Intraspecific variations in seedling emergence and survival of Potentilla matsumurae (Rosaceae) between alpine fellfield and snowbed habitats.
(1/21)
Potentilla matsumurae has a wide distribution from wind-blown fellfields to snowbeds in alpine regions of Japan. The environmental factors influencing seedling establishment differ between the fellfield and snowbed habitats; plants growing in each habitat may therefore have different germination strategies. Using a reciprocal sowing experiment, patterns of seedling emergence and survivorship were examined in both habitat types in the Taisetsu Mountains, Japan. Seeds derived from a fellfield population germinated earlier than did those derived from a snowbed population at both habitats, and the germination of fellfield seeds continued throughout the growing season. The timing of seedling emergence greatly affected subsequent survival at the fellfield. Seedlings that emerged in the first half of the growing season had low survivorship during the first year because of frost and drought damage, but the remaining seedlings had high survivorship during the winter; seedlings that emerged in the latter half of the growing season showed the opposite trend. At the snowbed, seedling survival was high throughout the growing season. Germination experiments in the laboratory highlighted a difference in the sensitivity of seeds from the fellfield and snowbed populations to fluctuating temperatures. These results indicate that intraspecific variation in emergence and survivorship may occur over a small scale in an alpine environment. (+info)
The effects of mechanical stress and spectral shading on the growth and allocation of ten genotypes of a stoloniferous plant.
(2/21)
BACKGROUND AND AIMS: Because plants protect each other from wind, stand density affects both the light climate and the amount of mechanical stress experienced by plants. But the potential interactive effects of mechanical stress and canopy shading on plant growth have rarely been investigated and never in stoloniferous plants which, due to their creeping growth form, can be expected to respond differently to these factors than erect plants. METHODS: Plants of ten genotypes of the stoloniferous species Potentilla reptans were subjected to two levels of mechanical stress (0 or 40 daily flexures) and two levels of spectral shading (15 % of daylight with a red:far red ratio of 0.3 vs. 50 % daylight and a red:far red ratio of 1.2). KEY RESULTS: Mechanically stressed plants produced more leaves with shorter more flexible petioles, more roots, and more but less massive stolons. Responses to spectral shading were mostly in the opposite direction to thigmomorphogenesis, including the production of thinner, taller petioles made of more rigid tissue. The degree of thigmomorphogenesis was either independent of light climate or stimulated by spectral shading. At the genotypic level there were no clear correlations between responses to shade and mechanical stress. CONCLUSIONS: These results suggest that in stoloniferous plants mechanical stress results in clones with a more compact, shorter shoot structure and more roots. This response does not appear to be suppressed by canopy shading, which suggests that wind shielding (reduced mechanical stress) by neighbours in dense vegetation serves as a cue that induces shade avoidance responses such as increased petiole elongation. (+info)
Simultaneous determination of seven flavonoids in Potentilla multifida by HPLC.
(3/21)
A reversed-phase high-performance liquid chromatographic method is described for the simultaneous determination of seven flavonoids in Potentilla multifida: hyperin, quercetin-3-O-beta-D-glucopyranoside, luteolin-7-O-beta-D-glucuronide, apigenin-7-O-beta-D-glucuronide, quercetin, tribuloside, and apigenin. The method involves the use of a Hypersil octadecylsilyl silica (ODS) analytical column (125A, 5 microm, 4.6 x 250 mm) at 25 degrees C with the mixture of acetonitrile and aqueous H(3)PO(4) as the mobile phase and detection at 254 nm. The recovery of the method is 95.4-104.8%, and linearity (r > 0.9998) is obtained for all the flavonoids. The results indicate that the flavonoid content of P. multifida varied significantly from locality to locality. (+info)
Methane emissions by alpine plant communities in the Qinghai-Tibet Plateau.
(4/21)
Leaf investment and light partitioning among leaves of different genotypes of the clonal plant Potentilla reptans in a dense stand after 5 years of competition.
(5/21)
Range shifts of Potentilla fruticosa on the Qinghai-Tibetan Plateau during glacial and interglacial periods revealed by chloroplast DNA sequence variation.
(7/21)