Calcium Oxalate Crystals and the Optimal Growing Conditions for Actinidia arguta

Abstract

The presence, distribution, and morphology of calcium oxalate (CaC₂O₄, CaOx) crystals were observed in the stunted bodies of Actinidia arguta (A. arguta) vines, and their ability of microorganisms to degrade CaOx crystals was analyzed. Leaves, branches, and roots of stunted A. arguta vines were collected. In the roots, CaOx crystal bundles were distributed in the form of dotted lines. In the branches, CaOx crystal bundles were observed blocking and accumulating in the vessels. In the leaves, CaOx crystal bundles were observed in a net-like entanglement. Therefore, CaOx crystals present in the roots, branches, and leaves hinder the growth. A hydroponic cultivation with different calcium (Ca) concentrations showed that the growth of A. arguta was best at a Ca concentration of 1 cmol⁺/kg; at a Ca concentration of 2 cmol⁺/kg, the edges of the leaves began to dry out after 7 days; and at a Ca concentration of 4 cmol⁺/kg, the entire leaves died within 14 days. From this study, it was concluded that CaOx crystals hindered the growth of A. arguta, and the Acinetobacter calcoaceticus (A. calcoaceticus) strain was effective in degrading CaOx crystals. Therefore, the Ca concentration in the soil of the cultivation site should be managed at less than 2 cmol⁺/kg.