Influence of Light Regime and Leaf Nitrogen Concentration on 77k Fluorescence in Leaves of Four Tropical Grasses: No Evidence for Photoinhibition

1988 ◽  
Vol 15 (5) ◽  
pp. 669 ◽  
Author(s):  
MM Ludlow ◽  
SP Samarakoon ◽  
JR Wilson
Keyword(s):  
Nitrogen Content ◽  
Nitrogen Availability ◽  
Nitrogen Concentration ◽  
Chlorophyll Concentration ◽  
Leaf Nitrogen ◽  
Nitrogen Supply ◽  
Poor Growth ◽  
Full Sunlight ◽  
Nitrogen Treatments ◽  
Low Nitrogen

This work was undertaken to determine if the stimulation of growth associated with shading of some tropical C4 grasses growing on soils with low to moderate nitrogen availability is partly due to overcoming photoinhibition (i. e. damage caused by excessive light). Four grasses (green panic, carpet grass, buffalo grass and kikuyu) were grown in full sunlight and at 37% of full sunlight, and given a low or high nitrogen supply. Despite differences of up to twofold in leaf nitrogen and chlorophyll concentration between high and low nitrogen treatments in all four grasses, photoinhibition measured by reduction in chlorophyll fluorescence was less than 3% in leaves of low nitrogen content that developed in full sunlight. Therefore, photoinhibition is not a contributor to the poor growth of nitrogen-limited grasses in full sunlight. A second objective was to determine if low nitrogen content predisposed shade-grown leaves to photoinhibition when they were subsequently exposed to full sunlight. Green panic plants that had been given either high or low nitrogen supply and grown in 37% of full sunlight were transferred to full sunlight and the extent of photoinhibition was followed over 8 days. The amount of photoinhibition that occurred was small (<6%) compared with plants grown at either nitrogen level in full sunlight. Therefore, shade and low nitrogen content separately or in combination did not cause any appreciable photoinhibition in green panic.

Physiological Responses of Amaranthus Cruentus L. to Drought Stress Under Sufficient- and Deficient-Nitrogen Conditions

2021 ◽  
Author(s):  
Inês Cechin ◽  
Laura Prado da Silva ◽  
Elisa Teófilo Ferreira ◽  
Sarah Corrêa Barrochelo ◽  
Fernanda Pereira de Souza Rosa de Melo ◽  
...  
Keyword(s):  
Water Stress ◽  
Plant Growth ◽  
Photosynthetic Pigments ◽  
Dry Matter ◽  
Nitrogen Availability ◽  
Leaf Nitrogen ◽  
Nitrogen Supply ◽  
Plant Performance ◽  
In Planta ◽  
Phenolic Contents

Abstract Water and nitrogen availability are environmental factors that can impair plant growth, and when they are combined their effects can be intensified or reduced. The objective of this study was to analyse the influence of nitrogen availability on the responses of Amaranthus cruentus’s metabolisms to water stress. The plants were cultivated in plastic pots filled with vermiculite and kept under greenhouse conditions and were watered with 70% of full strength nitrogen-free Long Ashton solution, containing 1.97 or 9.88 kg N ha−1 as ammonium nitrate, three times a week. Photosynthetic parameter were evaluated in planta and leaves were harvested for chemical analysis of proline and phenolic contents. Higher nitrogen supply increased the shoot dry matter, photosynthetic pigments, photosynthesis, stomatal conductance, transpiration, total leaf nitrogen, proline, nitrate and ammonium but reduced the concentration of flavonoids and total phenols. Water stress for 6 days did not affect dry matter, photosynthetic pigments, leaf nitrogen, ammonium or specialized metabolites but increased the proline and affected negatively the other variables. The observed interactions between nitrogen and water supply resulted in no alleviation of the negative effects of drought on amaranth. Although the increase in nitrogen supply had benefits on plant performance, it intensified the negative effect of water stress. The study shows the importance of choosing the correct level of nitrogen fertilization in order to obtain satisfactory results in terms of plant growth under drought conditions.

The accumulation of terpenoid oils does not incur a growth cost in Eucalyptus polybractea seedlings

2006 ◽  
Vol 33 (5) ◽  
pp. 497 ◽  
Author(s):  
Drew J. King ◽  
Roslyn M. Gleadow ◽  
Ian E. Woodrow
Keyword(s):  
Nitrogen Availability ◽  
Nitrogen Concentration ◽  
Leaf Nitrogen ◽  
Primary Metabolism ◽  
Oil Accumulation ◽  
Oil Concentration ◽  
Net Assimilation ◽  
Positive Correlations ◽  
The Cost ◽  
The Impact

The deployment of secondary metabolites, such as terpenes, as anti-herbivore defences is thought to be costly for plants in terms of primary metabolism. Moreover, it is assumed that the cost of this deployment is modified by resource availability. In this study we examined the impact of terpenoid oil accumulation on the growth of Eucalyptus polybractea R.T.Baker seedlings from four maternal half-sib families, under conditions of sufficient and limiting nitrogen. The foliar oil concentration measured was extremely variable, varying almost 20-fold to a maximum of 13% (w / DW). Oil concentration was higher in plants grown under high nitrogen than in low-nitrogen plants, and it was positively correlated with foliar nitrogen concentration. Oil concentration was related to maternal concentration, although this relationship was weak because of the variation encountered. The composition of oil, dominated by monoterpenes, was also extremely variable, although this variation could not be adequately explained by either nitrogen availability or the seedling parentage. Importantly, we detected no negative correlations between oil concentration and relative growth rate (RGR), net assimilation rate (NAR), or leaf nitrogen productivity (LNP). Rather, under nitrogen limiting conditions, positive correlations were detected between oil concentration and all three indices. We conclude that oil accumulation is associated with factors that promote growth and if there is a cost to oil deployment, it could not be detected using the experimental design employed here.

scholarly journals The Role of Gibberellins in Regulation of Nitrogen Uptake and Physiological Traits in Maize Responding to Nitrogen Availability

2020 ◽  
Vol 21 (5) ◽  
pp. 1824
Author(s):  
Yubin Wang ◽  
Qingqing Yao ◽  
Yushi Zhang ◽  
Yuexia Zhang ◽  
Jiapeng Xing ◽  
...  
Keyword(s):  
Nitrogen Availability ◽  
Physiological Responses ◽  
N Uptake ◽  
Nitrogen Supply ◽  
Rna Seq ◽  
Uptake Capacity ◽  
Use Efficiency ◽  
Low Nitrogen ◽  
N Use

Modified gibberellin (GA) signaling leads to semi-dwarfism with low nitrogen (N) use efficiency (NUE) in crops. An understanding of GA-mediated N uptake is essential for the development of crops with improved NUE. The function of GA in modulating N uptake capacity and nitrate (NO3−) transporters (NRTs) was analyzed in the GA synthesis-deficient mutant zmga3ox grown under low (LN) and sufficient (SN) N conditions. LN significantly suppressed the production of GA1, GA3, and GA4, and the zmga3ox plants showed more sensitivity in shoots as well as LN stress. Moreover, the higher anthocyanin accumulation and the decrease of chlorophyll content were also recorded. The net NO3− fluxes and 15N content were decreased in zmga3ox plants under both LN and SN conditions. Exogenous GA3 could restore the NO3− uptake in zmga3ox plants, but uniconazole repressed NO3− uptake. Moreover, the transcript levels of ZmNRT2.1/2.2 were downregulated in zmga3ox plants, while the GA3 application enhanced the expression level. Furthermore, the RNA-seq analyses identified several transcription factors that are involved in the GA-mediated transcriptional operation of NRTs related genes. These findings revealed that GAs influenced N uptake involved in the transcriptional regulation of NRTs and physiological responses in maize responding to nitrogen supply.

Mass loss and nitrogen dynamics of decaying litter of grasslands: the apparent low nitrogen immobilization potential of root detritus

1992 ◽  
Vol 70 (2) ◽  
pp. 384-391 ◽  
Author(s):  
T. R. Seastedt ◽  
W. J. Parton ◽  
D. S. Ojima
Keyword(s):  
Mass Loss ◽  
Nitrogen Availability ◽  
Inorganic Nitrogen ◽  
Nitrogen Concentration ◽  
C:N Ratio ◽  
Nitrogen Dynamics ◽  
Nitrogen Immobilization ◽  
Litter Bag ◽  
Root Litter ◽  
Low Nitrogen

Litter-bag studies and simulation modeling were used to examine the relationship between mass loss and nitrogen content of decaying prairie foliage and root litter. In contrast with forest studies, grassland roots were low in lignin and nitrogen, decayed more rapidly than foliage, and demonstrated very low nitrogen immobilization potentials. Our findings agree with reports indicating that buried substrates with high C:N ratios do not immobilize substantial amounts of nitrogen and that nitrogen-limited environments induce steeper slopes in the mass loss – nitrogen concentration relationship. However, results suggesting rapid nitrogen mineralization contradict our own studies demonstrating reduced inorganic nitrogen availability in soils of frequently burned prairie. Simulation of observed patterns using the CENTURY grassland model indicated that these results could not occur without creating soil organic matter with unrealistically high C:N ratios. Litter-bag studies of buried substrates therefore may provide an incomplete perspective on the mass loss and nitrogen dynamics of buried litter in grassland and agroecosystem soils. Key words: Andropogon gerardii, C:N ratio, decomposition, immobilization, mineralization, nitrogen.

Sulfur and nitrogen fertilizer effects on wheat. II. Influence on grain quality

1981 ◽  
Vol 32 (2) ◽  
pp. 213 ◽  
Author(s):  
HJ Moss ◽  
CW Wrigley ◽  
R MacRichie ◽  
PJ Randall
Keyword(s):  
Grain Quality ◽  
Nitrogen Concentration ◽  
High Mobility ◽  
Nitrogen Supply ◽  
Small Scale ◽  
Dough Quality ◽  
Wide Range ◽  
Highly Correlated ◽  
Nitrogen Treatments ◽  
Low Sulfur

A wide range of grain quality tests (on both a large and a small scale) was performed on samples obtained from a factorial (5 sulfur x 3 nitrogen treatments) field experiment in which Olympic wheat responded in yield of grain to both sulfur and nitrogen. Grain nitrogen concentration responded mainly to nitrogen supply and ranged from 1.38 to 2.56%. Grain sulfur concentration responded to both sulfur and nitrogen supply and varied from 0.08 to 0.18%. Flour sulfur was highly correlated with, but lower than, grain sulfur. Compared with high sulfur grain, low sulfur grain was harder (higher pearling resistance) and the dough had a greater resistance to extension and a lower extensibility. In fact, a restricted supply of sulfur seriously affected grain quality, producing a dough that was excessively tough and umuitable for normal use. These changes in dough quality were accompanied by decreases in the proportions of albumins and of high mobility gliadins in the total protein in the low sulfur grain.

Seasonal changes in the nitrogen content of three warm-climate pasture grasses

1964 ◽  
Vol 4 (15) ◽  
pp. 336 ◽  
Author(s):  
EF Henzell ◽  
DJ Oxenham
Keyword(s):  
Nitrogen Content ◽  
Nitrogen Fertilizer ◽  
Nitrogen Deficiency ◽  
Nitrogen Supply ◽  
High Rate ◽  
Warm Climate ◽  
Stage Of Development ◽  
Pasture Grasses ◽  
Chloris Gayana ◽  
Nitrogen Treatments

The nitrogen content of three pasture grasses was measured under irrigation at Samford, south-east Queensland, during the period February-September 1962. The grasses were Paspalum plicatulum, Sefaria sphacelata, and Chloris gayana. Two nitrogen treatments were used-nil, and a high rate. The high rate comprised frequent nitrogen fertilizer dressings in amounts chosen to match the shape of the plant growth curve. Addition of nitrogen fertilizer caused a marked increase in the nitrogen content of all parts of the plant and maintained a higher nitrogen content in mature grass samples. Flowering had relatively less effect on the nitrogen content of the grasses than nitrogen supply. Frost had very little effect on the nitrogen content of these grasses. It is suggested that warm-climate pasture grasses generally are subjected to a greater degree of nitrogen deficiency than their temperate counterparts, and that this accounts, at least in part, for their comparatively low nitrogen content. In the nil nitrogen treatment, Setaria sphacelata and Chloris gayana consistently exhibited a higher nitrogen content than Paspalum plicatulum. The differences were greatest in the leaf blades and least in the stems. The relative influences of nitrogen supply and stage of development on the nitrogen content of pasture grasses are discussed.

Soil plant nitrogen relations of tobacco at Mareeba, north Queensland

1965 ◽  
Vol 5 (17) ◽  
pp. 180
Author(s):  
PJ Goodman
Keyword(s):  
Nitrogen Uptake ◽  
Nitrogen Availability ◽  
Nitrogen Concentration ◽  
Leaf Nitrogen ◽  
Soil Nitrate ◽  
Nitrate Accumulation ◽  
Plant Nitrogen ◽  
Leaf Nitrogen Concentration ◽  
Red Earth ◽  
Nitrogen Relations

Nitrogen changes were studied in a red earth on which tobacco grew with very small additions of nitrogen fertilizer. Soil nitrate accumulation in the dry season before transplanting, and mineralization during the tobacco season, provided most of the plant's nitrogen requirements. Plant nitrogen uptake continued longer than in other countries, and the total amount was greater, particularly in stems and suckers. Though the plants gained nitrogen during the harvest period, leaf nitrogen concentration decreased. This resulted from translocation from lower leaves and growth of upper leaves. Decrease in leaf nitrogen concentration was essential to quality. The necessary sequence, of sufficient nitrogen for yield, followed by decreasing nitrogen availability for quality, occurs on this soil with small fertilizer additions. There is need for survey work on nitrogen availability and the time sequence of nitrogen uptake by plants on related Mareeba soils.

scholarly journals Evaluation of the Non-destructive Method Efficiency of Estimating Nitrogen Content in Jambu Plants Grown in Hydroponic System

2020 ◽  
Vol 8 (2) ◽  
pp. 466
Author(s):  
Italo Marlone Gomes Sampaio ◽  
Mário Lopes da Silva Júnior ◽  
Erika Da Silva Chagas ◽  
Ricardo Falesi Palha de Moraes Bittencourt ◽  
Vivian Christine Nascimento Costa ◽  
...  
Keyword(s):  
Nitrogen Content ◽  
Nutrient Solution ◽  
Linear Models ◽  
Nitrogen Concentration ◽  
Chlorophyll Concentration ◽  
Technical Information ◽  
Dry Mass ◽  
Leafy Vegetables ◽  
Total Chlorophyll ◽  
N Content

Jambu is considered a leafy vegetable with expressive relevance in the regions that compose the Brazilian Amazon. However, there are challenges regarding its cultivation, particularly for the nutritional management, since there is little technical information that allows an increase in the efficiency of its production. In this sense, nitrogen (N) gains prominence, since it is related to the increased yield and quality of leafy vegetables, therefore its monitoring of N content in plants is necessary. The objective of this study was to evaluate the efficiency of using the SPAD index to estimate the N content of jambu leaves, total chlorophyll concentration, as well as its relationship with dry mass accumulation due to the increase of nitrogen concentration in the nutrient solution. The design used was completely randomized with eight replications. The treatments were six nitrogen concentrations in the nutrient solution (11, 13, 15, 17, 19 and 21 mmol L-¹). After 21 days of transplantation, the SPAD index was measured. Then, these plants were collected to quantify the total chlorophyll, dry mass and nitrogen content. In general, the variables were explained by increasing linear models. There was a positive correlation between the SPAD index and the other characteristics evaluated. Based on the results, the best response at the concentration of 21 mmol L-¹ in the nutrient solution stands out. In addition, the SPAD index has potential to be used in the diagnosis of nitrogen status in jambu leaves.

scholarly journals Calibration of Nitrogen Content of Soil with Sweet Corn

2006 ◽  
Vol 55 (1) ◽  
pp. 223-230
Author(s):  
István Buzás ◽  
E. Hoyk ◽  
I. Cserni ◽  
J. Bors-Pető
Keyword(s):  
Nitrogen Content ◽  
Dry Matter ◽  
Sweet Corn ◽  
Nitrate Nitrogen ◽  
Nitrogen Concentration ◽  
Soil Layer ◽  
Nitrogen Supply ◽  
Corn Yield ◽  
Beet Root ◽  
Matter Production

It was found that quantitative and qualitative indices of the sweet corn yield correlate with the nitrate nitrogen content of the upper soil layer (0-30 cm). As no correlation was established between the nitrate nitrogen content of the lower layers and the sweet corn, the conclusion was drawn that the quantity of sweet corn yield is determined even before its roots reach deeper down than 30 cm and the nitrogen content of the lower layers could affect the sweet corn.  Depending on the NO 3 -N content of the soil before fertilization the maximal corn ear mass achievable with fertilization may vary. In the study the same yield could not be accomplished in the case of the lowest soil nitrogen concentration (2.9 mg NO 3 -N/kg) with the highest fertilizer rate (200 kg N/ha) - but probably irrespective of any amount of fertilizer - as on the soil of 4.6 mg NO 3 -N/kg. In the case of the poorly supplied soil the fertilization curve becomes flat sooner or turns negative. The phenomenon that, regarding various soils, the maximal yield achievable on soils with good production features with fertilization is higher than in the case of soils having worse features, is well-known. That this fact is also valid in the case of the same soils was expected after calibration experiments carried out with winter oilseed rape and beet root, but it has not been proven for sweet corn as yet.  The results also showed that the grain dry matter production of sweet corn per hectare can still be enhanced with the increase in the soil's nitrogen supply, even if the corn ear does not grow.  The presented calibration curves show - in the range of 2.9-4.6 mg NO 3 -N/kg soil - how much corn ear and grain dry matter produce are expected on soils with differing nitrogen supply, distributing 0-200 kg nitrogen fertilizer in spring.

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