The contents of free amino acids and elements in As-hyperaccumulator Pteris cretica and non-hyperaccumulator Pteris straminea during reversible senescence

Abstract

The objectives of this study were to analyse the relationship between the contents of elements and free amino acids (AAs) in fronds of As-hyperaccumulator Pteris cretica cv. Albo-lineata (PC) and non-hyperaccumulator Pteris straminea (PS) during reversible senescence. The time-course effect on senescence was also investigated. The two ferns were grown in a pot experiment with soil containing 16 mg Astotal/kg soil for 160 days. The contents of elements and AAs in both ferns and in individual sampling periods differed. The highest accumulation of elements and AAs was measured in PS fronds after 83 days; however, the accumulation of As, Ca, Cu, Fe, Mg, P and asparagin in PC fronds was highest after 160 days. The results of principal component analysis showed more rapid senescence of PS compared to PC. This was caused by changes in the relationship between the contents of elements (cofactors of metalloenzymes, stress metabolites) and AAs (transport of NH2 group and stress metabolites). The hyperaccumulator plant (PC) was more resistant than the bioindicator plant (PS) to the conversion from reversible to irreversible senescence.

Keywords

• metallophytes
• anabolic and catabolic processes
• stress metabolism plants
• nitrogen assimilation