Mycorrhizas and Global Climate Change
Climate broadly refers to average weather over a long time period resulting from subtle interactions of a number of factors operative at many spatio-temporal stages and scales. Climate is inherently dynamic and has been changing historically due to very natural causes, yet there is now a broad scientific consensus that the rate and extent of global climate change has witnessed a multifold increase over the last few decades, mainly due to anthropogenic causes. The global climate change potentially influences most of the ecological processes and biotic interactions directly or indirectly, mycorrhizal symbiosis being no exception. Hence, understanding how mycorrhizal association of plants has responded to the factors and rate of climate change over time and how it is expected to change in future in response to such changes are some interesting and challenging discourses for mycorrhizologists. Since a multitude of factors and drivers of climate often interact in complex and nonadditive ways to influence plant–mycorrhiza feedback relationships, different components of global climate change need to be understood together vis-a-vis mycorrhizal mutualism in a broad conceptual and integrated framework. In view of the unequivocal empirical evidence for the fact that increasing atmospheric concentration of carbon dioxide is one of the most significant factors of global change (e.g. Keeling et al. 1995), the two fundamental aspects of mycorrhizal symbioses (Fig. 4.1) merit attention: (a) the role of mycorrhizas in offsetting the climate change caused due to elevated CO2 and (b) the impact of climate change on mycorrhizas. This chapter begins with an overview of the role of mycorrhizas in carbon sequestration, followed by a synopsis of the impact of elevated CO2 on root turnover and mycorrhizal colonisation of host plants. Finally the role of mycorrhizas in the adaptation of host plants to withstand various elements of global climate change is briefly discussed, and some future directions in these areas of research are identified.
KeywordsFine Root Mycorrhizal Colonisation Mycorrhizal Symbiosis Mycorrhizal Association Root Turnover
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