The effect of spermidine and melatonin on antioxidant enzymes, the amount of routine active ingredient and yield in Buckwheat (Fagopyrum esculentum Moench) under drought stress

Buckwheat (Fagopyrum esculentum Moench) is an annual plant of the Polyganales family, native to the United States of America. This plant is one of the most important medicinal plants. However, Drought stress as a limiter has a great effect on reducing its yield. Therefore, this study aimed to investigate the effect of seed per treatment and seedling foliar application with polyamine compounds on the activity of antioxidant enzymes, routine and Seed yield was monitored under drought stress. This study was created out in 3 stages in agricultural faculty and natural resources at Shiraz university during the 2019-2020 arable years. The first experiment was for the effect of pretreatment of Buckwheat seed with polyamines on germination characteristics which was performed as a two-factor factorial in a randomized complete block design with four replications in vitro.

Experimental treatments included drought stress at seven levels (zero, -0.2, -0.4, -0.6, -0.8, -1 and -1.2 MPa) and seed pretreatment with melatonin (zero, 0.125, 0.250., 0.375 and 0.500 mmol) and spermidine (zero, 0.5, 1, 1.5 and 2 mmol). The second experiment (greenhouse) and the third (farm) were performed as three-factor and split-factorial factories in a randomized complete block design with three replications, respectively. In greenhouse conditions, drought stress at three levels of irrigation (irrigation at 10, 40, and 70 % field capacity depletion), and on-farm drought stress at three levels: full-field irrigation (no stress), 8-day irrigation once (mild stress) and irrigation Applied once every 16 days (severe stress).

In the first stage, the results of the laboratory section showed that different treatments of spermidine and melatonin in comparison with the control treatment had a significant effect on germination traits so that under drought stress concentrations of 1.5 mM spermidine and 0.375 ml Melatonin molar had the greatest effect on improving dilar germination, so they were selected as experimental treatments in greenhouses and farms. In greenhouse experiments, the three-way interactions of drought stress, seed pretreatment and foliar application of spermidine and melatonin on the activity of antioxidant enzymes and proline content were significant and the highest amount of catalase was 259.8 mg (mg protein). Per minute) and proline 5.12 (μg / ml) in combination of seed pretreatment with melatonin (0.375 mmol) and melatonin foliar application (0.375 mmol) under 70% discharge conditions Crop capacity was observed. In field conditions, the interaction of drought stress, seed pretreatment and foliar application of spermidine and melatonin had a significant effect on plant growth period and grain yield and the highest grain yield to seed pretreatment with melatonin with foliar application. With a concentration of 0.375 mmol and normal moisture conditions were allocated.

Seed pretreatment and seedling treating with melatonin in 0.375 mmol concentration, showed more effects in Buckwheat plant in both greenhouse and open field condition and the highest yield (538.2 kg/ha) seen in this concentration too.