Factors affecting the production, growth, and survival of sprouting stems in the multi-stemmed understory shrub Lindera triloba

Abstract

We investigated the structure and dynamics of the multi-stemmed understory shrub Lindera triloba (Sieb. et Zucc.) Blume over 3 years in an old-growth coniferous forest, and quantitatively evaluated the factors affecting the ramet production, growth, and survival. Most genets sprouted continuously and exhibited multiple-stemmed structures with a few large and many small ramets. The skewed ramet-size distribution within genets resulted from the local crowding of neighboring trees, but not from the number of ramets within genets. This indicated that inter-plant competition is asymmetric (i.e., larger individuals outcompete one-sidedly smaller ones), but intra-plant competition (i.e., competition among ramets within genets) is symmetric (i.e., smaller ones also competitively affect larger ones). The local crowding of neighboring understory trees consistently negatively affected the ramet production, growth, and survival of L. triloba. Intra-genet crowding (i.e., crowding of ramets within genets) also negatively affected the ramet dynamics. On the other hand, the largest-ramet size within genets had positive relationships with the ramet dynamics, indicating that physiological integration within genets plays a role as supporting younger ramets. Based on our results, to fully understand genet persistence strategies in clonal shrub species, it is important to consider the effects of intra-genet crowding and modular integration, as well as plant-to-plant interaction.

Inter-specific and sexual differences in architectural traits of two dioecious Lindera species (Lauraceae)

“…The two species are often found sympatrically, but L. praecox tends to be observed in relatively moist sites, such as the lower slope and stream banks at our study site (Isogimi et al 2014). Most individuals of the two species form clumps of a few large and many smaller ramets sprouting from the ground (i.e., genets) (Matsushita et al 2010;Isogimi et al 2014). In an oldgrowth forest, the size of the largest ramet within a genet (hereafter, the main ramet) of L. triloba is larger than that of L. praecox in both genders.…”

Sex-different response in growth traits to resource heterogeneity explains male-biased sex ratio

“…This response of males might confer a genet-size advantage (Matsushita and Tomaru, 2012). Larger genets can utilize resources more advantageously than smaller ones and grow to predominate in the long term (Matsushita et al, 2010(Matsushita et al, , 2016. In the clonal dioecious shrub Ilex leucoclada, the genets identified by genetic markers consisted of many spatially extending stems, indicating that layering allowed them to occupy extensive areas (Torimaru and Tomaru, 2005).…”

The effects of resource availability on sprouting: a key trait influencing the population dynamics of a tree species

“…Seeds are long-lived (Medina and Francisco 1994) and may remain dormant until the beginning of the rainy season, which is a more favorable time for seedling establishment (Garwood 1983). Basal sprouting is the production of sprouts from dormant stem buds near the root collar (Bellingham and Sparrow 2000;Bond and Midgley 2001;Matsuchita et al 2012;Dodd et al 2013). Following total aerial biomass loss, a genet (i.e., an individual plant) can produce one or more stems (ramets) by basal sprouting.…”

“…Following total aerial biomass loss, a genet (i.e., an individual plant) can produce one or more stems (ramets) by basal sprouting. In this study, the term ''ramets'' is used according to the definition of Matsuchita et al (2012). In adult trees, the collar develops at or just below the ground (Del Tredici 2001); thus, basal sprouting can be identified by observing the presence of buds protruding from the trunk.…”

“…Sprouting (used synonymously with ''resprouting''), is defined as the production of ramets from new vegetative growth, induced by injury (e.g., stem removal near the root surface) or a substantial change in growth conditions (Del Tredici2001). In terms of aboveground structure, basal sprouting results in a genet comprised of multiple ramets (Matsuchita et al 2012). However, the influence of environmental conditions on the population dynamics of sprouting woody plants is still not well known, especially in tropical areas (Bond and Midgley 2001).…”