Cellular and ultrastructural changes in mesophyll and bundle sheath cells of maize in response to water stress.

Ultrastructural changes were correlated with leaf water potential, relative water content, and abscisic acid levels in the leaf. Mesophyll cells were more prone to damage than bundle sheath cells at a leaf water potential of -18.5 bars. Tonoplast breakdown and cell disruption occurred in 25% of the mesophyll cells. On rewatering, these disrupted cells did not recover. In bundle sheath cells, starch, lost at about -13.5 bars leaf water potential, reappeared within 2.5 hours of rewatering.