Ozone Sensitivity Differences in Five Tomato Cultivars: Visible Injury and Effects on Biomass and Fruits

A complete record derived from the core from the Daihai Lake in a remote area provides new insights into the changing atmospheric heavy metal deposition associated with historical industrial activities, the Asian monsoon, long-range transport, and the chemical composition of matter derived from weathering of catchment. The fluctuation of lithogenic element concentration in the lake sediments can readily be explained by a particle sorting effect induced by the Asian monsoon. The variation of atmospheric deposition of Cu and Pb shows a similar profile in the lower part of the core sediments, and coincides with environmental change, with high atmospheric deposition coupled with wet, temperate period; while low deposition with dry, cold period, indicating a transport variation of heavy metal pollutants entrained by the Asian summer monsoon. From the beginning of nineteenth century, the atmospheric deposition of Cu and Pb decreased and then slowly increased. This may be associated with the destroyed industry induced by long-term wars in China and the less heavy metal pollutants relative to the weak Asian summer monsoon in this period. Comparison between atmospheric-derived metal and sediment trap metal using Ga as the reference element shows that atmospheric Cu and Pb budgets do not exceed the fluvially-induced Cu and Pb budgets in the indirectly disturbed area. On average, there have been approximately 5.4 mg m^?2 yr^?1 of Cu and 5.1 mg m^?2 yr^?1 of Pb atmospherically deposited in the region.     

Smart spatial incentives for market-based conservation

Market-based instruments such as payments, auctions or tradable permits have been proposed as flexible and cost-effective instruments for biodiversity conservation on private lands. Trading the service of conservation requires one to define a metric that determines the extent to which a conserved site adds to the regional conservation objective. Yet, while markets for conservation are widely discussed and increasingly applied, little research has been conducted on explicitly accounting for spatial ecological processes in the trading. In this paper, we use a coupled ecological-economic simulation model to examine how spatial connectivity may be considered in the financial incentives created by a market-based conservation scheme. Land use decisions, driven by changing conservation costs and the conservation market, are simulated by an agent-based model of land users. On top of that, a metapopulation model evaluates the conservational success of the market. We find that optimal spatial incentives for agents correlate with species characteristics such as the dispersal distance, but they also depend on the spatio-temporal distribution of conservation costs. We conclude that a combined analysis of ecological and socio-economic conditions should be applied when designing market instruments to protect biodiversity.     

Soil organic‐matter stocks and characteristics along an Alpine elevation gradient

Mountain regions are known to be especially vulnerable to climatic changes; however, information on the climate sensitivity of alpine ecosystems is still scarce to date. In this study, we investigate the impacts of climate and vegetation composition on soil organic‐matter (SOM) stocks and characteristics along an elevation gradient (900 to 1900 m asl) in the Austrian Limestone Alps. The soils classified as Leptic Histosols, i.e., organic soils directly overlying the calcareous bedrock. Soil organic‐carbon stocks (SOC; mean ± standard deviation) to bedrock increased in the low‐elevation forest sites from 19 ± 3 kg m^–2 (900 m asl) to 31 ± 3 kg m^–2 (1300 m asl), reached a maximum (38 ± 5 kg m^–2) in the shrubland at 1500 m asl, but decreased again in the high‐elevation grassland sites (26 ± 3 kg m^–2 at 1700 m asl and 13 ± 3 kg m^–2 at 1900 m asl). Thermogravimetic measurements and Fourier‐transform infrared spectroscopy (FTIR) suggest that the upper soil layers were dominated by more labile organic compounds, whereas more persistent materials increased with depth. Along the studied climosequence, the aliphatic FTIR band (2920 cm^–1) was lower in the low‐elevation forest sites compared to the high‐elevation grassland sites. Most other FTIR bands did not change with altitude, but were related to specific site conditions, such as vegetation composition and associated differences in soil pH. Our results demonstrate that differences in SOM stocks and characteristics are not consistently related to variations in climatic conditions along the studied elevation gradient, but are strongly affected by the vegetation composition, their C input and litter quality. This, in turn, is expected to shift in response to climate change.     

Review: Denitrification in temperate climate riparian zones

Excess nitrate (NO3-) in lakes and streams has deleterious effects for environmental and human health. Nitrate concentrations have become problematic in agricultural watersheds due to increased use of fertilizers and improper management of livestock wastes. Research has indicated that the planting and/or preservation of riparian buffer zones can be an effective means of reducing pollution from agricultural fields (Osborne and Kovacic, 1993; Jordan et al., 1992; Simmons et al., 1992). Biological denitrification is the most desirable means of nitrate attenuation as the microbial conversion of NO3- removes nitrate from the watershed in the form of N gases. Despite the inherent value of biological denitrification, a comprehensive review discussing the role of this process in removing nitrate from riparian zones is lacking. In this paper we examine the results and conclusions of past research on the topic of denitrification in riparian zones and make recommendations for future research in this area. The need for subsurface denitrification assays in riparian zones is emphasized.     

Nitrogen fixation by red clover as related to the supply of Cobalt and Molybdenum from some Norwegian soils

A field trial, a pot experiment and a survey of organically farmed leys were undertaken to investigate whether N fixation in red clover pastures in Norway was limited by a low supply of cobalt and/or molybdenum. Fertilization with Mo did not result in any higher production or N fixation, whereas the N yield both from established clover leys and red clover grown in pots increased slightly after application of Co to many of the investigated soils. In the organically farmed leys there was a significant and positive correlation between Co content and the N content of the red clover. As many of the investigated clover-soil systems were of those previously known to be very low in Co and Mo, and the gain in N yield obtained by extra Co supply was marginal, it is unlikely that deficiency of these trace elements is a problem of great concern in legume based forage production systems in Norway.     

Tomato response to long‐term potassium and lime application on a sandy ultisol high in non‐exchangeable potassium

In a ten‐year study of potassium (K) and lime application to a Kalmia sandy loam (fine‐loamy, siliceous, thermic Typic Hapludult), a soil high in nonexchangeable K, corn (Zea mays L.) and soybean [Glycine max (L.) Herr.] have not responded to applied K. The objectives of this study were to determine if a high K‐requiring crop such as tomato (Lycocersicon esculentum Mill. cv. Redpak) would respond to KCl fertilizer rate or lime type (dolomitic, calcitic, and mixed) and rate on such a soil. Potassium was applied at 0, 56, and 112 kg K/ha every year for ten years. Lime was applied at 0, 2, and 9 Mg/ha in calcitic, mixed, and dolomitic forms twice in ten years (1970 and 1973). In 1980, the tenth year of the study, tomato fruit was harvested by hand once‐over to simulate machine harvest and divided into four maturity groups by color. Soil pH was higher with dolomitic than calcitic lime. Soil K saturation was not influenced by lime rate or type. Fruit yield and leaf phosphorus (P), calcium (Ca), and magnesium (Mg) concentrations increased with increasing lime rates. Leaf K, manganese (Mn), iron (Fe), boron (B), copper (Cu), zinc (Zn), barium (Ba), strontium (Sr), and aluminum (Al) concentrations decreased with increasing lime rate. Leaf Mn, Ba, and Sr concentrations were lower with dolomitic than with calcitic lime. Lime type had no effect on tomato yield. Wide ranges in basic cation saturation ratios had little effect on yield. Soil K saturation and leaf K, Zn, and Ba concentrations increased with increasing K rate. Soil Ca and leaf Ca, Mg, and Al concentrations decreased with increasing K rate. Applied K had no effect on total yield but onceover marketable yield increased linearly with increasing K rate. Marketable yield increased 14% with an increase in K rate from 0 to 56 kg/ha. Thus, fruit maturity was apparently hastened by K fertilization.     

Metabolomic responses in grain,ear, and straw of winter wheat under increasing sulfur treatment

Only little is known about the effect of a varying sulfur (S) nutrition on the pattern of metabolites in different organs of the ears of winter wheat (Tritcum aestivum L.) at final maturity. More insights into the metabolome as influenced by increasing S‐fertilizer rates would, however, be of particular interest in order to unravel S‐dependent physiological processes related to grain filling in wheat. We have therefore investigated the effects of varying sulfur nutrition on metabolite composition and distribution in the organs of the wheat ear and vegetative organs at final maturity. Gas chromatography–mass spectrometry–based metabolite profiles revealed that S deficiency decreased the bulk of metabolites in the straw in favor of an increasing metabolite concentration in the husk, rachis, and grains. Surprisingly, only four out of 109 detectable metabolites, namely N‐acetyl glucosamine, lysine, ferulic acid, and β‐aminoisobutyric acid were most responsible for organ‐specific differences in the metabolite profiles. Under S‐deficient conditions, N‐acetyl‐glucosamine, lysine, and β‐aminoisobutyric were increasingly transferred from source tissues into the ears and grains.     

Bioavailability and efficacy of vitamin D2 from UV-irradiated yeast in growing, vitamin D-deficient rats

New food sources are needed to bridge the gap between vitamin D intake and recommended intake. We assessed the bioavailability and efficacy of vitamin D in an 8 week dose-response study of bread made with vitamin D2-rich yeast compared to vitamin D3 in growing, vitamin D-deficient rats. Plasma 25-hydroxyvitamin D (25OHD) levels increased in a curvilinear, dose-dependent manner with both forms of vitamin D, but rats fed vitamin D2-rich yeast achieved lower levels than rats fed vitamin D3. Rats fed the highest doses of vitamin D had significantly greater (p<0.05) trabecular BMC, BMD, bone volume, and connectivity density, and greater midshaft total cross-sectional area, compared to rats on the vitamin D-deficient diets, with no significant difference due to vitamin D source. Vitamin D2-rich yeast baked into bread is bioavailable and improves bone quality in vitamin D-deficient animals.     

Trade-offs in the design of cost-effective habitat networks when conservation costs are variable in space and time

The consideration of economic costs can dramatically influence the cost-effective allocation of resources spent on the conservation of biodiversity. In the face of ecological and economic data scarcity, simple rules are needed for the design of cost-effective habitat networks. A conceptual semi-analytical ecological-economic model is developed that is based on metapopulation theory and takes into account that the costs of conservation may be spatially heterogeneous and changing in time. The model is used to study trade-offs between amount, spatial connectivity and temporal continuity of habitat. The cost-effective levels of habitat connectivity and continuity are determined as functions of species attributes and economic parameters like the distribution of conservation costs. The results are relevant for the design of cost-effective conservation instruments.     

Effect of antioxidants on oxidation during the production of whey fat concentrate

Whey fat has a relatively high level of unsaturated fatty acids, and as such, whey products with a high fat content are vulnerable to oxidation. The purposes of the present study were to assess the oxidative development in whey fat concentrate (WFC) during production and investigate the effect of the addition of antioxidants. Green tea extract (GTE) or a mixture of ascorbyl palmitate and tocopherol (AP/TOC) were used, each in two concentrations. Samples were taken before and after pasteurization of WFC and after drying. The level of volatile oxidation products decreased during processing, while dityrosine concentrations increased during drying. GTE reduced oxidation in both unpasteurized and pasteurized WFC, while the effect of AP/TOC was nonsignificant. In the WFC powder, there was no significant effect of the antioxidants. In conclusion, results indicated that GTE was able to inhibit oxidation in WFC during production and that AP/TOC addition had no effect.