To cope better with desert harsh conditions or to improve their growth magnitude and productivity, jojoba
plants might need some aid. One week drought, over a period of two months, was stressful as it induced
severe growth inhibition compared with maintained 50% field capacity. In addition, jojoba sustained
growth throughout the whole experimental period (4 months) relying on a minimum of nitrate (tap water
or 25% Hoagland concentration). Extra nitrate (1 25%) was stimulatory to growth in full hydration and
may overcome growth inhibition in partial hydration but not in drought. The osmoregulants (soluble
sugars, proline and amino acids), membrane properties (leakage of K, electrolytes and UV absorbing
metabolites as well as lipid peroxidation) and antioxidants (phenolics, catalase, guiacol peroxidase and
superoxide dismutase activity) were assessed to evaluate drought stress impacts. They did not respond
identically to drought leading to confusion which is most-expressing manifestation of drought stress.
From which, enhanced proline accumulation and lipid peroxidation with inhibited ascorbate peroxidase
displayed a clear cut and reliable stress biomarkers. The antioxidant phenolics increased with increasing
nitrate in water-stressed jojoba leaves (50% field capacity or one week drought). Nitrate may participate
in scavenging electrons since lipid peroxidation was lowered at high nitrate levels.