Low levels of ozone increase bean leaf maintenance respiration

Pinto bean (Phaseolus vulgaris) plants were exposed to charcoal-filtered air with or without added low levels of ozone (90 nL∙L−1). Dark respiration (CO2 efflux) by expanding primary leaves of the plants was measured and mathematically partitioned into growth and maintenance components. The growth respiration coefficient was unaffected by ozone, whereas the maintenance respiration coefficient increased 15%. Such a relative increase in maintenance respiration results in a diversion of energy and metabolic intermediates from growth processes.