Cost of reproduction in Fucus distichus

Abstract

Reproductive effort (ratio of fertile to total plant dry weight) was measured in Fucus distichus L. emend. Powell. On average, 12.7 % of plant dry weight is in reproductive biomass and this amount is relatively constant over most months. Reproductive effort does not vary among plants of different sizes and dry weights. However, fertile plants are significantly (p ~0 . 0 5 ) bigger than the nonfertile plants, and have a better survival rate. There is no clear indication of cost of reproduction with respect to the longevity of fertile vs non-fertile plants. Fertile plants, especially those > 17 cm in length, tend to exhibit negative or zero growth much more often than non-fertile plants, suggesting that the cost of reproduction may be manifested in the form of reduced growth, rather than in greater mortality or shorter longevity of the fertile plants. The failure to detect cost of reproduction with respect to mortality and longevity may be due to the modular nature of the plants, where cost occurs at the level of the modules (branches) rather than at the level of the whole plant.

Seasonal Pattern of Reproduction Of Hizikia Fusiformis (Sargassaceae, Phaeophyta) from Nanao Island, Shantou, China

“…The interpretation for the reproductive size-dependence in Hizikia could be that larger plants may generate a greater number of reproductive meristems per unit of vegetative biomass as in the case of S. muticum (Arenas & Fernández, 1998). However, Ang (1992) did not find a correlation between reproductive allocation and plant size in F. distichus which exhibits continuous reproduction throughout the year (Ang, 1992), whereas H. fusiformis in our study only has a very shorter sexual reproductive period (from April to June). Therefore, the discrete reproductive event in such alga as H. fusiformis might give a clearer picture of the size dependence of reproductive allocation.…”

“…Therefore, the negative relationship between growth and reproduction in H. fusiformis does not involve the traditional view of reproductive allocation, which involves a trade-off between these two processes and between the alternate strategies of sexual reproduction by means of receptacle formation and asexual reproduction by means of investment in the holdfast where new shoots are initiated, as suggested by McCourt (1984). The coincidence of fertility, termination of growth and/or senescence has also been reported in other brown algae such as S. muticum (Norton, 1977;Arenas et al, 1995) and Fucus distichus (Ang, 1992). Rico and Fernández (1997) also showed that the senescence of S. muticum along the north coast of Spain coincided with the onset of a period of N-limited growth.…”

Simulation and analysis of the dynamics of a Fucus distichus (Phaeophyceae, Fucales) population

“…With a high mortality of the recruits, iteropanty should be favoured (Charnov & Schaffer 1973). Iteroparity in F. distichus appears to be achieved by the formation of receptacles at different terminal branches at different times (Ang 1992). This enables other non-reproductive terminal branches of the plant to continue to grow, thus minimizing the cost of reproduction (Ang 1992).…”

Seaweed reproductive biology: environmental and genetic controls

“…Individuals growing in deeper water with lower available resource levels (less light and water displacement) have been shown to have lower reproductive efforts and shorter reproductive seasons, as well as a smaller minimal size for reproduction (De Ruyter van Steveninck andBreeman 1987, Engelen et al 2005). Ang (1992) reported that fertile thalli of Fucus distichus manifested zero or negative growth, but no difference was found in longevity and mortality. Åberg (1996) demonstrated differences in the annual reproductive effort of Ascophyllum nodosum between small and large individuals, which were interpreted as a reproductive trade-off by arguing that small individuals are better off investing in growth, which offers them a better chance of survival, while larger individuals can afford to invest in reproduction.…”