【摘要】 <正> 农业生产中,经济用肥是人们特别关注的问题。因此,作物对氮的利用效率成为重要的研究课题。O’Sullivan和Gabelman等（1974）首先提出了氮利用效率的概念,是指植物每吸收1毫克氮相应产生的干物重增长量。早在1971年Wilson和Haydock就研究了包括C₃和C₄植物的21种牧草中氮、磷对生长的效应。他们发现,C₄植物生长优于C₃植物,特别是在氮、磷都不足的情况下,C₄植物表现了其优越性。1975年Wilson进一步的更多还原

【Abstract】 Wheat and maize were grown in the modified Hoagland’s solution containing 0 mgN/1, 5 mgN/1,10 mgN/1 and 20 mgN/1. The hydroponic system was set up in the controlled environment growth chambers under 18/18, 25/18, and 32/18℃ day/night temperature regimes. At 18/18℃, the nitrogen uptake rate, the relative growth rate, and the biomass and nitrogen use efficiency were higher in wheat than in maize, but at 25/18 and 32/18℃ all the parameters were higher in maize than in wheat. These data indicated that C₄ species might not always make utilize their nitrogen more efficiently. Growth temperature had significant effect on it. The comparison of the dry weight ratio of shoot/root between wheat and maize showed that more shoot tissue representing the photosynthetic area established was in maize with increasing nitrogen supply and growth temperature. This was one of the reasons why higher nitrogen use efficiency could be obtained in maize. The higher leaf nitrogen content in wheat, relative to maize, also implied that more nitrogen supply was needed for wheat leaf growth.更多还原