Acidic mist reduces foliar membrane-associated calcium and impairs stomatal responsiveness in red spruce.

Acidic deposition can leach essential pools of calcium (Ca) directly from plant foliage. Because of the central role of Ca in environmental signal transduction, disruptions of labile foliar Ca pools could impair physiological responses to a variety of environmental stimuli and stressors. We investigated the possibility that acidic mist-induced depletion of membrane-associated Ca (mCa), which is one form of labile Ca, may alter stomatal responsiveness to water stress, a process known to include Ca in signal transduction cascades.

Accretion, partitioning and sequestration of calcium and aluminum in red spruce foliage: implications for tree health.

Calcium (Ca) is an essential macronutrient in plants and is an important component of many cellular structures and physiological processes as well as overall forest function. Aluminum (Al) in soil solution can inhibit Ca uptake by plants and disrupt many Ca-dependent metabolic and physiological processes of plants. The ratio of Ca to Al in soil solution can be an important indicator of forest health, especially on acid soils.