Genotype-specific responses to light stress in eelgrass Zostera marina, a marine foundation plant

Abstract

Within mono-specific meadows of clonal plants, genotypic diversity may functionally replace species diversity. Little is known about the variability in performance and plasticity of different genotypes towards anthropogenically induced stressors. In this field experiment we compared light-limitation stress responses and recovery of different eelgrass Zostera marina genotypes to assess the variability in phenotypic plasticity and gene expression between different genotypes. Replicated monoculture plots of 4 genotypes were subjected to a simulated turbidity period of 4 wk using shading screens, and their performance during light limitation and 4 wk of recovery was compared to non-shaded controls. In addition to growth and biomass, we investigated storage carbohydrates and quantified the expression of genes involved in carbohydrate metabolism, photosynthesis and control of oxidative stress. Plants showed remarkable plasticity in their stress responses and all phenotypic variables recovered to the control level within 4 wk. Depletion and subsequent restoration of sucrose levels differed among genotypes. In terms of gene expression, no consistent patterns were observed. Our study confirms that stress responses and recovery processes can vary substantially between genotypes and the results emphasize the importance of preserving regional genotypic diversity for immediate positive diversity effects and for adaptive evolution in response to global change.

Additive response to multiple environmental stressors in the seagrass Zostera marina L.

“…The amount of available C resembled that allocated to growth, but was less than half of that in the control resulting in slower growth and smaller shoots. These responses correspond to those from other studies showing that prolonged exposure to shade causes reduced net fixation of C, depleted energy reserves, slower growth, smaller shoots, and sometimes higher mortality (e.g., Alcoverro et al ; Alcoverro et al ; Collier et al ; Collier et al ; York et al ; Salo et al ). The close correspondence between the quantity of available C and that allocated to growth shows that growth is dictated by the former, but also, that exposure to shade did not induce a substantial allocation of C to acclimation.…”

Family‐level variation in early life‐cycle traits of kelp

“…), and regulation of genes that control for photosynthesis differ among genotypes in seagrass, influencing stress responses and recovery times to light stress (Salo et al. ). Whether variation in F v / F m of Ecklonia radiata sporophytes is directly associated with genetically determined pigment profiles or other attributes that influence photosystem activity in autotrophs is not known.…”

Baltic Sea genetic biodiversity: Current knowledge relating to conservation management

“…Human‐induced pressures on the Baltic Sea are extensive and have contributed to high levels of pollutants, eutrophication, large areas of oxygen‐depleted sea beds, extensive fishing and stocking, spread of alien species and rapid climate change (Björklund & Almqvist, ; Diaz & Rosenberg, ; Ducrotoy & Elliott, ; Jansson & Dahlberg, ; Lehtonen & Schiedek, ; Neumann, ). These pressures are expected to increase the importance of genetic variation as a basis for population and species adaptation and resilience (Johannesson, Smolarz et al, ; Salo, Reusch, & Boström, ). Thus, incorporation of knowledge of genetic diversity in management and conservation efforts is of importance in this region, and would, for example, include that genetically distinct populations are identified and maintained at sufficient sizes and with sufficient degree of genetic exchange among them (connectivity) to assure long‐term viability.…”