Effect of PGPR Arthrobacter sp. CTF1 and foliar iodine spraying on pea microgreens growth in hydroponic culture

Abstract

The use of plant growth-promoting rhizobacteria (PGPR) along with additional biofortification of agricultural plants with scarce essential elements, such as iodine, is a promising area of agricultural biotechnology. The seeds of Pisum sativum L. (var. Madras) pre-inoculated for two hours with PGPR Arthrobacter sp. strain CTF1 (108 CFU/mL) were grown for 14 days in a hydroponic culture at foliar spraying with iodine solution (0.01% KI or KIO3) on the 7th day of the vegetation. Growth parameters such as the length of shoot, fresh and dry biomass of seedlings were studied, the germination percentage and vigor index were calculated, and the content of photosynthetic pigments in pea leaves was assessed. The results showed inoculation of pea seeds with PGPR strain CTF1 had a positive effect on the biomass of two-week-old pea microgreens and their vigor index. At the same time, a significant increase in photosynthetic pigments was also observed in the leaves of pea seedlings, especially chlorophyll a (by almost 25%) and carotenoids (by almost 40%). Additionally, application of iodine via foliar spraying, irrespective of its form (KI or KIO3), resulted in nearly a 26-fold surge in amount of microgreens. However, the significant effect of such iodine treatment had a positive effect only on the content of carotenoids.