采前喷施草酸对芒果果实细胞钙含量和分布的影响

利用焦锑酸钾沉淀-透射电子显微镜观察的方法, 观测了采前喷施草酸或钙后采收期芒果(Mangifera indica)果实细胞钙含量和分布情况, 探讨钙含量和分布变化对果实成熟和衰老的影响。结果表明, 与对照相比, 采前经草酸或钙处理的果实果皮和果肉细胞排列较规则且致密, 淀粉粒分布较多。采前草酸或钙处理均能显著提高芒果果皮和外果肉组织的钙含量;疏松结合态钙均匀分布在果皮和果肉细胞的细胞壁、细胞膜、液泡膜和质体中, 并在液泡内堆积; 而对照果实的液泡膜模糊, 钙颗粒较少。实验证明采前喷施草酸或钙能维持果实细胞的形态, 提高果实细胞的钙含量, 影响钙的分布, 有利于保持果实的硬度并可增加果实营养。

Effect of Preharvest Oxalic Acid Sprays on Calcium Content and Distribution in Mango Fruit Cells

We observed cell structure and analyzed total calcium content and distribution in mango fruits treated with oxalic acid (OA) or calcium (Ca) spray before harvest by transmission electron microscopy combined with in situ precipitation of calcium with an improved technique of potassium pyroantimonate.Compared with controls, the pericarp and outer flesh of OA-and Ca-treated fruits showed a regular, tight cell structure with an increase in starch grains and Ca content. Loose, bound Ca was mainly distributed in the cell wall, cell membrane, tonoplast and plastid, and more Ca was deposited in vacuoles. In contrast, the membrane structures of vacuoles in control fruit cells became obscure. Preharvest OA or Ca sprays may maintain cell structure and increase Ca content of the pericarp and outer flesh of mango, which is beneficial for maintaining fruit firmness and improving Ca nutrition.