MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824.
Plant Physiol. 1987 Jun;84(2):353-60. doi: 10.1104/pp.84.2.353.
A mutant of Arabidopsis thaliana with reduced content of C(18:3) and C(16:3) fatty acids in membrane lipids exhibited a 45% reduction in the cross-sectional area of chloroplasts and had a decrease of similar magnitude in the amount of chloroplast lamellar membranes. The reduction in chloroplast size was partially compensated by a 45% increase in the number of chloroplasts per cell in the mutant. When expressed on a chlorophyll basis the rates of CO(2)-fixation and photosynthetic electron transport were not affected by these changes. Fluorescence polarization measurements indicated that the fluidity of the thylakoid membranes was not significantly altered by the mutation. Similarly, on the basis of temperature-induced fluorescence yield enhancement measurements, there was no significant effect on the thermal stability of chlorophyll-protein complexes in the mutant. These observations suggest that the high content of trienoic fatty acids in chloroplast lipids may be an important factor regulating organelle biogenesis but is not required to support normal levels of the photosynthetic activities associated with the thylakoid membranes.
拟南芥突变体的膜脂中 C(18:3)和 C(16:3)脂肪酸含量降低，导致叶绿体横截面积减少 45%，叶绿体片层膜数量减少相似幅度。突变体中叶绿体数量增加了 45%，部分补偿了叶绿体大小的减少。以叶绿素为基础计算时，CO(2)固定和光合电子传递的速率不受这些变化的影响。荧光偏振测量表明，突变并未显著改变类囊体膜的流动性。同样，根据温度诱导的荧光产率增强测量，突变体中叶绿素-蛋白复合物的热稳定性没有显著影响。这些观察结果表明，叶绿体脂质中三烯脂肪酸的高含量可能是调节细胞器生物发生的重要因素，但不需要支持与类囊体膜相关的正常光合活性水平。
