Abstract
In many crop plants, pre-treatment of seeds with different chemicals results in an increase in seed germination under saline conditions. For this purpose, the potential use of gibberellic acid (GA), kinetin(K), GA+K mixture,Ixjtasiumcyaxijde (KQJ), potasium phosphate (KH2PO4), and Hoagland’s solution in increasing germinaiton of Jojoba seeds [Simmondsia chinensis (Link) Sch.] was studied. For each treatment, 50 seeds after being disinfected with 0.5% sodium hypochl(ride solution, were soaked in graded solutions of GA,K,GA+K, KCN,KH,PO4 at 0,10,20,50,100, and 200 PPm and of Hoagland’s solution at 0, 1/2 and full strength for 12 hours. Seeds were then placed in petri—dishes and were exposed to 0, -0.4, —0.8, —1.2, and -1.6 MPa salinity induced by NaCl, CaCl2, and NaCl+CaCl2. The dishes were held at 29± 0.5°C and 60% relative humidity in a germinator. Results obtained from this experiment indicated that pre-treatment of Jojoba seeds with GA,K, and GA+K was effective in increasing germination under medium and low saline conditions. Use of GA at 20 PPm alleviated the inhibitory effects of NaCl and CaCl2 at —0.4 and —0.8 MPa. But at higher salinity levels, none of the GA concentrations were effective. In case of soaking seeds in K solutions, higher levels of K was necessary in order to obtain seed germination at higher salinity levels. Treating Jojoba seeds with CA+K was also effective in increasing germination under NaCl salinity of —0.8 MPa. However, at -1.2 and -1.6 MPa, germinatidn was not increased. Soaking seeds in different concentrations of KCN, KH2PO4 and Hoagland’s solution did not show any significant increase in germination.