光照强度对广西地不容光合特性和生长的影响

以盆栽当年生广西地不容为材料,研究不同光照强度(100%、50%、30%和15%自然光强)对其光合特性和生长的影响。结果表明:随着光照强度的降低,广西地不容最大净光合速率(P_(max))、光饱和点(LSP)、光补偿点(LCP)先减小,而后稍有增大;表观量子效率(AQY)在30%和50%光强下显著高于100%和15%光强处理;叶片叶绿素总量(Chl)、叶绿素a(Chla)、叶绿素b(Chlb)、类胡萝卜素(Car)含量随光强的减弱而增大,Car/Chl随光强的减弱而减小,Chla/Chlb比值在各处理间无显著差异;单叶面积随生长光强的减弱而增大,比叶重(LMA)则随着生长光强的减弱而减小;30%光强下广西地不容块根生物量最高,光照过强和过弱都不利于其生物量的积累。广西地不容对光强的适应范围较广,但光照过强或过荫均对生长造成不良影响,光合速率降低,生长减缓,块根生物量积累下降,30%光强是其当年生苗生长的最佳光强。

Effect of different light intensities on photosynthetic characteristics and growth of Stephania kwangsiensis

Potted Stephania kwangsiensis seedlings were grown under 100%,50%,30%,15% of natural light intensity. It was found that with the reducing light intensity,the maximum net photosynthetic rate(P_(max)),light saturation point(LSP),light compensation point(LCP) showed a trend of decrease-to-increase,and the apparent quantum yield(AQY)under 30% and 50% of light intensity were significantly higher than those under 100% and 15% of light intensity. The contents of total chlorophyll(Chl),chlorophyll a(Chla),chlorophyll b(Chlb)and carotenoid(Car)in leaves increased with decreasing light intensity,while Car/Chl decreased under low light,and Chla/Chlb had no remarkably change. As the light intensity decreased,the single leaf area increased and leaf mass per area(LMA) decreased. The root tuber biomass was the highest under 30% of light intensity. Therefore,it seemed that S.kwangsiensis had a wide range of light adaptability,but its photosynthetic rate decreased when grown in either strong or weak light intensity,resulting in inhibition of growth and biomass. 30% of light intensity was the best light environment for seedlings on the current growth season.