Effect of osmo- and hydropriming of chickpea seeds on seedling growth and carbohydrate metabolism under water deficit stress

Seven-day-old seedlings obtained from seeds primed with mannitol (4%) and water showed three to four fold more growth with respect to root and shoot length in comparison with seedlings obtained from non-primed seeds. Seedlings were grown under water deficit stress conditions created by 15% polyethylene glycol (PEG) 6000 in the medium. Priming of chickpea seeds with NaCl and PEG was not effective in increasing seedling growth under these water deficit stress conditions. The activities of amylase, invertases (acid and alkaline), sucrose synthase (SS) and sucrose phosphate synthase (SPS) were higher in shoots of primed seedlings. An increase in the activities of SS, and both the acid and alkaline invertases was also observed in roots of primed seedlings. The two fold increase in specific activity of sucrose phosphate synthase was observed in cotyledons of primed seedlings. The higher amylase activity in shoots of primed seedlings enhanced the rapid hydrolysis of transitory starch of the shoot leading to more availability of glucose for shoot growth and this was confirmed by the low level of starch in shoots of primed seedlings.