Response of cytokinins and nitrogen metabolism in the fronds of Pteris sp. under arsenic stress

PLoS One. 2020 May 15;15(5):e0233055. doi: 10.1371/journal.pone.0233055. eCollection 2020.

Abstract

Given the close relationship between cytokinins (CKs), photosynthesis and nitrogen metabolism, this study assessed the effect of arsenic (As) contamination on these metabolic components in the As-hyperaccumulators Pteris cretica L. var. Albo-lineata (Pc-A) and var. Parkerii (Pc-P) as well as the As-non-hyperaccumulator Pteris straminea Mett. ex Baker (Ps). The ferns were cultivated in a pot experiment for 23 weeks in soil spiked with As at the levels 20 and 100 mg·kg-1. For the purpose of this study, the CKs were placed into five functionally different groups according to their structure and physiological roles: bioactive forms (bCKs; CK free bases); inactive or weakly active forms (dCKs; CK N-glucosides); transport forms (tCKs; CK ribosides); storage forms (sCKs; O-glucosides); and primary products of CK biosynthesis (ppbCKs; CK nucleotides). An important finding was higher CKs total content, accumulation of sCKs and reduction of dCKs in As-hyperaccumulators in contrast to non-hyperaccumulator ferns. A significant depletion of C resources was confirmed in ferns, especially Ps, which was determined by measuring the photosynthetic rate and chlorophyll fluorescence. A fluorescence decrease signified a reduction in the C/N ratio, inducing an increase of bioactive CKs forms in Pc-P and Ps. The impact of As on N utilization was significant in As-hyperaccumulators. The glutamic acid/glutamine ratio, an indicator of primary N assimilation, diminished in all ferns with increased As level in the soil. In conclusion, the results indicate a large phenotypic diversity of Pteris species to As and suggest that the CKs composition and the glutamic acid/glutamine ratio can be used as a tool to diagnose As stress in plants.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acids / metabolism
  • Arsenic / toxicity*
  • Biomass
  • Cytokinins / metabolism*
  • Nitrogen / metabolism*
  • Photosynthesis / drug effects
  • Plant Leaves / drug effects
  • Plant Leaves / growth & development
  • Plant Leaves / metabolism
  • Pteris / drug effects*
  • Pteris / growth & development
  • Pteris / metabolism*
  • Soil Pollutants / toxicity

Substances

  • Amino Acids
  • Cytokinins
  • Soil Pollutants
  • Arsenic
  • Nitrogen

Grants and funding

This study was supported by the Czech Science Foundation [grant number 17-10591S] and by the Ministry of Education, Youth and Sports. It was also supported by the European Regional Development Fund-Projects “Centre for Experimental Plant Biology” [grant number CZ.02.1.01/0.0/0.0/16_019/0000738] and “Centre for the investigation of synthesis and transformation of nutritional substances in the food chain in interaction with potentially harmful substances of anthropogenic origin: comprehensive assessment of soil contamination risks for the quality of agricultural production” [grant number CZ.02.1.01/0.0/0.0/16_019/0000845].