The growth and differentiation of living organisms are continuously adjusted to a multitude of environmental factors, each of which underlies a perpetual variation. The sessile existence of plants further emphasizes the requirement for efficient adaptation and defence mechanisms. The changes in environmental factors may range from moderate to dramatic and can concern many components at the same time. They may be abiotic or biotic in nature and range from essential to toxic in their effects. Among the numerous abiotic factors are nutrients, light, oxygen, water, temperature, gravity, wind,...