Nitrogen Nutrition of Cowpea (Vigna unguiculata)

1977 ◽  
Vol 13 (4) ◽  
pp. 369-380 ◽  
Author(s):  
A. R. J. Eaglesham ◽  
F. R. Minchin ◽  
R. J. Summerfield ◽  
P. J. Dart ◽  
P. A. Huxley ◽  
...  
Keyword(s):  
Nutrient Solution ◽  
Vigna Unguiculata ◽  
Nitrogen Nutrition ◽  
N Content ◽  
N Assimilation ◽  
Total Plant ◽  
Reported Data ◽  
Total Seed ◽  
N Status

SUMMARYEffectively nodulated, pot-grown cowpea plants were irrigated with nutrient solution containing 25 ppm 15N, and the relative contributions to total plant N status of inorganic and nodule-fixed N were determined. Maximum rates of N assimilation occurred during pod-fill, with nodules contributing ten times more nitrogen than the applied source. Symbiotic fixation supplied over 80% of total plant N throughout growth, and contributed significantly to seed N during late pod-fill, when nutrient N assimilation was negligible. Vegetative N content was greatest at mid pod-fill, and mobilization from this 'pool' was equivalent to 44% of total seed N. The implications of these (and previously reported) data are discussed.

Effects of Water Stress on Nitrogen Nutrition of Grain Sorghum

1986 ◽  
Vol 13 (4) ◽  
pp. 499 ◽  
Author(s):  
TJ Rego ◽  
NJ Grundon ◽  
CJ Asher ◽  
DG Edwards
Keyword(s):  
Osmotic Potential ◽  
Nitrogen Nutrition ◽  
N Uptake ◽  
Grain Sorghum ◽  
Solution Culture ◽  
Root Weight ◽  
N Content ◽  
N Supply ◽  
Total Plant ◽  
Leaf N Concentration

A solution culture experiment was conducted to study the effects of solution osmotic potential and nitrogen (N) supply on growth and N content of grain sorghum cv. Texas 610SR. Polyethylene glycol-6000 was used to impose solution osmotic potentials of -0.1, -0.4, -0.8, and - 1.1 MPa during the fourth week of growth. Plants were harvested at 6 weeks. Dry matter yields, total plant N content and mean rate of N uptake per unit root weight were significantly decreased by decreases in solution osmotic potential and N supply. Numbers of leaves expanded after imposition of the solution osmotic potential treatments were also reduced significantly by decreasing solution osmotic potential and decreasing N supply. Decreasing solution osmotic potential decreased mean N concentrations in leaves, had no effect on mean N concentrations in roots, and increased N concentrations in stems plus immature leaves, and in whole tops. The form of relationships between leaf N concentration and yield prevented the calculation of critical N concentrations at any level of solution osmotic potential.

NITROGEN NUTRITION OF CITRUS NURSERY STOCK IN PINE BARK SUBSTRATES.

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1161f-1161
Author(s):  
John D. Lea-Cox ◽  
Irwin E. Smith
Keyword(s):  
Nutrient Solution ◽  
Nitrogen Nutrition ◽  
Dry Mass ◽  
Pine Bark ◽  
Growing Period ◽  
Rough Lemon ◽  
Nursery Stock ◽  
Citrus Rootstock ◽  
Cleopatra Mandarin ◽  
Nutrient Solutions

Pine bark is utilized as a substrate in citrus nurseries in South Africa. The Nitrogen (N) content of pine bark is inherently low, and due to the volubility of N, must be supplied on a continual basis to ensure optimum growth rates of young citrus nursery stock. Three citrus rootstock (rough lemon, carrizo citrange and cleopatra mandarin) showed no difference in stem diameter or total dry mass (TDM) when supplied N at concentrations between 25 and 200 mg ·l-1 N in the nutrient solution over a 12 month growing period. Free leaf arginine increased when N was supplied at 400 mg·l-1 N. The form of N affected the growth of rough lemon. High NH4-N:NO3-N (75:25) ratios decreased TDM when Sulfur (S) was absent from the nutrient solution, but not if S was present. Free arginine increased in leaves at high NH4-N (No S) ratios, but not at high NH4-N (S supplied) ratios. Free leaf arginine was correlated with free leaf ammonia. These results have important implications for reducing the concentration of N in nutrient solutions used in citrus nurseries and may indicate that higher NH4-N ratios can be used when adequate S is also supplied.

Effects of root environment on the kinetics of 1st month growth and nodulation of alfalfa

1982 ◽  
Vol 60 (6) ◽  
pp. 888-896 ◽  
Author(s):  
F. D. H. Macdowall
Keyword(s):  
Plant Growth ◽  
Nutrient Solution ◽  
Dry Matter ◽  
Nitrogenase Activity ◽  
Plant Root ◽  
N Content ◽  
Shoot Height ◽  
Pot Size ◽  
Solid Substratum ◽  
Soil Mix

Measurements were made of plant, root, and nodule dry matter, nodule number, acetylene reduction by nitrogenase, plant N content, and shoot height of Medicago sativa L. cv. Algonquin and expressed chiefly as rate constants of growth (k1′). The effects of the nature and quantity of solid substratum, of the form and concentration of combined N and of symbiotic and non-symbiotic growth, were compared in optimum growth room conditions. Plants grew at the same maximum k1′ in vermiculite with or without gravel and in a soil mix when supplied with 15 mM NO3− in the nutrient solution. Plant growth was retarded with decreasing pot size but maximum nodule growth k1′ occurred in 7-cm pots. Nodulation and nitrogenase activity showed maximum k1′ with least added N but moderate additions produced larger yields of roots and nodules. Plant growth in dry matter and N content, expressed as k1′, yield, or absolute rate (k1′∙yield), was under no circumstance increased by symbiosis in this phase of exponential growth. Nodulation was completely inhibited by 15 mM NO3− and higher concentrations of N were generally inhibitory. A transient, postgerminative treatment with 15 mM NO3− provided a sustained boost to growth. Combined N supplied as NO2− or NH4+ at 15 mM in the nutrient solution without NO3− suported k1′ values comparable to those obtained with less than 1.5 mM NO3−.

scholarly journals Data Mining Nitrogen-Responsive Gene Expression for Source–Sink Relations and Indicators of N Status in Potato

Agronomy ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1617
Author(s):  
Mia T. Parenteau ◽  
Hong Gu ◽  
Bernie J. Zebarth ◽  
Athyna N. Cambouris ◽  
Jean Lafond ◽  
...  
Keyword(s):  
Gene Expression ◽  
Amino Acid ◽  
N Uptake ◽  
Field Trials ◽  
Amino Acid Biosynthesis ◽  
Lasso Regression ◽  
Acid Biosynthesis ◽  
N Assimilation ◽  
Source Sink ◽  
N Status

Potato tuber yields depend on nitrogen (N) supply, which affects source–sink relations. Transcriptome sequencing of the foliar source using a single field trial identified gene expression responsive to 180 kg N ha−1. The expression of N-responsive genes was further analyzed in the next stage using a NanoString nCounter over an expanded number of foliar samples from seven field trials with varying N rates, sites, and cultivars. Least absolute shrinkage and selection operator (LASSO) regression models of gene expression predictive of yield, total plant N uptake, and tuber-specific gravity (proxy for dry matter) were built. Genes in the LASSO model for yield were associated with source–sink partitioning. A key gene regulating tuberization and senescence, StSP6A Flowering locus T, was found in the LASSO model predicting tuber yield, but not the other models. An aminotransferase involved in photorespiratory N assimilation and amino acid biosynthesis was found in all LASSO models. Other genes functioning in amino acid biosynthesis and integration of sulfur (S) and N metabolism were also found in the yield prediction model. The study provides insights on N responses in foliage of potato plants that affect source–sink partitioning. Additionally, N-responsive genes predictive of yield are candidate indicators of N status.

scholarly journals Dissection of hyperspectral reflectance to estimate nitrogen and chlorophyll contents in tea leaves based on machine learning algorithms

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Hiroto Yamashita ◽  
Rei Sonobe ◽  
Yuhei Hirono ◽  
Akio Morita ◽  
Takashi Ikka
Keyword(s):  
Machine Learning ◽  
Learning Algorithms ◽  
Visible Region ◽  
Machine Learning Algorithms ◽  
Hyperspectral Reflectance ◽  
N Content ◽  
Green Leaves ◽  
Leaf N Content ◽  
N Status ◽  
Leaf N

Abstract Nondestructive techniques for estimating nitrogen (N) status are essential tools for optimizing N fertilization input and reducing the environmental impact of agricultural N management, especially in green tea cultivation, which is notably problematic. Previously, hyperspectral indices for chlorophyll (Chl) estimation, namely a green peak and red edge in the visible region, have been identified and used for N estimation because leaf N content closely related to Chl content in green leaves. Herein, datasets of N and Chl contents, and visible and near-infrared hyperspectral reflectance, derived from green leaves under various N nutrient conditions and albino yellow leaves were obtained. A regression model was then constructed using several machine learning algorithms and preprocessing techniques. Machine learning algorithms achieved high-performance models for N and Chl content, ensuring an accuracy threshold of 1.4 or 2.0 based on the ratio of performance to deviation values. Data-based sensitivity analysis through integration of the green and yellow leaves datasets identified clear differences in reflectance to estimate N and Chl contents, especially at 1325–1575 nm, suggesting an N content-specific region. These findings will enable the nondestructive estimation of leaf N content in tea plants and contribute advanced indices for nondestructive tracking of N status in crops.

Nitrogen Nutrition of Cowpea (Vigna unguiculata)

1977 ◽  
Vol 13 (3) ◽  
pp. 241-252 ◽  
Author(s):  
P. J. Dart ◽  
P. A. Huxley ◽  
A. R. J. Eaglesham ◽  
F. R. Minchin ◽  
R. J. Summerfield ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Vigna Unguiculata ◽  
Symbiotic Nitrogen Fixation ◽  
Nitrogen Nutrition ◽  
Combined Nitrogen ◽  
Nitrogen Treatments ◽  
Seed Yields ◽  
Applied Nitrogen

SUMMARYAverage seed yields of effectively nodulated cowpea plants were 38% greater than those of non-nodulated plants when both received applied nitrogen at concentrations ranging from 60 to 240 ppm during one of three periods: emergence to first flower, first flower to mid pod-fill, or mid pod-fill to maturity. Nodulation increased seed yields by 45% when plants received a ‘basal’ level of 30 ppm N throughout growth. None of the combined nitrogen treatments could compensate non-nodulated plants for the loss of symbiotic nitrogen fixation. Non-nodulated plants relying on applied N branched less, produced fewer peduncles and set fewer pods on each peduncle than nodulated plants.

scholarly journals Bud Necrosis of Green Ash Nursery Trees Is Influenced by Nitrogen Availability and Fertilizer Type

2010 ◽  
Vol 20 (1) ◽  
pp. 206-212 ◽  
Author(s):  
Carolyn F. Scagel ◽  
Richard P. Regan ◽  
Guihong Bi
Keyword(s):  
Nitrogen Availability ◽  
Urea Formaldehyde ◽  
Shoot Biomass ◽  
Similar Amount ◽  
Green Ash ◽  
N Content ◽  
Ash Trees ◽  
Nursery Trees ◽  
C And N ◽  
N Status

A study was conducted to determine whether the nitrogen (N) status of nursery-grown green ash (Fraxinus pennsylvanica ‘Summit’) trees in the autumn is related to bud necrosis during the following spring. In 2005, different rates of N from urea formaldehyde (UF) or a controlled-release fertilizer (CRF) containing ammonium nitrate were applied during the growing season to green ash trees and leaves were sprayed or not with urea in the autumn. Biomass and N content was determined in Autumn 2005 and Spring 2006, and stem biomass and bud necrosis were evaluated for necrosis in Spring 2006. Trees with low N content in Autumn 2005 grew less in Spring 2006 but bud necrosis was more prevalent on trees grown at the highest N rate. Compared with trees grown with a similar amount of N from UF, growing trees with CRF altered N allocation in 2005 and the relationship between carbon (C) and N dynamics (import, export, and metabolism) in stems in 2006. Additionally, trees grown with CRF had less total shoot biomass in Spring 2006 and more bud failure than trees grown with a similar N rate from UF. Significant relationships between bud failure and N status and C/N ratios in different tissues suggest that a combination of tree N status and the balance between N and C in certain tissues plays a role in the occurrence of bud failure of green ash trees in the spring.

scholarly journals Calcium Accumulation, Calcium Distribution, and Biomass Partitioning in Collards

1991 ◽  
Vol 116 (6) ◽  
pp. 991-994 ◽  
Author(s):  
Jon R. Johnson
Keyword(s):  
Root System ◽  
Nutrient Solution ◽  
Accumulation Rate ◽  
Moisture Stress ◽  
System Size ◽  
Solution Culture ◽  
Calcium Accumulation ◽  
Young Leaves ◽  
Nutrient Solution Culture ◽  
Total Plant

`Vates' collard (Brassica oleracea L. Acephala Group) was more susceptible to tipburn than `Blue Max' or “Heavi Crop' in field and nutrient solution culture experiments. The root system of Vates' was smaller than that of `Blue Max' in all experiments. Because of its smaller root system, `Vates' may be more susceptible to moisture stress than `Blue Max' when grown under high-temperature conditions on sandy soils, thus increasing susceptibility to tipburn. Root system size, however, did not influence Ca accumulation or Ca concentration in the plants. Calcium accumulation rate was higher for `Blue Max' and `Heavi Crop' than for Yates' during the 3rd through the 5th weeks of culture, in a nutrient solution that contained 5 mM Ca. Calcium efficiency ratio (CaER, milligrams of dry matter produced per milligram of Ca in tissue) for young leaves was higher for `Blue Max' and `Heavi Crop' than “for `Vates' when plants were grown with 1 mM Ca, which may partly explain the greater susceptibility of `Vates' to tipburn. `Heavi Crop' had a higher total plant CaER than `Blue Max' when grown with 5 mM Ca.

scholarly journals Wpływ szczepów bakterii wyizolowanych z hydroponicznej uprawy sałaty (Lactuca sativa L.) na wzrost siewek sałaty, rosnących w obecnosci rożnych form pożywienia azotowego [Influence of bacterial strains isolated from hydroponic cultures of lettuce (Lactuca sativa L.) on the growth of lettuce seedlings growing in the presence of various forms of nitrogen nutrition]

2015 ◽  
Vol 32 (2) ◽  
pp. 195-206
Author(s):  
Z. Kobierzyńska-Gołąb
Keyword(s):  
Ammonium Nitrate ◽  
Nutrient Solution ◽  
Lactuca Sativa ◽  
Nitrogen Nutrition ◽  
Cultivated Plants ◽  
Bacterial Strains ◽  
Lactuca Sativa L ◽  
Hydroponic Cultures ◽  
Nutrient Solutions ◽  
Growth Of Seedlings

320 bacterial strains isolated from the surface of cultivated plants, as well as from other parts of hydroponic cultures showed stimulating (49 bacterial strains) or inhibitory (9 bacterial strains) properties in respect to the investigated plant. The following bacteria were isolated: <i>Pseudomonas, Flavobacterium, Agrobacterium, Achromobacter</i> and <i>Chromobacterium</i>. The effects of active bacterial strains on the growth of seedlings were investigated in dependence on the kind of inorganic form of nitrogen present in the nutrient solutions. The same bacterial strains exerted a stimulating effect on seedlings growing on nitrates, weaker stimulation was observed in cultures with ammonium nitrate; the growth of lettuce seedlings on nutrient solution with ammonium only, was, as a rule, inhibited by the bacteria.

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