Characteristics of carbon fixation in different rice cultivars during yield formation process

明确不同水稻品种产量形成过程的固碳特性。测定三系杂交稻汕优63、二系杂交稻两优2186和常规稻IR64生长过程各器官干物质积累、碳含量。完熟期，汕优63、两优2186和IR64全株平均碳含量依次为：40.65%、41.81%和40.44%，各器官间碳含量大小为：籽粒＞叶＞茎＞鞘＞根；汕优63、两优2186和IR64的碳积累量均在黄熟期达到最大，分别达到853.68、827.61和810.13gand#8226;m-2。完熟期，汕优63、两优2186和IR64的碳积累量下降到773.17 gand#8226;m-2，783.65gand#8226;m-2和767.94gand#8226;m-2，其中分配到籽粒中的比例分别为：53.23%、45.66%和47.83%，同期的释氧量依次为2 061.80gand#8226;m-2、2 089.73gand#8226;m-2和2 047.84gand#8226;m-2，这对维持稻田生态系统的碳氧平衡起到重要作用。汕优63、两优2186和IR64在孕穗初期至齐穗期间的碳净固定量最高，依次为339.60 gand#8226;m-2、369.33 gand#8226;m-2和309.62 gand#8226;m-2，分别占全生育期碳总固定量的43.92%，47.13%和40.31%，是水稻固碳的关键时期。3种水稻在完熟期均出现耗碳吸氧现象，汕优63吸氧量为214.69 gand#8226;m-2，分别是两优2186、IR64的1.83倍和1.91倍。三系杂交稻汕优63在产量形成过程中具有高积累、高消耗碳的特性，其灌浆过程消耗的碳对促进其产量形成具有重要作用。 The objectve was to reveal characteristics of carbon fixation in different rice cultivars. Dry matter accumulation and carbon content were measured in different plant parts of three rice cultivars. These were Shanyou 63 (three-line hybrid rice), Liangyou 2186 (two-line hybrid rice) and IR64 (traditional rice). The