Effects of salicylic acid and spermine exogenous application on functional and physiological characteristics of isabgol (Plantago ovata Forssk.) under cutoff irrigation

This study was conducted as split plot factorial experiment was done based on a randomized complete block design with 18 treatments and three replications, on research field of the Gonbad Kavous University, Golestan, Iran in winter 2017. In this experiment the treatments of irrigation included; control (non-stress), irrigation cutoff at flowering stage and irrigation cutoff at seed filling stage) was the main-plot and factorial of salicylic acid (SA) (0, 0.4 and 0.8 mM), spermine (Spm) spraying (0 and 0.02 mM) was as a sub-plot. According to the results of the experiment, the highest 1000-grain weight (2.00 g) was obtained in irrigation cutoff at seed filling with 0.4 mM salicylic acid spraying and biological yield (2472.37 kg/ha) was observed under normal irrigation conditions and SA0.8mM+Spm0.02mM spraying. In addition, the most of Seed swelling factor (12.42 ml) and seed mucilage percentage (21.33%) were obtained in under moderate and severe stress conditions, respectively. Also, the highest grain yield (574.05 kg ha-1), seed mucilage yield (102.12 kg ha-1) and seed husk percentage (72%) were observed to foliar spraying 0.8 mM salicylic acid and 0.02 mM spermine in irrigation cutoff at seed filling. According to the results, the spraying of salicylic acid and spermine in irrigated conditions at flowering and seed filling stages prevented significant traits from being studied and the highest grain yield, biological yield, harvest index, seed husk percent, seed mucilage percentage, seed mucilage yield were caused.