Effect of ammonium/nitrate ratio on growth and development of avocado plants under hydroponic conditions

Lobit, Philippe; López-Pérez, Luis; Cárdenas‐Navarro, Raúl; Castellanos‐Morales, Vilma; Ruiz-Corro, R.

doi:10.4141/p06-029

Cited by 11 publications

(3 citation statements)

References 20 publications

(18 reference statements)

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“…Nitrate N was associated with induction of phytohormonal cascade transduction from root to shoot, leading to expansive leaf growth. This is in concurrence with findings of Lobit et al (2006), who found that a 49% reduction in the shoot length under dominant NH 4 + nutrition. These results were also in agreement with the findings of Gweyi- Onyango et al (2009) who observed a higher relative growth rate under nitrate even with lower concentrations as compared to ammonium.…”

Section: Plant Heightsupporting

confidence: 92%

Effects of different nitrogen forms on growth, phenolics, flavonoids and antioxidant activity in amaranth species

Rozy¹,

Changamu²,

Korir³

et al. 2017

Trop. Plant Res.

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Abstract:Higher plants, accumulate large number of polyphenolic compounds which are believed to act as defence compounds against different environmental constraints. Nitrogen (N) is a critical element for plant growth, absorbed as (NH 4 + ) and (NO 3 -), which affects plant growth and to some extent contributes to secondary metabolites accumulation. Greenhouse experiment was carried out to determine the effect of N forms on growth and phytochemical accumulation in Amaranthus species. Two amaranth varieties; AB6 and AB7 constituted the main plot while three N forms; ammonium, nitrate, ammonium nitrate and control (no N form) represented the subplot. Destructive sampling was done and plant height was recorded. Folin-Ciocalteu's and aluminium trichloride methods were used to determine total phenolic content (TPC) and total flavonoid content (TFC) respectively. DPPH (diphenylpicrylhydrazyl) radical scavenging activity assay was used to obtain total antioxidant activity. variety and TPC accumulation by 23% AB6 and 20% AB7 varieties respectively. Correspondingly, NH 4 + -N form resulted to superior antioxidant DPPH scavenging activity indicated by high scavenging activity and lower IC 50 value (concentration which scavenged 50% of the DPPH radicals). Plant height displayed a significant negative correlation with TFC and TPC accumulation of r= 0.75 and r= 0.81 respectively. The results indicated that ammonium-induced stress enhanced total flavonoids and phenolics accumulation; a salient phytochemical plasticity observed during plant growth and survival trade-off in a vegetable amaranth.

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Section: Plant Heightsupporting

confidence: 92%

Effects of different nitrogen forms on growth, phenolics, flavonoids and antioxidant activity in amaranth species

Rozy¹,

Changamu²,

Korir³

et al. 2017

Trop. Plant Res.

View full text Add to dashboard Cite

show abstract

“…These results are in agreement with those of Watson et al (1994) who reported delayed dissociation of urea to release N to a maximum period of 14 days depending on soil conditions resulting to low plant height. Other previous studies (Yong et al 2000;Lobit et al 2006;Borgognone et al 2013) also reported similar results of sharply reduced plant heights due to NH 4…”

Section: Plant Heightsupporting

confidence: 71%

Optimizing Maize Yield, Nitrogen Efficacy and Grain Protein Content under Different N Forms and Rates

OCHIENG’

Gitari

Mochoge

et al. 2021

J Soil Sci Plant Nutr

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This study aims to evaluate the efficacy of nitrogen (N) forms: ammonium, nitrate, and urea on maize performance, N uptake and use efficiency, and the grain protein content. The experiment was laid out as a split-plot with the whole plot factor being the three fertilizer treatments and the subplot being four N levels (0, 25, 50, and 100 kg N ha −1 ) with three replicates. Plant tissues were analyzed for total N uptake. Grain and stover yields and grain protein were determined at maturity. The highest (62 cm) plant height (at the vegetative stage) was recorded in nitrate treatment. Grain yield was highest (2.9 t ha −1 ) in plots that received nitrate. Fertilization with nitrate enhanced grain protein more (11.6%) than when urea or ammonium was used. N uptake was highest (42 kg N ha −1 ) under ammonium treatment, intermediate (22 kg N ha −1 ) in those treated with nitrate, and lowest (21 kg N ha −1 ) in urea-receiving plots. Application of 25 kg N ha −1 resulted in the least N uptake efficiency with optimal values registered at 50 kg N ha −1 . Agronomic N use efficiency differed among the rates with values ranging from 44 to 183 t ha −1 per N kg ha −1 applied in the order of 25 < 50 < 100 kg N ha −1 . This study showed that for optimal growth, productivity, and nutritional benefits, maize ought to be grown using nitrate N form at the rate of 50 kg N ha −1 .Keywords Nitrogen (N) fertilizer sources . N forms . N use efficiency indices . Grain protein content * Harun I. Gitari

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“…Manthey & Crowley (1997) used 30 L hydroponic tank systems to test 'Hass' seedlings for physiological responses to Fe deficiency. Lobit et al (2007) andMiyasaka et al (1999) also successfully maintained avocado plants in hydroponic systems; however both of these studies employed the use of solid substrates to provide root system support. Use of such substrates for studies of avocado has the added benefit of in-built root system aeration.…”

Section: Discussionmentioning

confidence: 99%

Evaluation of phytophthora root rot resistance in avocado

Neilsen¹

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Avocado trees (Persea americana) affected by Phytophthora root rot caused by Phytophthora cinnamomi produce copious amounts of small, poor quality fruit and without intervention, affected trees eventually die. Current management practices involve an integrated approach to disease management, including planting on well-draining soil with a high total cation exchange capacity, application of organic mulch, carefully monitored organic and inorganic nutrition, phosphonate applications and the use of tolerant rootstock varieties. Selection of rootstocks in breeding programs is a time consuming process involving extensive glasshouse and field screening but little is understood about the mechanisms underlying tolerance in elite selections. The overall aim of the research described in this thesis was to identify phenotypic differences across a range of avocado rootstock varieties with varying degrees of resistance/ susceptibility that may be associated with known field susceptibility.The first hypothesis tested in this thesis is that field resistant rootstock varieties have greater root regenerative ability than susceptible varieties. This hypothesis was tested using a glasshouse study of inherent root growth of seedlings as well as an inoculation study to investigate root system health and wilting in response to infection by P. cinnamomi. To investigate whether inherent root growth correlates with known field susceptibility of seedling rootstock varieties, a 2-pot root regeneration system was successfully developed and varietal differences in root: shoot ratio across nine seedling avocado varieties assessed. Seedling 'Hass' produced the greatest amount of feeder roots relative to the surface area of mature leaves, although overall differences between seedling varieties were not significant. The main finding of the glasshouse root growth studies was that there were no strong indications that inherent root growth and root system necrosis correlated with known field susceptibility.The second hypothesis tested was whether increased surface feeder root growth of mature trees and other tree physiology attributes such as stored non-structural starch, yield, tree health and growth measurements such as tree height and canopy volume have any association with known field susceptibility. At one experimental site, feeder root growth of mature trees measured over two seasons was not significantly different between rootstocks 'Dusa' and 'SHSR-04' and no significant differences or associations were found in stored starch, tree health, yield or tree growth parameters.At the second experimental site, there were also no significant differences detected in feeder root growth of rootstock varieties. Significant differences in tree physiology were detected among rootstocks with 'Velvick' having the strongest determinate vegetative growth measured and the highest level of stored non-structural starch, although it wasn't significantly higher than fieldsusceptible 'Reed'. Overall, results of field studies at both sites indicated that t...

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Effect of ammonium/nitrate ratio on growth and development of avocado plants under hydroponic conditions

Cited by 11 publications

References 20 publications

Effects of different nitrogen forms on growth, phenolics, flavonoids and antioxidant activity in amaranth species

Effects of different nitrogen forms on growth, phenolics, flavonoids and antioxidant activity in amaranth species

Optimizing Maize Yield, Nitrogen Efficacy and Grain Protein Content under Different N Forms and Rates

Evaluation of phytophthora root rot resistance in avocado

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