Alleviation of exogenous oligochitosan on wheat seedlings growth under salt stress

Hydroponic experiments were carried out to study the role of oligochitosan in enhancing wheat (Triticum aestivum L.) resistance to salt stress. Data were collected on plant biomass, chlorophyll content, photosynthetic rate (Pn), stomatal conductance (gs), proline content, antioxidant enzyme activities, and malondialdehyde (MDA) content. Under 150 mM salt stress, plant growth was significantly inhibited. Shoot length, root length, and dry weight were sharply reduced by 26%, 31%, and 20%, respectively, of the control. Superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) were increased by 28%, 13%, and 26%, respectively, of the control and MDA content largely accumulated, which was 1.5-fold of the control. However, 0.0625% oligochitosan pretreatment alleviated the adverse effects of salt stress, which was reflected by increasing root length, shoot length, dry weight, chlorophyll content, Pn, and gs. Furthermore, it also showed that oligochitosan pretreatment significantly increased antioxidant enzyme (SOD, CAT and POD) activities, and reduced MDA content in leaves. Meanwhile, the accumulation of proline was markedly accelerated. The results indicated that oligochitosan pretreatment ameliorated the adverse effects and partially protected the seedlings from salt stress during the following growth period.