Establishment of axenic explant and callus culture of citrus limon using embryonic seed explant

Citrus limon is from the family of Rutaceae which has high demand in medicinal use and has industrial importance. It is used to treat asthma, cough, cold, heartburn, fever, rheumatism and prevent diseases like stroke, cardiovascular diseases and cancer. Because of its unique aroma, it is widely used as aromatherapy oil and very versatile remedy. The best protocol of surface sterilization of C. limon is by using 30% of Clorox concentration with 10 minutes exposure time and the seed coat is removed before surface sterilization procedure is carried out. This protocol was used to sterilize the embryonic seed for callus induction. Shoot and root explants were selected as the best explants to induce callus than embryonic seed explant. The shoot explants showed the best response to 2.0 mg/L of 2, 4-D and 0.5 mg/L of BAP while the root explants showed the highest percentage of callus growth when supplemented with treatment combination of 2.0 mg/L of 2, 4-D, 0.5 mg/L of BAP and 0.5 mg/L of IBA. For the shoot regeneration, all the calli were turned brown, dried and hence no shoot was formed. Fungal and bacterial contaminations were the major obstacle in getting aseptic culture during callus induction and shoot regeneration. Different approach can be developed in further studies for callus induction and shoot regeneration of C. limon