Epidermal Cell Changes and Anthocyanin Accumulation Patterns during Paeonia rockii Blotch Formation

doi:10.7525/j.issn.1673-5102.2026.04.016

Abstract

Abstract:

The basal petal blotch of Paeonia rockii is the primary genetic source of blotch traits in cultivated tree peonies. To clarify the timing of blotch initiation， its expansion pattern， and the relationship between blotch development and pigment accumulation， basal blotch formation at seven developmental stages were systematically examined in ten P.rockii cultivars. At stage S2， single pigmented cells first appeared and gradually developed into pigment cell clusters， consisting of a deeply pigmented central cell surrounded by lightly pigmented peripheral cells. Blotch expansion occurred through the proliferation and enlargement of these pigment cell clusters. The blotch outline was initially established at stage S3， preceding the visible coloration of the petal background， and a second peak of pigment cell proliferation was observed at stages S6-S7. During S2-S3， significant decreases in L* and b* values and an increase in a* value were recorded in the blotch region. Anthocyanins were detectable in the blotch as early as S2， with cyanidin-3，5-di-O-glucoside（Cy3G5G） and peonidin-3，5-di-O-glucoside（Pn3G5G） as the predominant components. Linear regression analysis indicated that Pn3G5G had strong explanatory power for changes in L*， a*， and b* values and was the key anthocyanin contributing to the formation of purple-red blotches. Pelargonidin-3，5-di-O-glucoside（Pg3G5G） may be involved in the formation of black blotches. In summary， blotch formation in P. rockii is a dynamic developmental process characterized structurally by the expansion of pigment cell clusters and biochemically by the spatiotemporally specific accumulation of anthocyanins.

Key words: Paeonia rockii, blotch, epidermal cell, anthocyanins

CLC Number:

S685.11

Wenjun LI, Sha LUO, Qianqian SHI. Epidermal Cell Changes and Anthocyanin Accumulation Patterns during Paeonia rockii Blotch Formation[J]. Bulletin of Botanical Research, 2026, 46(4): 764-776.

Figures/Tables 11

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References 25

[1]	程金水.园林植物遗传育种学［M］.北京：中国林业出版社，2000：81-82.
	Cheng Jinshui.Genetics and breeding of garden plants［M］.Beijing：China Forestry Publishing House，2000：81-82.
[2]	Fairnie A L M， Yeo M T S， Gatti S，et al.Eco-Evo-Devo of petal pigmentation patterning［J］.Essays in Biochemistry，2022，66（6）：753-768.
[3]	Zhang Y Z， Cheng Y W， Ya H Y，et al.Transcriptome sequencing of purple petal spot region in tree peony reveals differentially expressed anthocyanin structural genes［J］.Frontiers in Plant Science，2015，6：964.
[4]	成仿云.中国紫斑牡丹［M］.北京：中国林业出版社，2005：88.
	Cheng Fangyun.Chinese flare Mudan［M］.Beijing：China Forestry Publishing House，2005：88.
[5]	Wang L S， Hashimoto F， Shiraishi A，et al.Phenetics in tree peony species from China by flower pigment cluster analysis［J］.Journal of Plant Research，2001，114（3）：213-221.
[6]	Wang L S， Hashimoto F， Shiraishi A，et al.Chemical taxonomy of the Xibei tree peony from China by floral pigmentation［J］.Journal of Plant Research，2004，117（1）：47-55.
[7]	Zhang J J， Wang L S， Shu Q Y，et al.Comparison of anthocyanins in non-blotches and blotches of the petals of Xibei tree peony［J］.Scientia Horticulturae，2007，114（2）：104-111.
[8]	Shi Q Q， Yuan M， Wang S，et al.PrMYB5 activates anthocyanin biosynthetic PrDFR to promote the distinct pigmentation pattern in the petal of Paeonia rockii ［J］.Frontiers in Plant Science，2022，13：955590.
[9]	Shi Q Q， Li L， Zhang X X，et al.Biochemical and comparative transcriptomic analyses identify candidate genes related to variegation formation in Paeonia rockii ［J］.Molecules，2017，22（8）：1364.
[10]	Qi Y Y， Lou Q， Li H B，et al.Anatomical and biochemical studies of bicolored flower development in Muscari latifolium ［J］.Protoplasma，2013，250（6）：1273-1281.
[11]	Schindelin J， Arganda-Carreras I， Frise E，et al.Fiji：an open-source platform for biological-image analysis［J］.Nature Methods，2012，9（7）：676-682.
[12]	Zhang J， Wang L S， Gao J M，et al.Determination of anthocyanins and exploration of relationship between their composition and petal coloration in crape myrtle （Lagerstroemia hybrid）［J］.Journal of Integrative Plant Biology，2008，50（5）：581-588.
[13]	Hanbury A， Serra J.Mathematical morphology in the cielab space［J］.Image Analysis & Stereology，2002，21（3）：201.
[14]	Luo X N， Sun D Y， Wang S，et al.Integrating full-length transcriptomics and metabolomics reveals the regulatory mechanisms underlying yellow pigmentation in tree peony （Paeonia suffruticosa Andr.） flowers［J］.Horticulture Research，2021，8：235.
[15]	Suzuki K， Suzuki T， Nakatsuka T，et al.RNA-seq-based evaluation of bicolor tepal pigmentation in Asiatic hybrid lilies （Lilium spp.）［J］.BMC Genomics，2016，17（1）：611.
[16]	Wang Z， Li X， Chen M M，et al.Molecular and metabolic insights into anthocyanin biosynthesis for spot formation on Lilium leichtlinii var.maximowiczii flower petals［J］.International Journal of Molecular Sciences，2023，24（3）：1844.
[17]	Xu L F， Yang P P， Feng Y Y，et al.Spatiotemporal transcriptome analysis provides insights into bicolor tepal development in Lilium “tiny padhye”［J］.Frontiers in Plant Science，2017，8：398.
[18]	Zhu J， Wang Y Z， Wang Q Y，et al.The combination of DNA methylation and positive regulation of anthocyanin biosynthesis by MYB and bHLH transcription factors contributes to the petal blotch formation in Xibei tree peony［J］.Horticulture Research，2023，10（7）：uhad100.
[19]	Wilts B D， Rudall P J， Moyroud E，et al.Ultrastructure and optics of the prism-like petal epidermal cells of Eschscholzia californica （California poppy）［J］.New Phytologist，2018，219（3）：1124-1133.
[20]	林登贵，曾丽，裴峰，等.万寿菊营养器官及舌状花解剖结构的研究［J］.上海交通大学学报（农业科学版），2015，33（4）：59-64.
	Lin Denggui， Zeng Li， Pei Feng，et al.Anatomical structures of vegetative organs and ray floret in Tagetes erecta L.［J］.Journal of Shanghai Jiao Tong University（Agricultural Science），2015，33（4）：59-64.
[21]	殷涵泰，尹俊梅，廖易，等.基于秋石斛花朵颜色、色素分布及表皮细胞形态的表型分类［J］.园艺学报，2021，48（10）：1907-1920.
	Yin Hantai， Yin Junmei， Liao Yi，et al.Phenotype classification based on flower color，pigment distribution and epidermal cell shape of Dendrobium hybrids［J］.Acta Horticulturae Sinica，2021，48（10）：1907-1920.
[22]	Luan Y T， Tang Y H， Wang X，et al.Tree peony R2R3-MYB transcription factor PsMYB30 promotes petal blotch formation by activating the transcription of the anthocyanin synthase gene［J］.Plant and Cell Physiology，2022，63（8）：1101-1116.
[23]	Kicheva A， Briscoe J.Developmental pattern formation in phases［J］.Trends in Cell Biology，2015，25（10）：579-591.
[24]	Davies K M， Albert N W， Schwinn K E.From landing lights to mimicry：the molecular regulation of flower colouration and mechanisms for pigmentation patterning［J］.Functional Plant Biology，2012，39（8）：619-638.
[25]	Li Y， Kong F， Liu Z A，et al.PhUGT78A22， a novel glycosyltransferase in Paeonia ‘He Xie’， can catalyze the transfer of glucose to glucosylated anthocyanins during petal blotch formation［J］.BMC Plant Biology，2022，22：405.

时期 Stage	描述 Description	对应牡丹物候期 Phenological period
S1	无色斑	立蕾期、小风铃前期
S2	色斑逐渐显露，未形成完整轮廓	小风铃期、大风铃期
S3	色斑轮廓初步形成，花色初显或将显未显	大风铃后期、圆桃前期
S4	色斑增大加深，花色逐渐显露	圆桃期
S5	色斑继续扩增，花色基本形成	圆桃后期、平桃期
S6	色斑、花色已形成，面积仍有变化	破绽透色期、初开期
S7	花开放	盛开期