Phenotypic Plasticity Strategy of Aeluropus lagopoides Grass in Response to Heterogenous Saline Habitats.

Understanding the response variation of morphological parameters and biomass allocation of plants in heterogeneous saline environments is helpful in evaluating the internal correlation between plant phenotypic plasticity mechanism and biomass allocation. The plasticity of plants alters the interaction among individuals and their environment and consequently affects the population dynamics and aspects of community and ecosystem functioning. The current study aimed to assess the plasticity of Aeluropus lagopoides traits with variation in saline habitats. Understanding the habitat stress tolerance strategy of A. lagopoides is of great significance since it is one of the highly palatable forage grass in the summer period. Five different saline flat regions (coastal and inland) within Saudi Arabia were targeted, and the soil, as well as the morphological and physiological traits of A. lagopoides, were assessed. Comprehensive correlation analyses were performed to correlate the traits with soil, region, or among each other. The soil analysis revealed significant variation among the five studied regions for all measured parameters, as well as among the soil layers showing the highest values in the upper layer and decreased with the depth. Significant differences were determined for all tested parameters of the morphological and reproductive traits as well as for the biomass allocation of A. lagopoides, except for the leaf thickness. In the highly saline region, Qaseem, A. lagopoides showed stunted aerial growth, high root/shoot ratio, improved root development, and high biomass allocation. In contrast, the populations growing in the low saline region (Jizan) showed the opposite trend. Under the more stressful condition, like in Qaseem and Salwa, A. lagopoides produce low spikes in biomass and seeds per plant, compared to the lowest saline habitats, such as Jouf. There was no significant difference in physiological parameters except stomatal conductance (gs), which is highest in the Jizan region. In conclusion, the population of A. lagopoides is tolerant of harsh environments through phenotypic plasticity. This could be a candidate species to rehabilitate the saline habitats, considering saline agriculture and saline soil remediation.

Promising Application of Automated Liquid Culture System and Arbuscular Mycorrhizal Fungi for Large-Scale Micropropagation of Red Dragon Fruit.

Red dragon fruit (Hylocereus polyrhizus) is an economic and promising fruit crop in arid and semi-arid regions with water shortage. An automated liquid culture system using bioreactors is a potential tool for micropropagation and large-scale production. In this study, axillary cladode multiplication of H. polyrhizus was assessed using cladode tips and cladode segments in gelled culture versus continuous immersion air-lift bioreactors (with or without a net). Axillary multiplication using cladode segments (6.4 cladodes per explant) was more effective than cladode tip explants (4.5 cladodes per explant) in gelled culture. Compared with gelled culture, continuous immersion bioreactors provided high axillary cladode multiplication (45.9 cladodes per explant) with a higher biomass and length of axillary cladodes. Inoculation of H. polyrhizus micropropagated plantlets with arbuscular mycorrhizal fungi (Gigaspora margarita and Gigaspora albida) significantly increased the vegetative growth during acclimatization. These findings will improve the large-scale propagation of dragon fruit.