Effects of salinity stress on the germination capacity of xoan orange seeds (Citrus sinensis (L.) cv. Xoan) under conditions in vitro culture

Abstract

Citrus sinensis (L.) cv. Xoan is one of the delicious orange varieties with high economic value thanks to its sweet taste, and characteristic aroma. It is also a valuable remedy in oriental medicine. Currently, the situation of saltwater intrusion in the Mekong Delta provinces has been complicated, causing heavy damage to crops, including the Xoan orange variety. This study investigated the effects of NaCl at different concentrations on the germination of Citrus seeds under in vitro culture conditions. Seeds are sterilized with 25%; 50% NaClO; and HgCl₂ 0.1% for 1, 3, 5 minutes and cultured on MS medium, monitoring the survival rate and infection rate during 8 weeks of culture. After determining the disinfection solution with the appropriate concentration and time, the seeds were grown in an environment supplemented with NaCl at a concentration of 2 g/L - 10 g/L and the seed germination rate was monitored during 3 weeks of culture. The results showed that with 0.1% HgCl₂ solution in 5 minutes, seeds were best disinfected with a survival rate of 100%. When adding NaCl at different concentrations to the culture medium, the germination rate of Citrus seeds decreased and the seed germination time increased compared to the control treatment. In particular, the NaCl concentration of 10 g/L severely affects the germination of seeds, causing the seeds to show no signs of germination.