普通野生稻和武育粳8号剑叶光合功能衰退的比较

以武育粳 8号 (Wuyujing8)和普通野生稻 (Oryza.sativaL .f.spontaneaRoschev .)为材料 ,比较了它们剑叶光合功能衰退的进程。结果表明 ,在剑叶一生中 ,武育粳 8号剑叶的叶绿素含量和光合速率都高于普通野生稻 ,光合速率的最高值前者为 2 3 .5 μmolCO2 m 2 ·S 1,后者为 1 5 .5 μmolCO2 m 2 ·S 1。前者剑叶光合速率的高值持续期比后者长近 2 0d ,其叶源量是后者的 2 .8倍。武育粳 8号剑叶叶绿素含量最大值的SPAD值为 5 0 .1 ,而普通野生稻最大值的SPAD值为 42 .7。在可溶性蛋白质的基础上 ,核酮糖 1 ,5 二磷酸羧化酶比活性二者之间没有太大区别。内肽酶活力上升落后于光合功能的衰退。在光合功能衰退的早期 ,内肽酶的活力仅有小幅度提高 ,但在叶片衰老的末期升高幅度则较大。这说明内肽酶主要在光合功能衰退的后期即不可逆衰退期才发挥较大作用。

Comparison on photosynthetic declination of flag leaves between wild rice and Wuyujing 8

Wuyujing 8(sinica type cv.)and Wild rice(O. sativa L. f. spontanea Roschev.)were used to compare the differences in photosynthetic declination between their flag leaves. The results indicated that during the whole life span of flag leaf,Wuyujing 8 had higher photosynthetic rate and chlorophyll content,the maximum photosynthetic rates being 23.5 μmol CO 2 m -2·S -1 for the former and 15.5 μmol CO 2 m -2·S -1 for the latter;the APD(active photosynthetic duration)of Wuyujing 8 flag leaves was nearly 20 days longer than that of wild rice flag leaves;and its LSC(leaf source capacity)was 2.8 times more than that of wild rice. Maximums of chlorophyll content(valued as SPAD)were 50.1 and 42.7 for Wuyujing 8 and wild rice flag leaves,respectively. Based on content of soluble protein,there was a little difference in specific activities of RuBP carboxylase in flag leaves between wild rice and Wuyujing 8. The activity of endopeptidase started to rise later than beginning of photosynthetic declination,and exhibited slightly higher in early phase of photosynthetic declination,but reached very high level in the latest phase. It implied that endopeptidases play a role mainly in late phase or irreversible phase of photosynthetic declination.