无菌条件下小麦氨基酸态氮及铵态氮营养效应研究

对铵态氮(硫酸铵)、氨基酸态氮(甘氨酸，谷氨酸及赖氨酸)和缺氮无菌砂培条件下小麦单株干物重、全氮量及根、叶谷草转氨酶和谷丙转氨酶活性作了研究．结果表明，铵态氮和氨基酸态氮均可被小麦吸收，且吸收量相当．培养30d后，甘氨酸和谷氨酸处理的小麦干物重显著高于缺氮及铵态氮处理，而铵态氮、赖氨酸及缺氮处理的干物重相近．低浓度铵态氮(0．7mmol·L^1)培养15d的小麦仅根的GPT活性显著高于缺氮处理，而高浓度(35．7mmol·L^1)处理6h对这两种转氨酶活性影响不大.不同种类、不同浓度的氨基酸态氮培养15d或处理6h后，小麦植株根、叶的GOT或GPT活性变化趋势有较大差异，这反映出小麦外源氨基酸主要同化部位及同化量，与氨基酸种类及浓度有较大关系．

Effects of amino acid-N and ammonium-N on wheat seedlings under sterile culture

The dry weight, total N, and glutamate-oxaloacetate transaminase(GOT) and glutamate-pyruvate transaminase (GPT) activities in roots and leaves of wheat seedlings (Triticum aestivum) grown with ammonium sulfate or amino acids (glycine, glutamate or lysine) were studied under sterile sand culture. The results showed that both NH4(+)-N and amino acid-N could be absorbed by wheat. The total N of plant fed with NH4(+)-N was similar to that fed with amino acid-N. The dry weight of plants grown 30 days with glycine or glutamate was significantly higher than that of plants grown with NH4(+)-N or free N. The dry weight of ammonium treatment was similar to that of lysine treatment or free N. NH4(+)-N in concentration of 0.7 mmol.L-1 significantly increased GPT activity of roots, but had no significant effects on leaves or roots treated 6 h in concentration of 35.7 mmol.L-1. Different species or concentrations of amino acids had different abilities to increase the GOT or GPT activity in leaves or roots.