烟草种子成熟过程中膜脂的变化规律研究

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摘 要：该研究采用脂类组学方法，系统地研究了烟草种子成熟过程中膜脂含量及组成比例的变化规律。结果表明：（1）构成叶绿体和类囊体膜的重要脂类质体膜脂的含量及其在总膜脂中的组成比例，在种子成熟的整个过程中保持下降趋势;而构成细胞膜的重要脂类质外体膜脂含量在种子成熟前期则下降显著，在授粉21 d后基本保持不变。（2）总膜脂含量的变化规律与质体膜脂类似，但在授粉后第29天后含量却达到稳定状态。（3）因油脂在种子成熟过程中不断积累，且化学结构与膜脂相似，质体膜脂含量的降低可能与种子成熟过程中种子对油脂累积的持续需求以及对叶绿体及类囊体的需求降低有关。（4）质外体膜脂含量在授粉21 d后基本保持不变的原因，可能是由于脂质外体膜脂是细胞膜组成的主要膜脂，细胞膜在种子成熟以及成熟种子萌发过程中均发挥重要作用，因此质外体膜脂只在种子成熟的前期有部分转化为油脂。

关键词：烟草， 种子， 成熟， 膜脂

中图分类号：Q946.4， S572

文献标识码：A

文章编号：1000-3142（2019）11-1512-07

Abstract：In order to clarify the change rule of membrane lipids in tobacco seed during ripening process， the change rules of membrane lipid contents and components in the seeds of tobacco were studied systematically by the method of lipidomics. The results were as follows：（1） The content of plastidic membrane lipid and its proportion in total membrane lipids decreased continuously with the ripening of the seeds， which were important lipids that constituted chloroplast and thylakoid membranes. Whereas as important lipids that constituting cell membranes， the content of extraplastidic membrane lipids decreased significantly at the early stage of seed maturation which reached a stable state at 21 d after pollination.（2） The changes of total membrane lipids content were similar to that of plastid membrane lipids， which reached a stable state at 29 d after pollination.（3） Because grease accumulated continuously during seed maturation， and its chemical structure was similar to that of membrane lipids， the reduction of plastidic membrane lipids content could be related to the sustained demand for grease accumulation during seed maturation and the decrease of demand for chloroplasts and thylakoids.（4） The reason of extraplastidic membrane lipids remaining unchanged at 21 d after pollination was related to extraplastidic membrane lipids as the major membrane lipids involving in cell membrane， and cell membrane played an important role during seed maturation and mature seed germination， therefore， it was speculated that the decreased membrane lipids were transferred to grease.

Key words：tobacco， seeds， maturation， membrane lipids

膜系統的变化与种子质量、寿命和耐贮藏性等密切相关（尹田夫等，1989，1990;陈善娜等，1995;宋健和林维珍，2009）。膜脂是膜系统主要成分，膜脂组成及含量变化对膜系统的物理特性及相变温度都有重要影响，从而影响种子活力（杨永青和汪晓峰，2004）。膜脂主要包括磷脂酰胆碱（PC）、磷脂酰乙醇胺（PE）、磷脂酰肌醇（PI）、磷脂酰甘油（PG）、磷脂酸（PA）等磷脂（PL）和单半乳糖二甘油脂（MGDG）、双半乳糖二甘油脂（DGDG）等糖脂（宋健和林维珍，2009）。其中，MGDG、DGDG和PG是组成叶绿体膜的主要脂类，因此被称为质体膜脂（Dormann & Benning， 2002; Kobayashi et al.， 2007），剩余的其他极性甘油酯则称为质外体膜脂，是植物细胞膜、线粒体膜等其他细胞器膜的主要组成脂类。