Some synthetic cyclitol derivatives alleviate the effect of water deficit in cultivated and wild-type chickpea species.

Cyclitols were prepared from corresponding allylic hydroperoxides, synthesized by photooxygenation of the appropriate cyclic alkenes. These hydroperoxides were then separately treated with a catalytic amount of OsO4. Synthesized dl-cyclopentane-1,2,3-triol 9 (A), dl-cyclohexane-1,2,3-triol 12 (B), and dl-cycloheptane-1,2,3-triol 15 (C) were used in the investigation of plant stress. Antioxidants, lipid peroxidation, and water status of chickpea species exposed to synthetic cyclitols under water deficit were examined. Cyclitol derivatives significantly decreased leaf water potential, lipid peroxidation and H2O2 levels of wild and cultivated species under water deficit. Cyclitol treatments affected antioxidant enzyme activities differently in both species under water deficit. The highest SOD activity was found in A10-treated Cicer arietinum (cultivar) and C10-treated Cicer reticulatum (wild type) under water deficit. CAT activity increased in C. arietinum exposed to A cyclitols, while it increased slightly and then decreased in cyclitol-treated C. reticulatum under stress conditions. AP and GR activities were significantly increased in C. arietinum under water deficit. AP activity increased in C derivatives-treated C. arietinum, while it remained unchanged in C. reticulatum on day 1 of water deficit. GR activity was increased in A derivaties-treated C. arietinum and C derivatives-treated C. reticulatum on day 1 of water deficit and decreased with severity of stress (except for B10-treated C. arietinum). The level of AsA in C treatments and GSH in A treatments increased in C. arietinum on day 1 of water deficit, while in C. reticulatum, AsA and GSH levels decreased under stress conditions. We conclude that exogenous synthetic cyclitol derivatives are biologically active and noncytotoxic, resulting in higher antioxidant activities and lower water potential, thus increasing the water deficit tolerance of chickpea under water deficit, especially of cultivated chickpea. We also propose that synthetic cyclitol derivatives can reduce reactive oxygen species and membrane damage and are beneficial for stress adaptation.