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    花香代谢与调控研究进展

    Advances in metabolism and regulation of floral scent.

    • 摘要: 植物的花朵香味是由一系列低分子量的挥发性化合物组成,并形成其特有的特征。花香化合物主要由萜类、苯类/苯丙素类、脂肪酸衍生物和一些含氮或硫化合物等组成。这些花香化合物除了能吸引授粉者前来完成授粉,还是一种防御策略。一般对花朵周围气体进行采样分析,从而得到更真实的花香样本。花香化合物主要由植物花瓣的表皮细胞和特殊分泌组织释放,释放过程受到花发育和授粉状态、内源生物钟及环境条件的影响。大多数花香化合物是通过类异戊二烯途径、苯类/苯丙素类途径和脂肪酸途径合成。可以采用传统生化方法、同源克隆技术或基因组学等方法克隆花香相关基因。通过基因工程可以改良植物的花香性状,除了导入植物中没有的外源基因,还可以调控相关内源基因或转录因子的表达,但是其中还有很多难点有待解决。

       

      Abstract: Floral scent is a complex mixture of low molecular weight volatile compounds, which gives the flower its unique fragrance. Plant scent is mainly composed of terpenoids, benzenoids/phenylpropanoids, fatty acid derivatives, and compounds containing nitrogen or sulfur. These volatile compounds act as attractants to pollinators that provide the plant with reproductive benefit. While in plant cells, these compounds could be toxic to those organisms that ingest the plant. Scent substances from the air in the vicinity of the flower are sampled, providing a more realistic image of the volatile profile. Most of the floral scent compounds are emitted from petal epidermal cells or highly specialized secretory structures such as scent glands. The composition of floral scents is changing during the flower lifespan in relation to flower stage and pollination status, endogenous rhythms, environmental conditions. Most floral scent compounds are produced by only a few major biochemical pathways, such as isoprenoid, phenylpropanoid/benzenoid and fatty acid pathways. Traditional biochemical method, homology cloning technology, and genomics approach have been used to clone genes involved in floral scent production. Recent progress in the molecular biology of floral scents offers tools for modification of fragrance in flowering plants, including introducing new genes, regulating the expression of endogenous genes or transcription factors. But many difficulties remain to be overcome.

       

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