%0 Journal Article
%T Intraspecific Variation in Leaf Life Span for the Semi-evergreen Liana Akebia trifoliata is Caused by Both Seasonal and Aseasonal Factors in a Temperate Forest
%A Koyama
%A Kohei
%A Kihachiro Kikuzawa
%J Journal of Ecology and Field Biology
%D 2008
%I 
%X We investigated the leaf demography of a temperate woody liana, Akebia trifoliata, in a temperateforest in Japan. Akebia is semi-evergreen: some leaves are shed before winter, while others remain through thewinter. Previous studies of semi-evergreen species found that variation in leaf life span was caused by variationin the timing of leaf emergence. Leaves that appeared just before winter over-wintered, while leaves appearingearlier were shed. However, it is unclear whether leaves of the same cohort (i.e., leaves that appear at the sametime within a single site) show variation in life span under the effect of strong seasonality. To separate variationin life span among the leaves in each cohort from variation among cohorts, we propose a new method - thesingle leaf diagram, which shows the emergence and death of each leaf. Using single leaf diagrams, our studyrevealed that Akebia leaves within a cohort showed substantial variation in life span, with some over-winteringand some not. In addition, leaves on small ramets in the understory showed great variation in life span, whileleaves on large ramets, which typically reach higher positions in the forest canopy, have shorter lives. As a result,small ramets were semi-evergreen, whereas large ramets were deciduous. The longer lives of leaves on smallramets can be interpreted as a shade-adaptive strategy in understory plants.
%K Akebia trifoliata
%K Leaf demography
%K Leaf lifespan
%K Leaf phenology
%K Liana
%K Phenotypic plasticity
%K Semi-evergreen
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