally Endangered Harperella (Harperella nodosumRose) in Flood-Prone, Artificial, and Natural Habitats

Harperella (Harperella nodosum) is the only federally listed endangered plant species in the Chesapeake and Ohio Canal National Historical Park (C&O Canal NHP) in the National Park Service in Maryland and one of four federally listed endangered plant species in West Virginia. This paper contrasts unsuccessful and successful efforts to reintroduce harperella seedlings in the main stem of the flood-prone Potomac River and on opposite sides of the river in damp sites in western Maryland and in streams in northeastern West Virginia. The reintroduction efforts in Maryland unsuccessfully transplanted seedlings on cobble bars on the Maryland side of the Potomac River and in artificial sites in the prism of the C&O Canal where harperella had never been found; the reintroduction efforts in West Virginia successfully transplanted seedlings on cobble bars in two tributaries of the Potomac River in West Virginia where harperella populations once flourished but in the last decade or so had been decimated by floods and ice damage. This investigation has contributed to defining harperella's life-cycle characteristics and ecological requirements. The data and observations presented can be used as a guide for reintroducing harperella seedlings and, by extension, other semiaquatic plant species into appropriate sites.

Pharamcognostic Evaluation of Acorus calamus L.

Introduction:Acorus calamus L. is a semi aquatic medicinal plant, commonly used in traditional medicinal systems of Asian and European countries. Rhizomes are used as therapeutic agent for various diseases. The present study focuses on pharmacognostic evaluation of the rhizomes. Methods: Pharmacognostic evaluation was carried out by organoleptic evaluation, anatomical studies, powder microscopic analysis and ash valve studies. Results and Conclusions: Organoleptic studies showed presence of characteristic triangular leaf scars and the anatomical studies showed the presence of aerenchyma and amphivasal vascular bundles. Presence of tannins was also observed

Superhydrophobic surfaces of the water bugNotonecta glauca: a model for friction reduction and air retention

Superhydrophobic surfaces of plants and animals are of great interest for biomimetic applications. Whereas the self-cleaning properties of superhydrophobic surfaces have been extensively investigated, their ability to retain an air film while submerged under water has not, in the past, received much attention. Nevertheless, air retaining surfaces are of great economic and ecological interest because an air film can reduce friction of solid bodies sliding through the water. This opens perspectives for biomimetic applications such as low friction fluid transport or friction reduction on ship hulls. For such applications the durability of the air film is most important. While the air film on most superhydrophobic surfaces usually lasts no longer than a few days, a few semi-aquatic plants and insects are able to hold an air film over a longer time period. Currently, we found high air film persistence under hydrostatic conditions for the elytra of the backswimmer Notonecta glauca which we therefore have chosen for further investigations. In this study, we compare the micro- and nanostructure of selected body parts (sternites, upper side of elytra, underside of elytra) in reference to their air retaining properties. Our investigations demonstrate outstanding air film persistence of the upper side of the elytra of Notonecta glauca under hydrostatic and hydrodynamic conditions. This hierarchically structured surface was able to hold a complete air film under hydrostatic conditions for longer than 130 days while on other body parts with simple structures the air film showed gaps (underside of elytra) or even vanished completely after a few days (sternites). Moreover, the upper side of the elytra was able to keep an air film up to flow velocities of 5 m/s. Obviously the complex surface structure with tiny dense microtrichia and two types of larger specially shaped setae is relevant for this outstanding ability. Besides high air film persistence, the observation of a considerable fluid velocity directly at the air–water interface indicates the ability to reduce friction significantly. The combination of these two abilities makes these hierarchically structured surfaces extremely interesting as a biomimetic model for low friction fluid transport or drag reduction on ship hulls.

Development of a regeneration system via nodal segment culture in Veronica anagallis-aquatica L. – an amphibious medicinal plant

The present study describes an effective, reproducible and rapid regeneration protocol for in vitro shoot development of the medicinally important, semi-aquatic plant Veronica anagallis-aquatica L. through mature nodal segments on Murashige and Skoog (MS) medium. The most effective medium for shoot regeneration was MS medium fortified with 0.5 µM 6-benzyladenine (BA), on which the maximum number (43.7±1.85) of shoots per explant having a shoot length of 5.0±0.25 cm were produced. The addition of auxins along with optimal concentration (0.5 µM) of BA did not further improve the regeneration capacity of the explants; instead, it resulted in an adverse effect. Nodal segments cultured in MS liquid medium without agar provided a better and early response for efficient shoot regeneration, and simultaneous rooting as compared to solidified medium. The optimal liquid medium comprised of MS+BA (0.5 µM) on which a maximum 20.7±1.76 shoots per explant were produced and grew healthier. Both half strength MS and MS basal medium supplemented with α-naphthaleneacetic acid (NAA) responded equally for root induction. Rooted shoots were successfully transferred to field conditions with 80% survival. Histological studies revealed the de novo origin of shoots which would make this protocol suitable for transformation techniques.

Modelling the impacts of reservoir operations on the downstream riparian vegetation and fish habitats in the Lijiang River

River flow regulations have great impact on the downstream aquatic ecosystem. It is important to investigate the response of target species to the changes in hydrological regimes so that we can explore possible remediation measures. Ecohydraulics models that integrate hydrodynamics processes and ecological processes have been shown to be efficient in achieving these objectives. This study developed an integrated model which combined a two-dimensional hydrodynamic module with a vegetation evolution module and a fish habitat module. Owing to the ability to represent spatial heterogeneity and local interactions, the vegetation module used an unstructured cellular automata (UCA) approach. To describe the ambiguous relations between the physical conditions and habitat suitability, a fuzzy inference method was applied to the fish habitat module. The developed model was applied to a compound channel of the Lijiang River in southwest China, which has been greatly affected by the flow regulations of the Qingshitan Reservoir for navigation purposes. Through scenario simulations, the effects of flow regulation on riparian vegetation and fish habitat were analyzed. According to the results, water releases in the dry season imposed negative effects on the downstream semi-aquatic plant Rumex maritimus (R. maritimus) and Polygonum hydropiper (P. hydropiper) and favored the upland species Leonurus heterophyllus (L. heterophyllus). Regarding to the effects on fish Spinibarbus hollandi (S. hollandi) the results showed that water releases increased the suitability of the spawning conditions, especially during wet and dry years, but had little impact on the overwintering conditions.

Development and validation of an analytical method for the determination of derivatives of ortho-hydroxycinnamic acid of Echinodorus grandiflorus

Echinodorus grandiflorus (Cham. & Schltdl.) Micheli, a member of the family Alismataceae, is a native semi-aquatic plant widely distributed in Brazil, particularly in tropical regions of the country, and is popularly known as „chapéu-de-couro“ [1]. This plant is used in folk medicine as an anti-inflammatory and diuretic [2]. The chemical profile of E. grandiflorus consists basically of terpenoids, sesquiterpenes, and phenolic compounds [3–5]. A UV-Vis spectrophotometric method was developed and validated for the quantification of derivatives of ortho-hydroxycinnamic acid in leaves of E. grandiflorus. The method was validated by regulation RE 899/2003 of the National Health Surveillance Agency, Brazil, and the ICH guidelines. The response of this method was linear in concentrations ranging from 0.25–0.90µg mL–1 with a linear-regression correlation coefficient of 0.9972. The content of derivatives of ortho-hydroxycinnamic acid was successfully determined, with satisfactory reproducibility and recovery. The recovery was 107.56%. This method fulfilled all the validation parameters and was rapid, feasible, and low-cost. Thus, it can be applied by dispensing pharmacies and small laboratories for routine quality control analysis of E. grandiflorus.

AGRONOMIC PERFORMANCE AND BIOCHEMICAL GENETIC MARKERS FOR DROUGHT TOLERANCE IN RICE (Oryza sativa L.)

Rice (Oryza sativa L.) is considered one of the most important food crops not only in Egypt but also world wide. The demands of rice are in continuous increasing. The majority of rice ecotypes are semi-aquatic plants adapted to saturated soil conditions where it is difficult for crop species to survive (Champoux et al., 1995). Agricultural expansion in Egypt depends largely on water which is considered one of the main factors limiting agricultural development, so, one way to save water is increasing water intervals without any sharp effect on the yield. High degree of drought tolerance allows the plant to maintain its growth and development under water stress. The ability of the plant to produce new tillers and resume growth and development after irrigation is an important factor in drought tolerance (Chang et al., 1974). Identifying varieties with high yield potential and drought tolerance is one of the principal objectives of rice breeders. Several researchers have conducted studies on the effect of water deficit on rice. The effect of water stress on grain yield depends on the duration and timing of water deficit (Lenka and Garnayak, 1991; Castillo et al., 1992; Tsuda et al., 1994). Grain yield and yield components were significantly decreased with increasing irrigation intervals (Nour et al., 1994; Sorour et al., 1998; Adhikary et al., 1999; Sehly et al., 2001; Gaballah, 2009). Drought stress resulted in high spikelet sterility (Nour and Mahrous, 1994; Chauhan et al., 1999). Panicle length was decreased sharply when rice plants were subjected to irrigation intervals every 6 days (El-Wehishy and Ghanem, 1996) or longer than 6 days (Abou El-Hassan,1997). The conventional methods of plant selection for drought tolerance are not easy because of the large effects of the environment and low narrow sense heritability. Selection for drought tolerance genotypes of rice based on phenotypic performance alone is less reliable and will delay progress in breeding. Recent advent of molecular and biochemical markers, are used to find out drought tolerant rice genotypes. Molecular marker assisted identification with high power of genetic resolutions has emerged as a robust technique for cultivar fingerprinting, identity profiling, estimating and comparing genetic similarity, and variety protection. Several types of molecular marker i.e., allozymes (Devanand et al., 1999), RAPD (Wang and Lu, 2006; Ichii et al., 2003) and SSR (Nandakumar et al., 2004) have been used in this term. . The application of molecular markers in rice improvement has been reviewed recently (Mackill, 2007). Another indication for a response of the plant against abiotic stress is an increased level of free amino acids. Some of the amino acids are by themselves compatible solutes like proline, others are precursors of compatible solutes, like glycin or alanin (Hanson et al., 1994). But also other amino acids turned out to be enhanced (Rizhsky et al., 2004) which might be necessary for de novo synthesis of induced proteins. This study aimed to achieve reliable information about the relationships between morphological performance as some growth, yield as well as yield components and drought stress tolerance of 25 rice genotypes and to capture effective molecular and biochemical markers associated with drought tolerance to use in marker-aided selection breeding programs.

OPTIMIZATION OF PROTOCOLS FOR THE IN VITRO MULTIPLICATION AND CONSERVATION OF ACORUS CALAMUS, AN ENDANGERED MEDICINAL PLANT

ISHS IV International Symposium on Acclimatization and Establishment of Micropropagated Plants OPTIMIZATION OF PROTOCOLS FOR THE IN VITRO MULTIPLICATION AND CONSERVATION OF ACORUS CALAMUS, AN ENDANGERED MEDICINAL PLANT

Earliest rooting system and root : shoot ratio from a new Zosterophyllum plant

The enhanced chemical weathering by rooted vascular plants during the Silurian-Devonian period played a crucial role in altering global biogeochemical cycles and atmospheric environments; however, the documentation of early root morphology and physiology is scarce because the existing fossils are mostly incomplete. Here, we report an entire, uprooted specimen of a new Zosterophyllum Penhallow, named as Z. shengfengense, from the Early Devonian Xitun Formation (Lochkovian, c. 413 Myr old) of Yunnan, south China. This plant has the most ancient known record of a rooting system. The plant consists of aerial axes of 98 mm in height, showing a tufted habit, and a rhizome bearing a fibrous-like rooting system, c. 20 mm in length. The rhizome shows masses of branchings, which produce upwardly directed aerial axes and downwardly directed root-like axes. The completeness of Z. shengfengense made it possible to estimate the biomass allocation and root : shoot ratio. The root : shoot ratio of this early plant is estimated at a mean value of 0.028, and the root-like axes constitute only c. 3% of the total biomass. Zosterophyllum shengfengense was probably a semi-aquatic plant with efficient water use or a strong uptake capacity of the root-like axes.

Decontamination of water polluted by heavy metals with Taro (Colocasia esculenta) cultured in a hydroponic NFT system

The toxicity and bioaccumulation of two heavy metals—lead (Pb) and cadmium (Cd)—in a semi-aquatic plant, Colocasia esculenta (L. Schott), from a synthetic heavy metal solution were studied. Young plants of equal size were grown hydroponically in shallow raceways containing Hoagland medium amended with 20, 40, and 60 mg l−1 of Pb and 2, 4, and 6 mg l−1 of Cd. The medium containing heavy metals was allowed to flow through the raceways with a change in influent heavy metal solution on every 5th day. The experiment was continued for 20 days. A set of control raceways—one comprised of nutrient medium with heavy metal supplements, devoid of plants, and another with the plants and nutrient medium having no metal supplement—was also simultaneously run. Chlorosis in the leaves was the prominent toxicity symptom observed due to Pb and Cd on the test plants. A significant decrease in the relative growth, biomass productivity, and total chlorophyll content were noticed in the plants with an increase in concentration of metal supplement in the solution and exposure time. Both metals accumulated to higher concentrations in the roots than in shoots, suggesting that the metals were bound to the root cells and their translocation to the leaves was limited. The results of the 20-day-long experiments indicate that from a phytoremediation perspective, C. esculenta is a promising plant species for remediation of wastewater polluted with lower concentrations of Pb and Cd.

On the origin of Echinodorus grandiflorus (Alismataceae) in Florida (“E. floridanus”), and its estimated potential as an invasive species

A large semi-aquatic plant, Echinodorus floridanus, was described and considered as a rare Floridian endemic only 10 years ago. Recent phylogenetic studies revealed that the new species actually belongs into a South American species, E. grandiflorus. This species has been cultivated in Florida as an ornamental aquarium plant at least since the 1980s. This only known wild population in Florida most likely originated by escaping from cultivation, or it was intentionally planted. A maximum entropy niche model suggests a potential range expansion in the southern USA, although the suitability of this area is predicted to be relatively low for the species. Apparently low risk of invasion is also demonstrated by the non-invasive history of this only known wild population. The species may, however, threaten the local flora via hybridization with native Echinodorus species, and hence eradication of the species should be considered.

Macrophytes et groupements végétaux aquatiques et amphibies de la basse vallée du ferlo (Sénégal)

The reflooding of the Ferlo Valley since 1988 after 32 years of drying up has caused progressive growth of aquatic plants. 103 woody and herbaceous plants falling into 81 genera and 38 families were identified in the Valley. Analysis of the vegetation using the transect technique and the Braun Blanquet method helped to establish the floristic composition of 7 aquatic and semi aquatic plants groups. Typha domingensis and Pistia stratiotes are dominant in the aquatic miieu whereas Tamarix senegalensis plant groups were frequently found in the flood plain, indicating that the tidal range is important and soil salinity was still high.

Epidermal cells that undergo cell death differentially express cell identity genes

Rice (Oryza sativa L.) is a semiaquatic plant that forms adventitious root primordia at the stem nodes as part of normal development. Upon flooding, roots emerge, preceded by local death of epidermal cells above the root primordia. Cell death is strictly confined to cells above root primordia and is induced by ethylene and H2O2. These pro-death signals regulate expression of the transcription factor genes ANT-like, OsARF2, OsARF3 and Hox9 which have a proposed function in cell type specification, boundary formation, or organ polarity. It is hypothesized that local induction of cell death is dependent on epidermal cell identity as defined at the molecular level.

Chemistry and FT-IR spectroscopic studies of plants from contaminated mining sites in the Iberian Pyrite Belt, Portugal

AbstractSemi-aquatic and native plants collected from a mining site in the Iberian Pyrite Belt were analysed. Semi-aquatic plants showed enrichment of Cu (1.2—11 times), Zn (1.3—6 times), Pb (5—8 times) and As (24—1300 times) relative to typical concentrations in plants of the same species growing at uncontaminated sites. Translocation factors indicate limited internal metal transportation from roots to shoots. Infrared spectroscopy identified aromatic and aliphatic C-H (CH2) groups, S-O complexes and kaolinite in semi-aquatic plants.

Livestock Trampling and Lilaeopsis schaffneriana Var. Recurva (Brassicaceae)

Lilaeopsis schaffneriana var. recurva (Hill) Affolter, is a small aquatic to semi-aquatic plant restricted to mid-elevation cienega and riparian margins in southeastern Arizona and northwestern Sonora (Hendrickson and Minckley 1984). It was listed as Endangered in 1997 under the Endangered Species Act of 1973 (as amended) because of ‘‘degradation and destruction of habitat resulting from livestock overgrazing, water diversions, dredging, and groundwater pumping’’ (USFWS 1997). Trampling and overgrazing by livestock are commonly cited as threats to this species, however, we have found no documented cases or quantification of livestock effects. Herein, we document and quantify the effect of trampling by trespass livestock on Lilaeopsis schaffneriana var. recurva in Leslie Canyon National Wildlife Refuge, Cochise County, Arizona. During 2003, we established a pilot monitoring program for Lilaeopsis schaffneriana var. recurva, which occupied 12 distinct patches in Leslie Canyon National Wildlife Refuge. The protocol required taking multiple, cross-patch measurements of each patch and plotting the measurements on simplified drawings of the patches. The diagrams were then taken back to the lab, scaled polygons were drawn in TurboCAD (IMSI 2002), and from these polygons the area of each patch was estimated. The sum of the individual patch areas is the total area occupied. The trampling effect of trespass livestock was assessed in the same manner, where portions of patches destroyed by livestock were measured, described as polygons with area calculations, and summed across all trampled areas. All patch measurements were completed on 13 Jun 2003. Total area occupied by ten Lilaeopsis schaffneriana var. recurva patches along Leslie Creek was 27.11 m; individual patches averaged 2.71 m (SD 5 2.54). On 6 Jul 2004, a trespass bull entered Leslie Canyon National Wildlife Refuge and spent 4 d within the riparian area; it appeared that most of the individual’s time was spent away from the Lilaeopsis patches. During the time that the bull spent around the Lilaeopsis patches, 1.47 m (5.4% of the total area occupied) were lost to trampling. This event allowed us to quantify the effect of a single livestock individual on Lilaeopsis schaffneriana var. recurva, over a span of only 4 d. Even though resource use patterns by livestock could leave some patches unaffected, the damage caused by this single individual indicates that even a small number of livestock could eradicate most of the Leslie Creek Lilaeopsis population in several days to weeks. Therefore, based on the negative effect caused by this short-term event, our conclusion is that livestock should be excluded from areas occupied by Lilaeopsis schaffneriana var. recurva.

The dream of staying clean: Lotus and biomimetic surfaces

The Lotus has been the symbol of purity for thousands of years; contaminations and pathogens are washed off the surfaces of Lotus and some other plants with rain or even dew. After the introduction of scanning electron microscopy, we were able to resolve the mechanism behind this phenomenon. It took some further decades before in-depth studies on self-cleaning with plants were conducted and the effect could be understood in detail. We identified extreme water-repellency (‘superhydrophobicity’), characterized by very high contact angles and low sliding angles, as the prerequisite for self-cleaning properties. We could show that the combination of two factors is necessary for obtaining a high degree of water-repellency: (1) low energy surfaces being hydrophobic and (2) surface structures that significantly increase hydrophobicity. It is suggested that this mechanism plays an important role in the protection of plants against pathogens. Our technological application of this effect has resulted in the development of successful, eco-friendly and sustainable industrial products. Another interesting property was found with superhydrophobic surfaces of certain aquatic and semi-aquatic plants and animals: here a layer of air under water is retained. We present a new approach of using this feature for creating structured, air-retaining surfaces for technical underwater applications. It is proposed that such surfaces can reduce significantly the drag of large ships. We conclude that basic biological research is of particular importance for true innovation. Our research on superhydrophobic self-cleaning biological surfaces and the development of similar engineered materials suggests that biomimicry is a matter of multi-stage processes rather than a simple copying of biological developments.

An Inventory of the Aquatic and Subaquatic Plants in SASKWater Canals in Central Saskatchewan, Canada, Before and After the Application of the Herbicide Magnacide

This study focuses on the floristic composition of aquatic and semi-aquatic plants in the SASKWater canal system and their potential effect on irrigation systems. A checklist, evaluation, and synthesis of the species identified in this survey before and after the application of the herbicide Magnacide are provided, in addition to a brief discussion of the environmental effects of Magnacide. Thirty-three species in 26 genera within 20 plant families were identified. Two unidentified green algae were also collected. Common aquatics (i.e., green algae, Potamogeton spp., Alisma gramineum, A. plantago-aquatica, Ceratophyllum demersum, and Myriophyllum sibiricum) combined with debris from terrestrial plants were the primary contributors to blockage of irrigation drains. In general, the concentration of Magnacide used in this study had a minor effect on aquatic plant diversity, but effectively reduced plant density. However, the long-term effects of pesticides on the surrounding aquatic and terrestrial environments of the SASKWater irrigation system are unknown.

Pharmacological mechanisms involved in the vasodilator effects of extracts from Echinodorus grandiflorus

We investigated the vascular effects of a crude aqueous extract (AEEG) of Echinodorus grandiflorus (Alismataceae) using the in vitro experimental models of the rabbit isolated aorta and perfused kidney. Echinodorus grandiflorus, a native semi-aquatic plant widely distributed in Brazil, has been extensively used in Brazilian folk medicine for the treatment of high blood pressure and inflammatory diseases. The bolus injection of AEEG (0.1–10 mg) into the rabbit renal circulation pre-contracted with norepinephrine induced marked and dose-dependent vasodilator responses (maximum of 37 ± 4%; n = 6; P < 0.001), which was similar to that induced by injection of 10 mmol acetylcholine (41 ± 3%). Moreover, AEEG elicited a significant and concentration-dependent relaxation in the endothelium-intact, but not endothelium-denuded aortic rings, reaching the maximum of 81 ± 5% ( n = 7, P < 0.001). Inhibition of the nitric oxide-cGMP pathway with L-NAME (100 μM) or Methylene Blue (20 μM) reduced maximum relaxation induced by AEEG from 81 ± 5% to 46 ± 3 and 45 ± 3%, respectively ( n = 7, P < 0.001). A similar reduction was obtained with the incubation of the aortic rings with the selective PAF receptor antagonist WEB 2086 (10 μM) (from 81 ± 5% to 55 ± 3%; n = 7; P < 0.01). Conversely, blockade of muscarinic receptors with atropine (10 μM) did not affect the vasodilator effects of AEEG, while inhibition of the enzyme cyclooxigenase not only did not block, but rather potentiated vasodilation induced by AEEG ( n = 7, P < 0.001). Finally, blockade of Ca 2+- and ATP-activated K + channels using the specific blockers charydbotoxin (100 nM) and glibenclamide (3 μM), respectively, did not modify aortic relaxation induced by AEEG. We conclude that water-soluble extracts from leaves of Echinodorus grandiflorus elicit an endothelium-dependent, nitric oxide and PAF receptor-mediated vasodilation in rabbit aortic rings, which does not appear to involve the generation of vasodilating prostaglandins or the activation of K + channels. This potent vasodilator effect of the extracts was confirmed in the isolated rabbit renal circulation.

Invasion success of non-indigenous aquatic and semi-aquatic plants in their native and introduced ranges. A comparison between their invasiveness in North America and in France

Aquatic and semi-aquatic plants comprise few species worldwide, yet the introduction of non-indigenous plants represents one of the most severe examples of biological invasions.