Photosynthetic heterosis in single leaf of rice plant.

1.近几年来，水稻品种F_1丰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信息还不是很多。本研究通过F_1代与自交植株的比较，阐明了光合作用生产力和环境适应性在某些生产决定因素上的杂种优势现象。本试验以中国F1品种汕优63为材料，以日本主栽品种与非洲引进菌株AF-70杂交获得的F_1代为材料，表现为抽穗前期叶面积和茎重迅速增加，抽穗成熟后叶面积和茎重迅速下降。杂种优势效应主要表现在单株头数和头粒数上。F_1、品种和品系的增产主要取决于抽穗前叶片和茎中积累的光合作用产物的运转。&lt；19…F_1代品种和品系叶片的光合作用速率较高。汕优63的光合速率从生育前期到生育后期一直保持在较高的水平。与CO_2同化相关的关键酶之一RuBPCase的活性也一直很高。这些因素可能有效地促进了热解作用的增加。在有根竞争的生长条件下，研究了根系和FUN离子的发育。汕优63在总干物重和产量上均优于高产类型品种斯温258等其他品种。汕优63根系的高竞争能力可能是由地上部分的光合作用物质向根系的运转所支持的。汕优63根系干物质分配率较高。此外，杂交种具有较高的耐旱性，水分胁迫下的植株通过复水可以更顺利地恢复光合作用。从以上结果可以看出生产和光合作用中杂种优势现象的轮廓。在1991年的最后一年，为了使这些结果更加具体，对几个F_1品种和品系进行了更详细的分析。作为一项新发现，在F_1代品种的碳水化合物代谢和S雨中发现了一些有趣的事实。碳水化合物代谢和淀粉合成代谢与一些主要酶的光合作用速率和活性的关系将在明年利用更多的品种和品系进行分析。较少

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