Spaceflight-induced variation on biological traits and effective components of Cassia obtusifolia.

The dry seeds of Cassia obtusifolia were carried by the "ShenZhou 8" satellite and sowed after landing. Based on our pri- or study on SP1, the characteristics of plants growth, physiological index and content of effective components were examined. The results showed that the QC10, QC29 strains matured 5 d earlier compared with control. The plant height, across diameter and ground diameter of QC10, QC29, QC46 strains was superior to the control at whole growth period. The branch number increased ranging from 4 to 11 and the number of pods reached 321, 313,281, respectively, which was dramatically higher than the control (246). The yield of QC10, QC29, QC46 strains increased noticeably from 31.4 to 63.2 g. The 1000-seed-weight of QC10, QC29, QC46 strains was 25.86, 25.88, 24.06 g, while the control was 23.69 g. Compared to the control, the mass fraction of chlorophyll was enhanced 1.098, 1.016, 0.297 mg. There was no significant difference in aurantio-obtusin and chrysophanol content of seeds. Through two years research, three high-yield mutant strains were obtained. This study indicates that spaceflight-induced mutants could provide new germplasm for C. obtusifolia breeding and offers the theoretical basis for further utilization of spaceflight-induced mutation to breed high-quality C. obtusifolia strains.