Dark respiration of variegated leaves in plants of different life forms

Dark respiration was measured in albino and green regions of variegated lea ves in 22 plant species of various life forms. Depending on plant species, respiration rates in green regions were either equal to, lower, or even hig her than in albino regions. The relationships between the respiratory activ ity of green and albino regions in variegated leaves did not depend on the arrangement of albino regions over the leaf blade, the shape of these regio ns, or their total area. The comparatively high respiration rate in green r egions of Hosta undulata leaves was caused by a higher contribution of the transport component of respiration. Alternative oxidase was found to contri bute to respiration in albino regions of variegated leaves of H. undulata a nd reduce the energetic efficiency of respiration. This indicates different ial controls of respiration in green and albino regions. It is supposed tha t functional roles of albino regions in variegated leaves differ for variou s plants, depending on whether the respiration rate in albino regions is eq ual to or lower than that in green regions. In the first group of plants, a lbino regions represent a channel that supplies assimilates to heterotrophi c tissues, whereas, in the second group, albino regions perform the functio n of a storage, damping system characterized by a lower rate of assimilate export, as compared to that from green regions.