Jojoba: Adaptation to Environmental Stress and the Implications for Domestication

Jojoba (Simmondsia chinensis) is an arid-zone, perennial shrub which is being domesticated to exploit the liquid wax contained in the seed. The xeromorphic adaptations that allow jojoba to survive and reproduce in its arid habitat present special problems for its domestication. An accout of the natural history of jojoba introduces the specialized characteristics of the species. Details of the morphological and anatomical adaptations are then reviewed. The physiological adaptations of jojoba to temperature, water, and salt stresses in terms of water relations, growth and photosynthesis are extensively reviewed. The implications of these adaptations for survival in the wild and for domestication are discussed. The control of the reproductive cycle by temperature and water availability is also an adaptation to an arid habitat. The responses of flowering and seed growth to a range of environmental factors are considered, and the implications ofr domestication discussed. It is concluded that the extensive existing variability in the physiologycal responses to environmental factors will permit the selection of a range of jojoba cultivars.