scholarly journals Photosynthesis and Nitrogen Metabolism of Nepenthes alata in Response to Inorganic NO3- and Organic Prey N in the Greenhouse

ISRN Botany ◽  
2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Jie He ◽  
Ameerah Zain
Keyword(s):  
Nitrogen Metabolism ◽  
Photosynthetic Pigments ◽  
Photosynthetic Capacity ◽  
Organic N ◽  
Relative Importance ◽  
Light Saturation ◽  
Leaf Lamina ◽  
Inorganic N ◽  
Light Utilization ◽  
N Metabolism

This study investigates the relative importance of leaf carnivory on Nepenthes alata by studying the effect of different nitrogen (N) sources on its photosynthesis and N metabolism in the greenhouse. Plants were given either inorganic NO3-, organic N derived from meal worms, Tenebrio molitor, or both NO3- and organic N for a period of four weeks. Leaf lamina (defined as leaves) had significant higher photosynthetic pigments and light saturation for photosynthesis compared to that of modified leaves (defined as pitchers). Maximal light saturated photosynthetic rates (Pmax) were higher in leaves than in pitchers. Leaves also had a higher light utilization than that of pitchers. Both leaves and pitchers of plants that were supplied with both inorganic NO3- and organic prey N had a similar photosynthetic capacity and N metabolism compared to plants that were given only inorganic NO3-. However, adding organic prey N to the pitchers enhanced both photosynthetic capacity and N metabolism when plants were grown under NO3- deprivation condition. These findings suggest that organic prey N is essential for N. alata to achieve higher photosynthetic capacity and N metabolism only when plants are subjected to an environment where inorganic N is scarce.

Highly Specialized Nitrogen Metabolism in a Freshwater Phytoplankter, Chrysochromulina breviturrita

1987 ◽  
Vol 44 (4) ◽  
pp. 736-742 ◽  
Author(s):  
John D. Wehr ◽  
Lewis M. Brown ◽  
Kathryn O'Grady
Keyword(s):  
Nitrogen Metabolism ◽  
Laboratory Culture ◽  
Organic N ◽  
Acidic Precipitation ◽  
Inorganic N ◽  
Culture Study ◽  
N Source ◽  
Softwater Lakes ◽  
N Metabolism ◽  
N Compounds

A field and laboratory culture study was carried out on the nitrogen metabolism of isolates of the freshwater phytoplankter Chrysochromulina breviturrita Nich. (Prymnesiophyceae). These were isolated from two different softwater lakes, one believed to be influenced by acidic precipitation (Cinder Lake) and another which was experimentally acidified with H2SO4 (Lake 302-South). The alga was able to utilize only NH4+ as an inorganic N source. A range of irradiances and molybdenum concentrations failed to induce NO3− utilization. Among 17 organic N compounds including amino acids, purines, and other amines, only urea plus Ni2+ as a cofactor would serve as the sole N source for this species. Nonetheless, growth rates in media supplied with urea were significantly less than with NH4+. Field data from Lake 302-S indicate that a predominance of NH4+ versus NO3− as the major inorganic N species may have favored the development of a Chrysochromulina-dominated community during August 1984. A detailed depth profile also indicated that a metalimnetic peak (> 20 × 106 cells/L) of this alga coincided with a distinct NH4+ depletion, which occurred at no other time during the year. Experiments with isolates of C. breviturrita and a Nannochloris sp. (Chlorophyceae) (~ 1 μm in diameter) from this community indicated that the former alga possessed a highly specialized N metabolism much like the Cinder Lake isolate. The Nannochloris sp. from the same environment grew on NO3− and NH4+ equally well. It is suggested that the specialized NH4+ utilization by C. breviturrita may itself influence the pH regime of poorly buffered waters through selective NH4+ uptake and H+ generation.

Dynamics of nitrogen and dry-matter partitioning and accumulation in broccoli (Brassica oleracea var. italica) in relation to extractable soil inorganic nitrogen

1999 ◽  
Vol 79 (2) ◽  
pp. 277-286 ◽  
Author(s):  
P. A. Bowen ◽  
B. J. Zebarth ◽  
P. M. A. Toivonen
Keyword(s):  
Dry Matter ◽  
N Fertilization ◽  
N Fertilizer ◽  
Organic N ◽  
Soil N ◽  
Inorganic N ◽  
N Accumulation ◽  
Spring Planting ◽  
Extractable Soil ◽  
Soil Inorganic

The effects of six rates of N fertilization (0, 125, 250, 375, 500 and 625 kg N ha−1) on the dynamics of N utilization relative to extractable inorganic N in the soil profile were determined for broccoli in three growing seasons. The amount of pre-existing extractable inorganic N in the soil was lowest for the spring planting, followed by the early-summer then late-summer plantings. During the first 2 wk after transplanting, plant dry-matter (DM) and N accumulation rates were low, and because of the mineralization of soil organic N the extractable soil inorganic N increased over that added as fertilizer, especially in the top 30 cm. From 4 wk after transplanting until harvest, DM and N accumulation in the plants was rapid and corresponded to a rapid depletion of extractable inorganic N from the soil. At high N-fertilization rates, leaf and stem DM and N accumulations at harvest were similar among the three plantings. However, the rates of accumulation in the two summer plantings were higher before and lower after inflorescence initiation than those in the spring planting. Under N treatments of 0 and 125 kg ha−1, total N in leaf tissue and the rate of leaf DM accumulation decreased while inflorescences developed. There was little extractable inorganic soil-N during inflorescence development in plots receiving no N fertilizer, yet inflorescence dry weights and N contents were ≥50 and ≥30%, respectively, of the maxima achieved with N fertilization. These results indicate that substantial N is translocated from leaves to support broccoli inflorescence growth under conditions of low soil-N availability. Key words: N translocation, N fertilizer

scholarly journals Amazon forest structure generates diurnal and seasonal variability in light utilization

2015 ◽  
Vol 12 (23) ◽  
pp. 19043-19072 ◽  
Author(s):  
D. C. Morton ◽  
J. Rubio ◽  
B. D. Cook ◽  
J.-P. Gastellu-Etchegorry ◽  
M. Longo ◽  
...  
Keyword(s):  
Forest Structure ◽  
Seasonal Variability ◽  
Seasonal Changes ◽  
Forest Productivity ◽  
Dry Season ◽  
Airborne Lidar ◽  
Amazon Forest ◽  
Light Saturation ◽  
Light Utilization ◽  
Saturation Effects

Abstract. The complex three-dimensional (3-D) structure of tropical forests generates a diversity of light environments for canopy and understory trees. Understanding diurnal and seasonal changes in light availability is critical for interpreting measurements of net ecosystem exchange and improving ecosystem models. Here, we used the Discrete Anisotropic Radiative Transfer (DART) model to simulate leaf absorption of photosynthetically active radiation (lAPAR) for an Amazon forest. The 3-D model scene was developed from airborne lidar data, and local measurements of leaf reflectance, aerosols, and PAR were used to model lAPAR under direct and diffuse illumination conditions. Simulated lAPAR under clear sky and cloudy conditions was corrected for light saturation effects to estimate light utilization, the fraction of lAPAR available for photosynthesis. Although the fraction of incoming PAR absorbed by leaves was consistent throughout the year (0.80–0.82), light utilization varied seasonally (0.67–0.74), with minimum values during the Amazon dry season. Shadowing and light saturation effects moderated potential gains in forest productivity from increasing PAR during dry season months when the diffuse fraction from clouds and aerosols was low. Comparisons between DART and other models highlighted the role of 3-D forest structure to account for seasonal changes in light utilization. Our findings highlight how directional illumination and forest 3-D structure combine to influence diurnal and seasonal variability in light utilization, independent of further changes in leaf area, leaf age, or environmental controls on canopy photosynthesis. Changing illumination geometry constitutes an alternative biophysical explanation for observed seasonality in Amazon forest productivity without changes in canopy phenology.

scholarly journals Dynamic of nitrogen and dissolved organic carbon in an alpine forested catchment: atmospheric deposition and soil solution trends

2019 ◽  
Vol 34 ◽  
pp. 41-66 ◽  
Author(s):  
Raffaella Balestrini ◽  
Carlo Andrea Delconte ◽  
Andrea Buffagni ◽  
Alessio Fumagalli ◽  
Michele Freppaz ◽  
...  
Keyword(s):  
Soil Solution ◽  
Forest Ecosystem ◽  
Forest Floor ◽  
Mineral Soil ◽  
Chemical Species ◽  
Organic N ◽  
Seasonal Temperature ◽  
Inorganic N ◽  
Forest Floor Leachates ◽  
Throughfall Deposition

A number of studies have reported decreasing trends of acidifying and N deposition inputs to forest areas throughout Europe and the USA in recent decades. There is a need to assess the responses of the ecosystem to declining atmospheric pollution by monitoring the variations of chemical species in the various compartments of the forest ecosystem on a long temporal scale. In this study, we report on patterns and trends in throughfall deposition concentrations of inorganic N, dissolved organic N (DON) and C (DOC) over a 20-year (1995–2015) period in the LTER site -Val Masino (1190 m a.s.l.), a spruce forest, in the Central Italian Alps. The same chemical species were studied in the litter floor leachates and mineral soil solution, at three different depths (15, 40 and 70 cm), over a 10-year period (2005–2015). Inorganic N concentration was drastically reduced as throughfall and litter floor leachates percolated through the topsoil, where the measured mean values (2 µeq L-1) were much lower than the critical limits established for coniferous stands (14 µeq L-1). The seasonal temperature dependence of throughfall DOC and DON concentration suggests that the microbial community living on the needles was the main source of dissolved organic matter. Most of DOC and DON infiltrating from the litter floor were retained in the mineral soil. The rainfall amount was the only climatic factor exerting a control on DOC and N compounds in throughfall and forest floor leachates over a decadal period. Concentration of SO4 and NO3 declined by 50% and 26% respectively in throughfall deposition. Trends of NO3 and SO4 in forest floor leachates and mineral soil solution mirrored declining depositions. No trends in both DON and DOC concentration and in DOC/DON ratio in soil solutions were observed. These outcomes suggest that the declining NO3 and SO4 atmospheric inputs did not influence the dynamic of DON and DOC in the Val Masino forest. The results of this study are particularly relevant, as they are based on a comprehensive survey of all the main compartments of the forest ecosystem. Moreover, this kind of long-term research has rarely been carried out in the Alpine region.

Rapid determinations of dissolved inorganic and organic nitrogen in soil leachate using mid-infrared spectroscopy

2019 ◽  
Vol 99 (4) ◽  
pp. 579-583
Author(s):  
X.M. Yang ◽  
C.F. Drury ◽  
W. Xu ◽  
M. Reeb ◽  
T. Oloya
Keyword(s):  
Infrared Spectroscopy ◽  
Organic Nitrogen ◽  
Inorganic Nitrogen ◽  
Organic N ◽  
Inorganic N ◽  
Soil Leachate ◽  
Total N ◽  
Mid Infrared ◽  
Mid Infrared Spectroscopy ◽  
Dissolved Nitrogen

Mid-infrared spectroscopy in the transmission mode was used to predict inorganic nitrogen (N), organic N, and total N in soil leachate. The developed predictions were accurate and robust for total N, NH4+, NO3−, inorganic N (NH4+ + NO3−), and organic N (total N − inorganic N) with high determination coefficients (R2 = 96.7 − 99.0) and residual prediction deviation (RPD = 5.47 − 9.96). The proposed method simultaneously estimates the concentrations of dissolved nitrogen species in soil leachates accurately and with significant savings in time, cost, and chemicals relevant to conventional methods.

Fate and recovery of 15N-labelled fertilizer urea applied to winter wheat in spring in the Canterbury region of New Zealand

1999 ◽  
Vol 133 (2) ◽  
pp. 125-130 ◽  
Author(s):  
R. J. HAYNES
Keyword(s):  
New Zealand ◽  
Winter Wheat ◽  
Ammonia Volatilization ◽  
Organic N ◽  
European Research ◽  
Fertilizer N ◽  
Inorganic N ◽  
Organic Form ◽  
Soil System ◽  
Almost All

15N-labelled fertilizer urea was applied at increasing rates (0–200 kg N/ha), in spring, to winter wheat crops in the Canterbury region of New Zealand in three successive seasons (1993/94, 1994/95 and 1995/96). Recovery of fertilizer N by the crop (grain, chaff, straw and roots) ranged from 43–58% (mean 48%). The quantity of fertilizer N retained in the soil (0–40 cm), at harvest, ranged from 26–42%. Of the labelled N present in the soil, over 95% was present in organic form and 60–80% was retained in the surface 0–10 cm layer. Since soil organic matter represents a substantial sink for fertilizer N there is a need to characterize the nature of this organic pool of N more fully. The quantity of inorganic N present in the soil profile at harvest ranged from 20–46 kg N/ha and labelled fertilizer-derived N contributed less than 16% (mean 9·2%) to this inorganic pool. Loss of fertilizer N from the crop/soil system (i.e., labelled N not recovered in the crop or soil at harvest) varied from 12–26% (mean 18%). Losses were attributed mainly to denitrification since conditions were not conducive for ammonia volatilization or leaching of nitrate. In agreement with European research, it was concluded that almost all of the N at risk of leaching over the winter originates from mineralization of soil organic N and not from unused fertilizer-N applied in spring.

EFFICIENT TILLAGE AND NUTRIENT PRACTICES FOR SUSTAINABLE PEARL MILLET PRODUCTIVITY IN DIFFERENT SOIL AND AGRO-CLIMATIC CONDITIONS

2011 ◽  
Vol 48 (1) ◽  
pp. 1-20 ◽  
Author(s):  
G. R. MARUTHI SANKAR ◽  
P. K. MISHRA ◽  
K. L. SHARMA ◽  
S. P. SINGH ◽  
A. K. NEMA ◽  
...  
Keyword(s):  
Grain Yield ◽  
Pearl Millet ◽  
Monthly Rainfall ◽  
Organic N ◽  
Cost Ratio ◽  
Inorganic N ◽  
Grain Yields ◽  
Benefit Cost Ratio ◽  
Net Returns ◽  
Benefit Cost

SUMMARYLong-term field experiments were conducted at Agra, Solapur and Hisar from 2000 to 2008 to identify efficient tillage and nutrient management practices and to develop predictive models that would describe the relationship between crop yields and monthly rainfall for rainfed pearl millet grown on arid and semi-arid Inceptisol, Vertisol and Aridisol soils. Nine treatments comprising a factorial combination of three tillage practices, viz., conventional tillage (CT), low tillage + interculture (LT1) and low tillage + herbicide (LT2) and three fertilizer treatments viz., 100% N from an organic source (F1), 50% organic N + 50% inorganic N (F2) and 100% inorganic N (F3) were tested in a split-plot design at the three locations. Studies revealed that tillage and fertilizer treatments, and their interactions, significantly influenced pearl millet grain yields at the three locations. Prediction models describing the relation between grain yield and monthly rainfall indicated that rainfall occurring in June, July and August at Agra; June and July at Solapur; and June and August at Hisar significantly influenced pearl millet grain yield attained by different treatments. The R2 values of the model ranged from 0.64 to 0.81 at Agra; 0.63 to 0.92 at Solapur, and 0.75 to 0.89 at Hisar. When averaged over all the treatment combinations, mean pearl millet grain yields varied from 1590 to 1744 kg ha−1 at Agra; 1424 to 1786 kg ha−1 at Solapur; and 1675 to 1766 kg ha−1 at Hisar while their corresponding sustainability yield indice (SYI) varied from 35.4 to 42.2%, 19.9 to 45.6% and 64.1 to 68.3%, respectively. At Agra (Inceptisol), CTF3 resulted in significantly higher mean net returns (Rs 11 439 ha−1), benefit-cost ratio (2.33), rainwater use efficiency (RWUE) (3.52 kg ha−1 mm−1) and the second best SYI (39.9%). At Solapur (Vertisol), the LT1F3 resulted in significantly higher net returns (Rs 12 818 ha−1), benefit-cost ratio (3.52), RWUE (3.89 kg ha−1 mm−1) and the fourth best SYI (42.6%). At Hisar (Aridisol), the LT1F3 treatment gave higher net returns (Rs 3866 ha−1), benefit-cost ratio (1.26), RWUE (5.05 kg ha−1 mm−1) and the fourth best SYI (67.8%). These treatment combinations can be recommended for their respective locations to achieve maximum RWUE, productivity and profitability.

Atmospheric deposition and canopy interactions of nitrogen in forests

1993 ◽  
Vol 23 (8) ◽  
pp. 1603-1616 ◽  
Author(s):  
Gary M. Lovett ◽  
Steven E. Lindberg
Keyword(s):  
Linear Function ◽  
Dry Deposition ◽  
Wet Deposition ◽  
Particle Deposition ◽  
Cloud Water ◽  
Organic N ◽  
Total System ◽  
Inorganic N ◽  
Deposition Rates ◽  
Total Deposition

Wet deposition of nitrogen compounds was measured and dry and cloud water deposition were estimated at 11 forested sites in North America and one site in Europe. Dry deposition was a significant pathway of N input to all the forests, averaging 46% of the total deposition. At most of these sites, NH4+ was the dominant form of fixed N in the air, but HNO3 vapor dominated the dry deposition of N. Coarse-particle deposition was often important, but fine-particle deposition usually contributed only a small amount of the dry-deposited N. The deposition rates of inorganic N, which ranged between 4.8 and 27 kg N•ha−1•year−1, were generally much higher than has been reported by other studies measuring only wet or bulk deposition. The highest deposition rates were at the high-elevation sites in the southeastern and northeastern United States and much of the deposition at these sites was attributed to cloud water. Throughfall and stemflow (TF + SF) flux was also measured at all sites, and the net canopy exchange (NCE = (TF + SF)–total deposition) was found to be negative (indicating consumption of N in the canopy) for NH4+ and NO3−, and positive (indicating canopy release) for organic N. Past reports of canopy release of NO3− can probably be attributed to washoff of dry-deposited NO3− species. Consumption of inorganic N in the canopy ranged from 1 to 12 kg N•ha−1•year−1, and was highest in the spruce and spruce–fir stands. When organic N was included in the canopy N balance, the net canopy uptake of N was generally < 15% of the total system N requirement. Total N deposition was a linear function of wet deposition for low-elevation sites, and dry deposition was a linear function of the net throughfall flux for NO3−.

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