Functions of Exogenously Proline against Negative Effects of Salt Stress in Onion (Allium cepa L.)

The effects of proline on the seed germination, seedling growth (radicle lenght, radicle number and fresh weight), mitotic index, micronucleus frequency and chromosome aberrations of Allium cepa L. germinated under saline conditions were examined in this study. Salt stress markedly inhibited the seed germination and seedling growth of A. cepa L. Moreover, it reduced the mitotic index in the root-meristem cells of the seeds and fairly increased the number of chromosome aberrations and micronucleus frequency which is the simplest indicator, the most effective of cytological damage. On the other, the inhibitive effect of salt stress on the seed germination, fresh weight and mitotic index was significantly decreased with proline application. However, this amino acid was ineffective in reducing of salt damage on the radicle lenght, radicle number, micronucleus frequency and chromosome aberrations.