Abstract
This study investigated the effects of biostimulant treatment and chilling applied during the young phase of growth on stress indicators, antioxidant compounds and physiological status of coriander leaves. Coriander transplants were sprayed three times with Asahi SL or Goëmar Goteo (Arysta Life Science). After the last spraying, 6-week-old plants were placed in vegetative chambers at 6 °C (chilling stress) and 18 °C (control) for 6 days, and then stress biomarkers, total antioxidant activity, photosynthetic pigment concentration, chlorophyll fluorescence and photosynthetic activity were determined in leaves. In chilled conditions, biostimulant application significantly decreased electrolyte leakage from leaf tissues to the level determined for non-chilled plants. The comparison of hydrogen peroxide and malondialdehyde concentrations for control and biostimulant-treated plants did not confirm the protective effect of biostimulants against stress molecule accumulation in chilling conditions. Biostimulants increased maximal photochemical efficiency of photosystem II, the rate of transpiration and stomatal conductance but decreased intercellular carbon dioxide concentration. L-ascorbic acid, total phenolic concentration and total antioxidant activity increased as a result of biostimulant application to chilled plants. The increased values of most photosynthesis and stress indicators in coriander leaves after 6 days chilling showed that plants were in a phase of acclimation to low temperature. The results indicate that biostimulants can affect selected metabolic pathways, accelerating the adaptation of chilled coriander plants. The precise use of plant growth regulators with application of chilling can be a method for controlling nutritionally important compounds in coriander foliage.
Acknowledgements
We are very grateful His Magnificence Rector of the University of Agriculture in Krakow, Poland for the financial support of this study under the scholarship foundation.