入侵植物黄顶菊与5种共生植物叶片建成成本的比较

Comparison of leaf construction cost between invasive plant Flaveria bidentis and its five co-occuring plants

叶片建成成本(construction cost,CC)是衡量植物叶片建成所需能量的重要指标,反映了植物叶片的能量利用策略,较低的叶片建成成本可能会增加入侵植物的竞争优势。本研究以入侵植物黄顶菊(Flaveria bidentis)与其共生的本地植物苍耳(Xanthium sibiricum)、反枝苋(Amaranthus retroflexus)、狗尾草(Setaira viridis)、灰绿藜(Chenopodium glaucum)和绿豆(Vigna radiata)为对象,比较了其叶片建成成本的差异。结果表明,黄顶菊叶片单位质量建成成本(CC mass)均显著低于其共生植物,是5种共生植物均值的76.6%,而叶片单位面积建成成本(CC area)也显著低于除狗尾草以外其他共生植物,是5种共生植物均值的74.4%。黄顶菊叶片碳浓度和氮浓度显著低于其共生植物;叶片灰分浓度显著高于其共生植物(与灰绿藜差异不显著);叶片去灰分热值显著低于其共生植物(显著高于灰绿藜)。植物叶片CC mass与叶片碳浓度和去灰分热值呈显著性正相关,叶片CC mass与灰分浓度呈显著性负相关。与共生植物相比,较低的叶片建成成本可能是黄顶菊成功入侵的原因之一。

Leaf construction cost （CC） is an important indicator in measuring the energy demand for plant leaf construction, and reflects the energy utilization strategy of plant leaf. Lower leaf CC has been hypothesized to give invasive plants a growth advantage through efficient energy utiliza tion. In this paper, the invasive plant Flaveria bidentis and its cooccuring native plants Xanthi um sibiricum , Amaranthus retroflexus , Setaira viridis , Chenopodium glaucum , and Vigna radiata were selected as the objects to compare their differences in leaf CC and related characteristics. The construction cost per unit leaf mass （ CC ） of F. bidentis was significantly lower than that of the five cooccuring native plants, being 76.6% of the average CC of the native plants. Likewise, the construction cost per unit leaf area （ CC ） of F. bidentis was significantly lower than that of the native plants except S. viridis, being 74.4% of the average CC of the native plants. The leaf carbon and nitrogen concentrations of F. bidentis were significantly lower than those of the cooccuring plants. The leaf ash content of F. bidentis was significantly higher than that of X. sibiricum, A. retroflexus, S. viridis, and V. radiate, but had less difference with that of C. glaucum; while the leaf ashfree calorific value of F. bidentis was significantly lower than that of the native plants except C. glaucum. For all test plants, their leaf CC was significantly positively correlated with their leaf carbon concentration and leaf ashfree calorific value, butnegatively correlated with the leaf ash content. As compared with that of the cooccuring plants, the lower leaf CC of F. bidentis could be one of the reasons causing the successful invasion of this invasive plant.