Clark C J, Smith G S, Walker G D
Ruakura Soil and Plant Research Station, Ministry of Agriculture and Fisheries, Private Bag, Hamilton, New Zealand.
Ex Physics and Engineering Laboratory, Department of Scientific and Industrial Research, Private Bag, Lower Hutt, New Zealand.
New Phytol. 1987 Mar;105(3):477-486. doi: 10.1111/j.1469-8137.1987.tb00885.x.
Seasonal changes in the content of Ca and Mg in leaf blades collected from mature kiwifruit [Actinidia deliciosa (A. Chev.) C. F. Liang et A. R. Ferguson var. deliciosa] vines in a high-producing orchard were measured by a sequential fractionation procedure (14 M acetic acid, 0.25 M HC1 and residual). Total Ca and Mg concentrations decreased within the first 4 weeks of growth, but increased linearly thereafter to be 1322 and 197 μmol g dry weight, respectively, by leaf fall. Total quantities of Ca and Mg accumulated at this time were approximately 2500 and 380 μmol per blade. Calcium oxalate, dissolved in the HC1 extract, was the predominant fraction at every harvest, accounting for up to 79 % of the total Ca content shortly after leaf emergence, and decreasing to 42 % at leaf fall. The quantity of physiologically active Ca (acetic acid-soluble) ranged from a minimum of 15 % (8 weeks after emergence) to a maximum of 41 % at the end of the season. Forms of Ca remaining in the solid residue after extraction made only a minor contribution (3 to 21 %) to the total content at any time during the season. In contrast, however, 89 to 96% of the total Mg was extracted by acetic acid at every harvest, with the remainder dissolved by HC1. Scanning electron microscopy and X-ray microanalysis of the lamina of mature leaves indicated the presence of two crystalline, Ca-rich products which differed in their morphology, location and distribution. Large styloids (120 to 270 μm in length) were concentrated in idioblasts adjacent to vascular tissue, while bundles of four-sided raphides, containing wedge-shaped apices, were located predominantly between the major transport vessels of the vascular tissue. X-ray diffraction analysis of crystalline isolates confirmed that both morphological forms are calcium oxalate monohydrate (whewellite).
通过连续分级分离程序（14M 乙酸、0.25M 盐酸和残渣），测定了高产果园中成熟猕猴桃[美味猕猴桃（A. Chev.）C. F. Liang 及 A. R. Ferguson 美味变种]藤蔓叶片中钙和镁的含量季节性变化。在生长的前 4 周内，总钙和镁浓度下降，但此后呈线性增加，到落叶时分别达到 1322 和 197 μmol/g 干重。此时每片叶片积累的钙和镁总量分别约为 2500 和 380 μmol。溶解于盐酸提取物中的草酸钙在每次收获时都是主要部分，在叶片刚出现后不久占总钙含量的比例高达 79%，到落叶时降至 42%。生理活性钙（乙酸可溶）的含量范围从最低的 15%（出现后 8 周）到季节末的最高 41%。在季节中的任何时候，提取后残留在固体残渣中的钙形态对总含量的贡献都很小（3%至 21%）。然而，相比之下，每次收获时 89%至 96%的总镁可被乙酸提取，其余部分则溶解于盐酸。对成熟叶片叶片层的扫描电子显微镜和 X 射线微分析表明存在两种形态、位置和分布不同的富含钙的结晶产物。大的针晶体（长度为 120 至 270 μm）集中在与维管组织相邻的异细胞中，而包含楔形顶端的四边针晶束主要位于维管组织的主要输导管之间。对结晶分离物的 X 射线衍射分析证实这两种形态均为一水合草酸钙（水草酸钙）。
