Morph-physiological and biochemical properties effects of exogenous nitric oxide applications on spinach under flooding stress conditions

Abstract

Flooding stress with the impact of global climate change has recently become a major stress factor that limits the productivity and quality of many agricultural areas. Recently, researchers have been working to abate the negative impacts of flooding stress. Studies have shown that nitric oxide (NO) applications abate the negative impacts of different types of flooding stress. For this purpose, the current study tried to determine the effects of different NO doses on spinach under flooding stress situations. In te present study, there were six application subjects: full irrigation - control (FI), flooding stress (FS), FS + application of 50, 100, 150 and 200 µM NO. NO was applied to spinach as a foliar spray twice, one week apart, under flooding stress situations, which was applied for ten days close to the harvest period. Flood stress agronomic parameters, leaf number (LN), leaf area (LA), shoot fresh weight (SFW), root fresh weight (RFW), shoot dry weight (SDW) and root dry weight (RDW) caused decrease of 40, 24, 57, 46, 49 and 20%, respectively. In addition, actual photosynthetic efficiency (QPSII) caused significant decrease. On the contrary, flooding stress revealed significant increase in hydrogen peroxide (H2O2), malondialdehyde (MDA) and proline (PRO) contents. It has been observed that applied NO doses not only promote plant growth but also support photosynthesis by increasing pigment content. In addition, it promoted antioxidant enzyme activity by reducing H2O2 and MDA content. As a result, it was revealed that 50 µM NO application increased tolerance to spinach under flooding stress situations.