The Response of Plant Growth and Physio-biochemical Properties Inedible Flowers of Pelargonium peltatum L. to Soil Applied Potassium and Selenium

Since edible flowers have been widely used to treat different diseases, new management practices are required to improve their productivity. Potassium (K) and selenium (Se) as important nutrients can influence plant quality and quantity. The purpose of present study was to investigate the effect of soil applied potassium (K) and selenium (Se) on plant growth, flower quality, and some physiological and biochemical properties of Pelargonium peltatum (L.) L'Hér. In a completely randomized design (CRD). K was used as potassium nitrate (KNO3) in the concentrations of 2, 4, and 6 mM and Se was applied as sodium selenite (Na2SeO4) in soil application of 20, 40, and 60 µM. The results showed that the highest flower number was obtained at 5 mM K. Shoot fresh weight (SFW) significantly increased by both 6 mM K and 40 µM Se. Flower longevity was improved with increasing K concentration so that the highest flower longevity was obtained at 6 mM. The highest relative water content (RWC) and total chlorophyll (Chl.) content were observed at 4 mM K. In contrast, the lowest RWC was observed when plants were supplied with 60 µM Se. Anthocyanin and malondialdehyde ‎(MAD) significantly increased with K and Se concentrations. Although total phenolic compound (TFC) in all concentrations of K and Se was higher than control, there was no significant difference between K and Se levels. Ascorbic acid and phenylalanine ammonia-lyase (PAL) activity increased with K and Se application, in which its highest amounts were observed at 6 mM K. P. peltatum was identified as Se accumulator because of more than 100 mg Se/kg DW in the leaves when treated with Se levels. Heat map analysis represented that 4 and 6 mM K were obviously distinguished from other treatments. This experiment suggests using 4-6 mM K and 40 µM Se to improve growth and productivity of P. peltatum.