Plants adapt to different environmental conditions by developing structural and metabolic mechanisms. In this study, anatomical features and lipophilic metabolites were investigated in Cleome amblyocarpa Barr. & Murb., Cleomaceae plants growing in the arid desert of United Arab Emirates (UAE) in either low-water or extra-water areas, which were caused by the surrounding road run-off. The plant showed the presence of shaggy-like trichomes. The plant also developed special mechanisms to ensure its survival via release of lipophilic metabolites. The lipophilic metabolites, stained red with Sudan III, were apparently released by glandular trichomes and idioblasts of the shoot and roots, respectively. The identified lipophilic metabolites included those required for drought tolerance, protection against pathogens invasion, and detoxification. Plants growing in the low-water area caused an increase in the production of lipophilic metabolites-in particular, hydrocarbons and terpenoids. The lipophilic metabolites are known to provide the plant with unique waxy surfaces that reduce water loss and avoid penetration by pathogens. The release of lipid metabolites and the presence of shaggy-like trichomes represented unique features of the species that have never been reported. The provided chemical ecology information can be extended for several plant-related applications, particularly including drought tolerance.
Keywords: Cleome amblyocarpa; arid desert of United Arab Emirates; drought stress; lipid metabolites; rare plant; shaggy-like trichomes.