Browsing by Author "Rojas-Silva, Ximena"

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    Absorption and mobility of radio-labelled calcium in chili pepper plants and sweet cherry trees
    (2021) Bonomelli de Pinaga, Claudia Maria; Alcalde Eyheramendy, Carolina Maria; Aguilera Jacob, Camila Paula; Videla, Ximena; Rojas-Silva, Ximena; Nario, Adriana; Fernández, Victoria
    Calcium (Ca) is often supplied to crop species to prevent the occurrence of Ca-related disorders. Mechanisms of Ca absorption and transport are not fully understood and the effectiveness of root and/or foliar Ca fertilization may be variable. To characterize the rate of Ca absorption and transport, trials were developed with chili pepper and sweet cherry plants, using (CaCl2)-Ca-45 as a tracer. The Ca treatments supplied were: (1) No Ca-45 (control); (2) Ca-45 soil application; (3) Ca-45 supply to basal leaves, and (4) Ca-45 application to apical leaves. After two months, plants were harvested for biomass and Ca content determination. The recovery of Ca-45 in different plant parts was measured with a liquid scintillation counter and leaf traits were observed by scanning electronic microscopy. In general, the highest Ca-45 concentrations were recovered in treated organs, while root applications led to highest Ca-45 translocation rates, which varied between chili pepper and cherry plants. For chili pepper, Ca-45 applied to the soil was detected mainly in roots (44 %) followed by leaves (36.6 %) stems (17.4 %) and fruits (2 %). In sweet cherry trees, soil-applied Ca-45 was principally recovered in roots (45.3 %), shoots (28.5 %), leaves (14.3 %) and trunks (11.9 %). The results provide evidence of increased absorption of root-applied Ca, as well as different degrees of Ca mobility between species. Foliar application led to major Ca increases in treated leaves, with Ca transported to other plant organs after apical leaf Ca supply chiefly in cherry trees.
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    Sweet cherry response in absorption and mobility of 10B applied to soil and flowers under two soil boron conditions
    (2024) Arredondo, Gerado; Bonomelli, Claudia; Nario, Adriana; Rojas-Silva, Ximena; Gaete, Patricia
    Background: Boron (B) is an essential micronutrient for plants, and B deficiency reduces fruit set in sweet cherry trees. Several studies showed the advantages of foliar and soil B applications in fruit trees, but there is little information on the distribution of B in the plant, becoming an important issue when nutritional corrections are needed. Aims: The study aims to determine B mobility and distribution in sweet cherry trees, applying B-10 to the flowers and soil, at different timings and under two levels of soil B availability. Methods: Two experiments were conducted with sweet cherry trees. In the two previous seasons, the plants were managed in two soil B availability conditions (deficient and adequate). The experiments consisted of the applications of B-10 solution to the flowers and the soil at different timings and under both soil B conditions. Results: Higher B-10 absorption occurred when the B-10 was applied to the soil at full bloom than when it was applied before leaf senescence. Boron was mobilized to all the tissues, but mainly to the leaves. Nevertheless, the fruit presented no differences in B-10 excess for both application timings. Irrespective of soil B conditions, the B-10 applied to the soil at full bloom was absorbed and mobilized to different tissues, that is, roots + rootstock + trunk (39%-44%) and stems + leaves (53%-55%), showing no differences between them. A lower percentage of B was located in the fruit, with 1% and 8% at soil B-deficient and B-adequate conditions, respectively. The highest percentage of the B-10 applied to the flowers remained in the fruit (similar to 70%), and nearly 20% and 10% were mobilized to stems + leaves and roots + rootstock + trunk, respectively, independent of the soil B condition. Conclusions: Boron applied to soil at full bloom or before leaf senescence, under B-deficient soil condition, is absorbed and mobilized to all the plant tissues, enhancing the B status in sweet cherry trees particularly when it is applied at full bloom. However, B soil application before leaf senescence would improve the availability of B (reserves) to the flowers in the following season. Boron applied to the flowers, at full bloom, remains in a high proportion in the fruit, becoming an effective complementary method to meet the fruit demands of the growing season, independent of the soil B conditions.