Functional and ecophysiological traits of Halimione portulacoides and Sarcocornia perennis ecotypes in Mediterranean salt marshes under different tidal exposures

Abstract

The present paper aims to discuss the functional and ecophysiological traits of two abundant succulent halophytes in Mediterranean salt marsh systems, considering two ecotypes differing on their tidal exposure. In Halimione portulacoides the higher root/shoot (R/S) biomass ratio verified in low inundation frequency (LF) marshes, as compared with that in high inundation frequency (HF), indicates an optimal partitioning strategy, inducing differential allocation patterns along with varying environmental factors. Conversely, Sarcocornia perennis appear to have an isometric allocation strategy, based on intrinsic biomass allocation mechanisms independent from the surrounding environmental conditions. Similarly, the photosynthetic traits appear to reflect the intrinsic ecology of the species. Sarcocornia perennis habitat adaptation to HF conditions is clearly revealed by its high photosynthetic efficiency under HF conditions. On the other hand, the cosmopolitan H. portulacoides shows no differences between ecotypes, in which concerns this trait, mostly due to the high carotenoid content of the HF ecotype, which allows this specie to counteract the stress generated during submersion. Additionally, anti‐oxidant enzymatic activities revealed that S. perennis presents a high degree of stress tolerance under HF conditions, while H. portulacoides is highly adapted to LF conditions. These functional (biomass‐related) and physiological traits determine the optimal habitats for H. portulacoides and S. perennis. While H. portulacoides optimal biomass partitioning, along with its efficient anti‐oxidant defence system, makes this species fitter to LF conditions, S. perennis isometric allocation strategy, along with a higher photosynthetic efficiency under frequent flooding conditions, provides this species the mechanisms to efficiently colonize the intertidal habitat.

Functional Food from Endangered Ecosystems: Atriplex portulacoides as a Case Study

“…Carotenoids from 30 to 100 µg/g FW (approximate values estimated from graphical representations) were reported by Duarte et al [54] in plants stressed by frequent tidal floods, which decreased with the reduction of the flood frequency. In another study, Duarte et al [55] quantified the leaf carotenoids in about 109-230 µg/g FW, indicatively corresponding to 0.87-1.84 mg/g DW, assuming a moisture of 87.5%, amongst which zeaxanthin was the most abundant.…”

Metabolomic Profile of Salicornia perennis Plant’s Organs under Diverse In Situ Stress: The Ria de Aveiro Salt Marshes Case

“…However, the increase in glycerol concentration, often in conjunction with arabitol, is a hyperosmotic stress response where glycerol synthesis comes from glucose [ 59 ]. Furthermore, Dias et al [ 35 ] found that a decrease in glucose content and an increase in sugar alcohols suggests that the pool of polyols is maintained at the expense of glucose. The polyols found in plants from Ílhavo have a small concentration of glycerol and myo-inositol.…”

“…Some plants may increase the cuticular thickness of leaves, stems, and fruits in response to adverse environmental factors to protect themselves from radiation, prevent water loss, or protect against pathogens [ 62 ]. Plants in aquatic environments have very thin cuticles [ 10 , 35 , 63 ]; however, halophytes are not aquatic but amphibious plants, which may exhibit xeromorphic characteristics, such as cuticular thickening, similar to plants of drought conditions [ 64 ]. This factor prevents excess transpiration and water loss [ 65 ].…”

“…The Ria de Aveiro ( Figure 1 ) is a coastal lagoon situated on the Northwest Atlantic coast of Portugal, separated from the sea by a sand spit. The lagoon’s dynamics are mainly forced by semi-diurnal tides, with the tidal range varying between 0.6 m at neap tides and 3.6 m at spring tides, with an average of about 2 m [ 34 , 35 ]. Three sampling sites were chosen to collect the plants and the respective environmental conditions: Ílhavo channel salt marsh, Mira channel salt marsh, and São Jacinto channel salt marsh.…”

LED Lighting and High-Density Planting Enhance the Cost-Efficiency of Halimione Portulacoides Extraction Units for Integrated Aquaculture

“…On the other hand, Buhmann et al [42] reported lower productivity values of 33 g FW m −2 day −1 using very different experimental conditions. These first studies with H. portulacoides (Table 5) already suggest contrasting outcomes, most likely influenced by different culture conditions, genetic variability and the use of different ecotypes [64].…”