蕨类植物碳氮磷化学计量特征及其与土壤养分的关系

Carbon, Nitrogen and Phosphorus Stoichiometry of Two Fern Species and Their Relationships to Nutrient Availability

摘要:

为探讨蕨类植物碳氮磷化学计量特征与土壤养分的关系,对福建省亚热带森林林下芒萁和乌毛蕨地上部分和地下部分的碳、氮、磷(C、N、P)含量和0~10 cm 和10~20 cm 两个土层的养分含量进行了测定。结果表明,无论是芒萁还是乌毛蕨,地上部分的N、P 含量均高于地下部分,而C 含量则无显著差异,导致地上部分的C:N 和C:P 均低于地下部分。与乌毛蕨相比,芒萁地上部分的N、P 含量更低,地上和地下部分的C 含量、C:N和C:P 以及 N、P 含量的变异系数和表型可塑性指数则更高,表明芒萁采取了较高的养分利用效率和“表现最大化”的策略,而乌毛蕨则选择了较低的养分利用效率和“表现维持”的方式。两种蕨类植物地上和地下部分的N 含量与土壤N 含量(0~20 cm) 均无显著相关。芒萁两个部位的P 含量则均与土壤P 含量(0~10 cm 和10~20 cm)呈显著正相关,乌毛蕨P 含量总体上与土壤P 含量的相关性不显著(除地下部分的P 含量与10~20 cm土层的P 含量呈弱的正相关外)。这表明芒萁具有作为亚热带森林土壤P 库指示植物的潜力。

Abstract:

In order to determine the stoichiometric traits of two fern species and their relationships to soil available nutrient, the above-and belowground parts of Dicranopteris dichotoma and Blechnum orientale and soils at 0-10 cm and 10-20 cm layers were collected from subtropical forests in Fujian Province, respectively. The carbon (C), nitrogen (N) and phosphorus (P) contents in plant and soil were measured. The results showed that N and P contents were significantly higher in aboveground than those in belowground, while C content did not show significant difference, which led to lower C:N and C:P ratios in aboveground. Compared with B. orientale, D. dichotoma had low N and P contents in aboveground; high C content, C:N and C:P ratios in both above-and belowground; high coefficient of variation and phenotypic plasticity indices of N and P contents. These stoichiometric trends may indicate that D. dichotoma had high nutrient use efficiency by maximizing its performance, while B. orientale had low nutrient use efficiency by sustaining its performance. N contents in both of the above-and belowground of two fern species were not significantly correlated with available N in soil at depth from 0 to 20 cm. Total P content in soil (both in 0-10 cm and 10-20 cm layers), however, was significantly and positively correlated with the P contents in both parts of D. dichotoma, but not with those in B. orientale (only P content in belowground had weak positive correlation with total P content in soil of 10-20 cm layer. Therefore, it was suggested that D. dichotoma could be a potential indicator of soil P availability in subtropical forests.