Hot-water treatment before tissue culture reduces initial contamination in Lilium and Acer

In 1887, the Danish researcher Jensen used a hot-water treatment (HWT) to free plant tissues from pathogens. Ever since, heat treatments have been used to free plants from viruses, bacteria, fungi, nematodes and insects. In agricultural practice, HWTs are used on a large scale with bulbs, tubers and seeds [1]. The advantages of temperature treatments in comparison with chemical treatments are that there are no chemical residues and also that endogenous pathogens are removed. However, a HWT may damage the host plant [2]. The resistance of plant tissues to HWT strongly depends on their physiological condition, for example size, moisture content, vigour, condition of external layers, temperature conditions during growth, dormancy level, age, and genetic constitution [2]