Chin J Plan Ecolo ›› 2018, Vol. 42 ›› Issue (7): 734-740.DOI: 10.17521/cjpe.2018.0061

• Research Articles • Previous Articles     Next Articles

Characterization of nutrient elements at different leaf positions in Phragmites australis in Songnen degraded grassland

GUO Rui1,2,*(), ZHOU Ji3, LIU Qi1,2, GU Feng-Xue1,2   

  1. 1 Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing 100081, China
    2 Key Laboratory of Dryland Agriculture, Ministry of Agriculture, Beijing 100081, China
    3 Land Consolidation and Rehabilitation Centre, the Ministry of Land and Resources, Beijing 100034, China
  • Online:2018-07-20 Published:2018-06-01
  • Contact: Rui GUO
  • Supported by:
    Supported by the National Natural Science Foundation of China(31570328)

Abstract:

Aims This study was performed to compare the growth and characteristics of nutrient elements at different leaf positions of reed (Phragmites australis) under salinity stress. The adaptive mechanisms by which reeds at a Songnen grassland tolerate salinity stress were determined.

Methods Samples were collected from normal grassland, moderate degraded grassland and severe degraded grassland, respectively. Plant height, shoot dry mass, and nutrient elements at different leaf positions of reeds were measured.

Important findings The Na+ content, total salt content and pH value of soil are important factors that determine soil salinity in the Songnen grassland. The degree of soil salinity was aggravated stepwise from the single dominant reed communities to the reed coexisted with Suaeda salsa communities. Height and shoot dry mass decreased with increased salinity. The profiles of 10 key nutrient elements were measured, namely, K, Na, Ca, Mg, Fe, Cu, Zn, Mn, P, and B. Results from the principal component analysis indicated that all samples were distributed within the 95% confidence interval. The results showed that K and P contents decreased with lowered leaf positions; while Na, Ca, and Mg showed the opposite distribution trends. Fe and Cu contents were less in young leaves than in the other leaves, Mn accumulated in the old leaves. However, a large amount of Zn accumulated in the young leaves. No obvious change in B was observed. Thus, salinity stress produced a small effect on the distribution of nutrients in young leaves, but strongly affected the older leaves. Under salinity stress, old leaves accumulated more Na+ to protect the young leaves from ion harm. High accumulation of Ca, Mg, Fe, and Cu in mature and old leaves was more beneficial to maintain and protect the function of photosynthesis. The increased K and P contents in the young leaves could provide the necessary nutrition and improve the salinity resistance of reed. This process contributes to the physiological response strategy of reed under salinity stress.

Key words: Songnen grassland, Phragmites australis, nutrient elements, leaves positions, degraded grassland