Assessing desiccation tolerance of ferns under various humidity conditions
Presentation Type
Poster
Presentation Type
Submission
Keywords
desiccation tolerance, resurrection fern
Department
Biology
Abstract
Desiccation-tolerant (“resurrection”) plants are unique in their ability to dry out and temporarily stop metabolism and then resume function when rehydrated. The dominant theory on the evolution of desiccation tolerance postulates that desiccation tolerance originated when plants colonized dry land, expanding beyond water-based habitats, but overtime desiccation tolerance became unnecessary and was lost in the vegetative tissues (leaves, stems, and roots). It later reemerged in multiple independent evolutions, creating a phylogenetic pattern of desiccation-tolerant plants. In this experiment, we assessed the desiccation tolerance of Adiantum hispidulum and Pellaea rotundifolia in varied humidity conditions, using the desiccation-sensitive Adiantum raddianum as a control. Based on the literature and phylogenetic relationships, we hypothesized that A. hispidulum and P. rotundifolia, unlike A. raddianum, would recover following desiccation. P. rotundifolia is part of the taxa Cheilanthes, which consists of many resurrection ferns, but P. rotundifolia has never been confirmed as desiccation tolerant. A previous study reported desiccation tolerance in A. hispidulum, and we sought to verify their findings. Leaves from individuals of each species were dehydrated in humidity-controlled containers at either 35%, 50%, or 80% relative humidity. Following complete desiccation (Fv/Fm < 0.1), all leaves were rehydrated. Desiccation and recovery of the leaves were assessed by measuring dark-adapted chlorophyll fluorescence (Fv/Fm) daily during drying and rehydrating. The Fv/Fm of all leaves declined while drying, but A. hispidulum and A. raddianum reached the desiccated state faster than P. rotundifolia, in 2-3 days of drying. P. rotundifolia leaves dried at a more variable rate, depending on factors such as the relative humidity, and could take 2-3 days or more than 20 days to fully desiccate. Following rehydration, none of the species recovered photosynthetic capacity, showing that A. raddianum, A. hispidulum and P. rotundifolia are not desiccation tolerant. Our results highlight the importance of individually assessing the desiccation tolerance of all presumed resurrection fern species under varied humidity conditions.
Faculty Mentor
Helen I. Holmlund
Funding Source or Research Program
Academic Year Undergraduate Research Initiative
Location
Waves Cafeteria
Start Date
24-3-2023 2:00 PM
End Date
24-3-2023 4:00 PM
Assessing desiccation tolerance of ferns under various humidity conditions
Waves Cafeteria
Desiccation-tolerant (“resurrection”) plants are unique in their ability to dry out and temporarily stop metabolism and then resume function when rehydrated. The dominant theory on the evolution of desiccation tolerance postulates that desiccation tolerance originated when plants colonized dry land, expanding beyond water-based habitats, but overtime desiccation tolerance became unnecessary and was lost in the vegetative tissues (leaves, stems, and roots). It later reemerged in multiple independent evolutions, creating a phylogenetic pattern of desiccation-tolerant plants. In this experiment, we assessed the desiccation tolerance of Adiantum hispidulum and Pellaea rotundifolia in varied humidity conditions, using the desiccation-sensitive Adiantum raddianum as a control. Based on the literature and phylogenetic relationships, we hypothesized that A. hispidulum and P. rotundifolia, unlike A. raddianum, would recover following desiccation. P. rotundifolia is part of the taxa Cheilanthes, which consists of many resurrection ferns, but P. rotundifolia has never been confirmed as desiccation tolerant. A previous study reported desiccation tolerance in A. hispidulum, and we sought to verify their findings. Leaves from individuals of each species were dehydrated in humidity-controlled containers at either 35%, 50%, or 80% relative humidity. Following complete desiccation (Fv/Fm < 0.1), all leaves were rehydrated. Desiccation and recovery of the leaves were assessed by measuring dark-adapted chlorophyll fluorescence (Fv/Fm) daily during drying and rehydrating. The Fv/Fm of all leaves declined while drying, but A. hispidulum and A. raddianum reached the desiccated state faster than P. rotundifolia, in 2-3 days of drying. P. rotundifolia leaves dried at a more variable rate, depending on factors such as the relative humidity, and could take 2-3 days or more than 20 days to fully desiccate. Following rehydration, none of the species recovered photosynthetic capacity, showing that A. raddianum, A. hispidulum and P. rotundifolia are not desiccation tolerant. Our results highlight the importance of individually assessing the desiccation tolerance of all presumed resurrection fern species under varied humidity conditions.