Department of Environmental Biology, Research School of Biological Sciences, Australian National University, Box 475, Canberra City, 2601, Australia.
Plant Physiol. 1984 Apr;74(4):759-65. doi: 10.1104/pp.74.4.759.
The in vitro ribulose-1,5-bisphosphate (RuBP) carboxylase activity per unit of leaf nitrogen was found to be 30% greater in Triticum aestivum than in T. monococcum. This was due to a higher specific activity of the enzyme from T. aestivum, as the amount of RuBP carboxylase protein per unit of total leaf nitrogen did not differ between the genotypes. The occurrence of higher specific activity of RuBP carboxylase is shown to correlate with possession of the large subunit derived from the B genome of wheat.Despite the greater RuBP carboxylase activity per unit of leaf nitrogen in T. aestivum, the initial slopes of curves relating rate of CO(2) assimilation to intercellular p(CO(2)) are similar in T. aestivum and T. monococcum for the same nitrogen content per unit leaf area. The similarity of the initial slopes is the result of a greater resistance to CO(2) transfer between the intercellular spaces and the site of carboxylation in T. aestivum than in T. monococcum.
体外核酮糖-1,5-二磷酸(RuBP)羧化酶活性单位的叶氮含量被发现小麦比单粒小麦高 30%。这是由于小麦 RuBP 羧化酶的比活更高,因为单位总叶氮中的 RuBP 羧化酶蛋白量在基因型之间没有差异。RuBP 羧化酶比活的升高与小麦 B 基因组的大亚基的存在有关。尽管小麦的单位叶氮 RuBP 羧化酶活性更高,但在相同的单位叶面积氮含量下,小麦和单粒小麦的 CO2 同化速率与胞间 p(CO2)的关系曲线的初始斜率相似。初始斜率的相似性是由于在小麦中,细胞间隙和羧化部位之间的 CO2 传递阻力大于单粒小麦。