Title: Effects of soil nitrogen on pollen production, pollen grain size, and pollen performance in Cucurbita pepo (Cucurbitaceae).
Authors: Lau, Tak Cheung; Stephenson, Andrew G.
Authors affiliation: Dep. Biol., Pennsylvania State Univ., University Park, PA, USA.
Published in: American Journal of Botany (1993), 80(7), pages 763-8.
Abstract: “To det. the effects of soil nitrogen on pollen prodn., pollen size, and pollen performance, two cultivars of zucchini (Cucurbita pepo) were grown under two nitrogen regimes in an exptl. garden. The two cultivars were true breeding for alternative alleles for a one gene trait, ovary color. The soil nitrogen treatment had a significant effect on most measures of reproductive output through the female function. The nitrogen treatment did not affect the no. of staminate flowers per plant but did have an effect on the no. of pollen grains per staminate flower and the mean pollen grain size. A pollen mixt. expt. revealed that pollen produced by plants in the high nitrogen treatment sired significantly more seeds than pollen from low nitrogen plants. Moreover, the high nitrogen pollen sired even a greater percentage of seeds in the region of the fruit (ovary) previously shown to be fertilized by the fastest growing pollen tubes. Thus, the difference in the no. of seeds sired by pollen from the two nitrogen treatments is due to differences in pollen performance. Thus, spatial heterogeneity in soil nitrogen can influence the paternity of seeds in a plant population.”