泉州湾互花米草入侵滩涂中人工种植秋茄幼苗的叶片营养元素动态特征

于福建泉州湾洛阳江河口湿地保护区内互花米草入侵红树林生态修复滩涂内,采集并测定了种植后第2年的红树植物秋茄(Kandelia obovata)生长周期内(2017年6月—2018年3月)的叶片C、N、P含量及地上生物量,以阐明2年生秋茄的C、N、P营养元素含量与化学计量比随时间动态特征及其控制因子,了解红树植物秋茄在互花米草入侵地区生长第2年的养分利用与元素限制条件。结果显示:2年生秋茄叶片全碳含量为363.12～425.75 g·kg^-1;叶全氮含量为17.37～18.22 g·kg^-1;叶全磷含量为1.33～4.06 g·kg^-1。秋茄叶片C∶N、C∶P、N∶P随季节时间变化均呈现先下降后上升的趋势。研究表明,泉州湾滨海湿地秋茄在第2年生长周期内对营养元素的利用效率较好,氮元素可能是泉州湾河口湿地2年生秋茄的主要限制元素。研究结果为利用秋茄替代互花米草的生态入侵综合治理及红树林的人工种植养护提供了科学依据。

Dynamic characteristics of foliar nutrients in Kandelia obovata seedlings planted in Sporobolus alterniflorus-invaded mud flat in Quanzhou Bay

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.