Water distribution in stems of Amaranthus cruentus L. examined by NMR-microtomography

NMR-microtomography was applied to study the water distribution in stem tissues of Amaranthus cruentus L. at both the flower bud-formation and flowering stages. In amaranth stems, two buffer regions for water accumulation were shown: the inner aquiliferous pith parenchyma and an outer layer situated at the stem periphery and coinciding with the primary cortical parenchyma. In the course of gradual desiccation of the plant, water accumulated in the inner aquiliferous pith parenchyma cells was lost first, whereas the outer aquiliferous layer of cortical cells bordering the meristematic zone remained relatively unchanged. It was suggested that the central pith of the stem serves a damper function during desiccation, while the outer cortical layer maintains homeostasis. NMR-microtomography is promising for studying water relations in plants belonging to diverse ecological groups

Оценка неравномерности упругих свойств листов из закрытоячеистых пенополиолефинов акустическим методом

The widespread use of polyolefin foams in strategically important industries is due to their high thermal, sound and vibration insulation properties. The aim of the work was to evaluate the non-uniformity of elastic properties over the area of sheets of polyolefin foams of various types using the acoustic non-contact shadow amplitude method of testing and confirmation by the structural analysis method.The article presents the developed installation and a new method of non-contact acoustic testing of sheets made of closed-cell polyolefin foams based on recording the amplitude of the pulse that passed through the sheet and allowing to assess to the unevenness of its elastic properties during scanning. Studies of uneven elastic properties were carried out on sheets of closed-cell polyolefin foams of the ISOLON 500 and ISOLON 300 brands which differ in material and manufacturing technology (technique of cross-linking, method and multiplicity of foaming).It is shown that the absolute amplitude of the signal and its spread relative to the average value is affected by the structure of the foam polyolefin material and its heterogeneity over the area of the studied sheet determined by the production technology which is confirmed visually using microscopy.Studies have shown the effect on the indications unevenness of the method of obtaining and the apparent density of the material. It is shown that the most uneven elastic properties and structure belong to sheets of polyolefin foam obtained by chemical cross-linking technology (the unevenness of Δ was 6.5 %). Among the physically cross-linked sheets of polyolefin foam the most uniform in structure and elastic properties are samples made of ethylene vinyl acetate with Δ = 3.8 %, as well as sheets with a high foaming rate (Δ = 3.9 %). The unevenness of structure of the studied sheets of polyolefin foams was confirmed by optical microscopy of sections in two mutually perpendicular directions.Широкое использование пенополиолефинов в стратегически важных отраслях промышленности обусловлено их высокими тепло-, звуко- и виброизоляционными свойствами. Целью работы являлась оценка неравномерности упругих свойств по площади листов пенополиолефинов различных типов с использованием акустического бесконтактного теневого амплитудного метода контроля и подтверждением методом структурного анализа.Разработаны установка и новая методика бесконтактного акустического контроля листов из закрытоячеистых пенополиолефинов, основанная на регистрации амплитуды импульса, прошедшего сквозь лист, и позволяющая оценить неравномерность его упругих свойств в процессе сканирования. Исследования неравномерности упругих свойств проведены на листах из закрытоячеистых пенополиолефинов марки ISOLON 500 и ISOLON 300, различающиеся материалом и технологией изготовления (способ сшивки, метод и кратность вспенивания).Показано, что на абсолютную амплитуду сигнала и её разброс относительно среднего значения влияет структура материала пенополиолефина и её неоднородность по площади исследуемого листа, определяемая технологией производства, что подтверждено визуально с использованием микроскопии. Исследования показали влияние на неравномерность показаний способа получения и кажущейся плотности материала. Показано, что наиболее неравномерные упругие свойства и структуру имеют листы из пенополиолефинов, полученных по технологии химической сшивки (неравномерность Δ составила 6,5 %). Из физически сшитых листов пенополиолефинов наиболее равномерными по структуре и упругим свойствам являются образцы, изготовленные из этиленвинилацетата с Δ = 3,8 %, а также листы с высокой кратностью вспенивания (Δ = 3,9 %). Неравномерность структуры исследованных листов пенополиолефинов подтверждена оптической микроскопией срезов в двух взаимно перпендикулярных направлениях

Water distribution in stems of Amaranthus cruentus L. examined by NMR-microtomography

NMR-microtomography was applied to study the water distribution in stem tissues of Amaranthus cruentus L. at both the flower bud-formation and flowering stages. In amaranth stems, two buffer regions for water accumulation were shown: the inner aquiliferous pith parenchyma and an outer layer situated at the stem periphery and coinciding with the primary cortical parenchyma. In the course of gradual desiccation of the plant, water accumulated in the inner aquiliferous pith parenchyma cells was lost first, whereas the outer aquiliferous layer of cortical cells bordering the meristematic zone remained relatively unchanged. It was suggested that the central pith of the stem serves a damper function during desiccation, while the outer cortical layer maintains homeostasis. NMR-microtomography is promising for studying water relations in plants belonging to diverse ecological groups

Water distribution in stems of Amaranthus cruentus L. examined by NMR-microtomography

NMR-microtomography was applied to study the water distribution in stem tissues of Amaranthus cruentus L. at both the flower bud-formation and flowering stages. In amaranth stems, two buffer regions for water accumulation were shown: the inner aquiliferous pith parenchyma and an outer layer situated at the stem periphery and coinciding with the primary cortical parenchyma. In the course of gradual desiccation of the plant, water accumulated in the inner aquiliferous pith parenchyma cells was lost first, whereas the outer aquiliferous layer of cortical cells bordering the meristematic zone remained relatively unchanged. It was suggested that the central pith of the stem serves a damper function during desiccation, while the outer cortical layer maintains homeostasis. NMR-microtomography is promising for studying water relations in plants belonging to diverse ecological groups

Water distribution in stems of Amaranthus cruentus L. examined by NMR-microtomography

NMR-microtomography was applied to study the water distribution in stem tissues of Amaranthus cruentus L. at both the flower bud-formation and flowering stages. In amaranth stems, two buffer regions for water accumulation were shown: the inner aquiliferous pith parenchyma and an outer layer situated at the stem periphery and coinciding with the primary cortical parenchyma. In the course of gradual desiccation of the plant, water accumulated in the inner aquiliferous pith parenchyma cells was lost first, whereas the outer aquiliferous layer of cortical cells bordering the meristematic zone remained relatively unchanged. It was suggested that the central pith of the stem serves a damper function during desiccation, while the outer cortical layer maintains homeostasis. NMR-microtomography is promising for studying water relations in plants belonging to diverse ecological groups