Abiotic stress in Potato Tuber: Analysis of some factors related to Oxidative Stress

In previous studies about different kinds of stress (wounding and cold storage) below bud potato tuber (Solanum tuberosum L. cv. Kennebec), a relationship between lipoperoxides (LOOH) and indole-3-acetic acid (IAA) has been shown (Fabbri et al., 2000; J. Exp. Bot. 51: 1267-75; Reverberi et al., Free Rad. Res. 2001, 35: 833-841). Endogenous LOOH, originated from lipoxygenase (LOX) action and exogenously added, increased the formation of IAA at different times after wounding (20 min) and after cold storage (from 90 to 180 days). Furthermore LOX inhibitors (salicylhydroxamic acid, SHAM, 1mM and nordihydroguaiaretic acid NDGA, 1 mM) inhibited this effect confirming the correlation between LOOH and IAA in potato tubers. It is known that also the biosynthesis of jasmonic acid (JA) and its derivative methyljasmonate (MeJA) is related with the formation of LOOH. In this work a possible correlation between MeJA and IAA in potato tubers sliced below bud has been studied. MeJA (10 mM) added on potato tuber slices enhanced, after 24 h the production of IAA and IAA, added at the same concentration, increased the formation of JA and MeJA 20-30 min after wounding. These results, obtained by GC/MS analyses, showed a possible direct or indirect correlation between MeJA and IAA