Storage of pollen grains in organic solvents: effect of organic solvents on leaching of phospholipids and its relationship to pollen viability

Abstract

In vitro germinability and membrane integrity (as revealed by the fluorochromatic reaction (FCR) test) of pollen grains of Crotalaria retusa L. stored in various organic solvents for six months at −20±2°C were studied and correlated with leaching of lipids, phospholipids, sugars and free amino acids from pollen grains into organic solvents during storage. Pollen grains stored in organic solvents with low dielectric constants (a measure of their non-polar nature), such as hexane, cyclohexane and diethyl ether, showed high scores for germination and FCR and very little leaching of phospholipids, sugars and amino acids. Pollen grains stored in solvents with high dielectric constants (a measure of their polar nature) such as isopropanol and methanol did not show germination or positive FCR scores, but showed extensive leaching of phospholipids, sugars and free amino acids. The viability of pollen grains stored in organic solvents seems to be determined largely by the effect of the organic solvents on pollen phospholipid composition, which in turn affects membrane integrity and consequently pollen viability.