{"title":"可可树中的草酸钙晶体及其与镉的相互作用。","authors":"Fabien Letort, Eduardo Chavez, Hester Blommaert, Sylvain Campillo, Sabine Sentenac, Delphine Tisserand, Rachel Martin, Simona Denti, Géraldine Sarret","doi":"10.1016/j.plaphy.2025.109499","DOIUrl":null,"url":null,"abstract":"<p><p>Cadmium (Cd) concentrations in cacao beans from Latin America often exceed limits for trading. A better understanding of the mechanisms of Cd accumulation in Theobroma cacao L. trees is necessary to advance mitigation strategies. Recent studies on a high Cd accumulating cultivar of cacao revealed that calcium oxalate (CaOx) crystals were involved in Cd accumulation in the branches. The purpose of this study was to quantify soluble and crystalline oxalate in cacao compartments, to characterize their morphology and distribution in the tissues, and to evaluate the relationship between CaOx and Cd total concentrations in each plant compartment. Two representative cultivars from Latin America (CCN-51 and Nacional) were studied. CCN-51 trees grew on soils with low and high total Cd contents (0.120 ± 0.002 and 2.59 ± 0.48 mg kg⁻<sup>1</sup>, respectively), and Nacional trees grew on soils with low Cd content (0.188 ± 0.005 mg kg⁻<sup>1</sup>). Oxalate was present in all organs of the two cultivars. In mature leaves, oxalate content exceeded the limit of 5% per dry weight used to define extreme oxalate accumulators. The crystalline form predominated in branches and mature leaves (82-92%), whereas the soluble form predominated in nibs (67-82%). Calcium oxalate crystal size varied from <1 μm (generally agglomerated as crystal sand) to a few tens of μm (faceted crystals). Log CaOx and Cd concentrations were positively correlated in branches (R<sup>2</sup> = 0.77, p = 0.002) and roots (R<sup>2</sup> = 0.71, p = 0.005), whereas in nibs, the oxalate content was almost constant among conditions. The possible roles of CaOx crystals in the cacao plant, including Ca regulation, protection against herbivory, tissue stiffening and Cd detoxification are discussed.</p>","PeriodicalId":20234,"journal":{"name":"Plant Physiology and Biochemistry","volume":"220 ","pages":"109499"},"PeriodicalIF":6.1000,"publicationDate":"2025-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Calcium oxalate crystals in cacao trees and their interactions with cadmium.\",\"authors\":\"Fabien Letort, Eduardo Chavez, Hester Blommaert, Sylvain Campillo, Sabine Sentenac, Delphine Tisserand, Rachel Martin, Simona Denti, Géraldine Sarret\",\"doi\":\"10.1016/j.plaphy.2025.109499\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p><p>Cadmium (Cd) concentrations in cacao beans from Latin America often exceed limits for trading. A better understanding of the mechanisms of Cd accumulation in Theobroma cacao L. trees is necessary to advance mitigation strategies. Recent studies on a high Cd accumulating cultivar of cacao revealed that calcium oxalate (CaOx) crystals were involved in Cd accumulation in the branches. The purpose of this study was to quantify soluble and crystalline oxalate in cacao compartments, to characterize their morphology and distribution in the tissues, and to evaluate the relationship between CaOx and Cd total concentrations in each plant compartment. Two representative cultivars from Latin America (CCN-51 and Nacional) were studied. CCN-51 trees grew on soils with low and high total Cd contents (0.120 ± 0.002 and 2.59 ± 0.48 mg kg⁻<sup>1</sup>, respectively), and Nacional trees grew on soils with low Cd content (0.188 ± 0.005 mg kg⁻<sup>1</sup>). Oxalate was present in all organs of the two cultivars. In mature leaves, oxalate content exceeded the limit of 5% per dry weight used to define extreme oxalate accumulators. The crystalline form predominated in branches and mature leaves (82-92%), whereas the soluble form predominated in nibs (67-82%). Calcium oxalate crystal size varied from <1 μm (generally agglomerated as crystal sand) to a few tens of μm (faceted crystals). Log CaOx and Cd concentrations were positively correlated in branches (R<sup>2</sup> = 0.77, p = 0.002) and roots (R<sup>2</sup> = 0.71, p = 0.005), whereas in nibs, the oxalate content was almost constant among conditions. 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引用次数: 0
摘要
来自拉丁美洲的可可豆中的镉(Cd)浓度经常超过贸易限制。更好地了解可可树Cd积累的机制对制定防治策略是必要的。最近对一个高Cd积累品种的研究表明,草酸钙晶体参与了枝条中Cd的积累。本研究的目的是定量测定可溶草酸盐和结晶草酸盐在可可区室中的含量,表征其在组织中的形态和分布,并评价各植物区室中CaOx和Cd总浓度之间的关系。以拉丁美洲两个代表性品种CCN-51和Nacional为研究对象。CCN-51树生长在总Cd含量低和高的土壤上(分别为0.120±0.002和2.59±0.48 mg kg - 1),而国家树生长在低Cd含量的土壤上(0.188±0.005 mg kg - 1)。草酸盐存在于两个品种的所有器官中。在成熟叶片中,草酸含量超过了用于定义极端草酸积累物的每干重5%的限制。结晶形态在树枝和成熟叶片中占主导地位(82% ~ 92%),而可溶性形态在笔尖中占主导地位(67 ~ 82%)。草酸钙晶体大小在2 = 0.77 (p = 0.002)和根(R2 = 0.71, p = 0.005)之间变化,而在笔尖中,草酸钙含量在不同条件下几乎不变。讨论了CaOx晶体在可可植物中的可能作用,包括钙调节、抗草食、组织硬化和Cd解毒。
Calcium oxalate crystals in cacao trees and their interactions with cadmium.
Cadmium (Cd) concentrations in cacao beans from Latin America often exceed limits for trading. A better understanding of the mechanisms of Cd accumulation in Theobroma cacao L. trees is necessary to advance mitigation strategies. Recent studies on a high Cd accumulating cultivar of cacao revealed that calcium oxalate (CaOx) crystals were involved in Cd accumulation in the branches. The purpose of this study was to quantify soluble and crystalline oxalate in cacao compartments, to characterize their morphology and distribution in the tissues, and to evaluate the relationship between CaOx and Cd total concentrations in each plant compartment. Two representative cultivars from Latin America (CCN-51 and Nacional) were studied. CCN-51 trees grew on soils with low and high total Cd contents (0.120 ± 0.002 and 2.59 ± 0.48 mg kg⁻1, respectively), and Nacional trees grew on soils with low Cd content (0.188 ± 0.005 mg kg⁻1). Oxalate was present in all organs of the two cultivars. In mature leaves, oxalate content exceeded the limit of 5% per dry weight used to define extreme oxalate accumulators. The crystalline form predominated in branches and mature leaves (82-92%), whereas the soluble form predominated in nibs (67-82%). Calcium oxalate crystal size varied from <1 μm (generally agglomerated as crystal sand) to a few tens of μm (faceted crystals). Log CaOx and Cd concentrations were positively correlated in branches (R2 = 0.77, p = 0.002) and roots (R2 = 0.71, p = 0.005), whereas in nibs, the oxalate content was almost constant among conditions. The possible roles of CaOx crystals in the cacao plant, including Ca regulation, protection against herbivory, tissue stiffening and Cd detoxification are discussed.
期刊介绍:
Plant Physiology and Biochemistry publishes original theoretical, experimental and technical contributions in the various fields of plant physiology (biochemistry, physiology, structure, genetics, plant-microbe interactions, etc.) at diverse levels of integration (molecular, subcellular, cellular, organ, whole plant, environmental). Opinions expressed in the journal are the sole responsibility of the authors and publication does not imply the editors'' agreement.
Manuscripts describing molecular-genetic and/or gene expression data that are not integrated with biochemical analysis and/or actual measurements of plant physiological processes are not suitable for PPB. Also "Omics" studies (transcriptomics, proteomics, metabolomics, etc.) reporting descriptive analysis without an element of functional validation assays, will not be considered. Similarly, applied agronomic or phytochemical studies that generate no new, fundamental insights in plant physiological and/or biochemical processes are not suitable for publication in PPB.
Plant Physiology and Biochemistry publishes several types of articles: Reviews, Papers and Short Papers. Articles for Reviews are either invited by the editor or proposed by the authors for the editor''s prior agreement. Reviews should not exceed 40 typewritten pages and Short Papers no more than approximately 8 typewritten pages. The fundamental character of Plant Physiology and Biochemistry remains that of a journal for original results.