Physio-biochemical Responses of In Vitro Cooking Banana Musa paradisiaca cv Lang towards Pseudo Induced Drought Stress by Polyethylene Glycol (PEG)

Abstract

Musa paradisiaca cv Lang belongs to cooking banana group, and it has high potential to be used in banana chips production. Like other cultivars, M. paradisiaca cv Lang is susceptible towards water shortage, therefore affecting banana growth and productivity. In this study, to mimic the drought condition, pseudo-drought stress was given to in vitro Lang banana seedlings by adding polyethylene glycol (PEG). Overall, decrement of roots length and chlorophyll (Chl) content was displayed by the seedlings exposed to 1%, 2%, 3%, 4%, and 5% (w/v) of PEG after three weeks of exposure. The proline content, total soluble protein content, and antioxidant capacity in leaf and roots, however, countered differently towards different levels of drought. Proline content showed the highest in leaf of 2% (w/v) PEG-treated seedling (12.66±0.38 µmoles/g) while the total soluble protein content showed the highest in roots of 5% (w/v) of PEG-treated seedling (30.65±1.07 mg/g FW). Antioxidant capacity of stressed seedlings revealed the catalase (CAT), guaiacol peroxidase (POD), and ascorbate peroxidase (APX) activities were the highest in the leaf of 1% (w/v) (10.69±5.06 µmol/min/mg), 4% (w/v), (0.079±0.03 µmol/min/mg), and 5% (w/v) (9.11±8.47 µmol/min/mg) of PEG- treated seedlings, respectively. Meanwhile, the highest CAT, POD, and APX activities in the roots were determined in 3% (w/v) (0.49±0.04 µmol/min/mg), 2% (w/v) (0.03±0.02 µmol/min/mg), and 3% (w/v) (16.69±0.5 µmol/min/mg) of PEG-treated seedlings, respectively. These data show that PEG can be a priming agent to induce defense system at seedling stage of banana, which could enhance their survivability during ex vitro acclimatization.