大兴安岭南段蒙古栎粗根非结构性碳对不同坡向的响应

Effect of different slope characteristics on root nonstructural carbon of Quercus mongolica in the southern Daxing’anling Mountains

在半干旱区,掌握树木根部碳储存规律对探究水分胁迫影响地上、地下器官碳分配机制至关重要。本研究以蒙古栎(Quercus mongolica)为研究对象,在2021年(湿润年)、2022年(干旱年)、2023年(正常年)的生长季每月采集不同坡向(阳坡、半阳坡、阴坡)蒙古栎粗根样本,测定非结构性碳(Non-Structural Carbohydrate,NSC)及其组分(可溶性糖、淀粉)含量并分析其动态变化规律。结果表明:(1)粗根NSC组成以淀粉为主,粗根NSC及其组分含量随5月、6月、7月、8月、9月的顺序递增且差异显著(P<0.05)。(2)NSC含量及淀粉含量随湿润年、正常年、干旱年的顺序递增;不同坡向淀粉含量随阳坡、半阳坡、阴坡的顺序递减,且二者均差异显著(P<0.05)。(3)通过对粗根NSC及其组分影响的主导因素分析,坡向因素影响大,反应了粗根NSC对潜在蒸散量梯度反应敏感。研究结果有助于理解干旱环境下地下器官对树木生长碳分配的调节机制。

The distribution of carbon within plant aboveground and subsurface organs is important for understanding the carbon storage systems in tree roots in semi-arid areas.In this study,coarse root samples of Quercus mongolica.were collected monthly during the growing seasons of 2021(wet year),2022(dry year),and 2023(normal year).The changes in nonstructural carbon and its components(soluble sugar and starch)were analyzed;the NSC(Non-Structural Carbohydrate)content of coarse root was primarily starch,and it increased significantly with seasonal changes(P<0.05).The NSC and starch contents were highest during the wet season,followed by the normal and dry seasons.The starch content was highest on the sunny slope,followed by the semi-sunny and shady slopes regions(P<0.05).Slope characteristics affect the NSC and component contents of coarse roots,as NSC and component contents change in response to potential evapotranspiration gradients.The findings provide a better understanding of the mechanisms controlling carbon distribution within plant underground organs in response to arid conditions.