蕨类植物碳氮磷化学计量特征及其与土壤养分的关系

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。

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

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.