Plant Physiological Responses to Climate and Environmental Change

Abstract

Abstract Physiological implications of climate and environmental change are complicated because of potential multiple interactions between stresses, and incomplete theory to project net results. Rising atmospheric CO 2 may be positive for plant growth in some regions, but in temperate regions, is less than predicted from simple physiological photosynthetic theory, because of feedback effects from within the plant, and from ecosystem level effects such as soil nutrient limitation. Rising temperatures will reduce freezing and chill stresses but will increase metabolic rates, although acclimation processes will temper this. Impacts on volatile organic compound emissions are attracting greater attention. High temperatures will induce heat shock responses, with poorly understood species‐specific impacts. Higher plants are generally physiologically well defended against UV‐B flux increases, which may now be moot due to chlorofluorocarbon (CFC) mitigation. Long‐term field experiments have been important in reducing uncertainties about future physiological responses of plants to multiple environmental change drivers. Key Concepts Plants are not passive in the face of climate and environmental changes but employ a wide variety of mechanisms in responding. Physiological changes at cellular, organ and individual plant level occur in response to changing climate and environmental conditions. Much remains to be learned about how multiple climate and environmental changes interact to alter the performance of individual plants and their populations, partly because theory that translates physiological responses and changes to whole plant and population level responses is still developing. An understanding of physiological responses is useful but not sufficient to predict impacts at higher levels of ecological organisation, like communities and biomes. This is due to community level interactions, the fact that plants shape the environment to some extent, and thus, ecological feedback effects come into play. Long term field experimentation remains vital for testing theoretical projections of the net effects of climate and environmental change on plants.