三、硫、钙、镁的生理作用(一)硫的生理作用硫是以高度的氧化状态被作物吸收的一种元素。土壤中存在硫酸铵、硫酸镁、硫酸钙、硫酸钾等硫酸盐,以硫酸根形式被根系吸收,进入作物体后,一部分仍保持不变,大部分被还原为硫氢基(-SH)和联硫基(-S-S-),作为许多有机化合物的组成部分。例如,胱氨酸和半胱氨酸分子中均含硫。这些氨基酸几乎是所有蛋白质的构成分子,所以,硫是原生质和许多种酶结构中不可缺少的物质。在 Third, the physiological role of sulfur, calcium and magnesium (A) the physiological role of sulfur Sulfur is a highly oxidized state of the crop is absorbed by an element. In the soil, there are sulfate such as ammonium sulfate, magnesium sulfate, calcium sulfate, potassium sulfate and so on. It is absorbed by the root in the form of sulfate. After entering into the crop, some remain unchanged, most are reduced to the sulfhydryl (-SH) and Sulfanyl (-SS-), as part of many organic compounds. For example, both cystine and cysteine ​​molecules contain sulfur. Almost all of these amino acids constitute a protein molecule, so sulfur is a protoplasm and many kinds of enzyme structure indispensable material. in