Could abiotic environment shape fleshy fruit traits? A field study of the desert shrub Ochradenus baccatus A. Lotan, I. Izhaki * Department of Evolutionary and Environmental Biology, University of Haifa, Mount Carmel, Haifa 31905, Israel article info Article history: Received 16 September 2011 Received in revised form 18 August 2012 Accepted 31 December 2012 Available online 14 February 2013 Keywords: Fleshy fruit Fruit chemistry Fruit morphology Ochradenus baccatus Soil nutrients Water availability abstract In the reciprocal relations between fleshy-fruited plants and their seed dispersers, the pulp shape and content may have important consequences for the plant’s fitness through their influence on frugivore’s fruit choice and thus on seed dispersal success. It is completely unknown to what extent the variation of these fruit traits is affected by the abiotic environment. We tested the hypothesis that abiotic environ- ment governs fruit morphology and chemistry. We studied fruit morphology and analyzed the chemical content of the pulp of the fleshy-fruited desert shrub Ochradenus baccatus in its natural habitat and related these fruit traits to water availability and soil nutrients using Redundancy Analysis (RDA). We found that soil abiotic conditions such as short and long-term water availability and nutrients concentration affected fruit and seed size, pulp:seed ratio and pulp nutritional content (carbohydrates, fat, protein and glucosinolates). These results demonstrated for the first time a linkage between fleshy fruit traits and abiotic conditions in the plants’ microhabitat. We suggest that the abiotic environment plays a more important role in shaping fruit traits than has been proposed before. Thus, the abiotic environment may determine plant fitness through its effect on fruit traits and thereby on fruit choice by potential seed dispersers. Ó 2013 Elsevier Ltd. All rights reserved. 1. Introduction Many higher plants produce fleshy-fruits to attract frugivores to consume the fruits and consequently to disseminate their seeds at a distance from the parent plant. Fruit removal is a crucial stage in plant reproduction that significantly affects plant fitness, and its success depends on various intrinsic and extrinsic factors (Bronstein et al., 2007). There has been a long controversy regarding the effect of the selective pressure of seed dispersers on fruit traits (reviewed by Herrera, 2002). However, fruit traits such as nutritional value and size were found to be important factors that govern fruit choice by potential dispersers (Lepczyk et al., 2000; Wheelwright, 1985) and thereby can influence quality and quantity of seed delivery (Rey and Alcantara, 2000) as well as seedling recruitment (e.g. Wenny, 2000). The enormous inter- specific diversity in fleshy-fruit traits (e.g., color, size and shape) is related to adaptations between fruit traits and specific fruit con- sumers (Herrera, 1982; Valid et al., 2011), to phylogeny (Herrera, 1987; Jordano, 1995b), or to climatic and geographic distribution of the species (Debussche et al., 1987; Hampe, 2003). It is rather surprising that, although the raw material of natural selection is the intraspecific variation, only few studies explored this quality in fruit traits. Nevertheless, these studies found a considerable intraspecific variation in fruit attributes between populations (Latti et al., 2008; Tewksbury et al., 2006), among individuals within populations (Herrera, 1988; Izhaki et al., 2002; Jordano, 1987 , 1995a; Latti et al., 2008), and between years or seasons within individuals (Herrera, 1988; Jordano, 1995a). Although genetic variation probably explains an important portion of the observed variation of fruit traits, it has been suggested that they are influenced to a considerable degree by environmental conditions (Bollen et al., 2005; Izhaki et al., 2002). The variation in fruit size and seed weight of Prunus mahaleb was marginally related to the rock cover (Jordano, 1995a), and differences in fruit traits of Osyris quadripartita were speculatively linked to precipi- tation (Herrera, 1988). In wild berries, the between-population variations in fruit traits (e.g. Latti et al., 2008) were associated also to habitat light intensity (Agren, 1989). Chiarucci et al. (1993) clearly demonstrated the association between fruit attributes and abiotic factors in a natural environment. They found significant correlations between fruit morphology of Arbutus unedo and annual temperature and precipitation. However, most of the above findings refer to whole-fruit and seed morphology (size, weight, etc.) or to seed chemistry, but not to pulp nutritional and chemical * Corresponding author. Tel.: þ972 49838919. E-mail address: izhaki@research.haifa.ac.il (I. Izhaki). Contents lists available at SciVerse ScienceDirect Journal of Arid Environments journal homepage: www.elsevier.com/locate/jaridenv 0140-1963/$ e see front matter Ó 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.jaridenv.2012.12.013 Journal of Arid Environments 92 (2013) 34e41