ＳＴＳ溶液のＡｇＮＯ３とＮａ２Ｓ２Ｏ３・５Ｈ２Ｏの混合比率がカーネーション切り花の銀の吸収と分布および品質保持期間に及ぼす影響

Abstract

Cut carnation flower stems were immersed in solutions of silver thiosulfate (STS) having Ag to thiosulfate ratios of 1 : 1, 1 : 2, 1 : 4, 1 : 8, 1 : 16 and 1 : 32. The solutions were prepared by mixing AgNO3 and Na2S2O3•5H2O to give a final Ag+ concentration of 1 mM or 0.2 mM. Ag chelate in the solutions with high ratios of thiosulfate to Ag, i. e. 1 : 8 to 1 : 32, was quite stable, whereas at ratios of 1 : 1 to 1 : 4, it was not.1. Ag was detected in the flower head by atomic absorption analysis after cut carnations were treated with the solutions at ratios from 1 : 2 to 1 : 32. It was not detectable in the flower head when treated with AgNO3 solution alone (1 : 0). All or most of Ag was located in the lower stem when stems were treated with solutions having a ratio of 1 : 0 or 1 : 1.2. The amount of Ag translocated to the carnation flower head was closely associated with vase life. Treatment of cut flowers with solutions at the ratios of 1 : 4 to 1 : 32 doubled the vase life compared with flowers treated with deionized water. The solutions with ratios of 1 : 4 to 1 : 32 were equally effective in prolonging vase life. Treatment with the solutions with ratios of 1 : 0 to 1 : 2 extended vase life only slightly.3. Injury to upper leaves increased proportionally with the increase in Ag accumulation and with the increasing ratios of thiosulfate to Ag. Leaf injury symptoms appeared when stems were immersed in 1 mM Ag solutions.Thus, to extend the vase life of carnations we recommend the use of a 1 : 8 molar ratio of AgNO3 to Na2S2O3•5H2O in the STS solution.