氮对黄花蒿生长、光合特性和青蒿素含量的影响

Effect of soil nitrogen levels on the growth, photosynthetic properties and artemisinin content of Artemisia annua seedling

关键词:  光合特性  生长特性  生物量分配  青蒿素含量  黄花蒿

Key words:  photosynthetic properties  growth properties  biomass allocation  artemisinin content  Artemisia annua

摘要:

对不同氮处理黄花蒿生长、生物量分配、青蒿素含量和光合特性进行测定,结果表明:(1)供氮量在0～0.4 g·kg^-1之间,黄花蒿叶片单位重量的氮含量、最大净光合速率、光饱和点和表观量子效率均随供氮量的增大而增加,之后开始下降。在较大范围内,环境氮含量越高,黄花蒿的光合能力越强,能够利用的光强也更高;(2)黄花蒿根生物量分数和根冠比均随供氮量的减少而显著增大,低氮时分配更多的生物量到养分吸收器官,有利于减少氮素对生长的限制,供氮量在0.1～0.6 g·kg^-1之间,黄花蒿叶生物量分数随供氮量的增加而增大,高氮时更多的生物量投入到碳同化器官,提高了植株的竞争能力;(3)无论以最大净光合速率、地径、叶片生物量还是以总生物量来衡量,均以0.4 g·kg^-1氮处理的植株生长得最好,0.2 g·kg^-1氮处理的青蒿素含量最高,生产中推荐使用0.2 g·kg^-1剂量的氮更经济。

Abstract:

Nitrogen is a major determinant of growth rate in plants. In this study,Artemisia annua were cultured under five soil nitrogen levels for about five months. The effects of different nitrogen levels on the growth,biomass allocation,photosynthetic characteristics and artemisinin content of A.annua were examined. The results showed that,with the increase of nitrogen level,the nitrogen content per leaf mass,maximum net photosynthetic rate,light saturation point and the apparent quantum yield of A.annua increased significantly when nitrogen level were 0-0.4 g·kg^-1,and declined whereafter,which indicated that the photosynthetic properties of A.annua could acclimated adequately to nitrogen conditions. High nitrogen content could enhance the photosynthetic capacity of A.annua,and it could utilize higher light intensity. The root mass fraction and root mass/crown fraction of A.annua increased with the increase of nitrogen level,more biomass was invested into root system,nutrient absorbing organ,which could enhance nutrient-capture ability. With the increase of nitrogen level,leaf mass fraction of A.annua increased when nitrogen level were 0.1-0.6 g·kg^-1,more biomass was invested into leaf,assimilative organ,which could increase their carbon accumulation and improve their competitive abilities. Under 0.4 g·kg^-1 nitrogen level,the maximum net photosynthetic rate,diameter,leaf biomass and total biomass of A.annua were maximal,and the artemisinin content was maximal under 0.2 g·kg^-1 nitrogen level. It was suggested to supplement with 0.2 g·kg^-1 nitrogen during the course of cultivation.