Nutritional strategy underlying plant specialization to gypsum soils.

Gypsum soils are amongst the most widespread extreme substrates of the world, occurring in 112 countries. This type of hypercalcic substrate has a suite of extreme physical and chemical properties that make it stressful for plant establishment and growth. Extreme chemical properties include low plant-available nitrogen and phosphorus and high plant-available sulphur and calcium, which impose strong nutritional imbalances on plants.

Gypsum endemics accumulate excess nutrients in leaves as a potential constitutive strategy to grow in grazed extreme soils.

Extreme soils often have mineral nutrient imbalances compared to plant nutritional requirements and co-occur in open areas where grazers thrive. Thus, plants must respond to both constraints, which can affect nutrient concentrations in all plant organs. Gypsum soil provides an excellent model system to study adaptations to extreme soils under current grazing practices as it harbours two groups of plant species that differ in their tolerance to gypsum soils and foliar composition.

Recent and ancient evolutionary events shaped plant elemental composition of edaphic endemics: a phylogeny-wide analysis of Iberian gypsum plants.

The analysis of plant elemental composition and the underlying factors affecting its variation are a current hot topic in ecology. Ecological adaptation to atypical soils may shift plant elemental composition. However, no previous studies have evaluated its relevance against other factors such as phylogeny, climate or individual soil conditions.

Seed size, number and strategies in annual plants: a comparative functional analysis and synthesis.

Background And Aims: Plants depend fundamentally on establishment from seed. However, protocols in trait-based ecology currently estimate seed size but not seed number. This can be rectified.

Trade-offs between seed and leaf size (seed-phytomer-leaf theory): functional glue linking regenerative with life history strategies … and taxonomy with ecology?

Background And Aims: While the 'worldwide leaf economics spectrum' (Wright IJ, Reich PB, Westoby M, et al. 2004. The worldwide leaf economics spectrum.

Gypsophile chemistry unveiled: Fourier transform infrared (FTIR) spectroscopy provides new insight into plant adaptations to gypsum soils.

Gypsum soils are among the most restrictive and widespread substrates for plant life. Plants living on gypsum are classified as gypsophiles (exclusive to gypsum) and gypsovags (non-exclusive to gypsum). The former have been separated into wide and narrow gypsophiles, each with a putative different ecological strategy.

The crystallization water of gypsum rocks is a relevant water source for plants.

Some minerals, like gypsum, hold water in their crystalline structure. Although still unexplored, the use of such crystallization water by organisms would point to a completely new water source for life, critical under dry conditions. Here we use the fact that the isotopic composition of free water differs from gypsum crystallization water to show that plants can use crystallization water from the gypsum structure.

Differential nitrogen cycling in semiarid sub-shrubs with contrasting leaf habit.

Nitrogen (N) is, after water, the most limiting resource in semiarid ecosystems. However, knowledge on the N cycling ability of semiarid woody plants is still very rudimentary. This study analyzed the seasonal change in the N concentrations and pools of the leaves and woody organs of two species of semiarid sub-shrubs with contrasting leaf habit.

Seasonal and inter-annual variability of bud development as related to climate in two coexisting Mediterranean Quercus species.

Background And Aims: In trees, bud development is driven by endogenous and exogenous factors such as species and climate, respectively. However, knowledge is scarce on how these factors drive changes in bud size across different time scales.

Methods: The seasonal patterns of apical bud enlargement are related to primary and secondary growth in two coexisting Mediterranean oaks with contrasting leaf habit (Quercus ilex, evergreen; Quercus faginea, deciduous) over three years.

Replacement of species along altitude gradients: the role of branch architecture.

Background And Aims: Plant species typical of cold and warm habitats differ in a suite of morpho-physio-phenological traits, although their evolutionary routes have been poorly explored. Here, it is advocated that traits typical of different climate regimes can be largely driven by contrasting branch architectures. This is explored within Saxifraga.

Seasonal variability of dry matter content and its relationship with shoot growth and nonstructural carbohydrates.

This study assesses how different phases of shoot growth underlie seasonal change in leaf and stem dry matter content (LDMC and SDMC, respectively) of 12 woody Mediterranean species. The relationship between LDMC and nonstructural carbohydrate (NSC) concentrations is also explored and the seasonal vs interspecies variability of LDMC compared. LDMC, SDMC and shoot elongation rate (SER) were measured on a monthly basis for a minimum of 12 months.

Relationship between shoot-rooting and root-sprouting abilities and the carbohydrate and nitrogen reserves of Mediterranean dwarf shrubs.

Background And Aims: This study analysed the differences in nitrogen (N), non-structural carbohydrates (NSC) and biomass allocation to the roots and shoots of 18 species of Mediterranean dwarf shrubs with different shoot-rooting and resprouting abilities. Root N and NSC concentrations of strict root-sprouters and species resprouting from the base of the stems were also compared.

Methods: Soluble sugars (SS), starch and N concentrations were assessed in roots and shoots.

Plants living on gypsum: beyond the specialist model.

Background And Aims: Plants from gypsum habitats are classified as gypsophiles and gypsovags. The former include both narrow endemics limited to small gypsum areas and regionally dominant gypsophiles growing in gypsum areas of large regions, whereas gypsovags are plants that can grow both in gypsum and non-gypsum soils. Factors controlling the distribution of gypsum plants are still not fully understood.

Effect of root system morphology on root-sprouting and shoot-rooting abilities in 123 plant species from eroded lands in North-east Spain.

Background And Aims: The objective of this study was to test whether the mean values of several root morphological variables were related to the ability to develop root-borne shoots and/or shoot-borne roots in a wide range of vascular plants.

Methods: A comparative study was carried out on the 123 most common plant species from eroded lands in north-east Spain. After careful excavations in the field, measurements were taken of the maximum root depth, absolute and relative basal root diameter, specific root length (SRL), and the root depth/root lateral spread ratio on at least three individuals per species.

Bud morphology and shoot growth dynamics in two species of Mediterranean sub-shrubs co-existing in gypsum outcrops.

Background And Aims: Understanding the effects of the environment on the morphology and shoot growth activities of plants is crucial to identifying plant ecological strategies. This study analysed the bud morphology, bud activity, shoot growth dynamics and shoot water content at full hydration (WC(h)) of two species of Mediterranean sub-shrubs, Lepidium subulatum and Linum suffruticosum, co-existing in gypsum outcrops in north-east Spain.

Methods: Sampling was conducted monthly over 2 years in one population per species.