Effects of iron deficiency on the composition of the leaf apoplastic fluid and xylem sap in sugar beet.: Implications for iron and carbon transport
Effects of iron deficiency on the composition of the leaf apoplastic fluid and xylem sap in sugar beet.: Implications for iron and carbon transport
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DOI：
10.1104/pp.124.2.873
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发表时间：
2000-10-01
期刊：
影响因子：
7.4
通讯作者：
Abadía, J
中科院分区：
文献类型：
--
作者：
López-Millán, AF;Morales, F;Abadía, J
缺铁对甜菜（甜菜杂种）木质部汁液和叶质外体液组成的影响已被表征。pH值估计从直接测量质外体液和木质部汁液通过离心和荧光与5-羧基荧光素和异硫氰酸荧光素-葡聚糖孵育的叶子。缺铁导致甜菜叶质外体（从6.3下降到5.9）和木质部汁液（从6.0下降到5.7）的pH值略有下降。叶质外体液和木质部汁液中的主要有机酸为苹果酸和柠檬酸。在对照植物中的总有机酸浓度为4.3 mM的质外体流体和9.4 mM的木质部汁液和增加到12.2和50.4 mM，分别在缺铁植物。无机阳离子和阴离子浓度也发生了变化，无论是质外体液和木质部汁液铁缺乏。铁减少与铁缺乏从5.5到2.5 μ M的质外体流体和木质部汁液。两个室中的主要预测铁物种在对照中为[FeCitOH]（-1），在缺铁植物中为[FeCit（2）]（-3）。数据表明，存在的有机酸从根到叶通过木质部，可能与根的回补二氧化碳固定。
The effects of iron deficiency on the composition of the xylem sap and leaf apoplastic fluid have been characterized in sugar beet (Beta vulgaris Monohil hybrid). pH was estimated from direct measurements in apoplastic fluid and xylem sap obtained by centrifugation and by fluorescence of leaves incubated with 5-carboxyfluorescein and fluorescein isothiocyanate-dextran. Iron deficiency caused a slight decrease in the pH of the leaf apoplast (from 6.3 down to 5.9) and xylem sap (from 6.0 down to 5.7) of sugar beet. Major organic acids found in leaf apoplastic fluid and xylem sap were malate and citrate. Total organic acid concentration in control plants was 4.3 mM in apoplastic fluid and 9.4 mM in xylem sap and increased to 12.2 and 50.4 mM, respectively, in iron-deficient plants. Inorganic cation and anion concentrations also changed with iron deficiency both in apoplastic fluid and xylem sap. Iron decreased with iron deficiency from 5.5 to 2.5 muM in apoplastic fluid and xylem sap. Major predicted iron species in both compartments were [FeCitOH](-1) in the controls and [FeCit(2)](-3) in the iron-deficient plants. Data suggest the existence of an influx of organic acids from the roots to the leaves via xylem, probably associated to an anaplerotic carbon dioxide fixation by roots.