Nitrogen Uptake and Mobilization by Hydrangea Leaves from Foliar-sprayed Urea in Fall Depend on Plant Nitrogen Status

Rooted liners of Hydrangea macrophylla (Thunb.) Ser. ‘Berlin’ were fertigated with different rates of nitrogen (N) from July to Sept. 2007 and leaves were sprayed with 15N-labeled urea in late October to evaluate urea uptake and 15N translocation by hydrangea leaves in relation to plant N status. Four plants from each N fertigation rate were harvested before they were sprayed with urea and 2, 5, 10, and 15 days after urea spray. Increasing rate of N fertigation increased plant N content in October before being sprayed with urea. Leaves rapidly absorbed 15N from urea spray. The highest rate of 15N uptake occurred during the first 2 days after urea spray and then decreased. Export of 15N from leaves occurred rapidly after uptake and the highest rate of 15N export occurred during the first 2 days after urea spray and then decreased. During the first 5 days after urea spray, the rate of 15N uptake by leaves and export from leaves decreased with increasing rate of N fertigation. On a whole plant basis, the total amount of 15N from foliar 15N–urea spray increased with increasing rate of N fertigation; however, the percentage of 15N exported from leaves and the percentage of N that derived from foliar 15N–urea spray decreased with increasing rate of N fertigation. Results suggest that hydrangea plants with lower N status in the fall are more efficient in absorbing and translocating N from foliar urea than plants with higher N status.

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288 Effects of Foliar Urea on Reserve Nitrogen and Carbohydrates in Young Apple Trees with Different Nitrogen Background

HortScience ◽

10.21273/hortsci.34.3.492a ◽

1999 ◽

Vol 34 (3) ◽

pp. 492A-492

Author(s):

Lailiang Cheng ◽

Sunghee Guak ◽

Shufu Dong ◽

Leslie H. Fuchigami

Keyword(s):

N Content ◽

Carbohydrate Concentration ◽

Whole Plant ◽

Nitrogen Concentrations ◽

The Difference ◽

Natural Leaf ◽

Reserve Carbohydrate ◽

N Status ◽

Foliar Urea ◽

Whole Tree

Bench-grafted Fuji/M26 plants were fertigated with seven nitrogen concentrations (0, 2.5, 5.0, 7.5, 10, 15, and 20 mM) by using a modified Hoagland solution from 30 June to 1 Sept. In mid-October, half of the fertigated trees were sprayed with 3% urea twice at weekly intervals, while the other half were left as controls. The plants were harvested after natural leaf fall, stored at 2 °C, and then destructively sampled in January for reserve N and carbohydrate analysis. As N concentration used in fertigation increased, whole-plant reserve N content increased progressively with a corresponding decrease in reserve carbohydrate concentration. Foliar urea application increased whole-plant N content and decreased reserve carbohydrate concentration. The effect of foliar urea on whole-plant reserve N content and carbohydrate concentration was dependent on the N status of the plant, with low-N plants being more responsive than high-N plants. There was a linear relationship between the increase in N content and decrease in carbohydrate concentration caused by foliar urea, suggesting that part of the reserve carbohydrates was used to assimilate N from foliar urea. Regardless of the difference in tree size caused by N fertigation, the increase in the total amount of reserve N by foliar urea application was the same on a whole-tree basis, indicating that plants with low-N background were more effective in using N from urea spray than plants with high-N background.

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504 Urea Uptake and Nitrogen Mobilization by Apple Leaves in Relation to Tree Nitrogen Status in the Fall

HortScience ◽

10.21273/hortsci.35.3.481d ◽

2000 ◽

Vol 35 (3) ◽

pp. 481D-481

Author(s):

Lailiang Cheng ◽

Shufu Dong ◽

Leslie H. Fuchigami

Keyword(s):

Leaf Area ◽

N Uptake ◽

Urea Solution ◽

N Content ◽

Wide Range ◽

Leaf N Content ◽

N Status ◽

Foliar Urea ◽

Whole Tree ◽

Leaf N

Bench-grafted Fuji/M26 trees were fertigated with seven nitrogen concentrations (0, 2.5, 5.0, 7.5, 10, 15, and 20 mm) by using a modified Hoagland solution from 30 June to 1 Sept. In Mid-October, plants in each N treatment were divided into three groups. One group was destructively sampled to determine background tree N status before foliar urea application. The second group was painted with 3% 15N-urea solution twice at weekly interval on both sides of all leaves while the third group was left as controls. All the fallen leaves from both the 15N-treated and control trees were collected during the leaf senescence process and the trees were harvested after natural leaf fall. Nitrogen fertigation resulted in a wide range of tree N status in the fall. The percentage of whole tree N partitioned into the foliage in the fall increased linearly with increasing leaf N content up to 2.2 g·m–2, reaching a plateau of 50% to 55% with further rise in leaf N. 15N uptake and mobilization per unit leaf area and the percentage of 15N mobilized from leaves decreased with increasing leaf N content. Of the 15N mobilized back to the tree, the percentage of 15N partitioned into the root system decreased with increasing tree N status. Foliar 15N-urea application reduced the mobilization of existing N in the leaves regardless of leaf N status. More 15N was mobilized on a leaf area basis than that from existing N in the leaves with the low N trees showing the largest difference. On a whole-tree basis, the increase in the amount of reserve N caused by foliar urea treatment was similar. We conclude that low N trees are more effective in utilizing N from foliar urea than high N trees in the fall.

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The Regulation of N Uptake at the Whole-plant Level in Tree Crops

HortScience ◽

10.21273/hortsci.33.3.556d ◽

1998 ◽

Vol 33 (3) ◽

pp. 556d-556

Author(s):

Farbod Youssefi ◽

Patrick H. Brown ◽

Steve A. Weinbaum

Keyword(s):

N Uptake ◽

Xylem Sap ◽

Soil N ◽

N Content ◽

Whole Plant ◽

Soil N Uptake ◽

Almond Trees ◽

Plant Level ◽

N Demand ◽

N Status

Coordinating fertilization practices with tree N uptake is important for reduction of groundwater contamination with nitrate. To reach this goal, the regulation of nitrogen uptake at the whole-plant level must be further understood. A theory that has been proposed on this subject is that a pool of amino-N, whose size is determined by above-ground N demand, cycles in the plant and regulates soil N uptake by exerting an inhibitory effect at the root level. Several experiments were carried out to study this hypothesis in fruit trees. First, foliar applications of N were made in almond trees, which led to the observation that soil N uptake was reduced in treated trees. In these trees, foliar-applied N was present in the roots when uptake was reduced; further, amino-N content of leaf and bark phloem sap was increased after several hours in the treated tree. In another experiment, amino-N content of phloem and xylem sap of almond trees of varying N status was determined. Several trees under each N status were given a pulse of abundant N fertilizer, so that their N uptake would be compared. Trees of higher N status, with greater amounts of amino-N cycling in their sap, did not take up more N than equivalent control plants, whereas lower N status trees did. To complete this series of experiments, it was observed that fruit-bearing shoots in walnut trees exported smaller proportions of foliar-applied N than non-bearing shoots, indicating that above-ground N demand may regulate the pool of N that moves down in the plant. These results and the principles that regulate N uptake will be discussed.

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Variability for Nitrogen Management in Genetically-Distant Maize (Zea mays L.) Lines: Impact of Post-Silking Nitrogen Limiting Conditions

Agronomy ◽

10.3390/agronomy8120309 ◽

2018 ◽

Vol 8 (12) ◽

pp. 309 ◽

Cited By ~ 1

Author(s):

Isabelle Quilleré ◽

Céline Dargel-Graffin ◽

Peter J. Lea ◽

Bertrand Hirel

Keyword(s):

N Uptake ◽

Predictive Marker ◽

N Fertilization ◽

High Yield ◽

N Content ◽

Whole Plant ◽

Large Level ◽

N Remobilization ◽

N Management ◽

The Impact

The impact of nitrogen (N)-limiting conditions after silking on kernel yield (KY)-related traits and whole plant N management was investigated using fifteen maize lines representative of plant genetic diversity in Europe and America. A large level of genetic variability of these traits was observed in the different lines when post-silking fertilization of N was strongly reduced. Under such N-fertilization conditions, four different groups of lines were identified on the basis of KY and kernel N content. Although the pattern of N management, including N uptake and N use was variable in the four groups of lines, a number of them were able to maintain both a high yield and a high kernel N content by increasing shoot N remobilization. No obvious relationship between the genetic background of the lines and their mode of N management was found. When N was limiting after silking, N remobilization appeared to be a good predictive marker for identifying maize lines that were able to maintain a high yield and a high kernel N content irrespective of their female flowering date. The use of N remobilization as a trait to select maize genotypes adapted to low N input is discussed.

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Phosphorus nutrition of spring wheat (Triticum aestivum L.). 3. Part 2, Aust. J. Agric. Res., 1997, 48, 869-81.. Effects of plant nitrogen status and genotype on the calibration of plant tests for diagnosing phosphorus d

Australian Journal of Agricultural Research ◽

10.1071/a96161 ◽

1997 ◽

Vol 48 (6) ◽

pp. 883 ◽

Cited By ~ 8

Author(s):

D. E. Elliott ◽

D. J. Reuter ◽

G. D. Reddy ◽

R. J. Abbott

Keyword(s):

Vegetative Growth ◽

N Uptake ◽

Physiological Age ◽

Root Yield ◽

P Deficiency ◽

Plant Nitrogen ◽

N Supply ◽

P Concentration ◽

Labile P ◽

N Status

The influence of plant nitrogen (N) status and plant genotype on plant test criteria for diagnosing phosphorus (P) deficiency in wheat was examined in 2 glasshouse experiments. Criteria for both total and labile P in leaf blades of standard physiological age are, to only a minor extent, affected by variations in N supply and by genotypic diversity Interactions between N and P supply had marked and complex effects on shoot and root yield, P and N uptake in shoots and concentrations in leaf blades, and on the distribution of P and P fractions within wheat shoots. Thus, whilst the external P requirement (i.e. P level required for 90% maximum shoot yield) more than doubled as N supply was raised, variations in N supply had only minor effects on internalP requirement (i.e. the tissue P concentration required for 90% maximum shoot yield). On the other hand, the external P requirement for root yield varied markedly with plant age and N supply. N deficiency increased total P concentrations in leaf blades at all P levels, primarily by increasing the concentration of the labile P fraction. Also, N concentrations increased to adequate levels in the shoots of P-deficient plants but only at the 2 lower levels of applied N. Plant N status also affected the shape of diagnostic relationships between relative shoot yield and P concentrations in young and mature leaf blades by constricting P concentration in the adequate-luxury zone and increasing the slope of the relationship in the zone of deficiency. Whilst the asymptotic grain yield and external requirement for P for the tall cultivar (Halberd) was substantially less than for the semi-dwarf cultivars (Condor and Durati), consistent P cultivar interactions on shoot yield and P uptake during vegetative growth, were largely absent. For leaf blade classes examined, the shape of the diagnostic relationship for total and labile P was essentially similar for each cultivar. As a result, differences in estimated critical P concentrations for total and labile P between the cultivars for leaf blades during vegetative growth, or criteria for grain, glumes, and straw at maturity, were relatively small.

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Effect of Sources, Split and Foliar Application of KCl and KClO3 on Availability and Uptake of Nitrogen in Aerobic Rice

International Journal of Environment and Climate Change ◽

10.9734/ijecc/2021/v11i330377 ◽

2021 ◽

pp. 55-72

Author(s):

P. Anji Babu ◽

K. Omar Hattab ◽

L. Aruna ◽

R. Mohan

Keyword(s):

Nitrogen Uptake ◽

Foliar Application ◽

Rice Variety ◽

N Uptake ◽

Aerobic Rice ◽

N Availability ◽

Flowering Stage ◽

Positive Interaction ◽

Available N ◽

N Status

Aim: To investigate the effect of KCl and KClO3 as sources of potassium in aerobic rice with four types of split doses and two levels of foliar applications of potassium. Study Design: The experiment was laid out in Randomized Block Design with three replications. Place and Duration of Study: Pandit Jawaharlal Nehru College of Agriculture and Research Institute, Karaikal, Puducherry. Methodology: The rice variety PMK 4 was tested with two sources of potassium viz., Potassium chloride (KCl) and Potassium chlorate (KClO3), four types of split application viz., K control (S1), basal with no split (S2), two splits (S3) and three splits (S4) along with foliar application treatments viz., no foliar (F1) and foliar spray (F2). Results: The results of field experiment revealed that the N availability in soil was more at all stages of crop growth by two and three split doses of potassium. The KClO3 increased the available N status at active and panicle initiation stages. Whereas in flowering stage, the KCl recorded the higher available N status in soil. The nitrogen uptake at active tillering stage and flowering stage was evidently improved with three split doses of potassium. Whereas in panicle initiation stage, the two split doses registered higher N uptake. The nitrogen uptake by both grain and straw was conspicuously higher in three and two split doses of potassium. Conclusion: The split applications tested in this investigation influenced the available N status in soil. Almost in all the stages, three split applications retained more available N in soil. This implies the positive interaction of potassium with nitrogen.

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615 Growth Performance of Transplanted Young Apple Trees in Relation to Reserve Nitrogen and Carbohydrates

HortScience ◽

10.21273/hortsci.34.3.553d ◽

1999 ◽

Vol 34 (3) ◽

pp. 553D-553 ◽

Cited By ~ 1

Author(s):

Lailiang Cheng ◽

Leslie H. Fuchigami

Keyword(s):

Leaf Growth ◽

Free Medium ◽

N Content ◽

Carbohydrate Concentration ◽

N Supply ◽

Whole Plant ◽

Carbohydrate Levels ◽

Natural Leaf ◽

Reserve Carbohydrate ◽

Foliar Urea

Reserve N and carbohydrate levels of bench-grafted Fuji/M26 plants were altered by fertigation with seven N concentrations from 30 June to 1 Sept. in combination with or without 3% foliar urea application in mid-October. The plants were harvested after natural leaf fall and stored at 2 °C. One set of plants were destructively sampled in January for reserve N and carbohydrates analysis, and the remaining plants were transplanted into a N-free medium in the spring and supplied with or without 5 mM 15N-ammonium nitrate in a Hoagland solution for 60 days after budbreak. Plants fertigated with higher N concentrations had higher reserve N content and lower carbohydrate concentrations. Foliar urea application increased whole plant N content and decreased reserve carbohydrate concentration at each given N concentration used in fertigation. Regardless of N supply in the spring, total new shoot and leaf growth of plants fertigated with N was closely related to the amount of reserve N but not reserve carbohydrates. Plants treated with foliar urea had more new shoot and leaf growth than the fertigated controls. By pooling all the data concerning reserve N used for growth regardless of the spring N supply, a linear relationship was found between the amount of reserve N used for new shoot and leaf growth and the total amount of N. We conclude that the growth of apple nursery plants in the spring is mainly determined by reserve N, not reserve carbohydrates. The amount of reserve N used for new shoot and leaf growth in the spring is dependent on the total amount of reserve and is not affected by the current N supply.

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Use of fluorescence indices as predictors of crop N status and yield for greenhouse sweet pepper crops

Precision Agriculture ◽

10.1007/s11119-021-09837-4 ◽

2021 ◽

Author(s):

Romina de Souza ◽

M. Teresa Peña-Fleitas ◽

Rodney B. Thompson ◽

Marisa Gallardo ◽

Rafael Grasso ◽

...

Keyword(s):

Optical Sensors ◽

Management Practices ◽

N Uptake ◽

Relative Yield ◽

Sweet Pepper ◽

Growth Stages ◽

N Content ◽

Fluorescence Measurements ◽

N Management ◽

N Status

AbstractTo increase nitrogen (N) use efficiency and reduce water pollution from vegetable production, it is necessary to optimize N management. Fluorescence-based optical sensors are devices that can improve N fertilization through non-destructive field monitoring of crop variables. The aim of this work was to compare the performance of five fluorescence indices (SFR-R, SFR-G, FLAV, NBI-R, and NBI-G) to predict crop variables, as dry matter production, crop N content, crop N uptake, Nitrogen Nutrition Index (NNI), absolute and relative yield, in sweet pepper (Capsicum annuum) crops grown in greenhouse. Fluorescence measurements were periodically made with the Multiplex® 3.6 sensor throughout three cropping cycles subjected to five N application treatments. The performance of fluorescence indices to predict crop variables considered calibration and validation analyses. In general, the five fluorescence indices were strongly related with NNI, crop N content and relative yield. The best performing indices to predict crop N content and NNI at the early stages of the crops (i.e., vegetative and flowering phenological stages) were the SFR indices, both under red (SFR-R) and green (SFR-G) excitation. However, in the final stage of the crop (i.e., harvest stage), the best performing indices were NBI, both under red (NBI-R) and green (NBI-G) excitation, and FLAV. The two SFR indices best predicted relative yield of sweet pepper at early growth stages. Overall, the fluorescence sensor and the fluorescence indices evaluated were able to predict crop variables related to N status in sweet pepper. They have the capacity to be incorporated into best N management practices.

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Peach Leaves Do Take Up Foliarly Applied Urea Nitrogen

HortScience ◽

10.21273/hortsci.32.3.498b ◽

1997 ◽

Vol 32 (3) ◽

pp. 498B-498

Author(s):

Richard C. Rosecrance ◽

Scott Johnson ◽

Steven A. Weinbaum

Keyword(s):

Prunus Persica ◽

Leaf Abscission ◽

N Content ◽

Urea Nitrogen ◽

Urea Uptake ◽

Leaf Surfaces ◽

Peach Trees ◽

Foliar Urea

The ability of peach leaves to absorbed and translocated foliarly applied 15N-urea in mature peach (Prunus persica) trees was determined. Urea uptake experiments were conducted in June, October, and November 1995. Peach leaves absorbed ≈80% of the urea within 48 hr of application in all three experiments based on urea rinsed from leaf surfaces. Similarly, leaf 15N content reached a peak 48 hr after application. Translocation of 15N out of leaves, however, was more rapid in October then November. In October, 24% of the 15N remained in the leaves 2 weeks after application, while, in November, 80% stayed in the leaves and fell to the orchard floor. Thus, applying urea in mid November did not allow enough time for the N to be transported out of the leaves before leaf abscission. Timing of foliar urea application is critical to maximize N transport into perennial tissues of peach trees. 15Nurea resorption out of leaves and into perennial tree parts (roots, trunk, current year wood, etc.) is discussed.

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