不同光照强度对黄芪主要次生代谢物含量的影响

Effect of light intensity on the contents of main secondary metabolites in Astragalus

评价光环境对黄芪根部多种活性成分积累的共同影响,对提高黄芪培育和高值利用具有重要作用.采用不同光强处理膜荚黄芪[Astragalus membranaceus(Fisch.)Bge]和蒙古黄芪[A.membranaceus(Fisch.)Bge.var.mongholicus(Bge.)Hsiao]幼苗,运用超高效液相色谱系统(Ultra-Performance LC,Waters,Japan)分析光强变化对黄芪根部毛蕊异黄酮苷、毛蕊异黄酮、芒柄花苷、黄芪甲苷、环黄芪醇5种活性成分含量的同时影响.结果显示光强减弱对黄芪主要活性成分综合影响增加,黑暗条件有利于毛蕊异黄酮苷、毛蕊异黄酮和黄芪甲苷的积累,膜荚黄芪和蒙古黄芪毛蕊异黄酮苷含量在黑暗条件下比中度光强分别增加了6.39倍和4.42倍;低光有利于环黄芪醇的积累,低光条件下环黄芪醇在膜荚黄芪和蒙古黄芪根中分别比中光增加了4.80倍和1.75倍,高光有利于芒柄花苷的积累,高光比中光条件下膜荚黄芪和蒙古黄芪根中芒柄花苷分别增加了1.32倍和1.49倍.在黑暗及低光情况下,膜荚黄芪中毛蕊异黄酮和黄芪甲苷比蒙古黄芪中含量高,但芒柄花苷比蒙古黄芪中含量低.本研究表明不同光照强度适宜不同药用成分积累,定向培育应根据目的成分选择适宜光照强度.

The effects of light intensity on the accumulation of main secondary metabolites in roots has important consequences for improving the cultivation and utilization of Astragalus. Seedlings of A. membranaceus （Fisch.） Bge （Astragalus-1） and A. membranaceus （Fisch.） Bge. var. mongholicus （Bge.） Hsiao （Astragalus-2） were treated with different light intensities, and five secondary metabolites—isoflavone glycosides, isoflavones, ononin, astragaloside IV, and cycloastragenol—were detected by ultra-performance LC. The results showed that dark conditions were conducive for accumulation of isoflavone glycosides, isoflavones, and astragaloside IV. The contents of isoflavone glycosides in Astragalus-1 and Astragalus-2 increased by 6.39 times and 4.42 times, respectively, in the dark compared to those under moderate light intensity. Low light was beneficial for accumulation of cycloastragenol. The contents of cycloastragenol in Astragalus-1 and Astragalus-2 increased by 4.80 times and 1.75 times, respectively, under low light compared to those under moderate light intensity. High light was beneficial for accumulation of ononin. The contents of ononin in Astragalus-1 and Astragalus-2 increased by 1.32 times and 1.49 times, respectively, under high light compared to those under moderate light intensity. In the dark and low light conditions, the contents of isoflavones and astragaloside IV in Astragalus-1 were higher than those in Astragalus-2, but the content of ononin in Astragalus-1 was lower than that in Astragalus-2. The present study indicated that different light intensities were suitable for accumulation of different secondary metabolites and that proper light intensity should be chosen according to the target components in directional cultivation.