Phenotypic plasticity in two antarctic populations of Colobanthus quitensis (Caryophyllaceae) under a simulated global change scenario
Keywords:
Antarctic, water stress, reproductive effort, Fv / Fm, Shetland IslandsAbstract
Antarctica is characterized by extreme environmental conditions, which limit the establishment of vascular plants. These
environmental conditions include low temperatures, short growing season and shortage of water and nutrients. Low
water availability has been suggested as the main constraint to successful establishment, because it adversely affects the
reproductive and physiological responses of plants. Colobanthus quitensis (Kunth) Bartl. (Caryophyllaceae) is one of the
two native vascular plants that inhabit the Maritime Antarctic and its physiological performance and recruitment have been
shown to be negatively affected by soil water stress in the Antarctica. Phenotypic plasticity and local adaptation would
be two of the main strategies of C. quitensis to cope with adverse environmental conditions prevailing in the Antarctic
continent. It has been suggested that, under a future climate change scenario, water availability will increase by 30-40%,
improving the conditions for plant establishment. In this study we evaluated in a common garden experiment, conducted
in growth chambers, the morpho-physiological plasticity and reproductive effort in C. quitensis individuals from two sites
located in the Shetland Islands, under a simulated scenario of climate change (40% increase in water availability) and under
the current situation (water availability recorded in the sites of origin). Overall, individuals of C. quitensis of both sites
showed a plastic response, increasing the photochemical efficiency, leaf width and length and reproductive effort under
increased water availability. Plasticity was greater in those individuals from the more arid site as compared to con-specifics
from a mesic site. If current climate change patterns are maintained, abiotic conditions could become more favorable for C.
quitensis, improving ecophysiological performance and allowing the spread of its range in the Antarctic.
