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1.
Ecotoxicol Environ Saf ; 197: 110599, 2020 Jul 01.
Article in English | MEDLINE | ID: mdl-32304919

ABSTRACT

Hydroponic experiment was conducted to investigate the biochemical responses and accumulation behaviour of cadmium (Cd) in aquatic fern, Ceratopteris pteridoides, under four different levels of exposure. Plants were grown in 10 µM (CdT1), 20 µM (CdT2), 40 µM (CdT3) and 60 µM (CdT4) concentrations of Cd for 12 consecutive days and Cd accumulation in different plant parts, cell levels and growth medium was estimated. In C. pteridoides, Cd removal kinetics was best described by pseudo-second-order kinetic model. Increased accumulation of Cd in the plants was detected in a concentration dependent manner with maximum under 60 µM of Cd (CdT4) exposure (191.38 mg kg-1, 186.19 mg kg-1 and 1316.34 mg kg-1 in leaves, stems and roots, respectively). Cell wall of C. pteridoides is identified as crucial Cd storage site with the highest (28-69%) accumulation followed by organelles (14-44%) and soluble fraction (6-46%). Increased leaf proline, malondialdehyde (MDA) and protein content with significant reduction (P < 0.05) in chlorophyll concentration and upregulation of antioxidant enzymes catalase (CAT), guaiacol peroxidase (POD) and superoxide dismutase (SOD) reveals the presence of Cd resistance mechanism in C. pteridoides. Calculated higher (>1) bioconcentration factor (BCF) and lower (<1) translocation factor (TF) values evinced the suitability of C. pteridoides in Cd phytostabilization rather than phytoextraction.


Subject(s)
Cadmium/pharmacokinetics , Pteridaceae/metabolism , Antioxidants/metabolism , Biological Transport , Cadmium/toxicity , Catalase/metabolism , Cell Wall/metabolism , Chlorophyll/metabolism , Hydroponics , Malondialdehyde/metabolism , Peroxidase/metabolism , Plant Leaves/metabolism , Plant Roots/metabolism , Pteridaceae/drug effects , Pteridaceae/enzymology , Superoxide Dismutase/metabolism
2.
Physiol Plant ; 157(2): 135-46, 2016 Jun.
Article in English | MEDLINE | ID: mdl-26853807

ABSTRACT

Arsenic (As) pollution is a major environmental concern due to its worldwide distribution and high toxicity to organisms. The fern Pityrogramma calomelanos is one of the few plant species known to be able to hyperaccumulate As, although the mechanisms involved are largely unknown. This study aimed to investigate the metabolic adjustments involved in the As-tolerance of P. calomelanos. For this purpose, ferns with five to seven fronds were exposed to a series of As concentrations. Young fronds were used for biochemical analysis and metabolite profiling using gas chromatography-mass spectrometry. As treatment increased the total concentration of proteins and soluble phenols, enhanced peroxidase activities, and promoted disturbances in nitrogen and carbon metabolism. The reduction of the glucose pool was one of the striking responses to As. Remarkable changes in amino acids levels were observed in As-treated plants, including those related to biosynthesis of glutathione and phenols, osmoregulation and two photorespiratory intermediates. In addition, increases in polyamines levels and antioxidant enzyme activities were observed. In summary, this study indicates that P. calomelanos tolerates high concentration of As due to its capacity to upregulate biosynthesis of amino acids and antioxidants, without greatly disturbing central carbon metabolism. At extremely high As concentrations, however, this protective mechanism fails to block reactive oxygen species production, leading to lipid peroxidation and leaf necrosis.


Subject(s)
Arsenic/metabolism , Pteridaceae/physiology , Stress, Physiological , Amino Acids/biosynthesis , Antioxidants/metabolism , Arsenic/toxicity , Biodegradation, Environmental , Biomarkers/metabolism , Biosynthetic Pathways/drug effects , Gas Chromatography-Mass Spectrometry , Oxidative Stress , Plant Leaves/drug effects , Plant Leaves/physiology , Pteridaceae/drug effects , Soil Pollutants/metabolism , Soil Pollutants/toxicity
3.
Plant Physiol Biochem ; 97: 28-35, 2015 Dec.
Article in English | MEDLINE | ID: mdl-26408808

ABSTRACT

Arsenic (As) hyperaccumulation trait has been described in a limited number of fern species. The physiological basis of hyperaccumulation remains unclear, especially in non-Pteris species such as Pityrogramma calomelanos. Aiming at a better understanding of As-induced responses, P. calomelanos plants were exposed to 1 mM As for 21 days and compared with control plants. Chemical analyses revealed that As accumulation was ten times higher in pinnae then in roots and stipes. In pinnae, As was present mainly as arsenite, whereas arsenate was the dominant form in stipes and roots. Arsenic promoted an increase in antioxidant enzyme activities in both fern parts and several alterations in mineral nutrition, especially with regard to P and K. A higher content of non-protein thiols was observed in pinnae of plants exposed to As, whereas As induced the increase in lipid peroxidation in roots. The results showed that Pityrogramma calomelanos shares with Pteris vittata several aspects of As metabolism. High root-shoot As translocation showed to be essential to avoid toxic effects in roots, since the root is more sensitive to the metalloid. The higher capacity of P. calomelanos to sequester arsenite in the pinna and its efficient antioxidant system maintain the reactive oxygen species at a low level, thus enhancing the continuous accumulation of As. Molecular investigations are needed to elucidate the evolution of As-tolerance mechanisms in Pteridaceae species, especially with regard to membrane transporters and ROS signaling.


Subject(s)
Antioxidants/metabolism , Arsenic/metabolism , Minerals/metabolism , Pteridaceae/metabolism , Arsenates/analysis , Arsenates/metabolism , Arsenic/analysis , Arsenites/analysis , Arsenites/metabolism , Plant Roots/drug effects , Plant Roots/metabolism , Pteridaceae/drug effects
4.
Am J Bot ; 100(1): 161-74, 2013 Jan.
Article in English | MEDLINE | ID: mdl-23048014

ABSTRACT

PREMISE OF THE STUDY: Gravity regulates the magnitude and direction of a trans-cell calcium current in germinating spores of Ceratopteris richardii. Blocking this current with nifedipine blocks the spore's downward polarity alignment, a polarization that is fixed by gravity ∼10 h after light induces the spores to germinate. RNA-seq analysis at 10 h was used to identify genes potentially important for the gravity response. The data set will be valuable for other developmental and phylogenetic studies. METHODS: De novo Newbler assembly of 958 527 reads from Roche 454 sequencing was executed. The sequences were identified and analyzed using in silico methods. The roles of endomembrane Ca(2+)-ATPase pumps and apyrases in the gravity response were further tested using pharmacological agents. KEY RESULTS: Transcripts related to calcium signaling and ethylene biosynthesis were identified as notable constituents of the transcriptome. Inhibiting the activity of endomembrane Ca(2+)-ATPase pumps with 2,5-di-(t-butyl)-1,4-hydroquinone diminished the trans-cell current, but increased the orientation of the polar axis to gravity. The effects of applied nucleotides and purinoceptor antagonists gave novel evidence implicating extracellular nucleotides as regulators of the gravity response in these fern spores. CONCLUSIONS: In addition to revealing general features of the transcriptome of germinating spores, the results highlight a number of calcium-responsive and light-receptive transcripts. Pharmacologic assays indicate endomembrane Ca(2+)-ATPases and extracellular nucleotides may play regulatory roles in the gravity response of Ceratopteris spores.


Subject(s)
Apyrase/metabolism , Calcium-Transporting ATPases/metabolism , Calcium/metabolism , Gravitation , Pteridaceae/physiology , Sequence Analysis, RNA/methods , Adenosine Triphosphate/metabolism , Amino Acid Sequence , Apyrase/genetics , Calcium-Transporting ATPases/antagonists & inhibitors , Calcium-Transporting ATPases/chemistry , Cell Polarity/drug effects , Databases, Genetic , Enzyme Inhibitors/pharmacology , Extracellular Space/drug effects , Extracellular Space/metabolism , Gene Expression Regulation, Plant/drug effects , Genes, Plant/genetics , Molecular Sequence Data , Photoreceptors, Plant/metabolism , Pteridaceae/cytology , Pteridaceae/drug effects , RNA, Messenger/genetics , RNA, Messenger/metabolism , Signal Transduction/drug effects , Spores/drug effects
5.
Planta ; 233(5): 911-20, 2011 May.
Article in English | MEDLINE | ID: mdl-21234599

ABSTRACT

In single-celled spores of the fern Ceratopteris richardii, gravity directs polarity of development and induces a directional, trans-cellular calcium (Ca(2+)) current. To clarify how gravity polarizes this electrophysiological process, we measured the kinetics of the cellular response to changes in the gravity vector, which we initially estimated using the self-referencing calcium microsensor. In order to generate more precise and detailed data, we developed a silicon microfabricated sensor array which facilitated a lab-on-a-chip approach to simultaneously measure calcium currents from multiple cells in real time. These experiments revealed that the direction of the gravity-dependent polar calcium current is reversed in less than 25 s when the cells are inverted, and that changes in the magnitude of the calcium current parallel rapidly changing g-forces during parabolic flight on the NASA C-9 aircraft. The data also revealed a hysteresis in the response of cells in the transition from 2g to micro-g in comparison to cells in the micro-g to 2-g transition, a result consistent with a role for mechanosensitive ion channels in the gravity response. The calcium current is suppressed by either nifedipine (calcium-channel blocker) or eosin yellow (plasma membrane calcium pump inhibitor). Nifedipine disrupts gravity-directed cell polarity, but not spore germination. These results indicate that gravity perception in single plant cells may be mediated by mechanosensitive calcium channels, an idea consistent with some previously proposed models of plant gravity perception.


Subject(s)
Calcium Signaling/physiology , Gravitropism/physiology , Pteridaceae/metabolism , Calcium/metabolism , Calcium Channel Blockers/pharmacology , Calcium Signaling/drug effects , Cell Membrane/drug effects , Cell Membrane/metabolism , Cell Polarity/drug effects , Cell Polarity/physiology , Eosine Yellowish-(YS)/pharmacology , Germination/drug effects , Germination/physiology , Hypogravity , Nifedipine/pharmacology , Plant Roots/drug effects , Plant Roots/growth & development , Plant Roots/metabolism , Pteridaceae/drug effects , Pteridaceae/growth & development , Space Flight
6.
J Exp Bot ; 55(397): 685-93, 2004 Mar.
Article in English | MEDLINE | ID: mdl-14754921

ABSTRACT

The homosporous fern Ceratopteris richardii exhibits a homorhizic root system where roots originate from the shoot system. These shoot-borne roots form lateral roots (LRs) that arise from the endodermis adjacent to the xylem poles, which is in contrast to flowering plants where LR formation arises from cell division in the pericycle. A detailed study of the fifth shoot-borne root showed that one lateral root mother cell (LRMC) develops in each two out of three successive merophytes. As a result, LRs emerge alternately in two ranks from opposite positions on a parent root. From LRMC initiation to LR emergence, three developmental stages were identified based on anatomical criteria. The addition of auxins (either indole-3-acetic acid or indole-3-butyric acid) to the growth media did not induce additional LR formation, but exogenous applications of both auxins inhibited parent root growth rate. Application of the polar auxin-transport inhibitor N-(1-naphthyl)phthalamic acid (NPA) also inhibited parent root growth without changing the LR initiation pattern. The results suggest that LR formation does not depend on root growth rate per se. The result that exogenous auxins do not promote LR formation in C. richardii is similar to reports for certain species of flowering plants, in which there is an acropetal LR population and the formation of the LRs is insensitive to the application of auxins. It also may indicate that different mechanisms control LR development in non-seed vascular plants compared with angiosperms, taking into consideration the long and independent evolutionary history of the two groups.


Subject(s)
Indoleacetic Acids/pharmacology , Pteridaceae/cytology , Flowers/drug effects , Flowers/growth & development , Plant Roots/cytology , Plant Roots/drug effects , Plant Roots/growth & development , Plant Shoots/drug effects , Plant Shoots/growth & development , Pteridaceae/drug effects , Pteridaceae/growth & development
7.
Plant Physiol ; 127(2): 497-504, 2001 Oct.
Article in English | MEDLINE | ID: mdl-11598224

ABSTRACT

In the fern Adiantum capillus-veneris, chloroplast movement is induced by mechanical stimulation as well as by light stimulation. Directional movement of both types depends on an actin-based motile system. To investigate the physiological relationship between mechanical and light signaling in the regulation of chloroplast movement, we examined the mechano-response of chloroplasts whose motility had been already restricted after photo-relocation. Chloroplast mechano-avoidance movement was induced under all of the photo-relocation conditions tested, indicating that mechano-specific signals generated by mechanical stimulation dominate over the light signals and reactivate the motility of chloroplasts. When the effects of external Ca(2+) on the induction of mechano- and light responses were examined, strikingly different requirements of external Ca(2+) were found for each. In medium without Ca(2+), the mechano-response was suppressed but no effects were observed on photo-response. Mechano-relocation movement of chloroplasts was inhibited by 100 microM lanthanum (La(3+)), a plasma membrane calcium channel blocker, and by 10 microM gadolinium (Gd(3+)), a stretch-activated channel blocker. However, the same concentrations of these drugs did not affect the photo-relocation movement at all. These results suggest that the influx of external Ca(2+) is crucial for the early signaling step of chloroplast mechano-relocation but not for that of photo-relocation. This is the first report showing the separation of signaling pathways in mechano- and photo-relocation of chloroplasts.


Subject(s)
Actins/metabolism , Calcium/pharmacology , Chloroplasts/physiology , Pteridaceae/cytology , Biomechanical Phenomena , Calcium/metabolism , Calcium Channel Blockers/pharmacology , Chloroplasts/drug effects , Chloroplasts/radiation effects , Cytoskeleton/drug effects , Cytoskeleton/physiology , Cytoskeleton/radiation effects , Gadolinium/pharmacology , Lanthanum/pharmacology , Light , Models, Biological , Movement/drug effects , Movement/radiation effects , Myosins/metabolism , Physical Stimulation , Pteridaceae/drug effects , Pteridaceae/metabolism , Pteridaceae/radiation effects , Signal Transduction
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