Flower Position and Size Impact Ovule Number per Flower, Fruitset, and Fruit Size in Pomegranate

Abstract

<jats:p>Pomegranate trees (<jats:italic>Punica granatum</jats:italic>) produce large numbers of both hermaphroditic (bisexual) flowers that produce fruit and functionally male flowers that characteristically abort. Excessive production of male flowers can result in decreased yields resulting from their inability to set fruit. Within hermaphroditic flowers, sex expression appears to follow a spectrum ranging from those exhibiting strong to weak pistil development. Unknown is the scope that flower quality plays in influencing fruit production. A description of floral characteristics and how they vary with flowers of different sizes and positions is lacking in pomegranate and was the focus of this study. Furthermore, the effects of flower size and position on fruit set and fruit size were evaluated. This study documents that flower size characteristics and ovule development can be quite variable and are related to flower type and position. Single and terminal flowers within a cluster were larger than lateral flowers. In addition, lateral flowers exhibited a high frequency of flowers with poor ovule development sufficient to negatively impact fruiting in that flower type. Ovule numbers per flower were significantly influenced by flower size with more ovules in larger flowers. Pollination studies verified significantly higher fruit set and fruit weight, and larger commercial size distributions were obtained with larger vs. smaller flowers. Thus, flower quality is an important issue in pomegranate. Cultural and environmental factors that influence flower size and vigor may have a direct consequence on fruit production and yield.</jats:p>

Ovule bet‐hedging at high elevation in the South American Andes: Evidence from a phylogenetically controlled multispecies study

“…For example, a number of studies have shown larger flowers to favour greater numbers of pollinator visits (e.g., Eckhart, ; Glaettli & Barrett, ; see Krizek & Anderson, for additional references) such that flower size might increase over elevation to assure visitation. However, ovule number it is also known to increase with flower size (cf, Davis, ; López et al, ; Wetzstein et al, ). As it turns out, we found no evidence for an increase in floral/pseudanthium biomass on our gradient, but we did find a tendency for more ovules as flower/pseudanthium biomass increased.…”

“…In addition to the last-mentioned factors, some studies have found ovule number to increase with flower size (Davis, 1981;López, Rodriguez-Riano, Ortega-Olivencia, Devesa, & Ruiz, 1999;Wetzstein, Yi, Porter, & Ravid, 2013; see also Chalcoff & Aizen, 2016). A rigorous test of the ovule bet-hedging hypothesis over elevation requires taking flower size into account in order to discard the possibility that larger ovules numbers are simply a correlate of larger flowers selected to increase pollinator visitation or of elevational turnover in pollination mechanisms which is known to be associated with changes in flower size (e.g., Maad, Armbruster, & Fenster, 2013).…”

A Genome-Wide Association Study Reveals a Novel Regulator of Ovule Number and Fertility inArabidopsis thaliana

“…We obtained 189 Arabidopsis accessions from the ABRC and assayed them for variation in ovule number (Table S1). Since ovule number can vary throughout the life cycle of the plant 19 , we determined the average number of ovules from flowers 6-10 on the main stem of plants that were vernalized for 4 weeks and then grown in long days at 22˚C. Under these growth conditions, accessions displayed a remarkable diversity in ovule number per flower, with a range of 39-82 ovules per flower ( Fig.…”

Sweet cherry floral organ size varies with genotype and temperature

“…Flower size is generally considered the most important attribute for pollinators and flowers with large perianth usually attract more pollinators, partially because of the positive correlation between the petal size and nectar rewards (Cohen and Shmida, 1993;Molina-Montenegro and Cavieres, 2006). In fruit trees, such as peach (P. persica), pomegranate (Punica granatum) and rabbiteye blueberry (Vaccinium ashei), fruit set was significantly higher from larger flowers than smaller ones (Scorza et al, 1991;Johnson et al, 2011;Wetzstein et al, 2013). In addition, pollinators generally minimize energy expenditure and tend to visit bloom where the distance between flowers is short (Molina- Montenegro and Cavieres, 2006).…”