模拟CO2浓度升高对宁夏枸杞营养生长与果实品质的影响

Effects of Simulated Elevated CO2 Concentration on Vegetative Growth and Fruit Quality in Lycium barbarum

【目的】研究宁夏枸杞对大气CO2浓度升高的生理生态响应机制,为探究枸杞及其他木本经济林植物在气候变化背景下优质高效栽培与育种提供理论依据。【方法】以‘宁杞1号’扦插苗为材料,采用开顶气室(open-top chamber,OTC)及自动监控系统模拟控制CO2浓度,测定宁夏枸杞在升高CO2浓度环境下植株营养生长指标与果实糖分含量、主要活性物质含量和蔗糖代谢相关酶活性的变化。【结果】 1) CO2浓度升高,促进宁夏枸杞植株生长发育,苗高增长量较对照分别高11.67%和18.65%,地径分别高55.09%和62.58%,新梢加长和加粗生长均呈增加趋势。2) 2种CO2浓度升高处理下,宁夏枸杞果实横径较对照分别增加4.56%和7.71%,单果质量分别增加15.05%和34.53%,果实更加饱满。3) CO2浓度升高处理下,夏果(处理90天左右)果实中果糖含量较对照略高,秋果(处理120天后)含量比对照分别低1.39%和3.98%。试验处理期间,果实中葡萄糖和总糖含量均低于对照,且CO2浓度升高1倍[(760±20)μmol·mol^-1 ]处理下降最为明显。夏果果实蔗糖含量均低于对照,秋果在CO2浓度升高1倍[(760±20)μmol·mol^-1 ]下较对照略高。4)果实中枸杞多糖含量低于对照,黄酮含量在秋果期比对照分别低16.62%和18.35%,且CO2浓度升高1倍[(760±20)μmol·mol^-1 ]处理对果实活性物质含量影响较大。5) CO2浓度升高增加了酸性转化酶和中性转化酶活性;夏果蔗糖磷酸合成酶较对照明显增加,但秋果酶活性低于对照;蔗糖合成酶分解方向与合成方向酶活性变化趋势相同,夏果均高于对照,秋果酶活性低于对照,CO2浓度升高1倍[(760±20)μmol·mol^-1 ]处理下差异极显著。【结论】长期高CO2浓度处理促进宁夏枸杞植株营养生长,果实单果质量与纵横径增大,有利于改善果实外观品质;但果实中糖分含量和枸杞多糖、黄酮等生物活性物质的含量明显降低,相关酶活性发生变化,影响果实营养品质。

【Objective】 This study aimed to study the physiological and ecological response characteristics of Lycium barbarum to elevated atmospheric CO2 concentration([CO2 ]) in Ningxia,and to provide a theoretical basis for exploring the cultivation and breeding of wolfberry and other woody economic forests under the background of climate change.【Method】 In this study,‘Ningqi No.1’ cuttings were used as experimental materials,the changes of plant vegetative growth index,fruit morphological parameters,sugar content,active substance content and sucrose metabolism-related enzymes activity of fruits in response to elevated [CO2 ] were determined by using an open-top chamber (OTC) experimental facility and equipped with a concentration automatic monitoring system to simulate and control [CO2 ].【Result】 1) The increase of [CO2 ] by 0.5 times [(570±20)μmol·mol^-1 ] and 1 times [(760±20)μmol·mol^-1 ] significantly promoted the growth of L.barbarum plants.The net growth of seedling height was 11.67% and 18.65% higher than that of the control,and the ground diameter was 55.09% and 62.58% greater than that of the control,respectively.2) Under the two elevated [CO2 ] treatments,the transverse diameter of L.barbarum fruit in Ningxia increased by 4.56% and 7.71% respectively,and the weight of single fruit increased by 15.05% and 34.53% respectively,compared with the control.3) Under the two elevated [CO2 ] treatment,the fructose content of summer fruits (90 d after treatment) was slightly higher than that of CK,while that of autumn fruits (120 d after treatment) was 1.39% and 3.98% lower than that of control.During the treatment period,the contents of glucose and total sugars were lower than those in CK,especially under treatment with 1 times [CO2 ].The content of sucrose in summer fruits was lower than CK under the two [CO2 ] treatments,but the autumn fruits were slightly higher than that of control fruits when the CO2 concentration increased by 1 times.4) The content of polysaccharides decreased compared with CK flavonse decreased 16.62% and 18.35% in autumn fruits,and the increase of [CO2 ] by 1 times had greater impact.5) Changes in the activity of sucrose metabolism-related enzymes of fruit were obvious with the two elevated [CO2 ] treatments.Acid invertase and neutral invertase increased.Sucrose phosphate synthetase in the summer fruits increased significantly,but autumn fruit enzyme activity was lower than that in control.The change trend of enzyme activity in decomposition direction and synthesis direction was the same.During the summer period,they were all higher than the control,but in the autumn period lower than the CK.【Conclusion】Thus,long-term treatment with elevated [CO2 ] promotes vegetative growth of L.barbarum,increases the weight of single fruit,vertical diameter and horizontal diameter,which is helpful to improve the appearance of fruits.However,the content of sugar and bioactive substances such as polysaccharides and flavonoids are significantly reduced,and the activity of sucrose metabolism-related enzymes activity changes,which affected the nutritional quality of fruits.