title: Leaf structure affects a plant's appearance: combined multiple-mechanisms intensify remarkable foliar variegation.
abstract: The presence of foliar variegation challenges perceptions of leaf form and functioning. But variegation is often incorrectly identified and misinterpreted. The striking variegation found in juvenile Blastus cochinchinensis (Melastomataceae) provides an instructive case study of mechanisms and their ecophysiological implications. Variegated (white and green areas, vw and vg) and non-variegated leaves (normal green leaves, ng) of seedlings of Blastus were compared structurally with microtechniques, and characterized for chlorophyll content and fluorescence. More limited study of Sonerila heterostemon (Melastomataceae) and Kaempferia pulchra (Zingiberaceae) tested the generality of the findings. Variegation in Blastus combines five mechanisms: epidermal, air space, upper mesophyll, chloroplast and crystal, the latter two being new mechanisms. All mesophyll cells (vw, vg, ng) have functional chloroplasts with dense thylakoids. The vw areas are distinguished by flatter adaxial epidermal cells and central trichomes containing crystals, the presence of air spaces between the adaxial epidermis and a colorless spongy-like upper mesophyll containing smaller and fewer chloroplasts. The vw area is further distinguished by having the largest spongy-tissue chloroplasts and fewer stomata. Both leaf types have similar total chlorophyll content and similar  Fv/Fm(maximum quantum yield of PSII), but vg has significantly higher Fv/Fmthan ng. Variegation in Sonerila and Kaempferia is also caused by combined mechanisms, including the crystal type in Kaempferia. This finding of combined mechanisms in three different species suggests that combined mechanisms may occur more commonly in nature than current understanding. The combined mechanisms in Blastus variegated leaves represent intricate structural modifications that may compensate for and minimize photosynthetic loss, and reflect changing plant needs.
authors.affiliation: Department of Life Sciences and Center for Global Change Biology, National Chung Hsing University, 250, Kuo Kuang Rd., Taichung, 402, Taiwan, Republic of China.
authors.forename: Yun-Shiuan
authors.initials: YS
authors.lastname: Chen
authors.affiliation: Department of Life Sciences and Center for Global Change Biology, National Chung Hsing University, 250, Kuo Kuang Rd., Taichung, 402, Taiwan, Republic of China.|Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, 85721, USA.
authors.forename: Peter
authors.initials: P
authors.lastname: Chesson
authors.affiliation: Genome and Systems Biology Degree Program, National Taiwan University, No.1, Sec. 4, Roosevelt Rd., Taipei, 106, Taiwan, Republic of China.|Institute of Plant and Microbial Biology, Academia Sinica, No.128, Sec. 2, Academia Rd, Taipei, 115, Taiwan, Republic of China.
authors.forename: Ho-Wei
authors.initials: HW
authors.lastname: Wu
authors.affiliation: Department of Life Sciences and Center for Global Change Biology, National Chung Hsing University, 250, Kuo Kuang Rd., Taichung, 402, Taiwan, Republic of China.
authors.forename: Shang-Hung
authors.initials: SH
authors.lastname: Pao
authors.affiliation: Department of Life Sciences and Center for Global Change Biology, National Chung Hsing University, 250, Kuo Kuang Rd., Taichung, 402, Taiwan, Republic of China.
authors.forename: Jian-Wei
authors.initials: JW
authors.lastname: Liu
authors.affiliation: Department of Life Sciences and Center for Global Change Biology, National Chung Hsing University, 250, Kuo Kuang Rd., Taichung, 402, Taiwan, Republic of China.
authors.forename: Lee-Feng
authors.initials: LF
authors.lastname: Chien
authors.affiliation: School of Plant Biology, University of Western Australia, 35, Stirling Highway, Perth, Western Australia, 6009, Australia.
authors.forename: Jean W H
authors.initials: JWH
authors.lastname: Yong
authors.affiliation: Department of Life Sciences and Center for Global Change Biology, National Chung Hsing University, 250, Kuo Kuang Rd., Taichung, 402, Taiwan, Republic of China. crsheue@nchu.edu.tw.|Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, 85721, USA. crsheue@nchu.edu.tw.
authors.forename: Chiou-Rong
authors.initials: CR
authors.lastname: Sheue
mesh_terms: D002736:Chloroplasts / Q000378:metabolism; D035322:Melastomataceae / Q000033:anatomy & histology* / Q000502:physiology*; D058503:Mesophyll Cells / Q000378:metabolism; D018515:Plant Leaves / Q000033:anatomy & histology* / Q000502:physiology*; D036226:Seedlings / Q000033:anatomy & histology / Q000502:physiology; D030521:Zingiberaceae / Q000033:anatomy & histology / Q000502:physiology
keywords: Blastus cochinchinensis; Chloroplast; Crystal; Kaempferia pulchra; Physical color; Sonerila heterostemon