Membrane Behaviour and Stress Tolerance in Pollen

Abstract

Temperature and water stress are the most important of stresses imposed on pollen during maturation in the anther and after shedding. During dehydration, osmotic and salt stress become important, and enormous mechanical forces are exerted during the shrinking of the cell. Tolerance to desiccation, which is common among pollen species, requires the proper tactics of the cells towards both dehydration and rehydration. For long term survival in the dry condition a special biochemical composition may be required, which curtails free radical damage. Dry pollen usually ages slowly, particularly in the cold. In contrast, both high temperatures and elevated water contents considerably accelerate ageing. Because reduced vigour due to the above mentioned stresses usually coincides with increased solute leakage during imbibition, we focus on the conformational and compositional status of the membrane phospholipids.