The Arabian Peninsula is known to have a comprehensive and rich endowment of unique and genetically diverse plant genetic resources. Analysis and conservation of biological diversity is a crucial issue to the whole Arabian Peninsula. The rapid and accurate delimitation and identification of a species is crucial to genetic diversity analysis and the first critical step in the assessment of distribution, population abundance and threats related to a particular target species. During the last two decades, classical strategies of evaluating genetic variability, such as morphology and physiology, have been greatly complemented by phylogenetic, taxonomic, genetic diversity and breeding research molecular studies. At present, initiatives are taking place around the world to generate DNA barcode libraries for vascular plant flora and to make these data available in order to better understand, conserve and utilize biodiversity. The number of herbarium collection-based plant evolutionary genetics and genomics studies being conducted has been increasing worldwide. The herbaria provide a rich resource of already preserved and identified material, and these as well as freshly collected samples from the wild can be used for creating a reference DNA barcode library for the vascular plant flora of a region. This review discusses the main molecular and genomic techniques used in plant identification and biodiversity analysis. Hence, we highlight studies emphasizing various molecular techniques undertaken during the last 10 years to study the plant biodiversity of the Arabian Peninsula. Special emphasis on the role of DNA barcoding as a powerful tool for plant biodiversity analysis is provided, along with the crucial role of herbaria in creating a DNA barcode library.

Suaeda aegyptiaca is a facultative halophyte found in saline and non-saline habitats of the Arab Gulf desert, which produces small-sized undispersible seeds. The interactive effects of maternal salinity and other environmental conditions, such as salinity, light and temperatures, that are prevailing during seed germination have received little attention for a facultative halophyte. This study tested the effects of maternal salinity on salt tolerance during seed germination of S. aegyptiaca under different light and temperature regimes. Seeds collected from both saline and non-saline habitats of the United Arab Emirates (UAE) were germinated in 0, 50, 100, 200 and 400 mM NaCl, and incubated at 15/25 C, 20/30 C and 25/35 C in both 12-h light/12-h dark regimes and continuous darkness. Generally, seeds of the non-saline habitat were 56% heavier and attained greater germination at the lower temperatures than seeds of the saline habitat. Seeds of the saline habitat germinated better in saline solutions at higher temperatures and in light. Germination was faster for seeds of the saline habitat than for seeds of non-saline habitats. Germination recovery after transfer to distilled water was significantly greater for seeds from the non-saline habitat, compared with seeds from saline habitats. Recovery was greater at lower and/or moderate temperatures, compared with at higher temperatures. Germination was significantly faster during recovery, compared with in the saline solutions. The study indicates that the maternal effect of salinity was confounded with the seed-size effect and it cannot be conclusively confirmed.

In order to identify the migratory pathways and foraging grounds of post-nesting Green Turtles (Chelonia mydas) in the Red Sea, we attached satellite transmitters to four females immediately after egg deposition and tracked them between 207 and 647 days. We identified four geographically distinct post-nesting habitat areas and migration paths from Zabargad Island, Egypt which was remarkable given our small sample size. Our shortest migration was 140 km and the longest 940 km, with the migrations and post-nesting habitat encompassing the boundaries of four of the seven Red Sea countries (Egypt, Sudan, Eritrea, and Saudi Arabia). The post-nesting habitats were located in shallow coastal habitat and three consisted of near-shore archipelagos. Two turtles moved past areas of suitable post-nesting habitat that was occupied by other turtles, which suggests that these turtles may be exhibiting fidelity to certain feeding and nesting sites. Our results suggest that regional and multi-national cooperation will be needed to protect sea turtles that nest on Zabargad Island, a nesting site that is important for Egypt and other Red Sea nations.

Ex situ conservation in seed banks is a potential complementary conservation strategy for native plant species. It is well established that ex situ seed banking of native wild plants prolongs seed viability and thereby preserves genetic and species diversity for future use. We evaluated ex situ storage potential of eight halophytic species from deserts in the United Arab Emirates (UAE) by studying seed germination. Specifically, we examined the germinability of freshly collected seeds and seeds stored for three years in a seed bank. We also examined the effect of light conditions on fresh and stored seed germination. Fresh seeds of seven of the eight species tested had a higher germination rates under 12/12 h light/dark fluctuations than did those exposed to total darkness. Storage reduced light sensitivity in Halocnemum strobilaceum, Suaeda aegyptiaca, Salsola drummondii and Salsola imbricata, but increased the requirement for light in Arthrocnemum macrostachyum. In Anabasis setifera, storage decreased germination percentage when there was a 12-hour light/dark fluctuation, but increased germination rate when exposed to the dark treatment. Storage significantly reduced germination in both the light/dark and dark treatments in Suaeda vermiculata and S. aegyptiaca. Germination speed also responded differently to storage; whereas Timson's index significantly increased in A. macrostachyum and H. strobilaceum, it significantly decreased for S. drummondii, S. aegyptiaca and S. vermiculata. Germination of these species at a range of temperatures requires further testing; additionally, we strongly suggest that these laboratory findings be complemented by field studies.

In this study, salt tolerance during germination of Aeluropus lagopoides (L.) Trin. was tested using fresh seeds collected from three different maternal habitats under three thermoperiods and two light regimes. Additionally, we tested the ability of non-germinated seeds that had been exposed to different concentrations of NaCl to recover their germination in distilled water. The results showed a significant effect of seed source, temperature, and salinity, and some of their two- and three-way interactions on final germination and recovery percentage. The seeds from non-saline provenances had the highest percentages for germination (ca. 79%) under the 35/25 °C temperature regime, whereas the lowest percentages for germination (ca. 21%) was recorded for seeds from saline conditions under the 25/15 °C treatment. Additionally, percent germination was significantly lower for the seeds incubated in the saline solutions (100, 200, 400, and 600 mmol/L NaCl) and germinated under colder conditions (15/25 °C), compared with the seeds incubated in non-saline solutions (control group, 0 mmol/L NaCl) and germinated under warmer conditions (35/25 °C). The highest recovery percentage was recorded for seeds of the hyper-saline habitat incubated at 35/25 °C. Thus, seeds maintained their viability despite experiencing a range of saline conditions and were able to germinate upon the arrival of suitable conditions, which can be an adaptation to its saline arid desert habitat.