Chin J Plant Ecol ›› 2007, Vol. 31 ›› Issue (3): 497-504.DOI: 10.17521/cjpe.2007.0062

Special Issue: 红树林及红树植物

• Articles • Previous Articles     Next Articles

COMPARISONS OF LEAF CHLORIDE CONTENT AND LEAF TRAITS BETWEEN TRUE MANGROVE PLANTS AND SEMI-MANGROVE PLANTS

MU Mei-Rong, JIANG Qiao-Lan, WANG Wen-Qing*()   

  1. School of Life Sciences, Xiamen University, Xiamen 361005, China
  • Received:2006-04-10 Accepted:2006-07-22 Online:2007-04-10 Published:2007-05-30
  • Contact: WANG Wen-Qing

Abstract:

Aims Mangrove plants are usually categorized as true mangrove plants and semi-mangrove plants on the basis of their distribution in inter-tidal regions. However, the identification of some fringe mangrove species found mainly on the landward transitional zones is controversial. Specific leaf area (SLA, leaf area per unit dry mass) and mass- and area-based leaf nitrogen concentrations (Nmass and Narea) are important leaf traits for plants, but relevant comparative research on true and semi-mangrove plants is unavailable. Our objective was to determine differences between the two groups and to classify the controversial species according to their leaf traits. Ultimately, this will assist in the management, protection and utilization of mangrove forest.
Methods Three individuals in similar growth sites were chosen for each species from Hainan Island. Fully expanded mature leaves were sampled from the upper canopy of all plants. Succulence (water content per unit leaf area), SLA, Nmass and Narea of mature leaves were studied for 33 species, representing all but three of the mangrove species in China.
Important findings True mangrove plants accumulated more Cl and water per unit leaf area than semi-mangrove plants, except for Pemphis acidula, Hernandia sonora and Clerodendrum inerme. Cl and water content per unit leaf area of true mangrove plants were generally >2.5 mg·cm-2 and >2.4 g·dm-2, respectively. Cl concentrations were positively related to succulence for all mangrove species. True mangrove plants had low SLA (<100 cm 2·g-1) and high Narea; however, semi-mangrove plants had high SLA (mean of 160.4 cm 2·g-1). Pemphis acidula had much lower SLA than other semi-mangrove species. Our study suggested that there are significant differences between true mangrove plants and semi-mangrove plants in leaf Cl concentration, succulence, SLA, Nmass and Narea. Heritiera littoralis, Excoecaria agallocha, Acrostichum aureum and Acrostichum speciosum are better classified as semi-mangrove plants, while Acanthus ilicifolius and Acanthus ebrecteatus are classified as true mangrove plants, and Xylocarpus granatum needs further research.

Key words: true mangrove plants, semi-mangrove plants, identification, leaf chloride content, leaf traits