Is there a relationship between ferric-chelate reductase activity in roots of poncirus trifoliata and leaf chlorophyll contents?

Poncirus trifoliata is a citrus rootstock very sensitive to Fe deficiency. This deficiency is very common in crops grown in calcareous soils due to the detrimental effect of bicarbonate ion. Higher plants have distinct behaviours when faced with Fe chlorosis, and several mechanisms may be activated under Fe shortage. The aim of this study was to investigate the activity of ferric-chelate reductase (FC-R), a key enzyme in Fe uptake, and to verify whether relationships with leaf chlorophyll contents could be established. Plants were grown in nutrient solutions without Fe (0 μM Fe), with 1 μM Fe, with 120 μM Fe and with 120 μM Fe plus CaCO3 (1 g L-1). Total leaf chlorophyll in young and mature leaves was determined using a calibration model based on a relationship between SPAD readings and concentration of chlorophyll (r2=0.95; P<0.01). The activity of FC-R was determined in roots apexes and several biomass parameters in shoots (number of leaves, height, dry and fresh weight) and roots (dry and fresh weight) were evaluated at the end of the experiment. The activity of FC-R increased in plants grown without iron (0 μM Fe). The results about the relations between root FC-R and leaf chlorophyll are discussed.info:eu-repo/semantics/publishedVersio

Correction to: Can bicarbonate enhance the performance of carob seedlings grown in nutrient solutions with different Fe concentrations?

Correction to: Journal of Soil Science and Plant Nutrition https://doi.org/10.1007/s42729-019-00100-4info:eu-repo/semantics/publishedVersio

Responses of tomato (Solanum lycopersicum L.) plants to iron deficiency in the root zone

Iron deficiency induces a yellowing in the aerial part of plants, known as iron chlorosis, and reduces the growth, yield, and quality of the fruits. Understanding plant response to iron deficiency is essential for agronomic management. This study decoded the temporal response of tomato plants (Solanum lycopersicum L.) to iron deficiency by quantifying different vegetative parameters. Subapical root swelling in the first 2.0 mm and several shoot and root growth parameters were measured in plants grown in a nutrient solution with and without Fe, on different dates designated as days after transplantation (DAT). Correlations between the total chlorophyll concentration in young leaves and 22 morphological and physiological parameters were also calculated. The plants grown in the absence of Fe had a higher number of secondary roots at 3 DAT, compared to control plants. On the same date, subapical root swelling was also observed, particularly at 1.5 and 2.0 mm from the root tip. Those plants also had a lower chlorophyll content in young leaves and a higher ferric-chelate reductase activity (FCR; EC 1.16.1.17) in the roots. At 9 DAT, the overall vegetative performance (plant height, fresh weight of stems and leaves) was negatively affected. At the end of the experiment (14 DAT), significant correlations were found between chlorophyll and the studied parameters. In conclusion, tomato plants experienced a cascade of responses to Fe deficiency throughout nine days: firstly, root lateralization increased; later, root swelling was observed, and a decrease in leaf chlorophyll content was registered associated with an increase in root FCR. At the end, the biomass of tomato plants decreased.info:eu-repo/semantics/publishedVersio

Avaliação da tolerância à clorose férrica de porta-enxertos de citrinos em solução nutritiva

4 Pags.- 3 Figs.Um dos principais factores indutores da clorose férrica em solos calcários é o ião bicarbonato cuja acção parece afectar diversos processos metabólicos nas raízes e nas folhas, diminuindo a disponibilidade de Fe no interior da planta. Nestas condições, quando a absorção de Fe é baixa, os genótipos Fe-eficientes desencadeiam mecanismos de resposta ao nível da parte aérea e/ou radicular que incluem alterações fisiológicas, bioquímicas e morfológicas (Schmidt, 1999). Ao nível da parte aérea, o ferro é um elemento essencial para a formação das membranas dos tilacóides e para a biossíntese clorofilina (Abadía, 1992). Consequentemente, a eficiência de conversão da energia fotossintética é afectada pela clorose férrica e pode ser avaliada pelos parâmetros de fluorescência da clorofila a (Abadía et al., 1999). Neste ensaio em solução nutritiva pretendeu-se caracterizar a tolerância de três porta-enxertos de citrinos à clorose férrica com base em diversos parâmetros e processos fisiológicos da planta.Peer reviewe

Management of carob tree orchards in Mediterranean ecosystems: strategies for a carbon economy implementation

This paper offers a different framework for managing Mediterranean drought carob-tree orchard ecosystems. Two dry-farming systems were compared during two consecutive years: pure productive orchards and mixed orchards in a total of 360 mature trees distributed by 18 plots with areas of 0.55 and 0.30 ha per plot, respectively. Carob, fig, almond and olive trees compose mixed orchards. Trees of the mixed orchards were more productive than those of pure orchards. The main problem of both systems was the large variability and the low fruit production due to non-bearing trees, inducing unfavorable economic returns. Yield varied between 7.7 and 28.5 kg tree(-1) respectively in pure and mixed orchards. In this paper we propose to use carbon sequestration calculations as an added benefit to farmers. A carbon stocking model estimation was established, based on trunk diameters of different trees. We depicted two management scenarios based on fruits production and carbon sequestration incomes: a low value scenario, using mean fruit production, and a high valuable scenario based on the hypothesis that all trees reached its potential maximum. Since under dry-farming systems fruit production irregularity is still a pendent problem, mixed orchards may offer a potential higher revenue, while maintaining higher crop diversification and whole biodiversity. C sequestration benefit, as here we purpose, may represent 125-300 % of income, respectively under low or high valuable scenario. Thus, CO2 equivalent is a novel ecological economic incentive that may potentiate a new income for farmers while assuring carob ecosystem services.[AGRO306

Effect of Bacillus velezensis and Glomus intraradices on fruit quality and growth parameters in strawberry soilless growing system

This study evaluates the effect on the 'Splendor' and 'Primoris' strawberry cultivars of different dates of inoculation with Glomus intraradices, an arbuscular mycorrhizal (AM) fungus. Additionally, plants were grown in a soilless growing system with or without Bacillus velezensis at the beginning of the experiment. A completely randomized block design (2 biofertilizer treatments x 2 cultivars x 3 inoculation dates) with 2 replications was used. Each replicate consisted of one bag with 10 plants. Fruit weight, fruit quality, growth parameters, and SPAD values in young leaves were monitored from October 2011 to June 2012 in a greenhouse. At the end of the crop cycle, the microbial population of Bacillus spp. and the Glomus intraradices population were determined from the rhizosphere of the plant. Bacillus velezensis and Glomus intraradices were established in the strawberry soilless growing system. The effect of arbuscular mycorrhizae on strawberry fruit quality was more important than that on growth parameters. Biofertilizer with arbuscular mycorrhizal fungi had an inhibitory effect on fruit quality, as indicated by low TSS, pH, and TA values. The combined effect of the biofertilizer and inoculation dates of Glomus intraradices on growth parameters was more significant in the 'Primoris' cultivar than in 'Splendor'. In both cultivars, an increase in SPAD values was observed from week 12 to week 22 after planting. Depending on the cultivar selected, the date of inoculation may significantly affect plant response to AM fungal colonization in a soilless growing system.I2TEP Project (Hidroponfresa)info:eu-repo/semantics/publishedVersio

Effects of fertiliser practices on the growth and quality of two table grape cultivars: 'Cardinal' and 'D. Maria'.

In this study, the different fertilliser practices of four commercial vineyards (Vitis vinifera L. cv. 'Cardinal' and cv. 'D. Maria') in southern Portugal were assessed and compared in 2002. The vineyards were established in similar soils under the same climatic conditions and additional water was supplied by drip irrigation. At harvest, the mineral composition of petioles (P, K, Mg, Ca, Fe, Cu, Zn and Mn) and quality parameters of the grapes (total soluble solids expressed as degree Brix, cluster length and weight, number of grapes, grapes weight and rachis weight) were recorded. For the 'Cardinal' cultivar, the nutritional status of the plant was correlated with growth and yield, and the greatest values for most of the parameters studied were measured at Alvisquer farm. For the 'D. Maria' cultivar, a single correlation was found between nutrient levels and growth. Shoot and cluster lengths, and grape weight were similar at all farms, though cluster weight, number of grapes and total soluble solids were smaller at Pedras than at Alvisquer or Gomeira

The effects of the use of organic solid wastes on the growth of citrus trees

Two types of organic solid wastes were selected to be applied in a citrus orchard: the sewage sludge (the most common on the settlements) and the manure (the most common on the agricultural fields). The sewage sludge is a residue originated from the wastewater treatment - the solid phase. Its application as an organic fertilizer may represent an alternative to the pollution effects in nature. In an orchard of orange-trees (Citrus sinensis [L.] Osbeck), the application of sludge was compared with the application of manure and with the control in order to observe the growth response of the trees. Biometric methods where used - number of leaves per tree, diameter of the trunk, leaf area, specific leaf areas and leaf chlorophyll content. In general, the citrus plants response to the application of sewage sludge and manure was positive for the plant growth, compared to the control. The application of the manure, and especially the sewage sludge (once this fertilizer / soil amendment is available in larger amounts) may be a profitable alternative application to the use of mineral fertilizers and to other soil amendments. Moreover, as the possible destinations of sewage sludge (sea, deposition in land fields, incineration) provoke environmental problems, its agricultural reuse is essential to avoid those problems, when correctly applied in relation to trace elements and to pathogenic parameters. The reuse of this solid waste may be a clean and a safe technique to preserve the environment contamination

The memory of iron stress in strawberry plants

Research ArticleTo provide information towards optimization of strategies to treat Fe deficiency, experiments were conducted to study the responses of Fe-deficient plants to the resupply of Fe. Strawberry (Fragaria ananassa Duch.) was used as model plant. Bare-root transplants of strawberry (cv. ‘Diamante’) were grown for 42 days in Hoagland's nutrient solutions without Fe (Fe0) and containing 10 mM of Fe as Fe-EDDHA (control, Fe10). For plants under Fe0 the total chlorophyll concentration of young leaves decreased progressively on time, showing the typical symptoms of iron chlorosis. After 35 days the Fe concentration was 6% of that observed for plants growing under Fe10. Half of plants growing under Fe0 were then Fe-resupplied by adding 10 mM of Fe to the Fe0 nutrient solution (FeR). Full Chlorophyll recovery of young leaves took place within 12 days. Root ferric chelate-reductase activity (FCR) and succinic and citric acid concentrations increased in FeR plants. Fe partition revealed that FeR plants expressively accumulated this nutrient in the crown and flowers. This observation can be due to a passive deactivation mechanism of the FCR activity, associated with continuous synthesis of succinic and citric acids at root level, and consequent greater uptake of Fe.info:eu-repo/semantics/publishedVersio

Brief characterisation of Fe chlorosis in chia (Salvia hispanica L.) plants grown in nutrient solution

Chia (Salvia hispanica L.) plant is a well-known plant due to the nutraceutical value of its seeds. The aim of this preliminary study was to assess the response of Chia plants to Fe deficiency. Chia plants were grown for 12 days in Hoagland's nutrient solutions without Fe (Fe0) and with Fe (Fe10-10 mu M Fe). Biomass parameters and root ferric chelate-reductase activity (FC-R; EC 1.16.1.17) were determined at the end of the experiment. Chlorophyll estimations (expressed as SPAD readings) decreased progressively, showing the typical symptoms of iron chlorosis. In addition, iron-deficient chia plants exhibit smaller biomass (number of leaves, root, and shoot growth reduction) compared to control plants. These plants also showed morphological changes in roots. Furthermore, root FC-R activity was significantly lower in Fe0 plants.info:eu-repo/semantics/publishedVersio