Effect Of Elevated CO₂ Concentrations On Sugar Accumulation And Contents Of Main Active Components In Lycium Barbarum

Goji berry?Lycium barbarum L.?,is one of the importang economic crops in China.Due to its unique nutrient value and medicinal benefits that including some active component,such as flavonoids,Lycium barbanan polysaccharide,and caroteniods.Cliamate change has become an important facter impact natural ecosystems,biodiversity,crops development and food security,it has aroused widespread concern in the academic community for plant growth and development.With 'Ningqi No.7' as material,the change of plants vegetative growth index,fruits morphological parameters,and leaf chlorophyll content,gas exchange parameters,levels of soluble sugars?fructose,glucose,sucrose?and starch,activities of sucrose phosphate synthase?SPS?,sucrose synthase?SS?,acid invertase?AI?,neutral invertase?NI?of leaf and fruit,main active ingredient content in fruits were determined by using an open-top chamber?OTC?experimental facility and equipped with a concentration automatic monitoring simulates control system to reach the target CO₂ concentration?[CO₂]?.This experiment was mainly study the effect of physiological and ecological characteristics of L.barbarum to elevated atmospheric[CO₂].Result showed:1.Elevated[CO₂]treament makes the phenological period advance of goji berry,which is conducive to its growth and development;The plants height,ground diameter,new growth rate of the seedlings increased,and the maximum was observed under 760±20 ?mol· mol-1 treatment,and the net growth increased significantly.The fruit weight and transverse diameter increased,makeing fruit look fuller;the leaves fresh and dry weight increased significantly,and the leaf area increased,too.2.Elevated[CO₂]increased the Goji berry leaves photosynthetic capacity:chlorophyll content increased significantly in the final of summer period,stomatal conductance?Gs?and transpiration rate?Tr?were significantly reduced at[CO₂]760±20?mol·mol-1 treatment,net photosynthetic rate?Pn?,intercellular CO₂ concentration?Ci?and water use efficiency?WUE?increased under long-term elevated[CO₂]treatment.The maximum net photosynthetic rate,light saturation point,light compensation point,CO₂ saturation point and CO₂ compensation point increased under the treatment of 570±20 ?mol—mol-1[CO₂].3.Elevated[CO₂]increased accumulation of photosynthetic products in plants,leaves sucrose content increased,sucrose metabolic enzyme activity improved.It promoted plant photosynthetic product supply capacity and source-sink transport capacity.In the early staget,the leaves fructose,sucrose content and fruit glucose,sucrose and starch content increased,As treatment time increases,leaf and fruit sugar and starch content were lower.Fruit and leaf invertase?Ivr?activity were higher but not significant,fruit sucrose synthase?SS?activity was lower,and has significant difference when under long-term treatment.The activity of sucrose phosphate synthase?SPS?was consistent with the change of sucrose content,which increased first and then decreased.The change trend of leaf sucrose synthase activity was same with sucrose phosphate synthase,and it increased significantly under 760±20?mol·mol-1[CO₂]treatment.At the same time,the correlation between leaves with fruits sugar content,and sugar content with sucrose metabolic enzyme activity,was stronger than that of natural atmospheric[CO₂].4.The treatment of elevated[CO₂]reduced the content of carotenoids,Lycium barbarum polysaccharides?LBP?and taurine in goji berry fruit.The content of LBP and taurine in the treatment of long-term high concentration?760±20 ?mol·mol-1?was significantly different from the control.It is 17.46%and 26.99%higher.The flavonoid content showed a trend of increasing first and then decreasing,and the treatment was significantly different from the control.High[CO₂]reduced the main active ingredients in Goji berry fruitsit,it leads to affect the nutritional quality of fruits.