非损伤微测技术---在植物营养运输研究中的应用

非损伤微测技术在植物营养物质吸收和植物品种筛选上有自己独特的优势。如：植物硝酸盐营养可明显改善植株的生长发育。我国学者用NO₃^-微电极测定了小白菜和水稻活体细胞中NO₃^-的活度，使用NO₃^-微电极可以为选育氮素高效吸收的植物品种提供电生理指标。Colmer 和Blomm用NO₃^-和NH₄⁺微电极研究水稻不定根对NO₃^-和NH₄⁺的吸收情况时，发现NO₃^-和NH₄⁺在成熟区、分生区与伸长区的吸收之间有差异，认为厚壁组织的纤维限制了根对NO₃^-和NH₄⁺的吸收^{（Plant Cell Environ）。}

Figure 1 . Net fluxes of NH₄⁺ (closed symbols) and NO₃^– (open symbols) along intact rice adventitious roots, with either form of nitrogen as the sole source. Net fluxes were calculated from ion concentration gradients between 200 and 100 μm from the root surface (Henriksen et al. 1992). Plant growth and net flux measurements were in nutrient solutions with either 0·1 mol m–3 NH₄⁺ or NO₃^–. Each data point represents the mean ± standard error of four replicates, with each replicate being a separate experiment on an individual plant.

Figure 2 . Net fluxes of NH₄⁺ (closed symbols) and NO₃^– (open symbols) along maize primary seminal roots, when both forms of nitrogen were present. Net fluxes were calculated from ion concentration gradients between 200 and 100 μm from the root surface (Henriksen et al. 1992). Plant growth and net flux measurements were in nutrient solutions with 0.1 mol m^–3 NH₄NO₃. Each data point represents the mean ± standard error of four replicates, with each replicate being a separate experiment on an individual plant.

Figure 3 . Cross-section of a rice adventitious root taken 21 mm behind the apex and stained for lipids with Fluoral yellow (Brundrett et al. 1991). Fresh sections were stained for 1 h with Fluoral yellow as described in the Materials and Methods, and examined under ultraviolet illumination with a Olympus Vanox-T microscope. A layer of sclerenchymatous fibre cells was absent in sections taken at 6 mm, but was evident at 21, 41, and 61 mm behind the apex. (Magnification ×25).

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