Chapleo S, Hall J L
The Biology Department, Building 44, The University, Southampton, SO9 5NH, UK.
New Phytol. 1989 Mar;111(3):381-390. doi: 10.1111/j.1469-8137.1989.tb00700.x.
The accumulation of exogenous D-fructose, D-glucose and sucrose into root tips of Ricinus communis was studied. Accumulation of sucrose is biphasic with respect to substrate concentration, both saturable and non-saturable Phases being discerned. Accumulation is sensitive to pH, the exogenous solute potential, PCMBS, and other sugars. Sap representative of the apoplast was collected by centrifugation and contains approximately 40 mol m hexose equivalents. Plants were labelled to the steady state with respect to cotyledonary sucrose derivatives; whole roots were then analysed by compartmental analysis and the results indicated similar apoplastic hexose concentrations. The vacuoles of roots grown in low salt solution contain most of the root soluble sugars, at a concentration of about 70 mol m hexose equivalents. The sugar content of such roots decreases with availability of KCl to an extent which indicates that this involves a replacement of vacuolar hexose by alternative osmotica, supporting the results from compartmental analysis.
研究了外源D-果糖、D-葡萄糖和蔗糖在蓖麻根尖中的积累情况。蔗糖的积累相对于底物浓度呈双相性，可分为饱和阶段和非饱和阶段。积累对pH、外源溶质势、对氯汞苯甲酸（PCMBS）和其他糖类敏感。通过离心收集代表质外体的汁液，其含有约40 mol m己糖当量。用子叶蔗糖衍生物将植物标记至稳态；然后通过区室分析对整个根系进行分析，结果表明质外体己糖浓度相似。在低盐溶液中生长的根系液泡含有大部分根系可溶性糖，浓度约为70 mol m己糖当量。随着氯化钾的供应，此类根系的糖含量下降，下降程度表明这涉及用替代渗透剂取代液泡己糖，这支持了区室分析的结果。
