Changes in Triticum aestivum and Hordeum vulgare chlorophyll content and fluorescence parameters under impact of various sapropel concentrations

Abstract

The aim of this study was to investigate the impact of sapropel of Tarosiškis Lake on wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.) photosynthesis parameters (the  content of chlorophylls and chlorophyll fluorescence). Plants were sown in one-litre-volume pots by 10 seeds with light loamy soil and grown in growth chambers. Considering sapropel composition, 2.2, 3.1, and 4  t/ha dry sapropel concentrations were chosen for investigation. Sapropel-affected plants were compared with plants grown in unfertilized soils and soils fertilized with inorganic fertilizer. On day 14 of the experiment, when the plants reached the two-leaves development stage (BBCH 12), chlorophyll fluorescence parameters of the  investigated plants were measured. Then the plants were grown for another four weeks and at the stem elongation stage (BBCH 31) chlorophyll fluorescence parameters were measured repeatedly, and the content of chlorophylls and carotenoids were measured as well. By increasing sapropel concentration in soil, the ratio Fv/Fm in wheat leaves increased (r = 0.97) significantly (p < 0.05) at BBCH 12 stage, but at the  stem elongation stage the  correlation coefficient was insignificant (r = 0.97) (p > 0.05). Fv/Fm of barley followed the same tendency. By increasing sapropel concentration, the PI index value also increased for wheat (r = 0.4; p > 0.05) and barley (r = 0.82; p < 0.05) at BBCH 12 stage, but at BBCH 31 stage it decreased. The  electron transport rate increased in both wheat (r = 0.82; p < 0.05) and barley (r = 0.58; p < 0.05) at BBCH 12 stage too. With increasing sapropel concentration chlorophyll a+b content in wheat (r = 0.94) and barley (r = 0.81) increased significantly (p < 0.05), and the changes in the content of carotenoids in both plant species followed the same tendency (r = 0.87, p < 0.05).