Abstract: This study aimed to clarify the dynamic characteristics of and control factors on major nutrient element (C, N, P) contents and stoichiometric ratio in leaves of two-yearold mangroveKandelia obovata, and to understand nutrient use characteristics and nutrient limitation status of K. obovata in the second year after planting in Sporobolus alterniflorus invaded Luoyang River Estuary Wetland Reserve in Quanzhou Bay, Fujian Province. The C, N, P contents in leaves and aboveground biomass ofK. obovata during the growing season (June 2017-March 2018) in the second year after planting were measured. Results showed that total carbon content in leaves of two-year-old K. obovata ranged from 363.12 to 425.75 g·kg^-1. The range of total nitrogen content was 17.37-18.22 g·kg^-1, and the range of total phosphorus content was 1.33-4.06 g·kg^-1. The C∶N, C∶P, N∶P ratios of K. obovata leaves changed seasonally, showing a downward and then an upward trend. These results indicated high nutrient use efficiency in the two-year-oldK. obovata in coastal wetlands of Quanzhou Bay, and that nitrogen was the major limiting element of the two-year-oldK. obovata. Our results provided scientific guidance for comprehensive management of the replacement of invasive species S. alterniflorus with K. obovata, as well as the artificial planting and maintenance of mangroves.

Key words: Fusarium oxysporum of cucurbitaceae, SRAP, genetic diversity, Fusarium oxysporum f. sp. momordicae.