Acta Univ Latv (2009) 753: 125–136

Plasticity of a dune plant Alyssum gmelinii in response to sand burial in natural conditions

Abstract

Sand burial is one of the environmental factors affecting plant distribution on coastal dunes. The aim of the present study was to investigate putative morphological and physiological adaptations to sand burial in Alyssum gmelinii plants growing in natural conditions on coastal dunes. Morphological characteristics, photochemistry of photosynthesis and mycorrhizal symbiosis of plants growing on both grey dunes and white dunes with or without recent impact of burial by sand were analyzed. Burial conditions strongly affected the morphology of A. gmelinii plants. Plants on fixed dunes with no burial had a shrub-like appearance with lignified main stems. After burial by sand, new branches formed from vegetative buds located at nodes of a burried shoot and intensively elongated above sand surface. At the beginning of the next vegetation season new branches were formed from buds just above the soil surface. In relatively stable sand-level conditions burried stems formed well-rooted ramet-like underground structures. Burial did not affect intensity of mycorrhizal colonization in roots of A. gmelinii. No significant differences in mycorrhizal colonization parameters in plants between white and gray dunes were found except for a different trend of intensity of mycorrhizal symbiosis in July and September. Leaf chlorophyll content, potential quantum efficiency of photosystem II and apparent electron transfer rate of photosystem II was not affected by dune type and burial. Nonphotochemical quenching was significantly affected by plant location (white or grey dunes) as well as by sand burial of plants growing on white dunes. It is concluded that A. gmelinii plants exhibit both morphological (induced clonality) and biochemical adaptations (induced thermal energy dissipation) to maintain high performance after sand burial.