Effect of temperature on seed development in jojoba (Simmondsia chinensis (Link) Schneider). I. Dry matter changes

Abstract

Growth of the capsule and seed of jojoba were followed from pollination to maturity at eight temperature regimens ranging from 15/10 to 36/31¦C (8/16 h; photoperiod 16 h). There was an initial lag before the onset of rapid (linear) seed development, during which the capsule expanded, and this lag varied from 106 days at 15/10¦C to 7 days at 36/31¦C. The wax concentration in the seed was low during the initial stages of development, but reached a maximum when the seeds were 70-75% of their final dry weight. The maximum rate of dry matter accumulation in the seed increased with temperature up to 33/28¦C but, because of the longer growth period at low temperature, seed size at maturity was greatest at 18/13¦C. The current work suggests that prolonged periods with temperatures above 36/31¦C, or below 15/10¦C would be harmful to the development of jojoba seed. The high optimum temperature for growth rate of the seed (33/28¦C) and sensitivity to a temperature of 15/10¦C, puts jojoba into the same group as many subtropical species. However, the lower optimum temperature for seed weight at maturity (18/13¦C) is close to that observed for the temperate cereals.