Zhang Lingling, Luo Xianzhen, Zhang Guihua, Zang Xiaowei, Wen Dazhi
Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, No. 723, Xingke Road, Tianhe District, Guangzhou 510650, China.
Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, No. 723, Xingke Road, Tianhe District, Guangzhou 510650, China.
Tree Physiol. 2024 Feb 6;44(1). doi: 10.1093/treephys/tpad150.
In the context of the resource allocation hypothesis regarding the trade-off between growth and defence, compared with native species, invasive species generally allocate more energy to growth and less energy to defence. However, it remains unclear how global change and nutrient enrichment will influence the competition between invasive species and co-occurring native species. Here, we tested whether nitrogen (N) and phosphorus (P) addition under elevated CO2 causes invasive species (Mikania micrantha and Chromolaena odorata) to produce greater biomass, higher growth-related compounds and lower defence-related compounds than native plants (Paederia scandens and Eupatorium chinense). We grew these native and invasive species with similar morphology with the addition of N and P under elevated CO2 in open-top chambers. The addition of N alone increased the relative growth rate (RGR) by 5.4% in invasive species, and its combination with P addition or elevated CO2 significantly increased the RGR of invasive species by 7.5 or 8.1%, respectively, and to a level higher than that of native species (by 14.4%, P < 0.01). Combined N + P addition under elevated CO2 decreased the amount of defence-related compounds in the leaf, including lipids (by 17.7%) and total structural carbohydrates (by 29.0%), whereas it increased the growth-related compounds in the leaf, including proteins (by 75.7%), minerals (by 9.6%) and total non-structural carbohydrates (by 8.5%). The increased concentrations of growth-related compounds were possibly associated with the increase in ribulose 1,5-bisphosphate carboxylase oxygenase content and mineral nutrition (magnesium, iron and calcium), all of which were higher in the invasive species than in the native species. These results suggest that rising atmospheric CO2 concentration and N deposition combined with nutrient enrichment will increase the growth of invasive species more than that of native species. Our result also suggests that invasive species respond more readily to produce growth-related compounds under an increased soil nutrient availability and elevated CO2.
在关于生长与防御权衡的资源分配假说背景下，与本地物种相比，入侵物种通常将更多能量分配给生长，而将更少能量分配给防御。然而，全球变化和养分富集将如何影响入侵物种与共生本地物种之间的竞争仍不清楚。在此，我们测试了在二氧化碳浓度升高的情况下添加氮（N）和磷（P）是否会使入侵物种（薇甘菊和飞机草）比本地植物（鸡矢藤和华泽兰）产生更多生物量、更多与生长相关的化合物以及更少与防御相关的化合物。我们在开放式气室中，在二氧化碳浓度升高的情况下添加N和P，种植了这些形态相似的本地和入侵物种。单独添加N使入侵物种的相对生长速率（RGR）提高了5.4%，其与添加P或二氧化碳浓度升高相结合，分别使入侵物种的RGR显著提高了7.5%或8.1%，并达到高于本地物种的水平（高14.4%，P < 0.01）。在二氧化碳浓度升高的情况下，N和P联合添加降低了叶片中与防御相关的化合物含量，包括脂质（降低17.7%）和总结构性碳水化合物（降低29.0%），而增加了叶片中与生长相关的化合物含量，包括蛋白质（增加75.7%）、矿物质（增加9.6%）和总非结构性碳水化合物（增加8.5%）。与生长相关的化合物浓度增加可能与核酮糖-1,5-二磷酸羧化酶加氧酶含量和矿物质营养（镁、铁和钙）的增加有关，所有这些在入侵物种中都高于本地物种。这些结果表明，大气二氧化碳浓度上升、氮沉降以及养分富集相结合，将使入侵物种的生长比本地物种增加得更多。我们的结果还表明，在土壤养分有效性增加和二氧化碳浓度升高的情况下，入侵物种更容易响应产生与生长相关的化合物。
