玉米利用銨態氮肥的遺傳差異性

Genotypic Variations of Maize Seedlings in Utilizing Ammonium Nutrition

為了評估玉米品種利用銨態氮肥的能力，首先將幼苗生長於沙盆中，並施加不同形式及不等量之氮源。播種28天後將幼苗收穫並分別測定其乾重量，銨離子同化酵素和PEP carboxylase的活性，以及根部吸收銨離子的能力。所得結果顯示有幾個品種頗具利用銨離子的能力，且可以在高濃度的銨離子情況下生長。由於這幾個品種似乎各自採取不同的機制，因此育種專家應可利用這些品種間的差異性，而交配出具有高效率利用銨離子的雜交種。

In an effort to evaluate the ability of maize inbreds to utilize ammonium-nitrogen (NH4+-N), seedlings were grown in sand culture and supplemented with different amounts and forms of N. Seedlings were harvested at 28 days after planting and determined for gross differences in dry mass, activity of NH4+-assimilating enzymes. PEP carboxylase, and the ability to take up NH4+ ion. The results indicate that some inbreds retained the ability to effectively utilize NH4+, but they adapted various combinations of mechanisms to cope with NH4+ pressure and thereby allowed seedling growth and development in the presence of high NH4+ concentrations. Thus, plant breeders should be able to exploit this variability and to create hybrids with enhanced performance under predominantly NH4+-N conditions.