Studies on the reproductive physiology of common beans (Phaseolus vulgaris L.) II

On the fertility of pollen

Abstract

This paper deals with the germination tests of pollen in common beans, using chiefly a tall variety Kentucky Wonder and in part a dwarf variety Masterpiece.
(1) The artificial medium containing 1% agar and 30% sucrose is most suitable for the pollen germination and the optimum hydrogen ion concentration is 5.4_??_6.0.
(2) The germinability of pollen is already recognized at the afternoon before the flowering. The percentage of germination increases, towards the time of anther-dehiscence and then decreases rapidly and the pollen grains almost lose their vitality 5_??_6 hours after the anthesis.
(3) The pollen of common bean is the starchypollen.
(4) The number of pollen grains per anther is very small, but it seems to be more thean that of peanut.
(5) The optimum temperature for the pollen-germination is 20_??_25°C and the temperature above 35°C is very injurious to the pollen-germination.
(6) The most favorable humidity for the pollen-germination is 80%. The resistance of the pollen to water is very weak.
(7) When common bean plants are treated by high temperature (25_??_30°C), the germinability of their pollen grains is injured seriously.