Ohara, Masashi , Araki, Kiwako , Shimatani, Kenichiro .
Growth and survival patterns of a monocarpic perennial herb Cardiocrinum cordatum var. glehnii (Liliaceae), based on the 13-year monitoring study.
The transition from vegetative growth to flowering is a key decision in plant life-histories. The period before reproduction varies from within one year for annuals to several decades or hundred years for perennials. The transition also involves physiological and morphological changes, which is related to the strategies in the resource allocation, and thus consequently to the evolutionary perspectives that characterize species and/or species groups under given environmental conditions.
Cardiocrinum cordatum var. glehnii is a monocarpic perennial herb living in temperate broad-leaved deciduous forests in eastern Asia. In 1994, a permanent study plot (5m x 5m) was established and all individuals within the plot were marked. The fate and successive change of the growth stages of the marked individuals were monitored. Newly emerged shoots in the plot were additionally marked and measured until 2006. During 13 years period, 8546 individuals were identified.
The significant differences in sizes were detected between survived and dead individuals in earlier years of the juveniles. The age-wise size-dependent survival and stage-up models by the logistic regressions illustrated that the survival and stage-up probabilities increased until five years old but decreased over six year old, suggesting aging effects. The flowering probability also increased with size at the four-leaf stage and stages for plants having five or more leaves. The individual growth models picked up individuals that showed the similar curves with the models: most of the slowly growing individuals grew little and died within seven years. One flowering plant and three dead ones followed the growth models of the fast rate. Finally, the many plants and larger flowering plants showed the moderate growth rates. In conclusion, Cardiocrinum cordatum var. glehnii is characterized by the gradual and constant growth pattern to flowering with about 10 years longevity, which is quite different with other polycarpic forest herbs.
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1 - Hokkaido University, Faculty of Environmental Earth Science, Lab of Ecological Genetics, Sapporo, 060-0810, Japan
2 - The Institute of Statistical Mathematics, 4-6-7 Minami-Azabu, Tokyo, 106-8569, Japan
long term census
Presentation Type: Poster:Posters for Sections
Location: Ball Room & Party Room/SUB
Date: Monday, July 28th, 2008
Time: 12:30 PM