Water status and carbohydrate pools in tulip bulbs during dormancy release
Water status and carbohydrate pools in tulip bulbs during dormancy release
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DOI：
10.1046/j.1469-8137.2003.00719.x
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发表时间：
2003-04-01
期刊：
影响因子：
9.4
通讯作者：
Bendel, P
中科院分区：
文献类型：
--
作者：
Kamenetsky, R;Zemah, H;Bendel, P
研究了郁金香球茎（Tulipa gesneriana ‘Apeldoorn’）种植前储存过程中细胞水物理状态的变化及其与碳水化合物代谢的相互关系。使用磁共振成像、光学和扫描电子显微镜以及带脉冲电流检测的高性能阴离子交换色谱来跟踪球茎在 17 或 20°C（非冷冻）或 4°C（冷冻）储存期间随时间的变化。在显微镜下观察冷冻和非冷冻球茎的鳞片结构和中央芽发育。然而，冷冻球茎的鳞片表现出更高的含水量、更快的淀粉降解以及更高浓度的蔗糖和乙醇可溶性果聚糖。磁化转移 (MT) 的定量测量表明，冷冻球鳞片中存在较小部分的固体或受限迁移质子库。相比之下，冷藏球茎中心芽的 MT 效应明显高于非冷藏球茎。在休眠释放过程中，贮藏多糖降解为低分子量糖分子，可能伴随着与多糖颗粒紧密结合的水分子局部释放到大量水中，或者由于糖浓度升高导致渗透势增加而导致游离水分子流入，或者是两种效应的组合。
Changes in the physical state of cellular water and its interrelations with carbohydrate metabolism were studied during preplanting storage of tulip bulbs (Tulipa gesneriana 'Apeldoorn').Magnetic resonance imaging, light and scanning electron microscopy and high-performance anion exchange chromatography with pulsed amperometric detection were used to follow time-dependent changes during bulb storage at 17 or 20degreesC (nonchilled) or 4degreesC (chilled).No visible differences in scale structure and central bud development were observed microscopically between chilled and nonchilled bulbs. However, the scales of the chilled bulbs exhibited higher water content, faster starch degradation and increased concentrations of sucrose and ethanol-soluble fructan. Quantitative measurements of magnetization transfer (MT) indicated a smaller fraction of a solid or a restricted-mobility proton pool in the scales of the chilled bulbs. By contrast, the MT effect was significantly higher in the central bud of the chilled than in the nonchilled bulbs.Degradation of storage polysaccharides to low-molecular-weight sugar molecules during release from dormancy could be accompanied by local release of water molecules tightly bound to the polysaccharide granules into the bulk water, or by an influx of free water molecules due to increased osmotic potential caused by the raised sugar concentration, or by a combination of both effects.