遮荫对库拉索芦荟细胞超微结构和芦荟素含量的影响

Effects of Shading on Cellular Ultrastructure and Aloin Content of Aloe vera L.

分别用透射电子显微镜技术、高效液相色谱法研究了生长在遮荫和自然光照条件下库拉索芦荟叶片的超微结构和芦荟素含量.电镜观察结果表明,遮荫处理6个月后,库拉索芦荟叶片细胞中叶绿体基粒数量减少,类囊体片层数目减少且排列疏松,质体中原来积累的淀粉粒逐渐减少直至消失;内质网、高尔基体等内膜系统不发达.高效液相色谱分析结果显示,生长在遮荫条件下的库拉索芦荟叶片,芦荟素含量明显低于生长在自然光照下的含量.其中,遮荫下幼叶芦荟素的含量是自然光照下的63.33%,而成熟叶芦荟素含量仅有自然光照下的23.77%.无论自然光下还是遮荫条件下生长的芦荟,芦荟素的含量与叶龄有显著的负相关性,遮荫对成熟叶的影响更大.综合两方面的实验结果认为,遮荫首先影响芦荟叶片细胞内膜系统的发育,进而限制了芦荟素的合成和运输,使芦荟叶片中芦荟素含量降低.

Transmission electron microscope and HPLC were adopted to study cellular ultrastructures and aloin contents of Aloe vera L. growing under shaded condition and natural light. The observation by transmission electron microscope indicated that while A. vera L. had been shaded for six months,it showed decreased chloroplast grana and decreased and loosely arranged thylakoid lamellas in its leaf cells and the starch originally accumulated in its leaf plastids declined until it disappeared,presented such underdeveloped inner-membrane systems as endoplasmic reticula and golgiosomes. HPLC analysis indicated that A. vera L. growing under shaded conditions had remarkably lower aloin content in its leaves that it growing under natural light did. The aloin content of the young leaves under shaded conditions was only 63.33 % of that under natural light and the aloin content of the mature leaves under shaded condition was 23.77% of that under natural light. Whether A. vera L. grew under shaded conditions or natural light,its aloin content was significantly and negatively correlated with the age of the leaves and the age of its mature leaves showed much more influence. The results in these two respects indicated that shading first exerted influence on the development of inner-membrance systems in the leaves of A. vera L. and then affect aloin synthesis and transport thereby reducing the aloin content in the leaves of A. vera L.