超级杂交稻“两优培九”剑叶叶鞘的光合功能

Photosynthetic Function of the Flag Leaf Sheath for Super Hybrid Rice Liangyoupeijiu

以超级杂交稻“两优培九”及其父本“9311”、母本“培矮64S”和三系杂交稻组合“汕优63”为研究材料，采用^14C同位素示踪等技术，研究了“两优培九”剑叶叶鞘的光合能力与叶鞘光合产物的分配。结果表明，两优培九剑叶叶鞘的净光合速率均值比汕优63高0．10μmol CO2 m^-2s^-2，尤以第3期，即灌浆关键时期，极显著高于汕优63，其他时期差异不显著；其叶鞘叶绿素含量的均值比汕优63高2．36SPAD值，各期均高于汕优63，其中，第1、3期显著高于汕优63；其剑叶叶鞘的Rubisco初始活性和总活性与汕优63差异不显著，但Rubisco活化率均值比汕优63高1．52％，具有平均优势，其中第3期显著高于汕优63；其叶鞘光合产物输送到穗部的量即转化为经济产量的量比汕优63高；与父母本相比，其剑叶叶鞘光合能力的均值具有平均优势或超亲优势；水稻叶鞘完全具有同叶片一样的光合能力，只有值的大小差异；水稻叶鞘的光合产物对产量的贡献一般为10％～20％。两优培九叶鞘及叶片光合功能都较强是其具有超高产特性的一个重要原因。

This study was designed to research the photosynthetic capacities of the flag leaf sheathes and photosynthetic products＇ distribution of the leaf sheathes of Liangyoupeijiu, using Liangyoupeijiu （super hybrid rice）, its parents 9311, Pei＇ ai 64S and Shanyou 63 （three-line hybrid rice combination） by the isotopic labeling and other techniques. The results showed that the mean of the Pn of the flag leaf sheathes for Liangyoupeijiu was 0.10 μmol CO2 m^-2 s^- 1 higher than that for Shanyou 63, and it was significantly higher at the third stage which was the key period of rice profuse filling, while it was not at other stages. The mean of the chlorophyll content of the flag leaf sheathes for Liangyoupeijiu was 2.36 SPAD value higher than that for Shanyou 63, and it was higher at every stage, and significantly higher at the first and the third stages. There was no significant difference in Rubisco incipient activities and total activities between the flag leaf sheathes of Liangyoupeijiu and those of Shanyou 63. Rubisco activated percentage mean of the flag leaf sheathes for Liangyoupeijiu was 1.52% higher than that for Shanyou 63, and Liangyoupeijiu had mean potence. At the third stage, that for Liangyoupeijiu was significantly higher than that for Shanyou 63. The transportation of photosynthate to the spikes of all leaf sheathes for Liangyoupeijiu was more and quicker than that for Shanyou 63, leading to more economic yield for Liangyoupeijiu than for Shanyou 63. The photosynthetic capacity mean of the flag leaf sheathes for Liangyoupeijiu was of the mean potence or heterobeltiosis as comparison with that for its parents. Rice leaf sheath had completely the same kind of photosynthesis as comparison with rice leaf blade but their quantitive difference. The photosynthate of rice leaf sheath transported mostly to its spikes, blades etc, and the contribution to yields was between 10% and 20%. The strong photosynthetic function of both the sheath and blade is one of the main reasons why Liangyoupeijiu is of super high yield.