RESPONSE OF WHEAT PLANTS TO THE COMBINED IMPACT OF LOW TEMPERATURE AND CADMIUM

Abstract

The response of wheat plants (Triticum aestivum L.) to a combined (consecutive) impact of low temperature (4 °С) and cadmium sulphate (100 µM) was investigated. Pretreatment of the seedlings with cadmium for 1 day caused an increase in cold tolerance, which continued during the following exposure to the 4 °С temperature, reaching a maximum after 1–2 days, but decreasing somewhat in the end of the experiment (7 d). At the same time cadmium did not prevent the accumulation of fresh and dry biomass of the shoots at subsequent exposure of the seedlings to 4 °С temperature, although it negatively affectedthe total chlorophyll content in the leaves. Pretreatment of the seedlings by chilling during 1 day also caused an increase in their cold tolerance, which persisted for a few days at subsequent exposure to cadmium, but decreased significantly in 6–7 days. Moreover, the chilling pretreatment decreased the accumulation of fresh and dry biomass of wheat shoots as well as the total chlorophyll content in the leaves at the subsequent prolonged cadmium impact. It was concluded that the response of wheat plants to a prolonged impact (7 d) of a low non-freezing temperature or cadmium changed significantly if preceded even by a short-term (1 d) treatment with the other stress factor. In particular,exposure to cadmium before chilling partially ‘disrupted’ the programme of cold adaptation, wherefore the plants’ resistance did not reach the level typical for cold hardening at a temperature of 4 °С, and cold pretreatment of the plants, in turn, aggravated the negative effects of cadmium on cold tolerance, biomass accumulation and the content of photosynthetic pigments in wheat leaves.

Keywords

• triticum aestivum l.
• low non-freezing temperature
• cadmium
• pretreatment
• cold tolerance
• accumulation of biomass
• photosynthetic pigments.