Rapid viability tests and aging study of some coniferous pollen

Rapid viability tests of pollen were developed to facilitate hybridization in tree-breeding programs. Pollen constituents and membrane integrity, as measured by conductance, ultraviolet absorbance, and carbohydrate and amino acid content of leachate, were found to be significantly correlated with in vitro germinability of stored, air-dried pollen lots. A specific conductance of 20 μmho or less and an OD 260 of 0.2 or less per 100 mg pollen per 30 ml water leached for 30 min at 25 °C appeared to be indices with which to select highly viable pollen lots of Douglas fir (Pseudotsugamenziesii), noble fir (Abiesprocera), and western hemlock (Tsugaheterophylla) in less than 45 min. These viability tests appear to be the direct measurement of the products of aging in pollen, and one cause of aging was found to be the preferential retention and activation of hydrolases while the total soluble protein is degraded.