A study of functional traits reveals serpentinomorphoses and new taxa in populations of Mediterranean Genista (Fabaceae)

Abstract

In this work we try to determine whether the modifications in the functional traits of a plant species, both morphological and phenological, and caused by the adaptive serpentinomorphoses syndrome are enough to differentiate a new taxon. For this purpose, Genista hirsuta subsp. lanuginosa, a western Mediterranean serpentinophyte (subserpentinophyte) with populations both on serpentines and outside them was selected. The study of functional types (functional traits, which link morphology with adaptations, and phenological reproductive and vegetative phases) was performed in both populations. The results showed that there were statistically significant differences between the two types of populations (serpentine and non-serpentine) with respect to some of the quantitative functional characters studied (plant height, crown diameter, Specific leaf area (SLA), and length of photosynthetic stems). Moreover, other differences were detected with respect to semi-quantitative and qualitative traits: location of renewal buds, branch type, morphology of aerial part, bark consistency, leaf tomentosity, morphology of the root system, and organ redness. Some of them are consistent with serpentinomorphoses syndrome, such as the existence of dwarfism (height of plants), cushion habit, macro-rooted plants and lower SLA (stenophylly) in serpentine populations, besides the presence of redness, which could be a character also linked to serpentinomorphoses. However, neither glaucescent organs nor glabrescence were observed (on the contrary, there is a greater general tomentosity in the plants of the serpentine population). In addition, phenological differences were detected, consisting of a generalized shortening of the phenophases and a certain delay in the reproductive phenophases in the serpentine populations, a characteristic trait in serpentine flora, and differences in sequencing phenophases. These facts lead to propose the use of phenology, in combination with functional traits, to detect serpentinomorphoses syndrome. The detected differences are enough to separate taxonomically the two populations of Genista hirsuta subsp. lanuginosa, proposing for the non-serpentine populations a new variety: var. silicicola nov.

Adaptations to the stressful combination of serpentine soils and Mediterranean climate drive plant functional groups and trait richness

“…Halimium shrubland (HS) and Cistus shrubland (CS). process of serpentinomorphoses (Pichi-Sermolli, 1948;Hidalgo-Triana and Peŕez Latorre, 2019). H was the only FT that showed significant differences between our two shrubland types, with higher values in the HS shrubland.…”

“…Regarding drought avoidance mechanisms, we detected a relatively high content of trichomes in obligate serpentinophytes in contrast to glabrescence syndrome observed by Pichi-Sermolli (1948) and Hidalgo-Triana and Peŕez Latorre (2019). An important role of the indumentum covering the leaf surface is the absorption of harmful UV-B radiation (Agati et al, 2012).…”

“…In general, a comparison of plant heights in relation to the same plants inhabiting other, non-serpentine soils ( Blanca et al., 2011 ), reveals that their height is reduced on serpentine soils ( Sudarmono, 2007 ). Those generalists have modified their FTs to adapt to the serpentine ecosystem with an apparent specialization, probably due to the process of serpentinomorphoses ( Pichi-Sermolli, 1948 ; Hidalgo-Triana and Pérez Latorre, 2019 ). H was the only FT that showed significant differences between our two shrubland types, with higher values in the HS shrubland.…”

“… Wright et al., 2004 ; Breitschwerdt et al., 2018 ), such global databases do not include complete information about FTs for serpentine plants, which should show adaptations to harsh soil environments ( Kazakou et al., 2008 ; Harrison et al., 2017 ). Instead, only general traits have been identified for worldwide serpentine-endemic flora, including reduced specific leaf area (SLA), sclerophyllous leaves, and shorter heights compared with non-serpentine plants ( Harrison and Rajakaruna, 2011 ; Hidalgo-Triana and Pérez Latorre, 2019 ).…”

An updated checklist of serpentinophytes for research and conservation in ultramafic ecosystems on the southern Iberian Peninsula (Spain)

“…The flora and plant communities of Andalusian ultramafic ecosystems have been studied by several authors (e.g., Cabezudo et al, 1989; Gálvez Villamuela et al, 2021; López González, 1975; Pérez‐Latorre et al, 2018; Pérez‐Latorre, Hidalgo Triana, et al, 2013; Pérez‐Latorre, Hidalgo‐Triana, & Cabezudo, 2013; Rivas Goday, 1974; Rivas & López, 1979). Some species are hyperaccumulators of Ni (Díez‐Garretas et al, 2009; Rufo et al, 2004; van der Ent et al, 2013), whereas others exhibit characteristics of serpentine‐morph syndrome (Alados et al, 1999; Hidalgo‐Triana & Pérez‐Latorre, 2019; López González, 1975).…”