The interrelationships among leaf damage, anther development, and pollen production in Cucurbita pepo ssp. Texana (Cucurbitaceae)

We examined the impact of the timing of leaf damage on male function using Cucurbita pepo ssp. texana. To assess the impact of herbivory at known stages of pollen development, we determined the relationships between the position of a flower bud on a vine, its size, and the developmental stages of the pollen within the anther. Next, we examined the impact of a discrete event of simulated herbivory on flower abortion, pollen production per flower, and pollen grain size on pre- versus postmeiotic staminate flowers. We found that the length of the unopened corolla was useful to distinguish between pre- and postmeiotic staminate buds; meiosis occurred when the corolla of a flower bud was 8-10 mm long. Neither simulated herbivory nor the stage of pollen development at the time of leaf damage (pre- vs. postmeiosis) had an effect on the probability that a staminate flower bud would abort or on the size of mature pollen grains. However, staminate flower buds in which meiosis had already occurred responded to damage with a significant reduction in the number of mature pollen grains produced per flower.