Morphological and physiological responses of Arundo donax and Phragmites australis to waterlogging stress

Abstract

This study compared morphological and physiological responses of the two reeds, Arundo donax and Phragmites australis, grown either singly or together in pots, to various soil moisture regimes. Four-weeks-old plants were subjected to treatments for six months in a 2 × 3 factorial experiment with two species and three soil moisture regimes: well drained (WD); half flooded (½F) and completely flooded (F). Soil redox potential (Eh) in both species was higher in the WD (+58 to +83 mV) and significantly reduced in the flooded treatments (-80 to -83 mV). In both species, grown separately or together, prolonged complete flooding reduced growth rate, number and area of leaves, plant height, biomass, and root length. Flooding increased culm density and induced the development of aerenchyma and aerial adventitious roots. In both species grown separately or together, photosynthetic rates ranged from 16 to 28 µmol m−2 s−1 and were consistently higher in A. donax than in P. australis. Both species preferred moist to partially flooded conditions and exhibited symptoms of stress under complete waterlogging. Phragmites was more tolerant of waterlogging stress than Arundo.