Establishment of argan tree plantlets (Argania spinosa (L.) Skeels) grown from generative and vegetative propagation under different watering regimes at the nursery stage

The ongoing efforts to rehabilitate the argan tree (Argania spinosa (L.) Skeels) woodland have prompted pertinent socio-economic reconsiderations. However, its reserve biosphere is experiencing an escalating deterioration pace. To satisfy the economic and ecological requirements, accurate in vitro and ex vitro propagation protocols were suggested. However, the physiological state of the plantlets remains less investigated. Hence, this study aims to evaluate the physiological response of argan tree plantlets propagated from different stem cuttings compared to seedlings under two watering regimes at the nursery stage. The cuttings establishment was similar to the seedlings in terms of water uptake, transpiration rate (E), stomatal conductance (gs), and net photosynthesis (A). The plantlet's height, foliation, and stomatal density were significantly influenced by the type of propagation (P < 0.01). The seedlings exhibited better growth performances in height and foliation with 28.0 ± 9.9 cm and 79.6 ± 21.6 leaves per plantlet, respectively. The seedlings were followed by herbaceous, semi-woody, and woody cuttings. Remarkably, the seedlings' foliation was 38%, 68%, and three-fold higher than the cuttings. The woody cuttings were recalcitrant. However, their plantlets exhibited the highest stomatal densities with 140.3 stomata.mm⁻². Concerning the watering regime, both field capacities, 100% FC and 120% FC, allowed the establishment of the plantlets. Nevertheless, there were no significant differences regarding water uptake, foliation, stomatal density, and gas exchange. Remarkably, 120% FC has facilitated the plantlets' growth. Through these, the best establishment of argan tree plantlets from herbaceous cuttings under a 120% FC watering regime is currently obtained at the nursery stage.