水分胁迫对蒺藜光合作用、生物量和药材质量的影响

Effects of water stress on photosynthesis,biomass,and medicinal material quality of Tribulus terrestri

通过盆栽试验,分析了水分胁迫对蒺藜光合特性、生物量形成和主要药用成分积累的影响.结果表明:水分胁迫改变了蒺藜的光合日进程,使蒺藜的净光合速率和蒸腾速率显著降低,植株光合能力减弱,同化能力下降,最终导致干物质积累受阻,生物量降低.但水分胁迫促进了蒺藜总皂苷类物质积累.灌水量为150和450 mm处理下,蒺藜总皂苷含量分别为13.26和12.47 mg.g-1,与其余处理(250、350 mm)总皂苷含量差异显著.总皂苷和总黄酮类物质动态积累趋势与生物量积累趋势相反,生物量积累高峰期,次生代谢产物含量反而降低.生物量积累受外界环境因子的直接影响较大,而次生代谢产物除受外界环境因子的影响外,还受到生物量积累等内部因素影响.

A pot experiment was conducted to study the effects of water stress on the photosynthetic characteristics,biomass accumulation,and principal medicinal compositions of Tribulus terrestri.Water stress changed the diurnal variation of T.terrestri photosynthesis,decreased the net photosyn-thetic rate and transpiration rate significantly,weakened the plant photosynthetic and assimilative capability,and accordingly,hindered the dry matter accumulation and decreased the biomass.However,water stress promoted the accumulation of gross saponins in T.terrestri.In the treatments with irrigation amounts 150 and 450 mm,the gross saponins content was 13.26 and 12.47 mg·g^-1,respectively,being significantly different from that in the treatments with irrigation amounts 250 and 350 mm.The dynamic accumulation of gross flavonoids and gross saponins had an opposite tendency with that of biomass,namely,the contents of these principal medicinal compositions were the lowest when the biomass was the maximal.Correlation analysis showed that the biomass accumulation of T.terrestri was significantly correlated with outside environmental factors,while the contents of secondary metabolism products were affected not only by the outside environmental fac-tors,but also by the inside factors such as biomass accumulation.