Martínez Fuentes, Amparo
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Martínez Fuentes
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- PublicationSoil Temperature Regulates Fruit Color Change in Algerie Loquat: Nutritional and Hormonal Control(Springer-Verlag, 2016) Reig Valor, Carmina; Grillone, Nicola; Mesejo Conejos, Carlos; Martínez Fuentes, Amparo; Agustí Fonfría, Manuel; Dpto. de Producción Vegetal; Instituto Agroforestal Mediterráneo; Escuela Técnica Superior de Ingeniería Agronómica y del Medio Natural[EN] In Rosaceae fruit tree species, fruit and roots grow opposite because of carbohydrate competition, and root activity is thus reduced by fruit growth. In agreement with this, for some of these species soil temperature has been suggested as a factor regulating fruit ripening, but the mechanism with which it works remains unknown. In this study, we reduced loquat root activity by lowering soil temperature, expecting faster fruit growth and advanced fruit ripening. Eight 4-year-old 'Algerie' loquat trees, budded onto seedling rootstock, and grown outdoors in 39-l plastic containers filled with sandy-loamy soil were used. The roots of four trees were cooled by placing the containers in a cooling compartment (9.5 A degrees C), whereas those of the other four trees were maintained at air temperature (16.5 A degrees C). We measured lateral root primordia emergence, fruit diameter and fruit color development, carbohydrates and nitrogen partitioning, as well as GA, CK, IAA, ABA, and JA content. Lowering soil temperature increased carbohydrate translocation to the fruit and reduced root N uptake and translocation to both the canopy and the fruit. Changes in plant hormones were also caused by reduced soil temperature, and fruit color advanced. Loquat fruit ripened 8-10 days earlier when soil temperature was reduced to 9.5 A degrees C.
- PublicationGibberellin reactivates and maintains ovary-wall cell division causing fruit set in parthenocarpic Citrus species(Elsevier, 2016) Mesejo Conejos, Carlos; Yuste Gallasch, Roberto; Reig Valor, Carmina; Martínez Fuentes, Amparo; Iglesias, Domingo; Muñoz Fambuena, Natalia; Bermejo del Castillo, Almudena; Germanà, Maria Antonietta; Primo Millo, Eduardo; Agustí Fonfría, Manuel; Dpto. de Producción Vegetal; Instituto Agroforestal Mediterráneo; Escuela Técnica Superior de Ingeniería Agronómica y del Medio Natural[EN] Citrus is a wide genus in which most of the cultivated species and cultivars are natural parthenocarpic mutants or hybrids (i.e. orange, mandarin, tangerine, grapefruit). The autonomous increase in GA(1) ovary concentration during anthesis was suggested as being the stimulus responsible for parthenocarpy in Citrus regardless of the species. To determine the exact GA-role in parthenocarpic fruit set, the following hypothesis was tested: GA triggers and maintains cell division in ovary walls causing fruit set. Obligate and facultative parthenocarpic Citrus species were used as a model system because obligate parthenocarpic Citrus sp (i.e. Citrus unshiu) have higher GA levels and better natural parthenocarpic fruit set compared to other facultative parthenocarpic Citrus (i.e. Citrus clementina). The autonomous activation of GA synthesis in C. unshiu ovary preceded cell division and CYCA1.1 up regulation (a G2-stage cell cycle regulator) at anthesis setting a high proportion of fruits, whereas C. clementina lacked this GA-biosynthesis and CYCA1.1 up-regulation failing in fruit set. In situ hybridization experiments revealed a tissue-specific expression of GA20ox2 only in the dividing tissues of the pericarp. Furthermore, CYCA1.1 expression correlated endogenous GA(1) content with GA(3) treatment, which stimulated cell division and ovary growth, mostly in C clementina. Instead, paclobutrazol (GA biosynthesis inhibitor) negated cell division and reduced fruit set. Results suggest that in parthenocarpic citrus the specific GA synthesis in the ovary walls at anthesis triggers cell division and, thus, the necessary ovary growth rate to set fruit. (C) 2016 Elsevier Ireland Ltd. All rights reserved.
- PublicationThe flower to fruit transition in Citrus is partially sustained by autonomous carbohydrate synthesis in the ovary(Elsevier, 2019-08) Mesejo Conejos, Carlos; Martínez Fuentes, Amparo; Reig Valor, Carmina; Agustí Fonfría, Manuel; Dpto. de Producción Vegetal; Instituto Agroforestal Mediterráneo; Escuela Técnica Superior de Ingeniería Agronómica y del Medio Natural[EN] Why evergreen fruit tree species accumulate starch in the ovary during flower bud differentiation in spring, as deciduous species do during flower bud dormancy, is not fully understood. This is because in evergreen species carbon supply is assured by leaves during flower development. We suggest the existence of an autonomous mechanism in the flowers which counteracts the competition for photoassimilates with new leaves, until they become source organs. Our hypothesis is that starch accumulated during Citrus ovary ontogeny originates from 1) its own photosynthetic capacity and 2) the mobilization of reserves. Through defoliation experiments, we found that ovaries accumulate starch during flower ontogeny using a dual mechanism: 1) the autotrophic route of source organs activating Rubisco (RbcS) genes expression, and 2) the heterotrophic route of sink organs that hydrolyze sucrose in the cytosol. Defoliation 40 days before anthesis did not significantly reduce ovary growth, flower abscission or starch concentration up to 20 days after anthesis (i.e. 60 days later). Control flowers activated the energy depletion signaling system (i.e. SnRK1) and RbcS gene expression around athesis. Defoliation accelerated and boosted both activities, increasing SPS gene expression (sucrose synthesis), and SUS1, SUS3 and cwINV (sucrose hydrolysis) to maintain a glucose threshold which satisfied its need to avoid abscission.
- PublicationGibberellic acid and flower bud development in loquat (Eriobotrya japonica Lindl.)(Elsevier, 2011) Reig Valor, Carmina; Farina, Vitorio; Volpe, Giorgio; Mesejo Conejos, Carlos; Martínez Fuentes, Amparo; Barone, Francesca; Calabrese, Francesco; Agustí Fonfría, Manuel; Dpto. de Producción Vegetal; Instituto Agroforestal Mediterráneo; Escuela Técnica Superior de Ingeniería Agronómica y del Medio NaturalThe application of gibberellic acid (GA 3) to the whole loquat tree from mid-May to early June and from early August to the onset of flowering, significantly reduced the number of premature flowering shoots per current shoot and per m 3 of canopy, and so reduced the total number of panicles per m 3 of canopy. The number of vegetative shoots per m 3 of canopy was also significantly reduced by applying GA 3. The response depended on the concentration applied and produced optimal results at 50mgl -1. Differences in the number of flowers per panicle and leaves per shoot were not significantly modified by the treatment. Nevertheless, GA 3 applied directly to the developing apex near to flower differentiation reduced the number of flowers per panicle by 25-35% and without modifying the morphological characteristics of the panicle. Results suggest that less sprouting of lateral buds was largely responsible for the reduction in flowering intensity caused by GA 3. Best treatments reduced thinning costs (60%, approximately) of premature flowering shoots, slightly increased fruit diameter and significantly improved fruit colour and juice quality, thus advancing harvest date. © 2011 Elsevier B.V.
- PublicationInfluence of harvest date on fruit yield and return bloom in Marsh grapefruit trees (Citrus paradisi Macf.) grown under a tropical climate(2014-07) Betancourt, Mayda; Sistachs, V.; Martínez Fuentes, Amparo; Mesejo Conejos, Carlos; Reig Valor, Carmina; Agustí Fonfría, Manuel; Dpto. de Producción Vegetal; Instituto Agroforestal Mediterráneo; Escuela Técnica Superior de Ingeniería Agronómica y del Medio NaturalGrapefruit grown in tropical climates reach a suitable fruit size and juice content for fresh consumption during August – October in the northern hemisphere. However, some tropical plantations delay harvesting until November or December, with the fruit then being used for processing. In our experiments, delaying the harvest from October to December reduced the average mature fruit weight by 10% and increased abscission from 29 to 70 fruit per tree. Juice contents decreased slightly, from 44.5% (w/w) to 43.2% (w/w), while total soluble solids (TSS) contents barely changed, from 10.4 ºBrix to 10.2 ºBrix. Delaying the harvest date also reduced return flowering by 20% in the following Spring, and the number of fruit set by 20%. Mature fruit abscission and reduced flowering were not dependent on weather conditions.The former was spontaneous and due to senescence, while the latter was due to fruit remaining on the tree. Over a 4-year period, our results showed an average reduction of 30% in fruit yield per tree when harvest dates were delayed from October (153 kg tree–1) to December (105 kg tree–1). As juice content and TSS content values were suitable for processing in October, there was no reason to delay the harvest date.
- PublicationFruit Load and Root Development in Field-Grown Loquat Trees (Eriobotrya japonica Lindl)(Springer Verlag (Germany), 2013-06) Reig Valor, Carmina; Mesejo Conejos, Carlos; Martínez Fuentes, Amparo; Iglesias, D.J.; Agustí Fonfría, Manuel; Dpto. de Producción Vegetal; Instituto Agroforestal Mediterráneo; Escuela Técnica Superior de Ingeniería Agronómica y del Medio Natural; Ministerio de Ciencia e InnovaciónPhotosynthate translocation to the root in loquat trees decreases as fruit develops. Thus, during the most active period of fruit development, that is, from 50 % of its final size to the beginning of fruit color change, which correspond to BBCH growth scale stages 705 and 801, both translocating and reducing carbohydrate concentrations diminish greatly. Concomitantly, the results from our experiment show an increased abscisic acid (ABA) concentration and a decrease in the respiration rate detected by an accumulation of glucose-6-phosphate, which paralleled a reduced indole-3-acetic acid (IAA) concentration in roots. As a consequence, root development was strongly and significantly reduced. Because loquat fruit develops in winter and nonshoot growth takes place at this time, our results show that root development in loquat trees is controlled by the fruit, mediated by competition for carbohydrates and modulated by hormones. The experiment was conducted using field-grown loquat during two consecutive years and by comparing fruiting and defruited trees. Fruits were detached from the trees in the early fruit developmental stage (10 % of final size, 701 BBCH growth scale), and carbohydrate concentrations in leaves, shoot bark, and roots, as well as nitrogen fractions (N-NO 3 -, N-NH 4 +, and N-proteinaceous) and hormone (IAA, zeatin, and ABA) concentrations in roots, were analyzed throughout the period of fruit development. Root development was evaluated by counting the emerging lateral root primordia during the fruit developmental stages BBCH growth scale 701-809 (fruit color fully developed). © 2012 Springer Science+Business Media, LLC.
- PublicationSelf-pollination and parthenocarpic ability in developing ovaries of self-incompatible Clementine mandarins (Citrus clementina)(Wiley-Blackwell, 2013-05) Mesejo Conejos, Carlos; Yuste, Roberto; Martínez Fuentes, Amparo; Reig Valor, Carmina; Iglesias, Domingo J.; Primo-Millo, Eduardo; Agustí Fonfría, Manuel; Dpto. de Producción Vegetal; Instituto Agroforestal Mediterráneo; Escuela Técnica Superior de Ingeniería Agronómica y del Medio NaturalThis study aimed to determine if self-pollination is needed to trigger facultative parthenocarpy in self-incompatible Clementine mandarins (Citrus clementina Hort. ex Tan.). 'Marisol' and 'Clemenules' mandarins were selected, and self-pollinated and un-pollinated flowers from both cultivars were used for comparison. These mandarins are always seedless after self-pollination and show high and low ability to develop substantial parthenocarpic fruits, respectively. The time-course for pollen grain germination, tube growth and ovule abortion was analyzed as well as that for carbohydrates, active gibberellins (GA 1 and GA 4), auxin (IAA) and abscisic acid (ABA) content in the ovary. 'Clemenules' showed higher pollen grain germination, but pollen tube development was arrested in the upper style 9days after pollination in both cultivars. Self-pollination did not stimulate parthenocarpy, whereas both un-pollinated and self-pollinated ovaries set fruit regardless of the cultivar. On the other hand, 'Marisol' un-pollinated flowers showed greater parthenocarpic ovary growth than 'Clemenules' un-pollinated flowers, i.e. higher ovule abortion rate (+21%), higher fruit set (+44%) and higher fruit weight (+50%). Further, the greater parthenocarpic ability of 'Marisol' paralleled higher levels of GA 1 in the ovary (+34% at anthesis). 'Marisol' ovary also showed higher hexoses and starch mobilization, but lower ABA levels (-64% at anthesis). Self-pollination did not modify carbohydrates or GA content in the ovary compared to un-pollination. Results indicate that parthenocarpy in the Clementine mandarin is pollination-independent with its ability to set depending on the ovary hormone levels. These findings suggest that parthenocarpy in fertile self-incompatible mandarins is constitutively regulated. © Physiologia Plantarum 2012.
- PublicationToward a more efficient isolation of total RNA from loquat (Eriobotrya japonica Lindl.) tissues(EDP Sciences, 2015-01-20) Martínez Fuentes, Amparo; Mesejo Conejos, Carlos; Agustí Fonfría, Manuel; Reig Valor, Carmina; Dpto. de Producción Vegetal; Instituto Agroforestal Mediterráneo; Escuela Técnica Superior de Ingeniería Agronómica y del Medio Natural[EN] Loquat (Eriobotrya japonica Lindl.) tissues contain considerable amounts of polyphenolic compounds and polysaccharides which can copurify with RNA. This can render the RNA unsuitable for DNA synthesis and makes the isolation of high quality RNA from loquat tissues particularly difficult. Materials and methods. Total RNA was extracted from leaves, buds and fruit of loquat by adapting the method described by Song et al. in 2011. This involved improvements both to the extraction protocol and RNA purity. Results and discussion. Our modified method resulted in the isolation of high quality RNA with yields 6-20 times higher than that reported for existing methods. We obtained A(260/280) ratios of 2-2.40 A(260/230) ratios of 2-2.31 and RNA integrity numbers (RIN) of 8 to 8.3. The RNA obtained has reached the requested quality for downstream applications such as quantitative real-time polymerase chain reaction (RT-qPCR) experiments.
- PublicationTree water status influences fruit splitting in Citrus(Elsevier, 2016) Mesejo Conejos, Carlos; Reig Valor, Carmina; Martínez Fuentes, Amparo; GAMBETTA, GIULIANA; Gravina Telechea, Alfredo; Agustí Fonfría, Manuel; Dpto. de Producción Vegetal; Instituto Agroforestal Mediterráneo; Escuela Técnica Superior de Ingeniería Agronómica y del Medio Natural[EN] Fruit splitting or cracking is a major physiological disorder in fruit trees markedly influenced by environmental conditions, but conclusive data still are required to provide a definite explanation and preventive measures. Changes in climatic conditions critically influence fruit splitting incidence. We studied plant-soil-ambient water relations in splitting-prone citrus grown under 4 contrasting environmental conditions (climate type and soil), in Spain and Uruguay, over a six years period. Automatic trunk and fruit diameter measurements (trunk and fruit growth rate and maximum daily trunk shrinkage), which are a tree water status indicator, together with factors modifying the tree and fruit water relationship (temperature, ET, rainfall, soil texture, soil moisture, rootstock and xylem anatomy) were studied and correlated with splitting. A close fruit splitting and soil texture relationship was found, inversely correlated with clay and silt percentages, and positively with those for sand. Under 85%-sand soil conditions, slight changes in soil moisture due to fluctuations in temperature, ET, or rainfall changed trunk and fruit growth rate patterns during few hours and induced splitting. Splitting incidence was higher in trees with larger xylem vessels in the fruit peduncle due to rootstock ('Carrizo' and 'C-35' citrange being higher than 'FA-5', 'Cleopatra' and Poncirus trifoliata). Finally, reducing the frequency of irrigation by half increased midday canopy temperatures (similar to 5 degrees C) and splitting (+15%). We conclude that irregularities in the tree water status, due to interactions among soil moisture, rootstock and climatic conditions, leads to a number of substantial changes in fruit growth rate increasing the incidence of fruit splitting. (C) 2016 Elsevier B.V. All rights reserved.
- PublicationCobertura del suelo con cal: efecto de la reducción de la temperatura y cambio de color de las mandarinas precoces(2015) GAMBETTA ROMASO, GIULIANA; Mesejo Conejos, Carlos; Gravina Telechea, Alfredo; Agustí Fonfría, Manuel; Fasiolo, Carolina; Rey, Florencia; Reig Valor, Carmina; Martínez Fuentes, Amparo; Bentancour, Oscar; Dpto. de Producción Vegetal; Instituto Agroforestal Mediterráneo; Escuela Técnica Superior de Ingeniería Agronómica y del Medio Natural; European Commission; Universidad de la República, Uruguay[EN] Citrus fruit colour is an important marketing feature. In view of the relative independence between internal and external maturity, in early mandarins fruit harvest takes place before reaching fruit full colouration. Since citrus fruit colour break is associated to natural temperature reduction, this work evaluated the efficiency of hydrated lime soil coverage on the advance of fruit colour break of Satsuma and Clementine. Experiments were carried out in Spain (Satsuma 'Iwasaki' and Clementina 'Clemenpons', grafted on citrange 'Carrizo') and in Uruguay (Satsuma 'Okitsu' and 'Clementina de Nules', grafted on P. trifoliata). Hydrated lime was applied between two and four months before harvest. Treatment diminished soil temperature between 0.5 °C and 3 °C in all situations. In Satsuma, treatment could not advance colour break, since soil temperature remained above 23 °C and 18 °C, thresholds below which root metabolism of citrange 'Carrizo' and P. trifoliata, respectively, is reduced. In Clementine, maturing two months later, the soil temperature remained below thresholds during at least one month before harvest, significantly advancing fruit colour break and increasing the percentage of fruit harvested early