Are Photosynthetic Characteristics and Energetic Cost Important Invasive Traits for Alien Sonneratia Species in South China?
A higher photosynthesis and lower energetic cost are recognized as important characteristics for invasive species, but whether these traits are also important for the ability of alien mangrove species to become invasive has seldom been reported. A microcosm study was conducted to compare the photosynthetic characteristics, energetic cost indices and other growth traits between two alien species (Sonneratia apetala and S. caseolaris) and four native mangrove species over four seasons in a subtropical mangrove nature reserve in Shenzhen, South China. The aim of the study was to evaluate the invasive potential of Sonneratia based on these physiological responses. The annual average net photosynthetic rate (Pn), stomatal conductance (Gs) and total carbon assimilation per unit leaf area (Atotal) of the two alien Sonneratia species were significantly higher than the values of the native mangroves. In contrast, the opposite results were obtained for the leaf construction cost (CC) per unit dry mass (CCM) and CC per unit area (CCA) values. The higher Atotal and lower CC values resulted in a 72% higher photosynthetic energy-use efficiency (PEUE) for Sonneratia compared to native mangroves, leading to a higher relative growth rate (RGR) of the biomass and height of Sonneratia with the respective values being 51% and 119% higher than those of the native species. Higher photosynthetic indices for Sonneratia compared to native species were found in all seasons except winter, whereas lower CC values were found in all four seasons. The present findings reveal that alien Sonneratia species may adapt well and become invasive in subtropical mangrove wetlands in Shenzhen due to their higher photosynthetic characteristics coupled with lower costs in energy use, leading to a higher PEUE. The comparison of these physiological responses between S. apetala and S. caseolaris reveal that the former species is more invasive than the latter one, thus requiring more attention in future.
College of Life Sciences, Shenzhen University, Shenzhen, China.|Futian-CityU Mangrove Research and Development Centre, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China.
Feng-Lan
FL
Li
Guangdong Neilingding Futian National Nature Reserve, Shenzhen, China.
Qi-Jie
QJ
Zan
Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China.
Zheng-Yu
ZY
Hu
Futian-CityU Mangrove Research and Development Centre, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China.|Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China.
Paul-K S
PK
Shin
Futian-CityU Mangrove Research and Development Centre, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China.|Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China.
Siu-Gin
SG
Cheung
Futian-CityU Mangrove Research and Development Centre, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China.|School of Science and Technology, Open University of Hong Kong, Homantin, Kowloon, Hong Kong SAR, China.
Yuk-Shan
YS
Wong
Futian-CityU Mangrove Research and Development Centre, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China.|Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China.
Nora Fung-Yee
NF
Tam
College of Life Sciences, Shenzhen University, Shenzhen, China.
An-Ping
AP
Lei
D018533:Biomass; D002244:Carbon / Q000378:metabolism; D002681:China; D004734:Energy Metabolism; D058865:Introduced Species; D029561:Lythraceae / Q000254:growth & development / Q000502:physiology*; D010788:Photosynthesis; D018515:Plant Leaves / Q000254:growth & development / Q000502:physiology*; D012621:Seasons
D002244:Carbon