黄土丘陵区撂荒草地不同生态位物种非结构性碳水化合物对氮添加的响应

为研究氮添加对不同生态位物种非结构性碳水化合物的影响。通过对黄土丘陵区典型撂荒草地进行3年的氮添加试验N0(0 g/(N·m²·a))、N3(3 g/(N·m²·a))、N6(6 g/(N·m²·a))和N9(9 g/(N·m²·a)),JP]分析了不同生态位物种可溶性糖、淀粉和非结构性碳含量。结果表明:氮添加主要影响占据较高生态位的白羊草(Bothriochloa ischaemum)和长芒草(Stipa bungeana)的非结构性碳水化合物的储存,而对铁杆蒿(Artemisia sacrorum)和杂草影响较小。N6和N9处理对白羊草和长芒草非结构性碳、可溶性糖和淀粉的储存表现出明显的促进作用,这种作用在地上部分表现尤为明显。同时,植物相对重要值与植物地下非结构性碳和淀粉含量显著正相关,而与地上可溶性糖含量和可溶性糖/淀粉显著负相关。研究结果有利于加强对氮沉降背景下不同生态位物种碳储存及分配特征的认识。

Responses of Non-structural Carbon of Different Niche Species to Nitrogen Addition in Loess Hilly Region

To study the effect of nitrogen addition on the non-structural carbon of species in different ecological niches, we conducted a three-year nitrogen addition experiment on typical abandoned grasslands on the Loess Plateau and analyzed the soluble sugar, starch and non-structural carbon content of species in different ecological niches. The nitrogen gradients were N0 (0 g/(N·m²·a)),N3 (3 g/(N·m²·a)),N6 (6 g/(N·m²·a)) and N9 (9 g/(N·m²·a)). Our study showed that the nitrogen addition mainly affected the storage of non-structural carbohydrates in Bothriochloa ischaemum andStipa bungeanathat occupied the higher niches, while it had little effect on Artemisia sacrorumand weeds. The N6 and N9 treatments significantly increased the storage of non-structural carbon, soluble sugar and starch of Bothriochloa ischaemum andStipa bungeana, especially for the aboveground part. Besides, the relative importance value had significantly positive correlation with the belowground non-structural carbon and starch contents, but had significantly negative correlation with the aboveground soluble sugar content and the ratio of soluble sugar to starch. Our findings are helpful to strengthen our understanding of the carbon storage and distribution characteristics of species in different ecological niches under the background of nitrogen deposition.