Effect of storage method on spore viability in five globally threatened fern species.
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Spore germination of five globally threatened fern species [Culcita macrocarpa C. Presl, Dryopteris aemula (Aiton) O. Kuntze, D. corleyi Fraser-Jenkins, D. guanchica Gibby and Jermy and Woodwardia radicans (L.) Sm.] was determined after 1, 6 or 12 months of storage in glass vials (dry storage) or on agar (wet storage) at -20, 5 or 20 degrees C. In all species, storage technique, storage temperature and the technique-temperature interaction all had a significant effect on germination percentage. In most cases, the germination percentage was best maintained by wet storage at 5 or 20 degrees C. In the case of the hygrophilous species C. macrocarpa and W. radicans, 6 or 12 months' dry storage killed most spores. Only Woodwardia radicans germinated in the dark during wet storage at 20 degrees C. Wet storage at 5 degrees C prevented dark germination, and reduced bacterial and fungal contamination. Wet storage at -20 degrees C killed all or most spores in all species. In the three Dryopteris species, the differences among the storage conditions tested were smaller than in C. macrocarpa and W. radicans, and the decline in spore viability during storage was less marked, with high germination percentages being observed after 12 months of dry storage at all three temperatures. Dry storage, which has lower preparation time and space requirements than wet storage, was generally more effective at the lower temperatures (-20 or 5 degrees C). (+info)
Antioxidant activity of two phloroglucinol derivatives from Dryopteris crassirhizoma.
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The rhizome of Dryopteris crassirhizoma NAKAI exhibited significant antioxidant activity, as assessed by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity in vitro. Two phloroglucinol derivatives, flavaspidic acids PB (1) and AB (2), were isolated from the rhizome of D. crassirhizoma by a bioassay-guided fractionation. 1H-, 13C-NMR, and UV analysis were used to determine the structures. Furthermore, the two compounds were tested for their antioxidant activities, such as their DPPH radical scavenging, superoxide radical scavenging, and lipid peroxidation (LPO) inhibitory activities. Compounds 1 and 2 exhibited potent antioxidant activity against the LPO inhibitory test with IC(50) values of 12.9 and 13.1 microM, respectively, compared with alpha-tocopherol (IC(50); 15.6 microM) and butylated hydroxy anisole (BHA, IC(50); 10.8 microM), while the two compounds had a moderated effect on the DPPH radical scavenging activity (IC(50); 71.7, 76.3 microM) as well as superoxide radical scavenging activity (IC(50); 58.6, 64.4 microM). The potent activity of the flavaspidic acids (1, 2) on inhibiting LPO might be due to possible stabilization as a result of chelating with iron. (+info)
Overwintering leaves of a forest-floor fern, Dryopteris crassirhizoma (Dryopteridaceae): a small contribution to the resource storage and photosynthetic carbon gain.
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BACKGROUND AND AIMS: Dryopteris crassirhizoma is a semi-evergreen fern growing on the floor of deciduous forests. The present study aimed to clarify the photosynthetic and storage functions of overwintering leaves in this species. METHODS: A 2-year experiment with defoliation and shading of overwintering leaves was conducted. Photosynthetic light response was measured in early spring (for overwintering leaves) and summer (for current-year leaves). KEY RESULTS: No nitrogen limitation of growth was detected in plants subjected to defoliation. The number of leaves, their size, reproductive activity (production of sori) and total leaf mass were not affected by the treatment. The defoliation of overwintering leaves significantly reduced the bulk density of rhizomes and the root weight. The carbohydrates consumed by the rhizomes were assumed to be translocated for leaf production. Photosynthetic products of overwintering leaves were estimated to be small. CONCLUSION: Overwintering leaves served very little as nutrient-storage and photosynthetic organs. They partly functioned as a carbon-storage organ but by contrast to previous studies, their physiological contribution to growth was found to be modest, probably because this species has a large rhizome system. The small contribution of overwintering leaves during the short-term period of this study may be explained by the significant storage ability of rhizomes in this long-living species. Other ecological functions of overwintering leaves, such as suppression of neighbouring plants in spring, are suggested. (+info)
Phenolic constituents from the rhizomes of Dryopteris crassirhizoma.
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A new phenolic glycoside, dryopteroside (1), was isolated from the rhizomes of Dryopteris crassirhizoma (Dryopteridaceae), together with five known compounds, 4beta-carboxymethyl-(-)-epicatechin (2), isobiflorin (3), biflorin (4), 1-beta-D-glucopyranosyloxy-3-methoxy-5-hydroxybenzene (5) and (+)-catechin-6-C-beta-D-glucopyranoside (6). The new compound was elucidated to be 1-butanoyl-3-C-beta-D-glucopyranosyl-5-methyl-phloroglucinyl-6-O-beta-D-glucopyra noside (1) by chemical and various spectroscopic analyses. The known compounds 2-6 were first reported from the genus Dryopteris. (+info)
Spore fitness components do not differ between diploid and allotetraploid species of Dryopteris (Dryopteridaceae).
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BACKGROUND AND AIMS: Although allopolyploidy is a prevalent speciation mechanism in plants, its adaptive consequences are poorly understood. In addition, the effects of allopolyploidy per se (i.e. hybridization and chromosome doubling) can be confounded with those of subsequent evolutionary divergence between allopolyploids and related diploids. This report assesses whether fern species with the same ploidy level or the same altitudinal distribution have similar germination responses to temperature. The effects of polyploidy on spore abortion and spore size are also investigated, since both traits may have adaptive consequences. METHODS: Three allotetraploid (Dryopteris corleyi, D. filix-mas and D. guanchica) and three related diploid taxa (D. aemula, D. affinis ssp. affinis and D. oreades) were studied. Spores were collected from 24 populations in northern Spain. Four spore traits were determined: abortion percentage, size, germination time and germination percentage. Six incubation temperatures were tested: 8, 15, 20, 25 and 32 degrees C, and alternating 8/15 degrees C. KEY RESULTS: Allotetraploids had bigger spores than diploid progenitors, whereas spore abortion percentages were generally similar. Germination times decreased with increasing temperatures in a wide range of temperatures (8-25 degrees C), although final germination percentages were similar among species irrespective of their ploidy level. Only at low temperature (8 degrees C) did two allotetraploid species reach higher germination percentages than diploid parents. Allotetraploids showed faster germination rates, which would probably give them a competitive advantage over diploid parents. Germination behaviour was not correlated with altitudinal distribution of species. CONCLUSIONS: The results of this study suggest that (i) relative fitness of allopolyploids at sporogenesis does not differ from that of diploid parents and (ii) neither does allopolyploidization involve a change in the success of spore germination. (+info)
Two new triterpenes from the Rhizome of Dryopteris crassirhizoma, and inhibitory activities of its constituents on human immunodeficiency virus-1 protease.
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Two new hopane type triterpenes, named dryopteric acids A (1) and B (2), were isolated from the Rhizome of Dryopteris crassirhizoma (Aspiadaceae) together with sixteen known compounds (3-18). Of isolated compounds, ursolic acid (15), and dryopteric acid A (1) and B (2) showed potent inhibitory activities against HIV-1 protease with IC50 values of 8.9-44.5 microM. In addition, acetylated compounds 1 and 2 appreciably increased inhibitory activities with their IC50 values of 1.7 and 10.8 microM, respectively. (+info)
Reproductive and competitive interactions among gametophytes of the allotetraploid fern Dryopteris corleyi and its two diploid parents.
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