College of Horticulture and Landscape Achitecture, Southwest University, Chongqing 400715, China.
Key Laboratory of Horticulture Science for Southern Mountains Regions, Ministry of Education, Chongqing 400715, China.
Int J Mol Sci. 2018 Oct 22;19(10):3278. doi: 10.3390/ijms19103278.
Wintersweet () is a well-known traditional fragrant plant and a winter-flowering deciduous shrub that originated in China. The five different developmental stages of wintersweet, namely, flower-bud period (FB), displayed petal stage (DP), open flower stage (OF), later blooming period (LB), and wilting period (WP) were studied using a scanning electron microscope (SEM) to determine the distribution characteristics of aroma-emitting nectaries. Results showed that the floral scent was probably emitted from nectaries distributed on the adaxial side of the innermost and middle petals, but almost none on the abaxial side. The nectaries in different developmental periods on the petals differ in numbers, sizes, and characteristics. Although the distribution of nectaries on different rounds of petals showed a diverse pattern at the same developmental periods, that of the nectaries on the same round of petals showed some of regularity. The nectary is concentrated on the adaxial side of the petals, especially in the region near the axis of the lower part of the petals. Based on transcriptional sequence and phylogenetic analysis, we report one nectary development related gene (), and the other four YABBY family genes, (), , , and in . (accession no. MH718960-MH718964). Quantitative RT-PCR (qRT-PCR) results showed that the expression characteristics of these YABBY family genes were similar to those of 11 floral scent genes, namely, , , , , , , , , , , and . The expression levels of these genes were generally higher in the lower part of the petals than in the upper halves in different rounds of petals, the highest being in the innermost petals, but the lowest in the outer petals. Relative expression level of , , , and in the innermost and middle petals in OF stages is significant higher than that of in outer petals, respectively. SEM and qRT-PCR results in showed that floral scent emission is related to the distribution of nectaries.
腊梅（）是一种著名的传统芳香植物，也是一种冬季开花的落叶灌木，原产于中国。本研究采用扫描电子显微镜（SEM）观察腊梅花芽期（FB）、显色期（DP）、盛开期（OF）、晚花期（LB）和凋萎期（WP）等 5 个不同发育阶段，确定腊梅花芳香腺的分布特征。结果表明，花香可能是由分布在内层和中层花瓣腹面的芳香腺散发的，但背面几乎没有。不同发育时期花瓣上的芳香腺在数量、大小和特征上存在差异。虽然同一发育时期不同轮次花瓣上的芳香腺分布模式多样，但同一轮次花瓣上的芳香腺分布具有一定的规律性。芳香腺集中在花瓣的腹面，尤其是靠近花瓣下部轴的区域。基于转录序列和系统发育分析，我们报道了一个与花蜜腺发育相关的基因（），以及另外四个 YABBY 家族基因， （）、 （）、 （）和 （）在 （登录号 MH718960-MH718964）。定量 RT-PCR（qRT-PCR）结果表明，这些 YABBY 家族基因的表达特征与 11 个花香基因相似，即 （）、 （）、 （）、 （）、 （）、 （）、 （）、 （）、 （）和 （）。这些基因在不同轮次花瓣的下部表达水平普遍高于上部，内轮最高，外轮最低。在 OF 阶段，内轮和中层花瓣中 、 、 和 的相对表达水平显著高于外轮花瓣。SEM 和 qRT-PCR 结果表明，腊梅花香的释放与芳香腺的分布有关。
