高粱的光合特性和杂种优势

从杂交高粱及其亲本的PEP羧化酶、丙酮酸磷酸二激酶、NADP-苹果酸酶和NAD-苹果酸脱氢酶活性比较了它们的光合碳代谢特性,也比较了它们在光合强度、CO_2补偿点和产量指标上的差异,分析了不同组合的杂种的叶面积和产量构成因素在各生育期的变化。高产的杂交种比其亲本有较高的关键酶活性、高光合强度和低的CO_2补偿点,其光合特性具有超亲优势,并在这些优势和增加体内物质向穗内分配的基础上增加了穗粒数。

THE PHOTOSYNTHETIC CHARACTERISTICS AND HYBRID VIGOUR IN SORGHUM

The activities of PEP carboxylase (E. C. 4.1.1.31), pyruvate, Pi-dikinase (E. C. 2.7.9.1), NADP-malic enzyme (E. C. 1.1.1.40) and NAD-malate dehydrogenase (E. C. 1.1.1.37), and net photosynthetic rate and CO_2 compensation points of hybrids and their parents were compared. The changes of activities of RuBP carboxylase (E. C. 4.1.1.39) and PEP carboxylase in leaves varied their age and position,. With hybrids of different combination the leaf area and yield components were compared at various stages of development. It seems that the activities of the key enzymes and net photosynthetic rate of high-yielding hybrids were higher, but CO_2 compensation points were lower than those of their parents. The photosynthetic characteristics of hybrids show the superparent vigour, thus causing an increase in the number of ears. Basing on these results, it is concluded that there are significant correlations between photosynthetic characteristics and yield components.