Photosynthetic heterosis in single leaf of rice plant.

1. <1989-1990>F_1水稻品种的高产性已为人们所熟知。然而，关于杂交水稻的生产系统和光合作用的研究还不多。本研究通过F_1代与自交植株的比较，从一些产量决定因素上阐明了光合生产力和环境适应性的杂种优势现象。本研究以中国水稻品种汕优63为材料，以非洲引进的AF-70为材料，与日本主要水稻品种杂交，获得的F_1代品种和品系，其特点是叶面积和秆重在抽穗前期迅速增加，抽穗后迅速下降。单株穗数和穗粒数具有杂种优势。F_1、品种和品系的增产主要是靠抽穗前积累在叶片和茎秆中的光能运转. &lt;19岁 关于我们 90&gt; F_1品种和品系的单叶光合速率较高。特别是汕优63的光合速率从生育前期到后期一直保持在较高水平。e.与CO_2同化相关的关键酶RuBPCase的活性也一直保持较高水平。在根系竞争的生长条件下，研究了根系和真菌的发育。汕优63在总干物重和产量上均优于其他品种，包括籼粳高产品种斯温258。汕优63根系的高竞争力可能是由地上部分的光合产物向根系的转运所支持的。汕优63根系的干物质分配率较高。此外，杂交种对干旱的耐受性较强，复水可以使水分胁迫植株的光合活性更顺利地恢复. <1991>从以上结果可以看出杂种优势现象在产量和光合作用方面的轮廓。在最后一年，1991年，为了使这些结果更具体，更详细的分析重复使用几个F_1品种和菌株。在F_1代品种和小麦的碳水化合物代谢中发现了一些有趣的现象。计划明年利用更多的品种和品系，分析碳水化合物代谢和淀粉合成代谢与光合速率和一些主要酶活性的关系。少

1. <1989-1990> High productivity of F_1 rice cultivars has been well known recently. However there is not so much information about the production system and photosynthesis in hybrid rice. In this research the heterosis phenomenon on the photosynthetic productivity and environmental adaptability was elucidated on some production determinants by comparing F_1 and selfed plants. Main materials used here were a Chinese F_1 cultivar, Shanyou-63, and F_1 strains obtained by crossing some leading Japanese cultivars with AF-70, a strain introduced from Africa.These F_1 cultivar and strains were characterized by the rapid increase of leaf area and culm weight from early to heading stage and by the rapid decrease after heading ripening. Heterosis effects were recognized on the number of heads a plant and the number of grains a head. The increase of yield in F_1, cultivar and strains were mainly dependent on the translocation of photosynthate accumulated in leaves and culms before heading.2. <19 … More 90> Photosynthetic rate in sin le leaf was higher in F_1 cultivar and strains. Especially the photosynthetic rate in Shanyou-63 was held at a high level from early to late rowth sta. e. Also the activity of RuBPCase, one of key enzymes related to CO_2 assimilation was constantly high. These factors may effectively contribute to the pyrodubtion increase.The development of root system and fun ions were investigated under the growth condition with root competition. Shanyou-63 had a superiority in the total dry matter weight and yield to other cultivars including an Indica-Japonica high yielding type, Sweon-258. The high competitive ability of roots of Shanyou-63 may be supported by photosynthate translocation from aboveground parts to roots. A higher ratio of dry matter partitioning was found in the roots of Shanyou-63. In addition tries hybrid cultivar had a high tolerability to draughts and the water stressed plants could be more smooth recovered in Photosynthetic activity by rewatering.3. <1991> The outline of heterosis phenomenon in production and photosynthesis could be recognized from the results obtain above. In the final year, 1991, to make these results more concrete, more detailed analyses were repeated using several F_1 cultivars and strains. As a new finding, some interesting fact was evidenced in the carbohydrate metabolism of F_1 cultivars and s rains. The carbohydrate metabolism and starch synthetic metabolism are scheduled to be analyzed in relation to photosynthetic rate and activity of some main enzymes using more cultivars and strains in the next year. Less