Abstract: The hybrid of indica rice (Guanglu'ai 4) and japonica rice (Koganehikari or Sasanishiki) were used as experimental materials. The results indicated as follows: The growth of indica× japonica hybrid was greater than that of its parental lines. The difference of NH₄⁺ uptake rate between hybrid and parental lines is in following order: maternal line (indica rice) >hybrid>paternal line(japonica rice). The difference of NH₄⁺ uptake rate between maternal line and hybrid is less than that between hybrid and paternal line. It seems that the maternal line has larger influence on the NH₄⁺ uptake rate of hybrid as compared with paternal line. The K_m of NH₄⁺ uptake rate was in the order: hybridm was maternal line>hybrid>paternal line, but the difference between maternal line and hybrid was less. So hybrid had lower K_m and higher I_m and absorbed NH₄⁺ efficiently. The heterosis of NH₄⁺ assimilation efficiency was observed in hybrid rice, about 10% overthat of its paternal lines.

Key words: Indica-japonica hybrid, Ammonium uptake rate, Assimilation efficiency, Heterosis

摘要： 以籼稻广陆矮4号为母本与粳稻黄金光、笹锦为父本的杂交后代作试验材料。试验结果表明，籼粳杂交后代幼苗的生长大干它的亲本。杂交后代和它的亲本在NH4吸收速率上的差异为：母本（籼）>杂交后代>父本(粳)。杂交后代和母本在NH₄吸收速率上的差异小于和父本的差异．可能母本对杂交后代在NH₄吸收速率上的影响大于父本。NH₄吸收的Km杂交后代<父本<母本。Im是母本>杂交后代>父本，但母本与杂交后代之间的差异较小。杂交后代NH₄的吸收具有偏低的Km，偏高的Im，有较高的NH₄吸收效率。NH₄同化效率，杂交后代有杂种优势，比亲本高10%上下。

关键词: 杂交后代, 吸收速率, 杂种, 铵离子, 杂种优势