Floral plasticity in an iteroparous plant: the interactive effects of genotype, environment, and ontogeny in Campanula rapunculoides (Campanulaceae)

Abstract

Phenotypic variation in 11 floral and reproductive traits was studied in cloned plants of Campanula rapunculoides replicated in three discrete environments. Using an ANOVA approach, we determined the relative influence of genotype (G), environment (E), G × E interaction, and ontogeny (position on the raceme) on the 11 traits. Two traits, duration of flowering and pollen size, showed no significant variation. All nine remaining traits had significant genotypic variation, accounting for 21-38% of the total phenotypic variation. Correlations among variant traits in seven genotypes were predominantly positive, but several significant correlations in one environment changed sign or were nonsignificant in another environment. Ovule number was negatively correlated with most male function traits: the negative correlation between ovule and pollen number was particularly strong and consistent across environments. Six traits varied significantly across environments, including number of flowers, number of ovules per flower, and duration of the male phase, but pollen traits did not show a significant environmental main effect. The G × E interaction was significant for flower number, corolla size, nectar quality, duration of the male phase, pollen viability, and ovule number. The contribution of interaction variance to the total phenotypic variation (5-14%) was comparable to that of the environment alone (7-21%). Ovule number decreased in flowers on the upper part of the raceme by nearly 25%, but other traits did not vary significantly by floral position. These results suggest that (1) pollen traits are buffered against environmental change more than ovule number or other floral characters, (2) a male-female trade-off exists and is complicated by ontogenic factors, (3) G × E interactions are common but may have small effects, and (4) specific correlation patterns among floral traits can be dependent upon the environment under which they develop.

Effects of competition on sexual and clonal reproduction of a tunicate: the importance of competitor identity

“…Our observation that the production of testes was not affected by competition is similar to past studies showing that male reproductive traits, such as pollen number and size and sperm number, are less sensitive than are female traits to environmental variation (Young et al 1994, Havens et al 1995, Vogler et al 1999, Newlon et al 2003. Additionally, in hermaphroditic organisms, an emphasis on male reproduction frequently occurs in high-density and nutrient-depleted situations (Newlon et al 2003).…”

The best of both worlds? A review of delayed selfing in flowering plants

“…Physiological mechanisms include changes in selfincompatibility (SI) that allow for delayed selfing. SI systems generally prevent self-fertilization; however, a temporal breakdown in expression during anthesis, or transient SI, can be a mechanism (4) Geraniales (1) Myrtales(2) Crossosomatales Picramniales Sapindales (2) Brassicales(1) Santalales Berberidopsidales Caryophyllales(1) Cornales(1) Ericales(5) Garryales Gentianales (7) Solanales (2) Boraginales (1) Lamiales (7) Asterales ( Goodwillie et al, 2004) and Campanula rapunculoides (Campanulaceae, Vogler et al, 1999). Intriguingly, transient SI is accompanied by reduced herkogamy in Leptosiphon and progressive stigma curvature in Campanula, both of which promote late deposition of self-pollen as flowers become self-compatible (Stephenson et al, 2000;Goodwillie unpub.…”

Genotype-environment interactions in pollen competitive ability in an anemophilous tree, Betula pendula Roth

“…Mazer and Schick 1991;Boose 1997;Vogler et al 1999) extremely little is known about G × E interactions in pollen competitive ability. Vogler et al (1999) concluded that pollen traits are well buffered against environmental variation in Campanula rapunculoides. In their study, the only pollen trait in which significant G × E interactions were found was pollen viability.…”