目前人工栽培的食用菌均是腐生菌。它们不能象绿色植物那样利用无机物和太阳能合成有机养分,因而其生长发育是靠分解人工合成培养基或天然培养基的养分。从真菌营养代谢的基本规律中,我们知道四碳二羧基的琥珀酸延胡索酸、苹果酸、草酰乙酸是 Currently cultivated edible fungi are saprophytic bacteria. They can not make use of inorganic and solar energy to synthesize organic nutrients like green plants, so their growth depends on the decomposition of artificial synthetic medium or nutrient of natural medium. From the basic laws of fungal nutrient metabolism, we know that four carbon dicarboxy succinate fumarate, malate, oxaloacetate is