华南地区固氮与非固氮豆科树种叶片养分利用策略的对比研究

Different Leaf Nutrient Use Strategies of Nitrogen-fixing and Non-nitrogen-fixing Leguminous Trees in South China

摘要:

为探究富氮环境中固氮(nitrogen-fixing leguminous trees, NLT)与非固氮豆科树种(non-nitrogen-fixing leguminous trees, n-NLT)的叶片养分利用策略差异，以华南地区5种NLT植物[水黄皮(Pongamia pinnata)、大叶相思(Acacia auriculiformis)、朱樱花(Calliandra haematocephala)、海南红豆(Ormosia pinnata)、台湾相思(Acacia confusa)]和3种n-NLT植物[油楠(Sindora glabra)、中国无忧花(Saraca dives)、银珠(Peltophorum tonkinense)]为对象，测定其单位质量叶片碳(C)、氮(N)和磷(P)含量及其比值、单位面积叶片最大净光合速率(A_area)和叶片光合氮、磷利用效率(PNUE、PPUE)等功能性状。结果表明，NLT的单位质量叶片N、P含量和A_area均显著高于n-NLT，而两者PNUE和PPUE无显著差异；尽管两类植物单位质量叶片C含量无显著差异，但NLT的叶片C: N和C: P显著低于n-NLT。因此，这表明华南地区NLT比n-NLT具有更强的养分获取和光合能力，但叶片养分利用效率更低。

Abstract:

To reveal leaf nutrient use strategies of nitrogen-fixing leguminous trees (NLT) and non-nitrogen-fixing leguminous trees (n-NLT) under the nitrogen-rich environments in South China, five NLT (Pongamia pinnata, Acacia auriculiformis, Calliandra haematocephala, Ormosia pinnata, Acacia confuse) and three n-NLT (Sindora glabra, Saraca dives, Peltophorum tonkinense) were selected, the concentrations of carbon (C), nitrogen (N) and phosphorus (P) per leaf mass, leaf C: N and C: P, maximum net photosynthetic rate per leaf area (A_area), photosynthetic nitrogen use efficiency (PNUE) and photosynthetic phosphorous use efficiency (PPUE) were measured. The results showed that N and P contents and A_area of NLT were significantly higher than those of n-NLT, whereas their PNUE and PPUE had not significant difference. Although there was no significant difference in leaf C content between two types of species, leaf C: N and C: P of NLT were significantly lower than those of n-NLT. Therefore, these indicated that NLT in South China had stronger nutrient acquisition and photosynthetic capacity than N-NLT, but lower leaf nutrient utilization efficiency.