WATER DISTRIBUTION IN STEMS OF AMARANTHUS-CRUENTUS L EXAMINED BY NMR-MICROTOMOGRAPHY

NMR-microtomography was applied to study the water distribution in ste m tissues of Amaranthus cruentus L. at both the flower bud-formation a nd flowering stages. In amaranth stems, two buffer regions for water a ccumulation were shown: the inner aquiliferous pith parenchyma and an outer layer situated at the stem periphery and coinciding with the pri mary cortical parenchyma. In the course of gradual desiccation of the plant, water accumulated in the inner aquiliferous pith parenchyma cel ls was lost first, whereas the outer aquiliferous layer of cortical ce lls bordering the meristematic zone remained relatively unchanged. It was suggested that the central pith of the stem serves a damper functi on during desiccation, while the outer cortical layer maintains homeos tasis. NMR-microtomography is promising for studying water relations i n plants belonging to diverse ecological groups.