Cowles J R, Lemay R, Jahns G
University of Houston, TX 77004, USA.
Astrophys Lett Commun. 1988;27:223-8.
Lignin is a major cellular component of higher plants. One function of lignin is to support vertical plant growth in a gravity environment. Various investigators working in the 1 g environment have concluded that lignification is influenced by gravity. An experiment was designed for flight on Spacelab II to determine the effect of microgravity on lignification in young plant seedlings. A secondary objective of the experiment was to examine the effect of microgravity on overall seedling growth. Mung bean and oat seeds germinated and the seedlings grew under the Spacelab II mission. Growth of flight mung bean and oat seedlings, however, was slower, and the seedlings exhibited stem and root orientation difficulties. Flight pine seedlings were similar in appearance and growth to 1 g controls. The rate of lignin formation in seedlings grown in space was significantly less in all three species in comparison to 1 g controls. The experiment provided direct evidence that lignification is slowed in a microgravity environment.
木质素是高等植物的主要细胞成分。木质素的一个功能是在重力环境中支持植物的垂直生长。在1g环境下开展研究的众多研究者得出结论，木质化受重力影响。设计了一项在太空实验室二号上进行的飞行实验，以确定微重力对幼小植物幼苗木质化的影响。该实验的第二个目标是研究微重力对幼苗整体生长的影响。绿豆和燕麦种子发芽，幼苗在太空实验室二号任务期间生长。然而，飞行中的绿豆和燕麦幼苗生长较慢，并且幼苗在茎和根的定向方面存在困难。飞行中的松树幼苗在外观和生长方面与1g环境下的对照相似。与1g环境下的对照相比，在太空中生长的所有三个物种的幼苗中木质素形成的速率明显较低。该实验提供了直接证据，证明在微重力环境中木质化会减缓。
