Individual resource allocation to vegetative growth and reproduction in subgenus Cyclobalanopsis (Quercus, Fagaceae) trees

Abstract

The resource allocation for vegetative growth and female reproduction in three tree species of subgenus Cyclobalanopsis (Quercus, Fagaceae), i.e., Q. salicina, Q. sessilifolia, and Q. acuta, were examined on a per-individual basis in two consecutive reproductive seasons, in order to test whether these trees fit the predictions of the masting hypotheses about resource matching versus resource switching. Since the three Quercus species have a biennial fruiting habit, it takes 3 years for the observation of two reproductive events. Female flower and acorn production per tree were investigated by using a seed-trap method and a numerical analysis of seed dispersal. The net production of each individual was estimated as the sum of the annual increase in the dry mass of vegetative organs and reproductive investment per tree. In the data analyses, the three species were pooled, since all 12 sample trees of the subgenus apparently showed masting in the same year, with no exceptions. Female flower and acorn production per individual tree changed considerably between years. The net production per tree increased with tree size, but did not differ between years. Therefore, the reproductive allocation (proportion of a plant's annual assimilated resources which are used for reproduction) differed dramatically between years. On the other hand, within a year, the reproductive allocation increased with increasing net production per tree. These results suggest that the switching of resource allocation between years within an individual are occurring in subgenus Cyclobalanopsis species, and the intensity of the switching increases with increasing tree size.

Climate change and oak growth decline: Dendroecology and stand productivity of a Turkey oak (Quercus cerris L.) old stored coppice in Central Italy

“…Reproductive processes may reduce vegetative ones, to the extent of preceding the growth decline or even death of a tree (Piovesan and Adams, 2005;Hirayama et al, 2008). According to the "mast depression hypothesis", particularly intense reproduction can expose woody species to insect and parasite attacks (e.g.…”

An increase in canopy cover leads to masting in Quercus ilex

“…Positive relationships between the amount of leaves in the canopy and fruit production have been detected (McCarthy and Quinn 1992;Ichie et al 2005). Moreover, shoot mortality and increase in defoliation have been underlined by several authors after previous masting events (Gross 1972;Singh et al 1990;Innes 1994;Hirayama et al 2005). According to the results of Ishihara and Kikuzawa (2009), masting might be linked to changes in shoot and leaf production in the canopy.…”

Drivers of large‐scale geographical variation in sexual systems of woody plants

“…This extends previous findings that the frequency of life forms is correlated with the frequency of mating systems across latitude (Moeller et al, 2017) or that the proportion of dioecious species is higher among trees than among other life forms (e.g., Bawa et al, 1985;Renner & Ricklefs, 1995) and higher in canopy (24.5%) than in understorey species (9.8%) (Kress & Beach, 1994). Theoretical and observational evidence indicates that large plants could allocate more biomass to sexual reproduction (Niklas & Enquist, 2003), leading to a larger flower size and/or a higher number of floral structures (e.g., petals and stamens) than small plants in both herbaceous (Arroyo, Dudley, Jespersen, Pacheco, & Cavieres, 2013;Lambrecht & Dawson, 2007;Schmid, Bazzaz, & Weiner, 1995) and tree-sized species (Hirayama, Nanami, Itoh, & Yamakura, 2008).…”