黄瓜无毛突变体叶片叶绿体超微结构与光合特性

Ultrastructure and Photosynthetic Characters of Leaf Chloroplast in Glabrous Cucumber

观测了无毛突变体黄瓜与有毛黄瓜坐果期叶片的叶绿体超微结构和光合特性。与有毛黄瓜相比 ,无毛黄瓜光合机构的结构较简单 ,叶肉细胞内叶绿体数量少 ,叶绿体内基粒数和基粒片层数少。叶绿素a、b及类胡萝卜素含量仅为有毛黄瓜的一半。无毛黄瓜光合速率明显比有毛黄瓜低 ,在一天的大部分时间内低于有毛黄瓜 5 0 %。无毛黄瓜的光合速率日变化呈单峰曲线 ,峰值出现于 11时 ,有毛黄瓜光合速率日变化呈双峰曲线 ,两峰出现在 10时和 12时左右。无毛黄瓜的光合速率随CO2 浓度的增加而增加 ,在130 0 μL·L-1CO2 下 ,达到最大值 ,但同样浓度情况下 ,其光合速率明显比有毛黄瓜的低。

The ultrastructure and photosynthetic characters of chloroplast were investigated at setting stage in leaves of glabrous and normal cucumbers. Compared with that of normal cucumber, the structure of photosynthetic apparatus in glabrous cucumber was simple with less numbers of chloroplast and grana as well as the grana lamellae.The contents of chlorophyll a and b and carotenoid in glabrous cucumbers only reached half of the content in normal one. Therefore, the capacity of capturing light energy was low. The photosynthetic rate of glabrous was obviously lower than that of normal, no more than half of normal cucumber during most times in a day. Diurnal change of photosynthetic rate of glabrous was unimodal distribution with the maximum occurring at 11:00, whereas diurnal patterns of normal one displayed bimodal distribution which two peaks occurred at 10:00 and 12:00. The photosynthetic rate of glabrous cucumber increased as CO_2 concentration increased, the maximum reached 1300μL·L -1 of CO_2, but its level was significantly lower than that of normal cucumber under the same CO_2 concentration.