Sexual differences in biomass and nutrient allocation of first-year Silene dioica plants

Abstract

Reproductive and somatic biomass, nitrogen (N), and phosphorus (P) pools were compared between females and males in 1st-year plants of Silene dioica. We estimated irretrievable resources allocated to seeds, pollen, flowers, and unrecovered summer leaf investment by collecting plant parts at abscission throughout the season. At the end of the season, we determined resources lost through senescent stems and autumn leaf turnover and resources stored in perennial roots and overwintering buds. Sexual differences in allocation patterns depended on the resource used for comparison, and whether absolute or proportional resource pools were assessed. Total resource pools in terms of biomass and N were similar for females and males. However, male plants acquired relatively more P. The proportional reproductive investment, i.e., reproductive effort, was similar for males and females in terms of biomass and N. In terms of P, male reproductive effort was higher. There was no difference between sexes in the proportional and relative biomass allocated to perennial roots and overwintering buds. However, in terms of absolute and relative N allocation to below-ground parts, females had larger reserves than males. Females, moreover, had a larger proportion of their P in below-ground parts. However, as male total P pools were larger, absolute P reserves did not differ between sexes. The high reproductive effort and N depletion of below-ground parts in males resulted largely from higher flower production compared to females. In females, seeds were the major component of reproductive effort. These results show that if biomass and nutrient allocation are assessed in parallel for dioecious plants, we obtain a more complete view of their sexual differences.

Short‐term costs related to male and female structures in alpine Parnassia palustris

“…As reproductive costs could be demonstrated in 75% of more than 80 examined studies (Obeso 2002), our results are contradictory to the majority of these studies. Our results do, however, concur with previous findings that reproductive costs may be difficult to detect in long-lived plants in harsh environments (Hemborg and Karlsson 1999) and that high reproductive effort in one year sometimes has little effect on next year's reproductive output (Horvitz andSchemske 1988, Jennersten 1991). Such lack of reproductive cost can be explained in several ways.…”

Trade‐offs between clonal and sexual reproduction in Sagittaria latifolia (Alismataceae) scale up to affect the fitness of entire clones

“…Harris & Pannell, 2008;but see Å gren, 1988), which is more strongly limited by C stores (Ishida et al, 2005). Hemborg & Karlsson (1999) also found that females of Silene dioica have greater allocation of N to overwintering organs than males. For S. latifolia, corm resources are remobilized at the beginning of the growing season and corms wither completely by the time the plant is established in early summer.…”

Different rewards in female and male flowers can explain the evolution of sexual dimorphism in plants

“…In this system, repeated weather changes are therefore essential in driving beetles from male to female plants, exporting pollen in the process. Contradicting the advantage of large floral displays is the fact that they can be costly to produce (Hemborg & Karlsson, 1999) and involve high risks of dying prematurely, i.e. before the next fire (Bond & Maze, 1999).…”