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1.
Abstract

One‐year‐old slash pine seedlings (Pinus elliottii Engelm.) accumulated more radioactive phosphorus in needles at a 15–10°C day‐night temperature and 2500 foot candles than at higher temperatures and reduced light. Rate of phosphorus uptake was related to concentrations of ethanol‐soluble carbohydrates but not to those of starch or all carbohydrates. Results suggest that temperature and light can be important for optimum phosphorus nutrition of slash pine.  相似文献   

2.
Macrophomina phaseolina. the cause of damping-off and charcoal root rot disease on slash pine seedlings (Pinus elliottii Engelm var. elliottii), was antagonized by an unidentified basidiomycete species under laboratory and nursery conditions. Aseptically-grown slash pine seedlings died 3 days after inoculation with M. phaseolina, whereas seedlings inoculated with the basidiomycete sp., or basidiomycete sp. plus M. phaseolina, and uninoculated controls were alive after 6 months. In nursery studies, survival of slash pine seedlings in plots inoculated with M. phaseolina was significantly lower (57 per cent) than survival resulting from inoculations with the basidiomycete sp. (90 per cent), or basidiomycete sp. plus M. phaseolina (84 per cent), and the uninoculated controls (81 per cent). Electron microscopy showed that the basidiomycete sp. is a hyperparasite on mycelia of M. phaseolina. Preliminary evidence indicates that the hyperparasite is not host-specific but will infect other fungal pathogens. Two ectomycorrhizal fungi were not parasitized by the basidiomycete.  相似文献   

3.
Seasonal foliage and twig nitrogen (N) and phosphorus (P) dynamics were determined for 40‐year‐old pitch pine (Pinus rigida Mill.) and Japanese larch (Larix leptolepis Gord.) plantations established on similar soils in central Korea. Also, the effects of three levels of N plus P fertilizers on N and P retranslocation were evaluated. In general, Japanese larch had significantly higher current foliage N and P concentrations than pitch pine, and N and P concentrations were higher in foliage than those in twigs for both study species. Foliage N and P concentrations were highest in mid‐growing season and lowest in autumn whereas twig N and P concentrations increased during foliage senescence, suggesting that twig served as a storage tissue. We did not find differences in foliage N and P retranslocation between pitch pine and Japanese larch; current foliage N and P retranslocation of the control trees were 35% and 56% for pitch pine, and 39% and 59% for Japanese larch, respectively. There were no consistent patterns in foliage and twig N and P retranslocation following fertilization.  相似文献   

4.
Abstract

For Southeastern forest soils amounts of P, K, Ca, Mg, and Mn extracted by 0.05 N HCl + 0.025 N H2SO4 (double‐acid) were significantly correlated with amounts extracted by 0.2 N NH4Cl + 0.2 N HOAc + 0.015 N + NH4F + 0.012 N HCl (new‐Mehlich). The new‐Mehlich consistently removed more nutrients than the double acid.

Both P and Mn extracted by the two solutions were significantly correlated with their concentrations in the foliage of loblolly pine (Pinus taeda L.).  相似文献   

5.
In degraded land of South China, the shrub Rhodomyrtus tomentosa (Aiton) Hassk. grows in aggregations and creates “shrub islands” with increased soil porosity and soil moisture but reduced soil nutrient content and light penetration. Previous researches indicated that these shrub islands can facilitate establishment of broad‐leaved tree seedlings. Because conifers are commonly used in reforestation projects, we determined whether shrub islands created by R. tomentosa also facilitate coniferous seedlings. Two common conifers, the native Pinus massoniana and the exotic Pinus elliottii, were transplanted on shrub islands and in open spaces (controls) between islands, and their growth, chlorophyll fluorescence, and chloroplast ultrastructure were investigated. Neither of the pine species was facilitated by the shrub islands. P. elliottii grew obviously higher in the open than under the R. tomentosa canopy, while P. massoniana was not facilitated by shrub islands, but it was not hindered either. The reduced growth of P. elliottii on shrub islands was associated with dilation of thylakoids in chloroplasts of mesophyll cells, lowered chlorophyll content, and reduced electron transport rate values. The results of this study indicate that P. elliottii should be transplanted in open spaces, and P. massoniana can be transplanted in open spaces or on shrub islands as part of restoration efforts, and the restoration technology of shrub island should be carefully used in degraded land of South China according to the species identity. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

6.
Microbial biomass C and N, and activities related to C and N cycles, were compared in needle and leaf litter, and in the uppermost 10 cm of soil under the litter layer in Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies L.) and silver birch (Betula pendula L.) stands, planted on originally similar field afforestation sites 23–24 years ago. The ground vegetation was differentiated under different tree species, consisting of grasses and herbs under birch and pine, and mosses or no vegetation with a thick layer of needles under spruce. The C:N ratio of the soils was 13–21 and the soil pHCaCl 2 3.8–5.2. Both showed little variation under different tree species. Microbial biomass C and N, C mineralization, net ammonification, reduction) did not differ significantly in soil under different tree species either. Birch leaf litter had a higher pHCaCl 2 (5.9) than spruce and pine needle litter (pH 5.0 and 4.8, respectively). The C:N ratio of spruce needles was 30, and was considerably higher in pine needles (69) and birch leaves (54). Birch leaves tended to have the highest microbial biomass C and C mineralization. Spruce needles appeared to have the highest microbial biomass N and net formation of mineral N, whereas formation of mineral N in pine needles and birch leaves was negligible. Microbial biomass C and N were of the same order of magnitude in the soil and litter samples but C mineralization was tenfold higher in the litter samples.  相似文献   

7.
The 15N natural abundance in Pinus densiflora Sieb. et Zucco that had been inoculated and not inoculated with ectomycorrhizal fungi (Suillus granulatus (L.:Fr.) O. Kuntze) was compared. The inoculated pine needles showed a lower δ15N value, while the uninoculated ones showed a higher δ15N value. Higher δ15N values in the mycelial mat of the ectomycorrhizal fungi compared to those of the inoculated pine needles were also observed. These facts indicate that nitrogen isotope fractionation occurred during the nitrogen transport from mycorrhizal fungi to the host plants.  相似文献   

8.
Phosphorus (P) is a major plant nutrient, however, its availability in volcanic ash soils is presumed to be small, due to its specific sorption on short‐range order minerals. We analyzed distinct P fractions in volcanic ash soils of different age (60 to > 100,000 y BP) under pine forests in Central Mexico to investigate their changes along a chronosequence of Regosols, Andosols, and Lixisols, and to evaluate if P availability limits tree growth at any particular stage. Top soil and subsoil samples were first analyzed by the Tiessen and Moir method, which failed to extract exhaustively “organic” and “occluded P”, and “P associated with apatite”. Therefore, we modified the fractionation scheme by including a “recalcitrant organic P” fraction obtained from the difference between P determined in air‐dried subsamples and subsamples burned at 300°C; P adsorbed to short‐range order minerals was assessed in an extraction with NH4‐oxalate, and P in primary minerals by subtracting the sum of all other fractions from total P contents determined by XRF. This we did after discovering that primary P occurred in the form of fluorapatite included in plagioclase, volcanic glass or olivine. We also measured P contents in pine needles and related these with the “mobile soil P” fractions. The results show that “organic P” reaches maximum contents in 10,000‐y old soil, as does P associated with short‐range order minerals, while P occluded into crystalline oxides increases constantly over time. After 100,000 y, 31% of total P still remains in the form of primary P in A horizons. “Mobile P” was constant > 40 mg kg?1 in Regosols and Andosols and related positively with foliar P contents, which were within adequate nutritional ranges. Only in Lixisols small “mobile P” concentrations in soil correspond with inadequate P contents in pine needles.  相似文献   

9.
Abstract

Nutrient analysis of roots recovered by wet sieving may be biased by leaching which occurs during sampling. The objective of this experiment was to determine the potential for leaching of potassium (K) and phosphorus (P) from roots of slash pine (Pinus elliottii Engelm. var elliottii) and Panicum aciculare grass seedlings. Roots of both species were sampled by wet and dry methods. The wet method included soaking for 15 d in deionizd water. All samples were dried prior to measuring their contents of sand, K and P. The amount of sand retained by both types of roots was reduced by wet treatment. Concentrations of K and P in both species also were significantly lower for wet‐treated roots than for dry roots. Multipliers for converting concentrations in wet‐treated roots to concentrations in dry roots were, for pine; 5.4 and 1.2 for K and P, respectively, and for grass 5.9 and 3.1 for K and P, respectively. However, these factors may be inappropriate for roots that had less exposure to water, or to roots of different anatomy and nutrient concentrations.  相似文献   

10.
Microbial biomass C and N, and activities related to C and N cycles, were compared in needle and leaf litter, and in the uppermost 10 cm of soil under the litter layer in Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies L.) and silver birch (Betula pendula L.) stands, planted on originally similar field afforestation sites 23–24 years ago. The ground vegetation was differentiated under different tree species, consisting of grasses and herbs under birch and pine, and mosses or no vegetation with a thick layer of needles under spruce. The C:N ratio of the soils was 13–21 and the soil pHCaCl 2 3.8–5.2. Both showed little variation under different tree species. Microbial biomass C and N, C mineralization, net ammonification, reduction) did not differ significantly in soil under different tree species either. Birch leaf litter had a higher pHCaCl 2 (5.9) than spruce and pine needle litter (pH 5.0 and 4.8, respectively). The C:N ratio of spruce needles was 30, and was considerably higher in pine needles (69) and birch leaves (54). Birch leaves tended to have the highest microbial biomass C and C mineralization. Spruce needles appeared to have the highest microbial biomass N and net formation of mineral N, whereas formation of mineral N in pine needles and birch leaves was negligible. Microbial biomass C and N were of the same order of magnitude in the soil and litter samples but C mineralization was tenfold higher in the litter samples.  相似文献   

11.
Thirty eight accessions of brown mustard (Brassica juncea (L.) Czern. and Coss.) were screened after two weeks growth in solution culture containing 120 mol m‐3 NaCl. Considerable variation for salt tolerance was observed in this set of germplasm, since some accessions showed relatively vigorous growth in saline medium.

In order to determine the consistency of degree of salt tolerance at different growth stages of crop life cycle two salt tolerant accessions, P‐15 and KS‐51 and two salt sensitive 85362 and 85605 were tested at the adult stage in 0(control), 100 and 200 mol m‐3 NaCl. Both the tolerant accessions produced significantly greater fresh and dry biomass and had considerably higher seed yield than those of the salt sensitive accessions. Analysis of different ions in the leaves showed that salt tolerant accessions contained greater amounts of Na+, K+ and Ca2+ than the salt sensitive accessions, although they did not differ significantly for leaf Cl‐. Only one salt tolerant accession P‐15 had greater leaf K/Na ratio and K+ versus Na+ selectivity compared with the tolerant KS‐51 and the two salt sensitive accessions.

From this study it was established that there is a considerable variation for salt tolerance in B.juncea which can be exploited by selection and breeding for improvement of its salt tolerance. Since the degree of salt tolerance in B.juncea does not change at different growth stages of the crop life cycle, selection for salt tolerance at the initial growth stages could provide individuals that would be tolerant at all other growth stages. Accumulation of Na+, K+ and Ca2+ in the leaves are important components of salt tolerance in B.juncea.  相似文献   

12.
Mining activities leave large areas of post‐mining lands to be reclaimed. Increases in soil C and N pools and N availability are important to successfully reestablish trees on post‐mining land. In this study, we determined C and N concentrations and natural stable isotope of 13C and 15N in soil and plant in Mongolian pine (Pinus sylvestris L. var. mongolica Litv.) plantations 8 years after establishment on non‐mined land (NM), post‐mining land without soil amendment (NAM), and post‐mining land with soil amendment (AM) in a placer gold mining region of Northeast China. We found that the growth of Mongolian pine was significantly slower on NAM as compared with NM (decreasing by 73% in tree height and 63% in basal diameter), but tree growth improved on AM. Soil C and N concentrations, plant N concentration, and soil δ15N value decreased in the order of NM > AM > NAM, implying that soil N availability decreased in post‐mining land, but soil amendment could increase soil N availability. However, the values of δ15N in plant tissues of Mongolian pine were higher on NAM than on NM and AM, suggesting that soil inorganic N form absorbed by trees might be changed when trees were directly planted on post‐mining land with lower soil N availability. In addition, the values of δ13C in 1‐ and 2‐year‐old leaves of Mongolian pine were lowest when planted on NAM, indicating a decrease in intrinsic water‐use efficiency of Mongolian pine. Our results suggest that soil amendment helps us establish forests successfully on post‐mining lands. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

13.
The concentration of fluoride in needles, its effects on tree defoliation and on decomposition of needles (litter), and its subsequent accumulation in the upper soil horizons were observed in pine plantations near and far from a new aluminum smelter. Pinus taeda and Pinus palustris stands within 0.8 km of the smelter had significantly higher levels of foliar F than a P. taeda stand 1.8 km from the source. Neither temporal patterns nor amounts of needlefall were altered by airborne F from the smelter. In addition, elevated levels of foliar F did not affect the rate of decomposition of pine needles over a period of 6 mo. Soluble F in soil samples increased significantly in the upper 10 cm of the soils at the sites nearest the F source over a period of 7 yr since the start of F emissions.  相似文献   

14.
Abstract

Concentrations of N, P, K, Ca, Mg, and Mn were determined in one‐, two‐, and five‐year‐old needles from upper and lower crowns of declining and healthy red spruce (Picea rubens Sarg.) to assess nutritional deficiencies as causes of severe defoliation in upper‐elevation forests in western Massachusetts. Concentrations of N and K did not differ between stands or positions in crowns but decreased with leaf age. In declining stands, mean Ca concentrations were the same in the upper and lower crowns (3.2 mg g‐1), whereas in healthy stands, Ca was higher in the lower crown (4.8 mg g‐1) than in the upper crown (3.9 mg g‐1). Five‐year‐old needles of healthy trees had higher Ca than those of declining trees (6.0 and 3.8 mg g‐1, respectively). Mean concentrations of P and Mg in declining trees were 0.9 and 0.5 mg g‐1, respectively, with each element being at threshold levels of sufficiency. Mean concentrations of P and Mg, respectively, were 0.3 mg g‐1 and 0.2 mg g‐1 lower in needles of declining trees than in healthy trees. Five‐year‐old needles of declining trees were lower in P and Mg than those from healthy trees. Mean Mn concentrations were lower in needles of declining trees than in healthy trees (0.4 vs 1.3 mg g‐1). The results suggest that low P, Mg, and possibly Ca concentrations in needles of declining trees may contribute to the decline.  相似文献   

15.
Elevated emissions of nitrogen oxides (NOx) in the Athabasca Oil Sands Region, Alberta and higher foliar nitrogen (N) concentrations in jack pine (Pinus banksiana) needles close to major emission sources has led to concerns that the surrounding boreal forest may become N-saturated. Despite these concerns, N deposition and impacts on upland forests in the region is poorly quantified. The objective of this study was to characterize N cycling in five plots representing the two dominant upland forest types (jack pine and trembling aspen, Populus tremuloides) close (<30 km) to the largest mining operations in the region, during a 2-year period. Despite the high level of NOx emissions, bulk throughfall and deposition measured at both study sites were surprisingly very low (<2 kg N ha−1 year−1). Internal N cycling was much greater in aspen stands; annual N input in litterfall was ten times greater, and net N mineralization rates were two to five times greater than in jack pine stands. Nitrogen use efficiency (NUE) was much greater in jack pine when calculated based on N litterfall indices, but not when N pools in biomass were considered. Despite differences in internal cycling among forest types, nitrate leaching from mineral soil in both forest types was negligible (<0.1 kg N ha−1 year−1) and patterns of 15N in roots, foliage, and mineral soil were typical of N-limited ecosystems, and both sites show no evidence of N saturation.  相似文献   

16.
The objective of the investigation was to determine the effectsof sewage sludge application on nutrient concentrations in soil and plant biomass fractions in Scots pine forests (Pinus sylvestris, L.), situated on sandy soils with low pH, in a south to north temperature gradient in Sweden. Twenty tons dw ha-1 of sewage sludge was applied in 50 to 60 yr old pine forests at foursites from Brösarp in South Sweden to Jukkasjärvi in thenorthern parts of the country.Application of 20 ton dw ha-1 of sewage sludge significantlyincreased the concentrations of extractable N, P, K, Ca, Mg and Na, in both the mor layer and in the upper 10 cm of the mineral soil. Three years after sludge application K concentrations were only significantly increased in the upper 10 cm of the mineral soil. After 11 yr the concentrations of P were still at the samelevel in the mor layer as after three years. The concentrations of Ca, Mg and Na had slightly decreased only in the mor layer. There was, in most cases, a statistically significant positive correlation between the amount of applied sludge and nutrientconcentrations in the soil, as well as in pine needles and in leaves of Vaccinium vitis-idaea.In all sites, Mg concentrations in the mor layer was positivelyand significantly correlated with Mg concentrations in current-year pine needles. Similarly, concentrations of Ca, Mg,and P in the mor layer were correlated with concentrations of these elements in current-year shorts of Vaccinium vitis-idaea.  相似文献   

17.
This study investigated the genotypic variation in foliar nutrient concentrations, isotopic signature (δ13C), and chlorophyll fluorescence (Fv/Fm) and tree growth of 40 radiata pine clones grown on a New Zealand serpentine soil, and the relationships between growth and physiological traits of these clones from improved and unimproved groups. Genotypic variation in growth and physiological traits existed within (i.e., clonal) and between groups, with larger variation among clones. The clonal repeatabilities were greater for foliar nitrogen (N), calcium (Ca), magnesium (Mg), boron (B) concentrations, δ13C, and Ca : Mg ratio (0.35–0.64) than for growth traits (0.14–0.27) and other physiological traits (0.08–0.24). Significant phenotypic correlations were found between growth traits and foliar phosphorus (P), potassium (K), sulfur (S), iron (Fe), and K : Mg and Ca : Mg ratios and Fv/Fm (positive), and foliar Mg (negative). This study indicates that the trees on this serpentine soil generally suffered from multiple nutrient deficiencies and imbalances and the clonal variation in growth performance was more related to their capabilities of acclimation to nutrient than water stresses. Overall, the clones that absorbed more P, K, S, and Fe and less Mg from the soil grew better on this serpentine soil. For unimproved clones, the most limiting nutrients for tree growth were foliar K and Fe, while for improved clones it was foliar K.  相似文献   

18.
Temporal changes in the Hg content of balsam fir needles (Abies balsamea) and white spruce needles (Picea glauca) were monitored at a control site over two growing seasons. Results indicated a significant increase in the Hg content of needles of both species over the course of a growing season and from one year to the next. The Hg content of new foliage more than doubled within each growing season, and was 5–10 ng g?1 higher in the 1990 growing season than in the previous year. These results indicate that temporal variation is a potential source of error when mapping the spatial variation of Hg concentrations in vegetation. To minimize this source of error, field surveys should be completed as quickly as possible (i.e., within two or three weeks).  相似文献   

19.
Summary Microbial biomass in the upper 7 cm of soil and needle decomposition on the forest floor were measured seasonally for 10 months in a mountain hemlock (Tsuga mertensiana) old-growth forest and in a regrowth forest after Phellinus weirii, a root-rot pathogen infection, had caused disturbance. The microbial biomass was higher in the old-growth forest soil than in the regrowth forest soil. However, T. mertensiana needle decomposition rates were higher in the regrowth than in the old-growth forest. Total N, Ca, Fe, Cu, and Zn concentrations in needles increased during the 1st year of decomposition in both the old and the regrowth forests, but P, K, Mg, Mn, and B concentrations decreased. N, P, K, Mg, Cu, and Zn concentrations were lower in regrowth than in old-growth decomposing needles. During mineralization, needles in the regrowth forests released more N, P, and K as a result of higher needle decomposition rates. Our results suggest that higher needle decomposition rates increased the mineralization of N, P, and K, which may lead to increased soil fertility and faster tree growth rates in the regrowth forest.  相似文献   

20.
Abstract

Red pine (Pinus resinosa Ait.) seedlings were grown for 15 weeks over a range of nutrient regimes to calibrate a test procedure used for monitoring nutrient status of a common container growing medium. The test was based on a saturated aqueous extract of the growing medium, obtained by suction displacement. Seedling growth and nutrition exhibited typical responses of deficiency, sufficiency, luxury consumption and toxicity over the range of substrate fertility examined. Water extractable nutrients of the growing medium were related to yield and nutrient uptake of the seedlings. Ranges of nutrient levels associated with maximum dry matter production were selected as provisional values for optimum growth of containerized red pine seedlings. The following critical nutrient levels were considered optimum for red pine seedlings managed under similar cultural conditions: 15–65 ppm N (as NH4 +), 35–95 ppm P, 25–115 ppm K, 30–60 ppm Ca, 15–35 ppm Mg, and electrical conductivity of 1.0–2.2 dS/m.  相似文献   

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