Table 3.

Activity of photosynthetic enzymes in some field crops as influenced by drought and heat stress.

Crop	Stress	Enzyme	Activity	Reference
Alfalfa (Medicago sativa L.)	Drought	Rubisco	Unchanged	Medrano et al., 1997
Tobacco (Nicotiana tabacum L.)	Drought	Rubisco	Reduced	Parry et al., 2002
	Heat	Rubisco	Reduced	Crafts-Brandner and Salvucci, 2002
Maize (Zea mays L.)	Drought	PEPCase	Increased	Jeanneau et al., 2002
	Heat	Rubisco-activase	Reduced	Crafts-Brandner and Salvucci, 2002
Sugarcane (Saccharum officinarum L.)	Drought	Phosphoenol pyruvate	Reduced	Du et al., 1996
		carboxylase (PEPCase), PPDK
Cotton (Gossypium hirsutum L.)	Heat	Rubisco	Reduced	Crafts-Brandner and Salvucci, 2002
Wheat (Triticum aestivum L.)	Heat	Rubisco	Reduced	Salvucci and Crafts-Brandner, 2004