Postgraduate School of Studies in Biological Sciences, University of Bradford, Bradford, Yorkshire BD7 1DP, England.
Plant Physiol. 1971 May;47(5):635-9. doi: 10.1104/pp.47.5.635.
Rates and products of photosynthetic (14)CO(2) fixation by division synchronized cultures of Euglena gracilis strain Z were determined over the cycle. Rate of (14)CO(2) fixation doubled in a continuous manner throughout the light phase followed by a slight reduction of photosynthetic capacity in the dark phase. Greater (14)C incorporation into the nucleic acid-polysaccharide fraction occurred with mature cells. Products of (14)CO(2) fixation varied markedly over the cycle: although with mature cells (14)C-labeled sucrose was not detected, with dividing cells this was the main sugar labeled; in young cells (14)C maltose was formed. Cells removed at end of dark phase accumulated (14)C in glycolate, whereas at other stages over the cycle less (14)C was present in glycolate, and this was accompanied by a rapid incorporation of (14)C into glycine and serine. Glycerate was an early and major product of photosynthesis with cells at the mature stage of the cycle.Changes in ribulose 1,5-diphosphate carboxylase activity paralleled changes in photosynthetic rate, but activity was not great enough to account for the observed rates of CO(2) fixation at most stages of the division cycle investigated.
采用同步分裂培养的方法，测定了衣藻 Z 株光合作用（14）CO2 固定的速率和产物。在光照阶段，（14）CO2 固定的速率连续加倍，随后在黑暗阶段光合能力略有下降。成熟细胞中核酸-多糖部分的（14）C 掺入量较大。（14）CO2 固定的产物在周期内变化显著：虽然在成熟细胞中未检测到（14）C 标记的蔗糖，但在分裂细胞中，蔗糖是主要标记的糖；在年轻细胞中，（14）C 麦芽糖形成。在黑暗阶段结束时取出的细胞在甘氨酸和丝氨酸中迅速掺入（14）C，而在周期的其他阶段，甘醇酸中（14）C 的含量较少。在处于周期成熟阶段的细胞中，甘油酸是光合作用的早期和主要产物。核酮糖 1,5-二磷酸羧化酶活性的变化与光合速率的变化平行，但活性不足以解释在大多数所研究的分裂周期阶段观察到的 CO2 固定速率。
