Chin J Plant Ecol ›› 2022, Vol. 46 ›› Issue (4): 451-460.DOI: 10.17521/cjpe.2021.0291

Special Issue: 生态化学计量 光合作用

• Research Articles • Previous Articles     Next Articles

Responses of photosynthetic pigments composition, nitrogen and phosphorus stoichiometric characteristics of Myriophyllum aquaticum to exogenous ammonium

XIAN Ying-Nan1,2, ZHANG Ying1,3, LI Bao-Zhen1,*(), LUO Pei1, XIAO Run-Lin1, WU Jin-Shui1   

  1. 1Key Laboratory of Agro-ecological Processes in Subtropical Region, Changsha Research Station for Agricultural and Environmental Monitoring, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China
    2College of Resources & Environment, Huazhong Agricultural University, Wuhan 430070, China
    3College of Resources & Environment, Hunan Agricultural University, Changsha 410128, China
  • Received:2021-08-11 Accepted:2021-10-18 Online:2022-04-20 Published:2022-01-30
  • Contact: LI Bao-Zhen
  • Supported by:
    National Natural Science Foundation of China(42077103);Project of Water Science and Technology in Hunan Province(XSKJ2019081-52);Hunan Provincial International Science and Technology Innovation Cooperation Base Project(2018WK4012)

Abstract:

Aims Myriophyllum aquaticum has high tolerance to high concentration of ammonium (NH4+) and thus becomes the preferred species for swine wastewater treatment. It is of great significance to explore the effects of exogenous NH4+ on the photosynthetic pigment composition and the stoichiometric characteristics of nitrogen (N) and phosphorus (P) of the M. aquaticum for improving the purifying efficiency of artificial wetlands system of M. aquaticum.

Methods Six NH4+ concentration levels (0, 0.1, 1, 5, 15, 30 mmol·L-1) were set up in this study. After 21 days of indoor cultivation, the contents of chlorophyll, N and P of M. aquaticum were measured to analyze their characteristics of changes.

Important findings The results showed that the relative stem height and biomass increased initially and then decreased, which were well fitted by a curve equation. Moreover, the peak of them appeared at 16.22 and 12.58 mmol·L-1 exogenous NH4+, respectively, via fitting non-linear Gaussian equation. With the increase of exogenous NH4+ concentrations, the chlorophyll content in the leaves decreased significantly, but increased in the stems. In addition, there was a wide variation of chlorophyll a than chlorophyll b. The chlorophyll a/b did not change significantly among different NH4+ treatments, except the value in the stems of 5 mmol·L-1 NH4+ treatment, which was significantly decreased. With the increase of exogenous NH4+ concentrations, the N contents in the leaves and stems were significantly increased by 85%-235% and 127%-373%, respectively, and the P content in the leaves was increased by 49%-51% in comparison to the control (CK). When the concentrations of exogenous NH4+ was no more than 15 mmol·L-1, the N content and N:P ratio of the leaves and stems increased rapidly, so were relative stem height and relative biomass. Correlation analysis showed that the contents of N and P, and N:P ratio were negatively correlated with total chlorophyll content in the leaves, but positively correlated with total chlorophyll content in the stems. In conclusion, M. aquaticum grew well with larger biomass and higher absorption of N and P, when the concentrations of exogenous NH4+ were in the range of 12-16 mmol·L-1. Therefore, the constructed wetlands system planted with M. aquaticum can effectively remove N and P from polluted wastewater and achieve the purpose of efficient water purification.

Key words: Myriophyllum aquaticum, photosynthetic pigment, stoichiometry of nitrogen and phosphorus, ammonium