Seed Longevity in Desert Species and the Possibility of Forming a Persistent Soil Seed Bank

The formation of soil seed banks could be an important survival strategy for desert plant species that determine their persistence under harsh conditions, where temperature is extremely high, and chances of rainfall are low and unpredictable. Therefore, the assessment of the seed viability and germination potential of in-situ stored seeds could be important for understanding their reproductive strategies. Seeds of the studied species were collected in 2017 and divided into two batches. The first batch (fresh seeds) of each species was tested for seed germination within one week after collection. However, the second batch (in-situ stored seeds) was tested for seed germination in the first week of October 2022. In the current study, the germination potential of in-situ stored seeds was investigated in order to determine their ability to remain viable under natural conditions. Stored seeds of studied species showed higher germination percentages (53–89%) than fresh seeds (3–34%), except for Peganum harmala, indicating the presence of seed dormancy at the time of seed maturation. Seed germination percentages of all the species were significantly enhanced by storage, indicating their ability to form persistent soil seed banks, although the extent was species-specific. Fresh seeds of all the species attained higher germination in light as compared to complete darkness, suggesting that the germination of seeds can be restricted if they are buried deep in the soil under natural conditions. However, depending on species, in-situ seed storage changed the light requirement for germination. Additionally, the absence of an increase in the ratio of dead seeds between fresh and stored seeds indicates their ability to remain persistent in a soil seed bank and thus may offer great potential for maintaining and restoring desert ecosystems.