Flowering while leafless in the seasonal tropics need not be cued by leaf drop

Evidence from the woody genus Brachychiton (malvaceae)

Donald C. Franklin

    Research output: Contribution to journalArticleResearchpeer-review

    Abstract

    Background and aims: A suite of woody plants inhabiting the seasonally-dry tropics flower while leafless during the dry season. A functional hypothesis for this phenomenon is that leaf drop early in the dry season pre-empts dehydration, and that flowering is triggered by the improved water status caused by leaf drop. If true, this would strongly constrain adaption to optimise flowering times.

    Methods: I examine phenological patterns in the Australasian genus Brachychiton based primarily on summary descriptions in a published taxonomic treatise, along with relevant morphological, anatomical and ecophysiological evidence, in order to evaluate the role of leaf drop, and identify other sources of hydration that may initiate or support flowering while leafless.

    Key results: Most of the 31 Brachychiton species are deciduous and many flower during the dry season following leaf drop, but some flower later in the dry season, at leaf flush, or when leafy. Many have enlarged stems, branchlets or tap roots, and the limited ecophysiological evidence suggests that these organs are associated with enhanced water storage potential. Brachychiton displays both considerable evidence of divergence, and a degree of phylogenetic conservatism in these traits.

    Conclusions: Rehydration following leaf drop is not a necessary cue to initiate flowering even when leafless. Flowering time is likely to be adaptive and species-specific in a wide range of woody plants in the seasonally-dry tropics. Care is needed to disentangle phenological correlates and the proximal and ultimate factors driving flowering.

    Original languageEnglish
    Pages (from-to)272-279
    Number of pages8
    JournalPlant Ecology and Evolution
    Volume149
    Issue number3
    DOIs
    Publication statusPublished - 1 Nov 2016

    Fingerprint

    Brachychiton
    Malvaceae
    tropics
    flowering
    dry season
    leaves
    flowers
    woody plants
    tap roots
    rehydration
    desiccation (plant physiology)
    water
    stems
    phylogeny

    Cite this

    @article{9771a6ba6f3043fd970a39b9568738ec,
    title = "Flowering while leafless in the seasonal tropics need not be cued by leaf drop: Evidence from the woody genus Brachychiton (malvaceae)",
    abstract = "Background and aims: A suite of woody plants inhabiting the seasonally-dry tropics flower while leafless during the dry season. A functional hypothesis for this phenomenon is that leaf drop early in the dry season pre-empts dehydration, and that flowering is triggered by the improved water status caused by leaf drop. If true, this would strongly constrain adaption to optimise flowering times. Methods: I examine phenological patterns in the Australasian genus Brachychiton based primarily on summary descriptions in a published taxonomic treatise, along with relevant morphological, anatomical and ecophysiological evidence, in order to evaluate the role of leaf drop, and identify other sources of hydration that may initiate or support flowering while leafless. Key results: Most of the 31 Brachychiton species are deciduous and many flower during the dry season following leaf drop, but some flower later in the dry season, at leaf flush, or when leafy. Many have enlarged stems, branchlets or tap roots, and the limited ecophysiological evidence suggests that these organs are associated with enhanced water storage potential. Brachychiton displays both considerable evidence of divergence, and a degree of phylogenetic conservatism in these traits. Conclusions: Rehydration following leaf drop is not a necessary cue to initiate flowering even when leafless. Flowering time is likely to be adaptive and species-specific in a wide range of woody plants in the seasonally-dry tropics. Care is needed to disentangle phenological correlates and the proximal and ultimate factors driving flowering.",
    keywords = "Brachychiton, Deciduousness, Environmental cues, Kurrajong, Monsoonal tropics, Morphology, Phenology, Seasonal tropics, Stem water storage, Succulence",
    author = "Franklin, {Donald C.}",
    year = "2016",
    month = "11",
    day = "1",
    doi = "10.5091/plecevo.2016.1244",
    language = "English",
    volume = "149",
    pages = "272--279",
    journal = "Plant Ecology and Evolution",
    issn = "2032-3913",
    publisher = "Societe Royale de Botanique de Belgique",
    number = "3",

    }

    Flowering while leafless in the seasonal tropics need not be cued by leaf drop : Evidence from the woody genus Brachychiton (malvaceae). / Franklin, Donald C.

    In: Plant Ecology and Evolution, Vol. 149, No. 3, 01.11.2016, p. 272-279.

    Research output: Contribution to journalArticleResearchpeer-review

    TY - JOUR

    T1 - Flowering while leafless in the seasonal tropics need not be cued by leaf drop

    T2 - Evidence from the woody genus Brachychiton (malvaceae)

    AU - Franklin, Donald C.

    PY - 2016/11/1

    Y1 - 2016/11/1

    N2 - Background and aims: A suite of woody plants inhabiting the seasonally-dry tropics flower while leafless during the dry season. A functional hypothesis for this phenomenon is that leaf drop early in the dry season pre-empts dehydration, and that flowering is triggered by the improved water status caused by leaf drop. If true, this would strongly constrain adaption to optimise flowering times. Methods: I examine phenological patterns in the Australasian genus Brachychiton based primarily on summary descriptions in a published taxonomic treatise, along with relevant morphological, anatomical and ecophysiological evidence, in order to evaluate the role of leaf drop, and identify other sources of hydration that may initiate or support flowering while leafless. Key results: Most of the 31 Brachychiton species are deciduous and many flower during the dry season following leaf drop, but some flower later in the dry season, at leaf flush, or when leafy. Many have enlarged stems, branchlets or tap roots, and the limited ecophysiological evidence suggests that these organs are associated with enhanced water storage potential. Brachychiton displays both considerable evidence of divergence, and a degree of phylogenetic conservatism in these traits. Conclusions: Rehydration following leaf drop is not a necessary cue to initiate flowering even when leafless. Flowering time is likely to be adaptive and species-specific in a wide range of woody plants in the seasonally-dry tropics. Care is needed to disentangle phenological correlates and the proximal and ultimate factors driving flowering.

    AB - Background and aims: A suite of woody plants inhabiting the seasonally-dry tropics flower while leafless during the dry season. A functional hypothesis for this phenomenon is that leaf drop early in the dry season pre-empts dehydration, and that flowering is triggered by the improved water status caused by leaf drop. If true, this would strongly constrain adaption to optimise flowering times. Methods: I examine phenological patterns in the Australasian genus Brachychiton based primarily on summary descriptions in a published taxonomic treatise, along with relevant morphological, anatomical and ecophysiological evidence, in order to evaluate the role of leaf drop, and identify other sources of hydration that may initiate or support flowering while leafless. Key results: Most of the 31 Brachychiton species are deciduous and many flower during the dry season following leaf drop, but some flower later in the dry season, at leaf flush, or when leafy. Many have enlarged stems, branchlets or tap roots, and the limited ecophysiological evidence suggests that these organs are associated with enhanced water storage potential. Brachychiton displays both considerable evidence of divergence, and a degree of phylogenetic conservatism in these traits. Conclusions: Rehydration following leaf drop is not a necessary cue to initiate flowering even when leafless. Flowering time is likely to be adaptive and species-specific in a wide range of woody plants in the seasonally-dry tropics. Care is needed to disentangle phenological correlates and the proximal and ultimate factors driving flowering.

    KW - Brachychiton

    KW - Deciduousness

    KW - Environmental cues

    KW - Kurrajong

    KW - Monsoonal tropics

    KW - Morphology

    KW - Phenology

    KW - Seasonal tropics

    KW - Stem water storage

    KW - Succulence

    UR - http://www.scopus.com/inward/record.url?scp=85005952187&partnerID=8YFLogxK

    U2 - 10.5091/plecevo.2016.1244

    DO - 10.5091/plecevo.2016.1244

    M3 - Article

    VL - 149

    SP - 272

    EP - 279

    JO - Plant Ecology and Evolution

    JF - Plant Ecology and Evolution

    SN - 2032-3913

    IS - 3

    ER -