No Effect of Selective Maturation on Fruit Traits for a Bird-Dispersed Species, Sambucus racemosa

Abstract

Selective abortion, also called selective maturation, is a phenomenon wherein maternal plants selectively mature ovules that have the potential to grow into higher-quality fruits, such as those that contain more seeds. We hypothesized that the effects of selective maturation on fruit traits could be influenced by the dispersal mechanism. However, to date, limited studies have been conducted on selective maturation in bird-dispersed fruits. Unlike self- or wind-dispersed species, bird-dispersed species would not selectively mature fruits that contain more seeds because they are not preferred by birds. Here, we investigated the effect of selective abortion on the fruit traits of a bird-dispersed species, elderberry (Sambucus racemosa L. subsp. kamtschatica). We performed a flower-removal experiment. Half of the inflorescences on each individual tree were removed for the treatment group, whereas the control group was not manipulated. We found that the flower-removed trees showed higher fruit sets, suggesting the existence of resource limitation. The number of seeds per fruit did not increase by the experimental treatment. Additionally, the control individuals did not produce larger fruits. The lack of effects on fruit traits supported our hypothesis that the effect of selective maturation on fruit traits may differ among species with different dispersal mechanisms.

Diurnal Change of the Photosynthetic Light-Response Curve of Buckbean (Menyanthes trifoliata), an Emergent Aquatic Plant

“…To test the difference in the light-saturated gross photosynthetic rate (P g_max ) and stomatal conductance between early morning and during daytime hours on each day, a generalized linear model was constructed using the R function glm (family = Gamma (link = "log")); the values obtained in the earliest morning were compared with the lowest value observed during the midday hours (10:00-14:00) on each day. We used a Gamma error distribution because it is used to describe continuous and positive variables [125,126]. Diurnal changes in the curve parameters between two successive measurements within each day were estimated by interpolating these parameters every 10 min.…”

Shade Avoidance and Light Foraging of a Clonal Woody Species, Pachysandra terminalis

“…To predict binomial outcomes (a ramet either with at least one or without any flower bud), we used a logistic regression analysis with binomial error distribution (family = binomial (link = "logit")) [91,92]. To predict positive and discrete dependent variables (number of ramets per unit land area and number of flower buds on each ramet), we used Poisson distribution (family = poisson (link = "log")) [93,94]. To predict positive and continuous variables (the rest of the dependent variables), we used Gamma distribution (family = Gamma (link = "log")) [95].…”

Pollination Contribution Differs among Insects Visiting Cardiocrinum cordatum Flowers

“…We calculated fruit set (i.e., fruit-to-flower ratio [51,52]) and the seed number per fruit for the 85 bagged fruits used for the pollinator exclusion experiment and, additionally, for different 84 uncovered flowers (i.e., open pollination treatment [15,18,29]) from 15 individuals in the same population. The bags were removed when the flowering period was complete.…”