The influence of mesquite trees (Prosopis juliflora (Swartz) D.C.) on the physicochemical properties of soils and annual understory plants was investigated in the deserted rangelands of Bahrain. Soil properties were measured in the understory and the uncanopied adjacent areas of mesquite trees. Likewise, the number of plant species was assessed in four 1 × 1 m randomly distributed quadrates in the understory and the uncanopied adjacent areas. The results showed that sand particles exceed 96% of soil composition. Soil bulk density at the 0–5 cm soil depth was significantly higher in the understory of trees compared to the uncanopied adjacent areas. However, moisture at a depth of 40–60 cm was significantly higher in the uncanopied adjacent areas. No differences in the pH, EC, K, Na, and Ca were found between understory and the uncanopied areas in all soil depths. Levels of N, P, Mg, and organic matter were significantly higher in the understory of trees compared to the uncanopied adjacent areas. Organic matter was twice the amount in the upper 20 cm of soil layers in the understory of mesquite trees. Species richness did not differ between the understory and the uncanopied areas. Nevertheless, the density of ephemerals in the understory of mesquite trees was higher than the uncanopied areas by 18%. The Shannon-Weaver index of diversity was higher in the uncanopied areas compared to the understory. The study concluded that the canopy effects of mesquite trees on soil vary with depth. Nonetheless, the influence of mesquite on flora could be beneficial for annual understory plants but subject to many operating factors, including density and cover of mesquite trees.

Leptadenia pyrotechnica is an important multipurpose endangered plant in the Kingdom of Bahrain with restricted distribution. Nodal explants were cultured on Murashige and Skoog (MS) medium supplemented with different concentrations and combinations of indole acetic acid (IAA) and 6-benzylaminopurine (BAP). Initially, 80% and 60% explants responded in direct shoot and callus initiation response respectively in presence of 8.88 µM BAP with 5.71 µM IAA in modified MS media after two weeks of culture. The highest frequency of plant regeneration was observed in presence of 8.88 µM BAP with 1.14 µM IAA following organogenic pathway of differentiation. Hundred percent callus proliferation was observed while initial callus developed in presence of 4.44 µM BAP with 2.85 µM IAA and was transferred in media containing 4.44 µM, 6.66 µM BAP with 2.85 µM IAA and 13.32 µM BAP with 5.71 µM IAA. The callus derived plants were regenerated following the pathway of indirect somatic embryogenesis. The induction of somatic embryogenesis and plant regeneration from callus was also observed in modified MS media supplemented with 4.44 µM BAP and 2.85 µM IAA. The plant regeneration protocol we developed for Leptadenia pyrotechnica will be very beneficial for biodiversity conservation and environment protection of Bahrain. Moreover, the present paper reports for the first time specifically the somatic embryogenesis in this multipurpose desert plant Leptadenia pyrotechnica.

Heliotropium kotschyi (Ramram), is a very important plant in relation to environment protection and for its medicinal value in Bahrain. It has been detected as one of the endangered plants in Bahrain. Ex situ conservation of this plant applying tissue culture method was used in the present study. In vitro plant regeneration has been established via shoot organogenesis using nodal meristems. The effect of various plant growth regulators was evaluated to regenerate the whole plants by in vitro micropropagation in modified MS media supplemented with different plant growth regulators (PGRs). In vitro regeneration of plants was involved in three steps by shoot initiation, multiplication and rooting of microshoots. Initially 100% explants of Heliotropium kotschyi responded to initiate shoot in MS medium supplemented with 8.88 µM BAP with 5.71 µM IAA after 4 weeks of culture. Multiplication of shoots and ultimate plant regeneration capacity of Heliotropium kotschyi were compared and the highest performance of 578 shoots/explant was observed in presence of 8.88 µM BAP and 5.71 µM IAA after second transfer. Rooted plantlets were transferred to soil pots and 60% plants were survived after one and a half months. The highly efficient plant regeneration protocol of the desert plant is of great value in rapid plant propagation program for the purpose of conservation of biodiversity.

Heliotropium kotschyi (Ramram) is an important endangered medicinal plant distributed in the Kingdom of Bahrain. Plant tissue culture technique is applied for ex situ conservation study. Nodal stem segments are cultured in modified MS media supplemented with various combination and concentration of plant growth regulators (PGRs). Plants are regenerated via shoot organogenesis from the nodal meristems. Plants are regenerated in three different steps: initial shoot development, shoot multiplication, and rooting. After 4 weeks of culture, 100 % explants respond to shoot initiation on the medium containing 8.88 μM BAP and 5.71 μM IAA. The highest frequency of shoot regeneration is observed in the same media after second subculture of shoots. The highest rooting frequency is observed in the presence of 2.85 μM IAA. After root development, the plantlets are transferred to pots filled with soil and 60 % of plants survived after 45 days. This plant regeneration protocol is of great value for rapid desert plant propagation program.