Low temperature is one of the most important limiting factors for plant growth throughout the world. Exposure to low temperature may cause various phenotypic and physiological symptoms, and may result in oxidative stress, leading to loss of membrane integrity and to the impairment of photosynthesis and general metabolic processes. Salicylic acid (SA), a phenolic compound produced by a wide range of plant species, may participate in many physiological and metabolic reactions in plants. It has been shown that exogenous SA may provide protection against low temperature injury in various plant species, while various stress factors may also modify the synthesis and metabolism of SA. In the present review, recent results on the effects of SA and related compounds in processes leading to acclimation to low temperatures will be discussed.
The aim of the present study was to find the best way of measuring the viability of root and leaf samples from various plant species (pea, wheat and maize) exposed to different concentrations of the heavy metal Cd. A comparison was made of three viability tests, namely electrolyte leakage measurements, and TTC and NBT reduction. The results suggested that electrolyte leakage was the most useful method for measuring leaf viability, being simple, fast, reliable and reproducible. The TTC reduction measurement proved the most useful for maize roots, while NBT reduction was the best method for detecting the viability of pea and wheat roots.