Reproductive demography of ramets and genets in a rhizomatous clonal plant Convallaria keiskei

Abstract

Clonal growth occurring below the ground makes it difficult to identify individuals and demonstrate the demographic features of a focal plant species. In this study, genotypically identified ramets of a rhizomatous clonal herb, Convallaria keiskei Miq., were monitored for their growth, survival, and reproduction from 2003 to 2006. After the monitoring period, their subterranean organs were excavated to explore the underground connections of established ramets and the direction of clonal growth. We then combined data on the fate of the monitored ramets with the information of rhizome connections, clarifying reproductive demography at both the ramet and genet levels. Although each ramet initiated both sexual reproduction (via flowering) and clonal growth, clonal growth tended to precede sexual reproduction. In a surveyed genet, 51.0% of ramets produced flowers and 29.6% generated clonal offspring during the study period. Consequently, we clarified the reproductive demography of C. keiskei: clonal growth tended to precede flowering in a ramet, and a genet can keep reproducing every season at the genet level, despite a ramet not having inflorescence every year.

Consequences of Multiple Inflorescences and Clonality for Pollinator Behavior and Plant Mating

“…In contrast to the fixed number of flowers distributed evenly among inflorescences considered in our study, plants exhibit heterogeneity in floral display both during the lives of individual inflorescences (Meagher and Delph 2001;Harder and Johnson 2005) and among inflorescences (Huang et al 2002), as well as among flowering seasons (e.g., Araki and Ohara 2008). Such dynamics undoubtedly create variation in the interactions of individual genets with pollinators and the associated mating outcomes.…”

Deer herbivory and habitat type influence long-term population dynamics of a rare wetland plant

“…Vegetative ramets play a major role in resource acquisition, which is beneficial to other ramets of the genet. Genets with physically connected ramets may shunt resources to flowering ramets within the clone while vegetative ramets gather resources from the local environment (Araki and Ohara 2008). Within the clone, P. vanbruntiae ramets may also transit between flowering and vegetative phases as a method of switching between resource acquisition (vegetative) and sexual reproduction (flowering) in order to accomplish multiple years of the production of flowers, fruits, and seeds within a single ramet.…”

Dynamics of distribution and performance of ramets constructing genets: a demographic–genetic study in a clonal plant, Convallaria keiskei

“…We would also like to know whether genet diversity increases at the ramet level (Stehlik and Holderegger, 2000;Ruggiero et al, 2005) and whether genetic diversity may also differ according to ramet density. Linearly elongating rhizomes of C. keiskei connect distant ramets, which causes intermingled structure for different genets (Araki and Ohara, 2008). The results also suggest significant contributions of both sexual reproduction and clonal growth, as large genets have been maintained by clonal growth after seedling establishment (Soane and Watkinson, 1979;Eriksson, 1993;Watkinson and Powell, 1993).…”

“…As a consequence, the life history characteristics of clonal plants, as related to population structures and dynamics, are quite different from those of non-clonal plants (Eriksson and Bremer, 1993;Fischer and van Kleunen, 2002;Honnay et al, 2005). In terms of reproduction, for example, vegetative offspring ramets develop faster and become adults more quickly than seedlings; in contrast to seed dispersal, mobility via clonal growth is limited, and potentially independent offspring sometimes remain connected to the parent (Araki and Ohara, 2008). Moreover, such features should be addressed along the hierarchy of ramet, genet and population (Stone and Ezrati, 1996;de Kroon and van Groenendael, 1997) because the capacity for horizontal spreading by propagating ramets is likely to affect the spatial distribution at the genet level as well as the population level (Abrahamson, 1980;Tuomi and Vuorisalo, 1989).…”