Climate change is expected to drastically reduce precipitation levels, posing a major challenge to agricultural productivity, especially in arid and semi-arid regions like the Middle East, where water scarcity is already a critical concern. Research on Brassicaceae in this region is particularly important, as this plant family includes key staple crops that are highly susceptible to water stress. Moreover, the Middle East provides a unique opportunity to study domesticated crops alongside their wild relatives, many of which are native to the area. These wild relatives often exhibit greater genetic diversity and enhanced stress tolerance, offering valuable insights into adaptive traits that may have been diminished or lost through domestication.
In this study, we examined three widely cultivated crops: Canola (Brassica napus) and white mustard (Sinapis alba), which are grown primarily for their seeds, and radish (Raphanus raphanistrum), which has been domesticated for its roots rather than seeds. Each domesticated crop was compared with its native wild relative. To assess the potential impact of water shortage on plant performance, both wild and domesticated species pairs were subjected to five water treatments (0.5, 1, 2, 4, and 8 litres/hour). We measured key physiological traits, including leaf water potential, relative water content, specific leaf area, stomatal conductance, electron transport rate, and transpiration rate.
Physiological responses increased with higher irrigation levels in all three species, indicating a consistent sensitivity to water availability. However, floral volatile organic compound (VOC) concentrations were unaffected by irrigation treatment but differed significantly between wild and domesticated forms across all three species. Despite changes in water availability, pollinator visitation rates were not influenced by the irrigation treatment; instead, flower number was the primary factor driving pollinator attraction. By linking physiological performance to floral traits under water stress, our study provides deeper insight into how domesticated crops may respond to increasingly arid conditions and the implications for pollination services in the region.
