Write on changing scenario of climate and crop physiology.
Answers
Integrating knowledge from physiological ecology, evolutionary biology, phylogenetics, and paleobiology provides novel insights into factors driving plant physiological responses to both past and future climate change.
Since the Industrial Revolution began approximately 200 years ago, global atmospheric carbon dioxide concentration ([CO2]) has increased from 270 to 401 µL L−1, and average global temperatures have risen by 0.85°C, with the most pronounced effects occurring near the poles (IPCC, 2013). In addition, the last 30 years were the warmest decades in 1,400 years (PAGES 2k Consortium, 2013). By the end of this century, [CO2] is expected to reach at least 700 µL L−1, and global temperatures are projected to rise by 4°C or more based on greenhouse gas scenarios (IPCC, 2013). Precipitation regimes also are expected to shift on a regional scale as the hydrologic cycle intensifies, resulting in greater extremes in dry versus wet conditions (Medvigy and Beaulieu, 2012). Such changes already are having profound impacts on the physiological functioning of plants that scale up to influence interactions between plants and other organisms and ecosystems as a whole (Fig. 1). Shifts in climate also may alter selective pressures on plants and, therefore, have the potential to influence evolutionary processes. In some cases, evolutionary responses can occur as rapidly as only a few generations (Ward et al., 2000; Franks et al., 2007; Lau and Lennon, 2012), but there is still much to learn in this area, as pointed out by Franks et al. (2014). Such responses have the potential to alter ecological processes, including species interactions, via ecoevolutionary feedbacks (Shefferson and Salguero-Gómez, 2015). In this review, we discuss microevolutionary and macroevolutionary processes that can shape plant responses to climate change as well as direct physiological responses to climate change during the recent geologic past as recorded in the fossil record. We also present work that documents how plant physiological and evolutionary responses influence interactions with other organisms as an example of how climate change effects on plants can scale to influence higher order processes within ecosystems. Thus, this review combines findings in plant physiological ecology and evolutionary biology for a comprehensive view of plant responses to climate change, both past and present.
Figure 1.
Figure 1.
A, Abiotic conditions directly affect plant physiological traits. Also, the probability that a given species persists with climate change (both in the past and future) is influenced by the degree of phenotypic plasticity in these traits, the ability of ...
Due to rapid climate change, plants have become increasingly exposed to novel environmental conditions that are outside of their physiological limits and beyond the range to which they are adapted (Ward and Kelly, 2004; Shaw and Etterson, 2012). Plant migration may not keep pace with the unprecedented rate of current climate change (Loarie et al., 2009); therefore, rapid evolutionary responses may be the major process by which plants persist in the future (Franks et al., 2007; Alberto et al., 2013). In addition, although plants may have evolved physiological plasticity that produces a fitness advantage in novel environments, climate change may be so extreme as to push plants beyond tolerance ranges even in the most plastic of genotypes (Anderson et al., 2012).
ADVANCES
Rapid climate change is disrupting long-standing patterns of natural selection on plant physiological traits. Microevolutionary responses to these changes can occur over time scales relevant to ecological processes.
Emerging macroevolutionary analyses using large, time-calibrated phylogenies provide insight into evolutionary changes in plant physiology and species diversification rates following past climate change events.
Past conditions, such as low [CO2] during glacial cycles, likely produced lingering adaptations that could limit plant physiological responses to current and future climate change.
Climate change can affect plant traits, fitness, and survival indirectly via shifts in biotic interactions. The ecoevolutionary consequences of altered species interactions can be as important as the direct effects of climate change on plant physiology.