Mackender R O
Department of Botany, The Queen's University of Belfast, Belfast BT7 1NN, Northern Ireland.
Plant Physiol. 1978 Oct;62(4):499-505. doi: 10.1104/pp.62.4.499.
The ultrastructure of etioplasts and the acyl lipid and the fatty acid composition of sequential 2-centimeter sections cut from the base (youngest) to the top (oldest) of nonilluminated 5-day-old etiolated leaves of Zea mays L., and the acyl lipid and fatty acid composition of the etioplasts isolated from them have been investigated. There is a 2.5-fold increase in the size of the plastids from the base to the tip of the leaf, and an increase both in the size of the prolamellar body and in the length of lamellae attached to it. The etioplasts in the bundle sheath and mesophyll cells of the older, but not the younger leaf tissue, are morphologically distinct. The monogalactosyl and digalactosyldiglycerides, phosphatidylcholine, phosphatidylglycerol, and phosphatidylinositol were the only detectable acyl lipids in the isolated etioplast fractions. Together with phosphatidylethanolamine these were also the major acyl lipids in the whole leaf sections. With increasing age of the leaf tissue, increases occurred in two of the major plastid lipids, monogalactosyldiglyceride and phosphatidylglycerol, while the levels of essentially nonplastid lipids remained constant or declined slightly. The monogalactosyldiglyceride to digalactosyldiglyceride ratio increased from 0.4 to 1.1 in the tissue sections of increasing age and from 0.7 to 1.2 in the etioplasts isolated from them. Similarly, the galactolipid to phospholipid ratio increased from 0.8 to 1.4 in the tissue and from 0.5 to 4.5 in the isolated plastids. In the latter, the proportions of phosphatidylglycerol (as a per cent of total phospholipid) increased from 20 to 41% with increasing age of plastids.Linolenic acid was the major fatty acid in the total lipid of each of the etioplast fractions, but it was only the major fatty acid in the total lipid of the oldest leaf tissue. Its proportion in both total lipid extracts and individual lipids increased with age. The trans Delta(3) hexadecenoic acid was absent from all lipids. The protochlorophyllide content of the tissue increased with age. The results are discussed in relation to the use of illuminated etiolated leaves for studying chloroplast development.
对玉米（Zea mays L.）5日龄黄化未照光叶片从基部（最幼嫩）到顶部（最老）连续2厘米切段的黄化质体超微结构、酰基脂质和脂肪酸组成，以及从这些切段中分离得到的黄化质体的酰基脂质和脂肪酸组成进行了研究。从叶片基部到尖端，质体大小增加了2.5倍，原片层体大小和与其相连的片层长度均增加。较老叶片组织（而非较幼叶片组织）的维管束鞘和叶肉细胞中的黄化质体在形态上有所不同。单半乳糖基二酰甘油、二半乳糖基二酰甘油、磷脂酰胆碱、磷脂酰甘油和磷脂酰肌醇是分离得到的黄化质体组分中仅可检测到的酰基脂质。连同磷脂酰乙醇胺一起，这些也是整个叶片切段中的主要酰基脂质。随着叶片组织年龄的增加，两种主要质体脂质——单半乳糖基二酰甘油和磷脂酰甘油有所增加，而基本非质体脂质的水平保持不变或略有下降。在年龄增加的组织切段中，单半乳糖基二酰甘油与二半乳糖基二酰甘油的比值从0.4增加到1.1，从这些切段中分离得到的黄化质体中该比值从0.7增加到1.2。同样，半乳糖脂与磷脂的比值在组织中从0.8增加到1.4，在分离得到的质体中从0.5增加到4.5。在后者中，随着质体年龄的增加，磷脂酰甘油（占总磷脂的百分比）比例从20%增加到41%。亚麻酸是每个黄化质体组分总脂质中的主要脂肪酸，但它仅是最老叶片组织总脂质中的主要脂肪酸。其在总脂质提取物和单个脂质中的比例均随年龄增加。所有脂质中均不存在反式Δ(3)十六碳烯酸。组织中原叶绿素酸含量随年龄增加。结合使用照光黄化叶片研究叶绿体发育对结果进行了讨论。
