1. The change in the biometric and physiological parameters of aster (Callistephus chinensis), helichrysum (Helichrysum bracteatum) and echinacea (Echinaceae purpurea) under conditions of induced water deficit

Author: Valeria Ivanova, Nadejda Zapryanova


The global climate models predict changed precipitation patterns with frequent episodes of drought. Scarcity of water is a severe environmental constraint to plant productivity. Plants display a variety of physiological and biochemical responses at cellular and whole-organism levels towards prevailing drought stress. This study included container experiments with three flower crops aster (Callistephus chinensis), helichrysum (Helichrysum bracteatum) and echinacea (Echinaceae purpurea). Drought was simulated by reducing the number of watering’s to field capacity from 25–30 to 85–90 %. Three levels of watering were studied – three times, twice and once a week. The results showed that the cultivation of ornamental plants in containers under reduced watering conditions (twice or once a week) for a period of 3 months led to considerable inhibition of growth and even to plants death. The relative water content and the level of electrolyte leakage vary depending on the weekly number of waterings. The highest values of electrolyte leakage were reported in a single watering for aster -5107.1µS / g, for helichrysum -8314.9 µS / g and for echinacea -3722.8 µS / g. The high rates of conductivity, especially with one-time weekly watering, are evidence of the damage caused by the simulated water stress. This corresponds to the reported low percentages of RWC % and the low values for the height and diameter of the plants. The relative water content in plant tissues decreases depending on the irrigation regime. The lowest values for aster, helichrysum and echinacea were again observed in the variant with a single weekly watering, respectively 15%, 11.5% and 15.8%.

Keywords: Callistephus chinensis, Helichrysum bracteatum, Echinaceae purpurea, water deficit,
relative water content, conductivity