Malone Michael, Herron Michelle, Morales M-Angeles
Biology Department, University of Sussex, Brighton BN1 9QG, United Kingdom.
Plant Physiol. 2002 Nov;130(3):1436-42. doi: 10.1104/pp.007740.
A method is described for continuous, nondestructive analysis of xylem-borne mineral nutrients in intact transpiring plants. The method uses the xylem-feeding insect the meadow spittlebug (Philaenus spumarius L. [Homoptera: Cercopidae]). This insect will feed from a wide range of plant species and organs. Insect excreta can be collected at all times of the day and night, and its mineral ion content can be analyzed rapidly, and without purification, by ion chromatography. The excreta will have a mineral content virtually identical to that of xylem sap. Cages suitable for containing the insects and collecting excreta from any desired location on plants in both laboratory and greenhouse are described. Even in the greenhouse, evaporation had only a minor effect on the sample ion content. Example results are presented which illustrate dynamics, over several days, in the xylem concentrations of sodium (Na(+)), potassium (K(+)), NH(4)(+), magnesium (Mg(2+)), calcium (Ca(2+)), chloride (Cl(-)), NO(3)(-), PO(4)(3-), and SO(4)(2-). These data were collected from young plants growing in pots of compost in the laboratory and from fully mature pepper (Capsicum annuum L. cv Bellboy) plants growing in hydroponics (rockwool) in the greenhouse. This method should facilitate studies of macronutrient uptake and transport in a range of plants and environments.
本文描述了一种对完整蒸腾植物中木质部运输的矿质营养元素进行连续、无损分析的方法。该方法利用以木质部为食的昆虫——草地沫蝉（Philaenus spumarius L. [同翅目：沫蝉科]）。这种昆虫能取食多种植物种类和器官。昆虫排泄物可在白天和夜晚的任何时间收集，其矿质离子含量可通过离子色谱法快速分析，无需纯化。排泄物的矿质含量与木质部汁液几乎相同。文中描述了适合在实验室和温室中容纳昆虫并从植物上任何所需位置收集排泄物的笼子。即使在温室中，蒸发对样品离子含量的影响也很小。给出了示例结果，展示了钠（Na⁺）、钾（K⁺）、铵（NH₄⁺）、镁（Mg²⁺）、钙（Ca²⁺）、氯（Cl⁻）、硝酸根（NO₃⁻）、磷酸根（PO₄³⁻）和硫酸根（SO₄²⁻）在木质部中的浓度在数天内的动态变化。这些数据是从实验室中生长在堆肥盆中的幼苗以及温室中生长在水培（岩棉）中的完全成熟的辣椒（Capsicum annuum L. cv Bellboy）植株上收集的。该方法应有助于研究一系列植物和环境中大量营养元素的吸收和运输。
