Oxidative Stress in Pea (Pisum sativum L.)-Rhizobia Symbiosis is Induced under Conditions of Salt Stress

After exposing Pea (Pisum sativum L.)-rhizobia symbiosis to two levels of NaCl (namely, ۱۰۰ and ۱۵۰ mM) in perlite culture, the salt-stressed plants were analyzed for nodulation, plant dry weight, total phenols, Hydrogen peroxide (H۲O۲), Peroxidase (PO), PolyPhenol Oxidase (PPO), and Electrolyte Leakage (EL). In results, it was observed that the shoot dry weight of all examined P. sativum-rhizobia symbiosis had a statistically significant increase. It was also ascertained that the presence of salt increased the root length as well as the root dry weight. This increase ranged between ۷۶ and ۸۰%, respectively, under ۱۰۰ and ۱۵۰ mM NaCl. The same trend was detected for the nodule number and dry weight, which increased in response to salt stress in P. sativum-rhizobia symbiosis. Under salt stress (۱۵۰ mM), shoot N content was three times more than in root. A relationship was revealed between nodulation and growth that was associated with N level in shoot and root. Generally, EL values were affected by salt in leaves with variations ranging between ۲۲ and ۳۷% under ۱۵۰ and ۱۰۰ mM NaCl supply, respectively. Concerning H۲O۲ content in leaves, significant differences were noted in comparison to the control treatment that was stabilized after ۳۰ days of inoculation. After ۵۰ days of inoculation, H۲O۲ content in leaves was almost six times higher than after ۱۰ days. In general, salt stress did not affect PO activity. However, PPO activity increased over time, exceeding ۱۰ µmol g-۱ FW.

کلیدواژه ها:

Pea (Pisum sativum L.) ، Rhizobia ، Peroxidase ، Phenols ، Salinity.