In evergreen azaleas, major anthocyanins were detected from petals of wild species and cultivars by HPLC analysis. Depending on flower color, all samples were divided into three groups: red, purple or white, using the Japan color standard for horticultural plants. The chromatic components a* and b* values of red group samples showed a convergent distribution, whereas those of purple group samples showed a wider distribution. According to the HPLC analysis, red group samples had two to four major anthocyanins, and those of the purple group had two to six major ones. In contrast, no anthocyanins were detected in the white group petals, although anthocyanidins were detected. These results suggest that the anthocyanin constitution of the purple group flowers is more varied than that of the red group flowers, and this wider variety among purple flowers contributes to extending the diversity of flower color in evergreen azalea. 相似文献
Abstract Rooted cuttings of Rhododendron canescens “Brook” and Rhododendron austrinum were grown in sand culture with a modified Hoagland's solution under greenhouse conditions. The effect of varying ammonium:nitrate (NO3?:NH4+) ratios (100:0, 75:25, 50:50, 25:75, 0:100) on growth, chlorophyll content, plant quality, and elemental tissue concentration were determined. With NO3? as the nitrogen (N) form, both azalea cultivars exhibited less vegetative growth, lower overall plant quality, with leaves showing visual chlorotic symptoms in comparison to plants receiving NH4+ as the N‐form. Leachate pH was highest with NO3? as the predominate N‐form and decreased significantly with each increment of NH4+. With both azalea cultivars, N‐form significantly influenced uptake and utilization of essential plant nutrients. Leaf concentrations of N, potassium (K), calcium (Ca), sulfur (S), boron (B), and molybdenum (Mo) were highest with NO3?‐N. Leaf elemental concentrations of phosphorous (P), magnesium (Mg), copper (Cu), iron (Fe), manganese (Mn), and zinc (Zn) increased as NH4+ supplied more of the N‐ratio. Significant differences in Mg, Mn, and Zn were observed between species. Results from this study show that foliar N concentration is not an accurate indicator of plant growth response. Further investigations are needed to determine if foliarchlorosis and low growth rates observed with NO3? fed plants due to an Fe deficiency, to low nitrate reductase (NR) activity in the leaves, or to a combination of these factors. 相似文献
Atmospheric deposition of N and S appears to have caused nutrient imbalance in Norway spruce stands in southern Sweden. This calls for a change of forest management to procedures that promote nutrient balance. Studies have shown lower soil acidity in Norway spruce/deciduous mixed stands than in spruce monocultures, but the tree nutrient status in such mixtures has not been much investigated so far.
The nutrient status of Norway spruce foliage and top mineral soil chemistry in monocultures and in stands mixed with beech, birch, or oak was investigated through paired comparisons on 30 sites in southern Sweden (27 sites) and eastern Denmark (three sites). In total, 45 mixed stands and 34 pure stands were included in the study.
Spruce needles from mixed stands had higher concentrations and ratios to N of K, P, and Zn than needles from pure spruce stands. Among the mixed stands, the K status appeared to be positively correlated with the percentage of deciduous tree basal area. Soil samples from mixed stands had a higher Mg concentration, base saturation, and BC/Al ratio than soil samples from pure stands. The spruce needle nutrient status was comparable in pure stands on fertile sites and in mixed stands on poor sites. We did not detect any differences in spruce tree growth between pure and mixed stands.
This paper discusses possible reasons for a positive effect on the tree nutrient status in mixed-species stands and the possibility of using mixed-species stands as a forest management procedure to avoid nutrient imbalance. 相似文献
We compared patterns of acorn dispersal and predation by wood mice among four tree species (Quercus serrata, Quercus crispula, Castanea crenata, and Juglans mandshurica var. sieboldiana) that are abundant in cool temperate woodlands. We devised an acorn dispersal experiment using 400 magnet-inserted acorns and a magnetic locator in a 1.8-ha study plot, which spanned a cut-over area and an adjacent deciduous forest. Ten wire mesh baskets, each containing 40 acorns (10 acorns per species), were placed on the border between these two habitat types. About 13.0% (n = 52) of the total acorns remained in the baskets, while 77.3% (n = 309) were dispersed throughout the study plot and subsequently retrieved using the magnetic locator. Microhabitat, distance, and burial depth of transported acorns were significantly different among species. In the cut-over area, J. mandshurica var. sieboldiana acorns were dispersed under fallen trees or branches and near stumps, and were buried deeply in the soil. Dispersal distances of J. mandshurica var. sieboldiana acorns were significantly greater than those of Q. serrata acorns. The number and microhabitat of transported acorns significantly differed between habitat types. J. mandshurica var. sieboldiana acorns were dispersed in the cut-over area rather than in the forest. For all four species, the numbers of acorns delivered to fallen trees or branches, stumps, and crumbled soil with overhang under any vegetation type were greater in the cut-over area than in the forest. 相似文献