Polyethylene Glycol Mediated Osmotic Stress Impacts on Growth and Biochemical Aspects of Wheat (Triticum aestivum L.)

Abstract

Seed germination and seedling growth establishment are the most critical growth stages, and drought stress imposed at these stages highly limits crop productivity. In this regard, a hydroponic water culture experiment was conducted with the aim to assess the potential of 20 wheat genotypes against drought stress at the seedling stage. Water deficit was induced through polyethylene glycol (PEG-6000), by maintaining two osmotic potentials in water culture medium, i.e. −0.7 MPa (medium water stress) and −1.0 MPa (high water stress). After seed germination, drought stress was applied for 8 days. Seedlings shoot and root length and biomasses were restricted with an increase in osmotic deficit. Photosynthetic pigments and nitrate reductase activity (NRA) of wheat seedlings were reduced, while proline, total soluble sugars, total phenolics, and mineral ions (K+ and Ca2+) were augmented with the rise in water deficiency in most of the genotypes. On the basis of growth and biochemical attributes, six genotypes (NIA-AA-01, NIA-AA-08, NIA-AA-09, NIA-AA-13, NIA-AA-12, and NIA-AA-14) were categorized as drought tolerant, and three as medium tolerant. These genotypes exhibited better growth by showing the least reduction in root and shoot length, and fresh and dry biomasses, as well as modulation in biochemical processes to survive under water deficit. All studied traits indicated tolerance potential of these genotypes against moderate and extreme drought stress, which could also give better growth in arid and semi-arid regions of the country that facing water scarcity.