Plants, as sessile lifestyle organisms, have to face numerous environmental stresses including genotoxic stress, such as UV irradiation and chemical pollutants.
The transition to bud burst can be accelerated by numerous sub-lethal stresses, including transient inhibition of respiration, heat shock or hypoxia (Esashi and Nagao, 1973; Erez et al., 1980; Erez, 1987), as is also the case with seed germination (Roberts, 1962; Siegel et al., 1962, 1964; Chen, 1970; Al-Ani et al., 1985).
Plant growth, development and yield are influenced greatly by numerous biotic and abiotic stresses, including cold, salt, drought and soil salinization.
The most significant groups of the up-regulated genes were those associated with various biotic and abiotic stresses, including numerous disease resistances, pathogen induced and systemic resistance (SAR) related transcripts, as well as transcripts for heavy metal, draught, and osmotic stress tolerance.
EGR1 is induced by a variety of cellular stresses, including hypoxia, and may function as a master switch that triggers the expression of numerous key inflammatory mediators.
Numerous stresses activate AMPK, including treatment with heat shock or metabolic poisons (Corton et al., 1994), muscle contraction (Winder and Hardie, 1996), glucose deprivation (Salt et al., 1998), hypoxia (Evans et al., 2005), oxidative stress (Choi et al., 2001), and osmotic stress (Fryer et al., 2002).
Such stress response has been described for numerous stress factors including exposure to pollutants [ 38].
Bcl-2 family proteins are activated or inhibited in response to numerous stress factors including heat shock, γ and UV irradiation, nutrient deprivation, viral infection, hypoxia and increased intracellular calcium concentration [ 47, 48].
There are numerous forms of stress, including extreme temperature, drought, pathogens, parasites, and even internal genetic stress caused by the expression of deleterious alleles (Hoffmann and Hercus 2000; Frankham 2005; Kristensen et al. 2005).
