摘要
通过利用二维回转器模拟微重力,对20 d回转条件下雨生红球藻细胞结构、光合活性、初级糖代谢及次生代谢产物变化情况进行分析,发现回转作用使得藻细胞体积变小,形状变得不规则.超微结构分析显示,回转处理后,藻细胞的淀粉粒变小,类囊体膜结构排列松弛.叶绿素含量在回转前期降低,中后期提高.类胡萝卜素含量及光合系统Ⅱ活性在整个回转过程中均降低.由此得出藻细胞光合活性的下降与叶绿体类囊体膜结构的变化及色素含量下降有关.藻细胞淀粉粒变小、淀粉含量下降与淀粉酶活性的上升有关,说明回转作用通过提高淀粉酶水解活性造成淀粉含量下降.蔗糖和海藻糖的积累在藻细胞对早期回转条件的适应过程中发挥了一定保护作用,同时造成合成此两种糖的单糖底物-葡萄糖和果糖含量下降.在被称作适应期的回转中期,叶绿素、葡萄糖和果糖均出现补偿性合成,而蔗糖和海藻糖的积累相比回转前期出现相应下降.雨生红球藻次生代谢产物虾青素在整个回转过程中均下降,分析认为这是由虾青素的原初合成底物即类胡萝卜素合成的降低所导致.
During 20 days of simulated microgravity using clinostat （two-dimensional）, the cellular structure, photosynthetic activity, primary and secondary metabolism of Haematococcus pluvialis were investigated. Results showed that the cell shape appeared abnormal and the volume became smaller than the ground control＇s. Ultrastructure analysis revealed that the starch grains seemed smaller and the thylakoid membranes were more randomly distributed and loosened after 20 days of clinorotation. Chlorophyll content decreased during the early period of clinorotation, but increased in the late phase. Carotenoid content and photosystem II efficiency decreased during the whole clinorotation. It could be presumed that the decreased photosynthetic efficiency might have some relation with the decreased pigment synthesis and the structure changes that happened on chloro- plast after clinorotation. The smaller starch grains, together with the decreased starch content were probably due to an increased hydrolysis of amylase during clinorotation. The increased sucrose and trehalose played a protective role in the accommodation to early clinorotation. However, this led to a decrease of glucose and fructose utilized for the synthesis of protective disaccharides. In the middle phase of clinorotation （i. e. the acclimation period）, a compensatory synthesis of chlorophyll, glucose and fructose was observed, whereas synthesis of sucrose and trehalose reduced. The decreased astax- anthin production during the whole clinorotation was due to the depressed carotenoid participating in the astaxanthin synthetic pathway.
出处
《空间科学学报》
CAS
CSCD
北大核心
2013年第3期293-301,共9页
Chinese Journal of Space Science
基金
中国科学院战略先导专项(XDA04074002
XDA04020202-16)
载人航天二期项目共同资助
关键词
回转器
雨生红球藻
蔗糖
虾青素
糖代谢
Clinorotation, Haematococcus pluvialis, Sucrose, Astaxanthin,Carbohydrate metabolism
