@misc{oai:niigata-u.repo.nii.ac.jp:00004861,
 author = {Kaneko, Yohei},
 month = {Mar},
 note = {Lianas (woody vines) have distinctive growth form in terms of parasitic climbing to host tree, and they are diversified throughout a plenty of taxa and genera, playing important roles in forest community. However, information of lianas’ life history has been very limited. In this study thesis, we tried to make clear the lianas’ life history from the two different view point; (1) resource allocation and allometry, and productive structure, and (2) demography and habitat preference. In Chapter 2.1, allometric analysis of four Hydrangea species (H. petiolaris, H. paniculata, H. macrophylla var. megacarpa, and H. hirta) was conducted to test the hypothesis that the liana species (H. petiolaris) invests more in leaves and reproductive organs than the shrub species. Whole plants of the four species were sampled during the flowering seasons, and dry weights of each organ (leaves, trunks, roots and reproductive organs) were compared between H. petiolaris and the shrubs. H. petiolaris differed markedly from the three shrubs in terms of trunk and root allocations, while leaf allocation was not statistically different. The C/F ratios (the ratios of the dry weights of non-photosynthetic organs to photosynthetic ones) of the four species ranged from 9 to 12, and were not statistically different. These results did not support the hypothesis. The biomass of H. petiolaris was up to 100 times greater than those of the three shrubs. The growth form of H. petiolaris would minimize allocation to supporting tissue and produce a large biomass. This advantage might therefore serve as a driving force for the evolution of lianas. In Chapter 2.2, growth rate, growth speed, and productive structure of H. petiolaris were quantified. Cross-sectional disks of each main stem were obtained, and stem analysis was conducted. Whole plants with leaves and flowers were sampled, and productive structures were described. The juveniles of H. petiolaris in pre-climbing stage were sampled, and growth rate of the creeping length of stems to the number of cell layer at the base was quantified. The maximum elongation rate was approximately 1 m/year, and the maximum diameter growth was 0.5 cm/year. Leaves, trunks and reproductive organs were arranged from 2 to 6 m in heights. The number of cell layer of creeping juveniles ranged from 3 to 17. The growth rates of the juveniles ranged from 3 to 7 cm. In Chapter 3.1, demography during early regeneration of H. petiolaris (from germination to seedling establishment) was clarified. Germination experiment was conducted on 7 different types of substrates to quantify the effect of substrates for seedlings emergence and survival of current year seedlings., Demography of natural seedlings (〓1 year old seedlings) was also monitored in coniferous forest and beech forest. The results were as follows; (1) germination rates and survival rates of current year seedlings were very low, and the values were significantly different among the substrates, (2) survival rates of natural seedlings (｡ﾝ1 year old seedlings) were relatively high, and the values were not significantly different among the substrates, (3) moss rich substrates and bare ground had significantly positive effect on the seedling establishment, and (4) relative areas of these substrates were not more than 4 %. Lateral shoot length of all natural seedlings was also measured, and the values were not more than 20 cm, suggested that it is necessary to establish around the root collar of host trees to climb on. In Chapter 3.2, three dimensional light conditions were measured in coniferous forest in order to quantify the effect of light conditions to the distribution of H. petiolaris. Spatial heterogeneity of light condition was observed not only horizontally but also vertically. In 0.2 to 2 m in heights, the light conditions were homogenous and extremely dark in all areas, while in 4 to 8 m in heights, the horizontal heterogeneity was relatively high and bright patches caused by canopy gaps were observed. We also conducted concentric and cylindrical measurements of the light conditions around the host tree, Cryptomeria japonica. On the trunk surface, shaded by host tree and shrubs, the light conditions of forest floor and just below canopy (8 m in height) were very dark. Detaching 1 m in radius from the trunk surface, the shading by host’s canopy was seldom observed, and it was suggested that the space between canopy layer and shrub layer provides preferable light condition for H. petiolaris. On the other hand, comparing the light condition between host trees and non-host trees, the mean values of host trees were greater than those of non-host trees, and statistically differences were observed at some heights, suggested that the light conditions potentially controlled the distribution of H. petiolaris. In chapter 2 and chapter 3, we succeeded to make clear the advantages and disadvantages of the distinctive life form of H. petiolaris. The species accorded huge biomass with minimum supporting tissues, resulting in huge biomass of reproductive organs. The advantages would be able to compensate the low probability of regeneration. Our size advantage hypothesis would be applicable to various root climbers., 新大院博（農）甲第76号},
 title = {Life history strategies of temperate liana Hydrangea petiolaris and its implications for the evolution of lianas},
 year = {2007}
}