Dynamics of fruit growth, accumulation of wax esters, simmondsins, proteins and carbohydrates in jojoba

Abstract

The aim of this study was to learn the developmental aspects and compositional changes during the development of jojoba [ Simmondsia chinensis (Link) Schneider] fruit and seed. Three Israeli clones: Forti, Benzioni and Shiloh were used. By 50–60 days after pollination (DAP) the capsules had grown to attain their full dimensions. Only then did the embryos begin to rapidly gain weight and accumulate storage reserves. Seed growth followed a sigmoid pattern, reaching final weight by about 140 DAP. The appearance of wax bodies began at 55–65 DAP and wax deposition continued during the whole period of seed maturation, including late seed maturation. Protein concentration remained constant during the entire period of seed growth, increasing proportionately with seed weight. Sugar concentration was high at the beginning of the maturation period and declined throughout maturation. The sugar profile changed during maturation as the ratio of sucrose to reducing sugars increased several fold by 50–60 DAP, just as the embryos switched from the embryogenesis stage to maturation and began accumulating storage reserves. Simmondsins were present at concentrations of 3–4% when sampling first began (47–55 DAP) but no ferulate was detected until 75–86 DAP. During maturation, simmondsins concentration rose gradually and by late maturation, when dehydration began, simmondsins concentration had increased considerably to concentrations of 9–15%. Three developmental phases were identified: early embryogenesis lasting around 2 months from pollination, maturation with accumulation of storage reserves, and late maturation when simmondsins accumulate.