Lupinus angustifolius has a plastic uptake response to heterogeneously supplied nitrate while Lupinus pilosus does not

2001 ◽  
Vol 52 (4) ◽  
pp. 505 ◽  
Author(s):  
V. Dunbabin ◽  
Z. Rengel ◽  
A. Diggle
Keyword(s):  
Root System ◽  
Uptake Rate ◽  
Root Length ◽  
Nitrate Uptake ◽  
Lupinus Angustifolius ◽  
Nitrate Losses ◽  
Nitrate Supply ◽  
Nitrate Uptake Rate ◽  
The Difference ◽  
Set Up

Uptake rates calculated from plants uniformly supplied with a nutrient will underestimate uptake under heterogeneous conditions. A split-root nutrient solution experiment was set up to compare the uptake rate of 2 lupin species (Lupinus angustifolius L., L. pilosus Murr.) under conditions of uniform and heterogeneous nitrate supply. Nitrate was supplied uniformly to the root system at 250 M (low), 750 M (high), or 1500 M (high), or in a split low/high or high/low combination between the upper and lower root system. While L. pilosus had a greater total nitrate uptake over the treatment period due to a higher total root length, L. angustifolius had 1.5–2.5 times greater nitrate uptake rate per unit of root length. L. angustifolius also had the capacity to increase the nitrate uptake rate in sections of the root system supplied locally with high nitrate, compared with a root system uniformly supplied with high nitrate. This increased uptake rate under heterogeneous supply enabled the plant to take up 74–94% of the total nitrate taken up when uniformly supplied with high nitrate, while only 58–72% would have been taken up without such a compensation mechanism. L. pilosus did not show this response. The difference between the response of these 2 species suggests that a range of nitrate uptake responses may exist across the lupin germplasm, and that it may be possible to select a lupin species with an enhanced ability to capture nitrate from the profile, thus decreasing nitrate losses from leaching.

Combined effects of contrast between poor and rich patches and overall nitrate concentration on Arabidopsis thaliana root system structure

2011 ◽  
Vol 38 (5) ◽  
pp. 364 ◽  
Author(s):  
Manuel Blouin ◽  
Ruben Puga-Freitas
Keyword(s):  
Root System ◽  
Nutrient Status ◽  
System Structure ◽  
System Response ◽  
Correlative Inhibition ◽  
The Rich ◽  
The Difference ◽  
Set Up ◽  
The Cost

The law of correlative inhibition states that roots in a richer environment develop more intensively if other roots of the same plant are in a poorer environment. This probably occurs only when the cost of emitting these roots in the rich patch is compensated by the advantage of having more roots, i.e. in situations where the difference in concentration between rich and poor patches is strong or the overall nutrient amount in the environment is low. For the first time, we tested root system response to combined gradients of contrast between poor and rich patches and of overall NO3– concentration in agar gels. We set up a factorial in vitro experiment crossing contrast (null, weak, strong heterogeneity) with overall NO3– concentration (deficient, optimal, excessive). We observed an increase in ramification density with increasing heterogeneity in deficient situations; but a decrease with increasing heterogeneity in excessive situations. The interaction between overall NO3– concentration and heterogeneity had a significant effect on root ramification density and the distribution of root length in diameter classes. The overall nutrient status of the soil has to be considered to understand the effect of heterogeneity on plant development at the morphological as well as at the molecular level.

Low specific nitrate uptake rate: A common feature of high-nutrient, low-chlorophyll marine ecosystems

1991 ◽  
Vol 36 (8) ◽  
pp. 1678-1688 ◽  
Author(s):  
R. C. Dugdale ◽  
F. P. Wilkerson
Keyword(s):  
Uptake Rate ◽  
Nitrate Uptake ◽  
Marine Ecosystems ◽  
High Nutrient ◽  
Nitrate Uptake Rate

scholarly journals Removal of Nitrate from Groundwater by Cyanobacteria: Quantitative Assessment of Factors Influencing Nitrate Uptake

2000 ◽  
Vol 66 (1) ◽  
pp. 133-139 ◽  
Author(s):  
Qiang Hu ◽  
Paul Westerhoff ◽  
Wim Vermaas
Keyword(s):  
Uptake Rate ◽  
Large Scale ◽  
Nitrate Uptake ◽  
Nitrate Removal ◽  
Aeration Rate ◽  
Inoculum Size ◽  
Logarithmic Phase ◽  
Batch Mode ◽  
Nitrate Uptake Rate ◽  
Cyanobacteria And Algae

ABSTRACT The feasibility of biologically removing nitrate from groundwater was tested by using cyanobacterial cultures in batch mode under laboratory conditions. Results demonstrated that nitrate-contaminated groundwater, when supplemented with phosphate and some trace elements, can be used as growth medium supporting vigorous growth of several strains of cyanobacteria. As cyanobacteria grew, nitrate was removed from the water. Of three species tested, Synechococcus sp. strain PCC 7942 displayed the highest nitrate uptake rate, but all species showed rapid removal of nitrate from groundwater. The nitrate uptake rate increased proportionally with increasing light intensity up to 100 μmol of photons m−2 s−1, which parallels photosynthetic activity. The nitrate uptake rate was affected by inoculum size (i.e., cell density), fixed-nitrogen level in the cells in the inoculum, and aeration rate, with vigorously aerated, nitrate-sufficient cells in mid-logarithmic phase having the highest long-term nitrate uptake rate. Average nitrate uptake rates up to 0.05 mM NO3 − h−1 could be achieved at a culture optical density at 730 nm of 0.5 to 1.0 over a 2-day culture period. This result compares favorably with those reported for nitrate removal by other cyanobacteria and algae, and therefore effective nitrate removal from groundwater using this organism could be anticipated on large-scale operations.

scholarly journals 293 Genotypic and Temporal Variation in Nitrate Uptake Rate by Kentucky Bluegrass

HortScience ◽  
1999 ◽  
Vol 34 (3) ◽  
pp. 493A-493
Author(s):  
Zhongchun Jiang ◽  
W. Michael Sullivan ◽  
Carl D. Sawyer ◽  
Richard J. Hull
Keyword(s):  
Temporal Variation ◽  
Nutrient Solution ◽  
Uptake Rate ◽  
Nitrate Uptake ◽  
Poa Pratensis ◽  
Tap Water ◽  
Kentucky Bluegrass ◽  
Genotypic Differences ◽  
Half Strength ◽  
Nitrate Uptake Rate

Turfgrass cultivars that have superior nitrate uptake ability are needed for the protection of ground water from pollution by excess nitrate. Information on temporal variation of nitrate absorption is also needed to enhance the environmental safety of turfgrass N fertilization programs. Our objectives were to evaluate Kentucky bluegrass (Poa pratensis L.) cultivars for their differences in nitrate uptake rate (NUR) and temporal variation in NUR. Six cultivars (Barzan, Blacksburg, Connie, Dawn, Eclipse, and Gnome) were propagated from individual tillers and six plants of each cultivar were generated from one mother plant. Plants were grown in silica sand, mowed weekly, and watered daily with half-strength modified Hoagland's nutrient solution containing 1 mM nitrate. When 5 months old, the plants were excavated, the roots were washed to remove sand, and the plants were transferred to 120-mL black bottles. After 24 hours in tap water, the plants were supplied with half-strength nutrient solution containing 0.5 mM nitrate, and the solutions were replaced daily for 8 days. NURs expressed as micromoles per plant per hour were calculated from solution nitrate depletion data. Significant genotypic differences in NUR were found: `Blacksburg' > `Connie' > `Dawn' > `Barzan' = `Eclipse' > `Gnome'. Significant temporal variation in NUR was also found, with NUR on the second day more than the first day after tap water. A significant interaction was noted between genotype and time. Temporal variation was greatest in `Blacksburg', while none noted in `Connie' and `Eclipse'. In `Barzan' and `Gnome', NUR on the last day was higher than the first day.

scholarly journals Characterization of Nitrate Uptake by Kentucky Bluegrass at the Whole-plant and Organ Levels

HortScience ◽  
2000 ◽  
Vol 35 (5) ◽  
pp. 829D-829
Author(s):  
Yuexia Wang ◽  
Chhandak Basu ◽  
Zhongchun Jiang ◽  
W. Michael Sullivan
Keyword(s):  
Nutrient Solution ◽  
Uptake Rate ◽  
Nitrate Uptake ◽  
Poa Pratensis ◽  
Kentucky Bluegrass ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Whole Plant ◽  
Nitrate Uptake Rate ◽  
Nitrate Depletion

It has been suggested that shoot demand for nitrogen controls nitrate uptake in plant roots. In turfgrasses, shoots are partly removed by regular mowing, which may severely alter nitrate uptake ability. However, reported groundwater nitrate concentrations under intensively managed turf are well below the USEPA maximum contaminant limit of 10 mg·L-1 nitrate-N in potable water. We hypothesize that the turfgrass root can also exert significant control over its nitrate uptake ability. The present study was to test this hypothesis by comparing nitrate uptake rates of excised roots and intact, whole plants of six Kentucky bluegrass (Poa pratensis L.) cultivars. Three replications or cultures of each cultivar were grown in sand for 15 months. For whole-plant nitrate uptake, the roots were placed in a flask filled with 200 mL of a nutrient solution containing 0.125 mm nitrate. Nitrate depletion was monitored at 20-minute intervals over an 8-hour period under ≈600 μmol·m-2·s-1 photosynthetic photon flux density. After the whole-plant experiment, the plants were placed in an N-free nutrient solution for 15 hours, and the roots were then excised. The excised roots were placed in a beaker containing 60 mL of the 0.125-mm nitrate nutrient solution and nitrate depletion was monitored at 20-minute intervals over a 6-hour period. Whole-plant nitrate uptake rate differed significantly (P ≤ 0.05) among cultivars and was twice that of excised roots. Excised root nitrate uptake rate exhibited no cultivar difference but was positively and significantly (P ≤ 0.05) correlated with whole-plant nitrate uptake rate. Our results indicate that turfgrass roots exert substantial control over nitrate uptake.

Nitrate Uptake Rate by Soybean and Wheat Plants Determined by External Nitrate Concentration and Shoot-Mediated Demand

1998 ◽  
Vol 159 (2) ◽  
pp. 305-312 ◽  
Author(s):  
Carole H. Saravitz ◽  
Florence Devienne-Barret ◽  
C. David Raper, ◽  
Sylvain Chaillou ◽  
Thierry Lamaze
Keyword(s):  
Uptake Rate ◽  
Nitrate Uptake ◽  
Nitrate Concentration ◽  
Nitrate Uptake Rate

scholarly journals Relationship between Nitrate Leaching under Turf and Nitrate Uptake by Turfgrasses

HortScience ◽  
2000 ◽  
Vol 35 (5) ◽  
pp. 827B-827
Author(s):  
John W. Pote ◽  
Chhandak Basu ◽  
Zhongchun Jiang ◽  
W. Michael Sullivan
Keyword(s):  
Nutrient Solution ◽  
Nitrate Leaching ◽  
Uptake Rate ◽  
Nitrate Uptake ◽  
N Losses ◽  
Leaching Loss ◽  
Nitrate N ◽  
N Concentration ◽  
Nitrate Uptake Rate ◽  
Nitrate Leaching Loss

Leaching-induced N losses have been shown to be minimal under turfgrasses. This is likely due to superior ability of turfgrasses to absorb nitrate. No direct evidence for this theory has been reported. The present study quantified nitrate leaching under miniature turf and nitrate uptake by individual turfgrass plants, and established the relationship between nitrate leaching loss and nitrate uptake rate. Seedlings of six Kentucky bluegrass (Poa pratensis L.) cultivars, `Blacksburg', `Barzan', `Connie', `Dawn', `Eclipse', and `Gnome', were planted individually in polystyrene containers filled with silica sand. The plants were irrigated with tap water or a nutrient solution containing 1 mm nitrate on alternate days and mowed to a 5-cm height once each week for 25 weeks. Nitrate leaching potential was then determined by applying 15 to 52 mL of nutrient solutions containing 7 to 70 mg·L-1 nitrate-N into the containers and collecting leachate. After the leaching experiment, plants were excavated, roots were washed to remove sand, and the plants were grown individually in containers filled with 125 mL of a nutrient solution containing 8.4 mg·L-1 nitrate-N. Nitrate uptake rate was determined by monitoring nitrate depletion at 24-hour intervals. Leachate nitrate-N concentration ranged from 0.5 to 6 mg·L-1 depending on cultivar, initial nitrate-N concentration, irrigation volume, and timing of nitrate-N application. Significant intraspecific difference in nitrate uptake rate on a root length basis was observed. Nitrate uptake rate on a per plant basis was significantly (P ≤ 0.05) and negatively correlated (r = -0.65) with nitrate leaching loss. The results provide strong evidence that superior nitrate uptake ability of turfgrass roots could reduce leaching-induced nitrate-N losses.

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