The use of composted manure as alternative substrate can be suitable to produce ornamental potted plants. However, under water stress this substrate can result an additional stress for plants due to its physicochemical properties. In these conditions, mycorrhizae application can improve water and nutrients efficiency. The experiment was carried out in a growth chamber with a first phase (I) in which both inoculated and non-inoculated Cistus albidus L. plants at two substrates (commercial and mixtures of composted manure) were well irrigated and a second phase (II) in which the plants were submitted to water stress. Glomus iranicum (Blaszk., Kovács & Balázs) var. tenuihypharum sp. nova was well established in cistus roots, but water stress hindered mycorrhizal proliferation in compost, which resulted in plants with smaller leaf and root biomass. The plants in compost had the highest Cl, K, Na, P and Zn contents in leaf; mycorrhizae reduced the Na and increased phosphorus, especially when the substrate was well-watered. Water stress decreased leaf water potential (W l), and mycorrhizae induced higher W l values in both substrates. Compost induced leaf osmotic adjustment, lower gas exchange and photochemical quenching parameters (F v /F m , Y(II)) values. Mycorrhizal plants had higher Y(II) and qP values than non-inoculated plants. Compost decreased relative chlorophyll content in both phases, but in inoculated plants these values increased under water stress. C. albidus plants growing in compost maintain a good nutritional balance and efficient osmotic regulation. Under water stress, plants suffer more stress than plants in commercial substrate, as reflected by the lipid peroxidation and P n values.

Halophytes are capable of coping with excessive NaCl in their tissues, although some species may differ in their degree of salt tolerance. In addition, it is not clear whether they can tolerate other confounding factors and impurities associated with non-conventional waters. The experiment was performed in a greenhouse with Crithmum maritimum and Atriplex halimus plants, growing on soil and irrigated with two different water types: reclaimed wastewater (RWW) (EC: 0.8–1.2 dS m−1) and reverse osmosis brine (ROB) (EC: 4.7–7.9 dS m−1). Both species showed different physiological and nutritional responses, when they were irrigated with ROB. Atriplex plants reduced leaf water potential and maintained leaf turgor as consequence of an osmotic adjustment process. Atriplex showed higher intrinsic water use efficiency than Crithmum, regardless of the type of water used. In Crithmum, the water status and photosynthetic efficiency were similar in both treatments. Crithmum presented a higher leaf accumulation of B and Ca ions, while Atriplex a higher amount of K, Mg, Na and Zn. Crithmum plants irrigated with ROB presented higher concentrations of 1-aminocyclopropane-1-carboxylic acid and trans-zeatin-glucoside, whereas abscisic acid concentration was lower. Atriplex showed a lower concentration of trans-zeatin-riboside and scopoletin. The characteristics associated to water irrigation did not influence negatively the development of any of these species, which confirms the use of brine as an alternative to irrigate them with conventional waters.

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This work attempts to identify which of two species with different levels of salinity tolerance, Salvia officinalis L. or Asteriscus maritimus L., is more suitable for irrigation with reclaimed wastewater, as well as the effect of the arbuscular mycorrhiza Glomus iranicum on the plant. The experiment was carried out in a growth chamber with a first phase, where both species were irrigated with good quality water, a second phase in which the plants were irrigated with reclaimed wastewater, and a third phase in which the plants were irrigated with good quality water again (recovery). Salinity caused a reduction in leaf water potential, stomatal conductance and net photosynthesis in both species. The percentage of mycorrhization was higher in Asteriscus than in Salvia, mitigating the decrease in leaf water potential. There was osmotic adjustment in Salvia, although the proline content increased in both species. The damages produced were clearer in Salvia, in which lipid peroxidation values were higher. Likewise, the visual appearance of the leaves showed symptoms of toxicity in this species, although the mycorrhizae diminished these effects. Irrigation with good quality water induced the recovery of lipid peroxidation in both species, as well as the appearance of new leaves in Salvia.

The use of reclaimed water (RW) is considered as a means of maintaining agricultural productivity under drought conditions. However, RW may contain high concentrations of salts. The use of some practices, such as biofertilizers and organic substrates, is also becoming increasingly important in agricultural. production. The aim of this study was to evaluate the application of a mixed substrate (with coconut fibre) and arbuscular mycorrhizal fungi (AMF) on water relations, nutrient uptake and productivity in tomato plants irrigated with saline RW in a commercial greenhouse. Saline RW on its own caused a nutrient imbalance and negatively affected several physiological parameters. However, the high water-holding capacity of coconut fibre in the mixed substrate increased water and nutrient availability for the plants. As a consequence, leaf water potential, gas exchange, some fluorescence parameters (PhiPSII, Fv’/Fm’, qP and ETR) and fruit size and weight improved, even in control irrigation conditions. The use of AMF improved only some parameters because of the low percentage of colonization, suggesting that AMF effectiveness in commercial field conditions is slower and dependent of several factors.