Efecto del bicarbonato sobre el crecimiento de los patrones de cítricos: mandarino Cleopatra, Poncirus trifoliata, Forner-Alcaide nº 030131 y Forner-Alcaide nº 030141

Se ha llevado a cabo un ensayo en el que se estudia el crecimiento (altura y peso fresco y seco del brote nuevo) de mandarino Cleopatra, Poncirus trifoliata y dos de sus híbridos Forner-Alcaide (FA) FA 030131 y FA 030141 ante diferentes concentraciones de bicarbonato. Estos patrones se cultivaron durante 84 días, en macetas de 3L con arena silícea, regadas con soluciones nutritivas tipo Hoagland (20 μM de hierro) con diferentes concentraciones de bicarbonato sódico (0, 10 y 20 mM). El patrón menos afectado por la concentración creciente de bicarbonato ha sido el mandarino Cleopatra. Por el contrario el P. trifoliata fue el patrón en el que más se redujo el crecimiento, tanto en altura como en peso fresco y seco del brote nuevo. El efecto del bicarbonato fue diferente según el híbrido, el FA 030141 disminuyó más su crecimiento con altas dosis de bicarbonato (20 mM), aunque estadísticamente no fue significativo, mientras que en el FA 030131 el efecto reductor fue similar con ambas dosis de bicarbonato (10 y 20mM)

Quality Parameters of Spanish Lemons with Commercial Interest

The Spanish Mediterranean region concentrates the largest producers of lemons (Citrus limon Burm. f.) at the national level where the 98.4% of the cultivated area of lemons corresponds to the varieties “Verna” and “Fino”. In this study, the morphological and chemical variations of the fruits obtained in five variety/rootstock combinations were investigated in order to determine the influence and impact of the rootstock on the physicochemical properties of the fruits. The assay was carried out using three lemon varieties (“Fino 95”, “Fino 49” and “Verna”) grafted onto two different rootstocks (Citrus macrophylla and Citrus aurantium). The varieties were selected due to be consolidated commercial varieties, while the rootstocks are the most commonly used in the world. Both the morphological characteristics of the fruits (colour, weight, size) as well as their physicochemical characteristics (total soluble solids, titratable acidity, maturity index, antioxidant activity, sugars, and organic acids) were evaluated. Based on the results, the lemons with the best physicochemical and the best compositional characteristics were obtained in the “Fino 95” and “Fino 49” lemons grafted onto C. aurantium rootstock presented the highest quality fruits

Influence of New Citrus Rootstocks on Lemon Quality

Citrus fruits are one of the main crops produced in the world with oranges, tangerines, lemons and grapefruits being among the most important. Among them, lemons are beneficial for human health because of their antioxidant activity, phenols and vitamin C. This study evaluates three rootstocks obtained in a Spanish breeding program (Valencian Institute for Agricultural Research (IVIA)): Forner-Alcaide 5 citrus rootstock (‘FA 5’), Forner-Alcaide 13 (‘FA 13’) and Forner-Alcaide 517 (‘FA 517’) grafted onto cultivars `Eureka´, `Verna´, `Fino 49’ and `Betera´. The results determined that rootstocks have influenced cultivars in terms of a decrease in the fruit size, weight, and thickness of the peel; but has increased the percentage of juice and soluble solids. With respect to phenol content and antioxidant activity, higher values were found with all cultivars studied on rootstocks ‘FA 13’, followed by ‘FA 517’. Cultivars that were most influenced by rootstocks were 'Bétera' and 'Eureka' in physical properties, while in chemical properties they were 'Verna' followed by 'Fino 49'. This investigation demonstrated the interaction of rootstocks on different cultivars in morphological, biochemical and nutraceutical characteristics

Influence of Different Rootstocks on Fruit Quality and Primary and Secondary Metabolites Content of Blood Oranges Cultivars

Blood oranges have high concentrations of bioactive compounds that are beneficial to health. In Europe, the cultivation of blood oranges is increasing due to their excellent nutritional properties. In Citrus crops, rootstocks play an important role in juice and can increase the content of bioactive compounds. The morphological, qualitative and nutritional parameters were analyzed in cultivars ‘Tarocco Ippolito’, ‘Tarocco Lempso’, ‘Tarocco Tapi’ and ‘Tarocco Fondaconuovo’ grafted onto Citrus macrophylla and Citrus reshni. ‘Tarocco Lempso’ grafted onto Citrus macrophylla obtained the highest values of weight (275.78 g), caliber (81.37 mm and 76.79 mm) and juice content (162.11 g). ‘Tarocco Tapi’ grafted onto Citrus reshni obtained the most interesting qualitative parameters (15.40 °Brix; 12.0 MI). ‘Tarocco Lempso’ grafted onto Citrus reshni obtained the most intense red juice (a* = 9.61). Overall, the highest concentrations of primary metabolites were in proline, aspartate, citric acid, and sucrose. The results showed that ‘Tarocco Ippolito’ juice grafted onto Citrus reshni had the highest levels of total hydroxycinnamic acids (263.33 mg L−1), total flavones (449.74 mg L−1) and total anthocyanins (650.42 mg L−1). To conclude, ‘Tarocco Lempso’ grafted onto Citrus macrophylla obtained the best values of agronomic parameters, and the cultivars grafted onto Citrus reshni obtained significantly higher concentrations in primary and secondary metabolites

Efecto del patrón sobre el crecimiento del árbol, la productividad y la calidad de la fruta, sobre el naranjo, variedad Lane Late

This study analyses the influence of four citrus rootstocks, Citrus macrophylla Wester, Gou Tou Chen (Citrus hybrid), C. volkameriana Ten. & Pasq. and Cleopatra mandarin (C. reshni Hort. ex Tan.), on growth, yield and fruit quality on Lane Late navel orange. Trees were grown in a plot in Alicante (Spain), where the soil is clay loam, with pH 8.5 and electric conductivity in the 1/5 extract: 0.643 mmhos cm–1. Yield was weighed during four harvests, fruit quality was determined in 2007 and 2009. Cleopatra mandarin and Gou Tou Chen were found to be the most invigorating rootstocks for ‘Lane Late’ in heavy and calcareous soil. Trees on C. macrophylla rootstock produced the highest cumulative yield (328.81 kg tree–1), without significant differences compared to trees on Cleopatra mandarin (292.41 kg tree–1). Rootstock significantly affected fruit quality variables. C. macrophylla and C. volkameriana would appear to induce the highest fruit weight and ripening index.El presente estudio analiza la influencia de cuatro patrones de cítricos, Citrus macrophylla Wester, Gou Tou Chen (híbrido de Citrus), C. volkameriana Ten. and Pasq. y mandarino Cleopatra (C. reshni Hort. ex Tan.) en el tamaño del árbol, la productividad y la calidad de la fruta de la variedad ‘Lane Late’. Los árboles se cultivaron en una parcela en Alicante (España), donde el suelo es franco arcilloso, con pH 8,5 y conductividad eléctrica en el extracto 1/5: 0,643 mmhos cm–1. La productividad de los árboles se determinó durante cuatro cosechas; la calidad de la fruta se analizó en 2007 y 2009. El mandarino Cleopatra y el Gou Tou Chen fueron los patrones más vigorosos para Lane Late en suelos pesados y calizos. Los árboles sobre el patrón C. macrophylla produjeron una mayor cosecha acumulada (328,81 kg árbol–1), aunque sin diferencias significativas con los árboles injertados sobre mandarino Cleopatra (292,41 kg árbol– 1). El patrón afecta significativamente las variables de calidad del fruto. C. macrophylla y C. volkameriana inducen mayor peso del fruto, así como un mayor índice de madurez

Hydraulic and Chemical Responses of Citrus Seedlings to Drought and Osmotic Stress

In this work we investigated the function of abscisic acid (ABA) as a long-distance chemical signal communicating water shortage from the root to the shoot in citrus plants. Experiments indicated that stomatal conductance, transpiration rates, and leaf water potential decline progressively with drought. ABA content in roots, leaves, and xylem sap was also increased by the drought stress treatment three- to sevenfold. The addition of norflurazon, an inhibitor of ABA biosynthesis, significantly decreased the intensity of the responses and reduced ABA content in roots and xylem fluid, but not in leaves. Polyethylene glycol (PEG)-induced osmotic stress caused similar effects and, in general, was counteracted only by norflurazon at the lowest concentration (10%). Partial defoliation was able to diminish only leaf ABA content (22.5%) at the highest PEG concentration (30%), probably through a reduction of the active sites of biosynthesis. At least under moderate drought (3-6 days without irrigation), mechanisms other than leaf ABA concentration were required to explain stomatal closure in response to limited soil water supply. Measurements of xylem sap pH revealed a progressive alkalinization through the drought condition (6.4 vs. 7.1), that was not counteracted with the addition of norflurazon. Moreover, in vitro treatment of detached leaves with buffers iso-osmotically adjusted at pH 7.1 significantly decreased stomatal conductance (more than 30%) as much as 70% when supplemented with ABA. Taken together, our results suggest that increased pH generated in drought-stressed roots is transmitted by the xylem sap to the leaves, triggering reductions in shoot water loss. The parallel rise in ABA concentration may act synergistically with pH alkalinization in xylem sap, with an initial response generated from the roots and further promotion by the stressed leaves

Performance of Navel orange trees grafted onto two new dwarfing rootstocks (Forner-Alcaide 517 and Forner-Alcaide 418)

The aim of the present work was to study the performance of two new dwarfing citrus rootstocks (FornerAlcaide 517 and Forner-Alcaide 418) in comparison with Carrizo citrange. To carry out these experiments, rootstocks were budded with Navelina Navel orange scions. In young plants, rootstocks' size-controlling capacity was associated to their hydraulic conductance. In the case of Forner-Alcaide 418, lower hydraulic conductance was related to a smaller lumen area of root xylem vessels with respect to the other rootstocks. Also, hydraulic resistance of bud union segments of the stem was found to decrease with increasing vigour of plants grafted onto the different rootstocks. Furthermore, the graft union may provide resistance to sucrose transport in dwarfing rootstocks, as indicated by the reduced translocation of 13C-labelled photoassimilates from leaves to roots and reduced soluble sugar and starch concentrations under the graft union. This may result in a deficient carbohydrate supply to roots in dwarfing rootstocks, thereby stunting their growth. Accordingly, small root size and low hydraulic conductivity may cause water deficit in leaves during periods of high evaporative demand, inducing stomata! closure. This leads to a decrease in photosynthetic assimilation rate, which may affect plant growth negatively. These effects occur to a different extent in scions on both dwarfing rootstocks, appearing to be the cause of their reduced growth. Moreover, plants on both dwarfing rootstocks showed decreased translocation of 13 C-photoassimilates to roots, possibly contributing to higher availability of these compounds in the scion, and resulting in increased 13C transport towards the fruits. This effect could explain the higher yield efficiencies found in dwarfing rootstocks. A ten-year long field experiment, with trees grafted onto the three rootstocks, showed that FornerAlcaide 517 and Forner-Alcaide 418 induced lower canopy volumes and higher yield efficiencies than Carrizo citrange. In addition, our results show both dwarfing rootstocks produce good fruit quality, are suitable for high density plantings and can be cultured in alkaline soils. (C) 2014 Elsevier B.V. All rights reserved