鼎湖山季风常绿阔叶林不同生境蕨类植物的叶片功能性状研究

Leaf Functional Traits of Ferns from Different Habitats in Monsoon Evergreen Broad-leaved Forest in Dinghushan Mountain

摘要:

为了解不同生境中蕨类植物的叶片功能,对鼎湖山季风常绿阔叶林中的6 种优势蕨类植物的比叶面积、光合速率、元素含量、构建成本和水分利用效率等叶片性状进行了测定,研究了它们对环境的适应性。研究结果表明,两种附生蕨类(江南星蕨和崖姜蕨)的叶片具有较低的比叶面积(SLA)和光合速率(A_area),较高的构建成本(CC_area)和碳同位素比率(δ¹³C)。而两种林下土生蕨类(扇叶铁线蕨、桫椤)具有较高的A_area 和较低的δ¹³C。生长在岩石基质上的中华里白具有最高的养分利用效率和较高的δ¹³C。生长在溪流边的薄叶卷柏具有最高的SLA,最低的CC_area 和δ¹³C。这些揭示了蕨类植物叶片性状与生境之间具有紧密的相关性。由于附生蕨类的叶片具有高的能量投资和低的光合速率,对环境变化的适应能力弱,附生蕨类可能面临较大的生存压力。

关键词:蕨类植物;比叶面积;光合速率;构建成本;水分利用效率

Abstract:

The aim was to understand the leaf function of ferns grown under different habitats. The leaf characters of six ferns, such as specific leaf area, gas exchange rates, leaf nutrients, construction cost, and carbon isotope ratio, in monsoon evergreen broad-leaved forest in Dinghushan Mountain were measured, and their adaption to environment were studied. The results showed that two epiphytic ferns (Microsorum fortune and Pseudodrynaria coronans) had low specific leaf area (SLA) and photosynthetic rates (A_area), but high leaf construction cost (CC_area) and carbon isotope ratio (δ¹³C). In contrast, two terrestrial ferns (Adiantum flabellulatum and Alsophila spinulosa) showed high A_area and relative low δ¹³C. Hicriopteris chinensis growing on bared rocks at forest edge had the lowest leaf phosphorus contents, and the highest photosynthetic phosphorus use efficiency among the six fern species, while Selaginella delicatula growing in streamside had the highest SLA, and the lowest CC_area and δ¹³C. Therefore, it was suggested that there were close relationship between leaf traits of ferns and environment. In addition, because of high energy investment and low photosynthetic rate, epiphytic ferns have low adaption ability to environment, their survive might be under great pressure.

Key words:Fern;Specific leaf area;Photosynthetic rate;Construction cost;Water use efficiency