This Experiment was conducted during the 2003 and 2004 seasons to study the effect of GA₃ on Jojoba (Simmondsia chinensis, Link) seedlings which grown under osmotic stress. One-year old seedlings were grown in soil contains 0.0, 0.4 or 0.8% of NaCl + CaCl₂, (1:1 by weight) and irrigated up to 60, 80 or 100% of FC. Plants were sprayed 4 times with GA₃ at 0, 50 and 100 ppm to alleviate water and/or salt stress. Vegetative growth; plant height, stem diameter and stem and leaves fresh and dry weight, were gradually augmented by increasing FC up to 100%. On the contrary, root length as well as fresh and dry weights of roots were gradually reduced with the gradual increase in water supply. Growth of jojoba seedling responded negatively to salinity stress, this reduction in growth parameters was gradual up to the highest level (0.8%).
                GA₃ treatment significantly improved all investigated plant growth parameters except stem diameter. Treatment with 100 ppm GA₃ gave the tallest plants, deepest root system, and heaviest fresh and dry weights of stem, leaves and roots. GA₃ significantly alleviated the diverse impact of water and/or salt stress. The reduction in plant height, stem and leaves dry weight in the first season for plants grow in soil with 60% FC and 0.8% salt, compared with plants grow in soil with 100% FC and 0.0% salinity was 26.84, 51.71 and 107.45%, respectively. However, the equivalent values when the same plants which treated with 100 ppm GA₃ were 4.43, 32.03 and 74.70% respectively. Also, root length of plant grown in soil with 0.8% salinity and 60% FC was increased by 33.04% due to 100 ppm GA₃. The highest values of plant height, fresh and dry weights of stem and leaves were obtained due to treatment with 100% FC, 0.0% salinity and 100 ppm GA₃. Whereas, highest values of fresh and dry weight of roots being for plants treated with 100% FC, 0.0% salinity and 100 ppm GA₃. So that, it is recommended to irrigate jojoba seedling up to 100% FC and with spraying 100 ppm GA₃ to achieve highest growth values especially under salt stress.