Study design/Experiment 1

Aqueous concentrations of sucrose (0, 5, 10, 15, 20, 25, 30 and 35%) were tested to determine a suitable concentration for maximum germination of pollen grain from the flower buds. These concentrations contain the range of sugar concentrations found from previous experimentation to be suitable for this purpose. The 0% concentration was included to see if pollen could germinate in water alone. Higher concentrations up to 50% had been previously tested but the pollen had burst instead of germinating.

Uniform pollen grain samples were dispersed uniformly in drops of sucrose solution placed on each of 48 glass slides, one for each of the six buds and for each of the eight sucrose concentrations. The slides were incubated at 30^oC and at 90% relative humidity for three hours. The number of germinating pollen grains was then counted under a microscope.

Microscopic view of germinating pollen grains