逐步提高培养基蔗糖浓度诱导的黄皮胚轴耐脱水性与细胞超微结构的变化

Changes in Desiccation Tolerance and Cell infrastructures of Wampee Axes Induced by Progressively Raising Sucrose Concentration of Culture Medium

黄皮胚轴在蔗糖浓度按27％→50％→60％递增的WPM培养基中培养后耐脱水性显著提高,大部分胚轴脱水至含水量为18.8％时仍具有再生植株的能力。超微结构观察表明,对照下胚轴的细胞在脱水至36.3％含水量时质膜和液泡解体,叶绿体和线粒体崩溃。而经蔗糖逐步加浓培养的胚轴脱水至35.2％含水量时,大部分细胞发生质壁分离,细胞质稠密,叶绿体内部的淀粉粒变大;脱水至18.8％时细胞质壁分离加剧,大部分叶绿体和线粒体局部损伤。脱水至18.8％的胚轴重新吸胀4 d后细胞损伤被修复。

The desiccation tolerance of warnpee [Clausena lansium (Lour.) Skeels] axes was significantly increased when they were pre-cultured with woody plant medium with progressively increasing sucrose contents(27% → 50% → 60%). Most of the plumular axes could survive a moisture content as low as 18.8% and could regenerate plantlets. Results of electron microscopy showed that when the moisture content of the plumular axes of the control was brought down to 36.3%, the plasmolemma and vacuole disappeared, and the chloroplasts and mitochondra collapsed (Plate 1-1-4). While plumular axes had been pre-cultured by progressive raising of sucrose concentration of culture medium and then desiccated to a moisture content of 35.8%, plasmolysis occurred in most ofthe cells, with dense cytoplasm and big starch grains in the chloroplast (Plate Ⅰ-6-8, Plate Ⅱ-9). Furthermore, after they were desiccated to a moisture content of 18.8%, severe plasmolysis was observed, most of the chloroplasts and mitochondra were partly injured (Plate Ⅱ-10). The desiccative injury in cells of the plumular axes desiccated to a moisture content of 18.8% could be repaired after 4 d of rehydration (Plate Ⅱ-11-16).