ONGOING Project-3

Background

Most of the wheat growing areas of the world are faced water deficit that adversely affect growth and grain yield including Bangladesh (Semenov and Shewry, 2011). Drought stress changes in cell membrane structure and antioxidants including proline accumulation and chlorophyll contents and thereby plant senescence which leads to shortening of the period of photosynthetic activity (Rajala et al., 2009). Drought may induce over generation of reactive oxygen species (ROS) like superoxide radicals, singlet oxygen, hydrogen peroxide and hydroxyl radicals. To cope with drought stress, novel and dynamic approaches should be devised and phytohormone engineering could be a method to improve the productivity. Abscisic acid (ABA) is an important stress hormone induced in response to drought stress and acts as an early warning signal (Davies and Zhang, 1991). The drought induced ABA accumulation in leaves can reduce the stomatal conductance and shoot growth, thereby regulating water loss and CO₂ uptake and assimilation (Davies et al., 2005). Application of ABA under stressed conditions have proved beneficial in improving the stress tolerance mechanisms in plants. ABA can manipulate stomatal conductance to regulate water use in wheat exposed to terminal drought (Travaglia et al., 2010). Glycine betaine (GB) is one of the most effective compatible solutes that plays a key role in cellular osmotic adjustment, maintaining cell organelles and water use efficiency in the plants under water deficit (Ashraf and Foolad, 2007).