Effect of NaCl and KCl salinity on seed germination and seedling growth of dimorphic seeds of Cichorium intybus L. J. Environ. Sci. Mans.

Abstract

Cichorium intybus is a member of the family Compositae with outstanding medicinal importance. The plant produces two forms of seeds:  white and dark.  The present work investigates the effect of salinity (0, 25, 75, 150, 300 mM) applied either as NaCl or KCl on germination and seedling growth of the two seed forms of  C. intybus

            Salinity adversely affected seed germination and, in particular, seedling growth. C. intybus can be considered as a salt tolerant species as the seeds can withstand 150 mM (either as NaCl or KCl) with small reduction in germination percentage, and the white form seems more salt tolerant than the dark form. The white form exhibited an overall higher rate of germination than the dark form, particularly under salt stress and the inhibition in rate of germination of the white form by salinity was less than that of the dark form. Nevertheless, seedlings from dark seeds were more salt tolerant than those from white seeds.

 NaCl exerted a stronger  inhibitory effect on germination of seeds and seedling growth than did KCl. Germination percentage was steadily higher in KCl than in NaCl solutions. In fact, KCl in low and moderate levels (25-75 mM) seems beneficial to germination of C. intybus seeds.Rate of germination was affected by the treatments to a greater extent than germination percentage. While the inhibition in rate of germination under moderate salinity (up to 75 mM) was more severe in case of NaCl  than in case of KCl, the reverse was true at higher salinities. Salinity delayed onset of germination (increased T₁₀) and the effect was particularly evident in the dark seeds and at salinity levels greater than 75 mM.

 Upon transfer to distilled water, a considerable proportion (up to 80%) of the non-germinated seeds restored the ability to germinate and the recovery percentage from salt stress increased with the increase in salt level.

Key words: Germination/ seed dimorphism/ KCl salinity/ seedling growth