メタセコイアの発見と普及 ―三木 茂博士の発見から75年―

Based on an analysis of the current situation and current problems for dawn redwood, four detailed conservation measures are suggested: (1) to continuously improve the conditions of nature reserves forthe natural seed-source trees of dawn redwood, and to design a long-term programs to protect them. The organization and personnel as well a the funds should meet the needs for protection of the original natural seed-source trees of dawn redwood and their habitat; (2) to effectively implement relevant laws for protectino of dawn redwood; (3) to establish a gene-conservation forest in order to fully preserve all the original natural founder trees^ genes of dawn redwood; and (4) to actively coordinate the relationships among environmental protection agencies, forestry agencies, units of the Academy of Sciences, and other education and research units. We should cooperate and help each other in the fields of protecting dawn redwood and other natural resources by means of scientific research and exchange of research experiences.

Soil organic matter (SOM) molecular composition governs its stability and ecological functions in forest ecosystems. Nevertheless, how land-use changes (LUCs) regulate the SOM molecular composition remains poorly understood, particularly the underlying mechanisms mediated by soil properties. This study investigated the effects of LUCs on SOM molecular composition in a subtropical coastal region and examined the driving roles of soil nutrient availability and enzyme activities. The research was conducted in Huanghai National Forest Park, Jiangsu Province, China, focusing on four land-use types converted from historical wheat cropland (W, as control): monoculture plantations of Ginkgo biloba (G) and Metasequoia glyptostroboides (M), a ginkgo–metasequoia mixed forest (GM), and a ginkgo–wheat agroforestry system (GW). Soil samples were collected from 0 to 20 cm and 20–40 cm layers and analyzed for SOM molecular compositions using solid-state 13C nuclear magnetic resonance (NMR) spectroscopy. Soil chemical properties and enzyme activity activities were also determined, with redundancy analysis (RDA) and correlation analysis applied to identify key influencing factors. Results demonstrated that LUCs significantly altered SOM molecular composition. The GW system exhibited the highest proportion of labile O-alkyl carbon (42.65%), while the M plantation accumulated greatest levels of stable aromatic carbon (up to 49.25%). During the initial decades following afforestation, soil nutrient availability and enzyme activities were confirmed as pivotal drivers of SOM molecular variation. Specifically, available potassium (AK), ammonium nitrogen (AN), and the carbon/phosphorus (C/P) ratio were significantly correlated with specific SOM components (p < 0.05). The elevated O-alkyl carbon proportion in GW was closely associated with its higher invertase activity. Notably, vertical differentiation in SOM stability was observed across land-use types, with the agroforestry system achieving the highest carbon pool management index in surface soil but showing a weakened capacity for subsoil C stabilization. RDA further confirmed that AK and AN were dominant factors shaping SOM molecular composition. In conclusion, LUCs modulate SOM chemical composition and stability primarily through altering soil nutrient availability and associated enzyme activities. Agroforestry system facilitates labile C accumulation in surface soil, whereas monoculture plantations are more conducive to stable C sequestration, especially in subsoil layers. These findings provide novel mechanistic insights into SOM dynamics following LUCs and offer a theoretical basis for formulating tailored management strategies to enhance C sequestration efficiency in subtropical coastal ecosystems.

This study reviews the various conservation strategies applied to the four redwood species, namely coast redwood (Sequoia sempervirens), Sierra redwood or giant sequoia (Sequoiadendron giganteum), dawn redwood (Metasequoia glyptostroboides) and South American redwood or alerce (Fitzroya cupressoides), which are endemic in the USA, China and South America, respectively. All four redwood genera belong to the familyCupressaceae; they are monospecific, share a number of common phenotypic traits, including red wood, and are threatened in their native ranges due to human activity and a changing climate. Therefore, the management objective should be to conserve representative populations of the native species with as much genetic diversity as possible for their future survival. Those representative populations exhibiting relatively high levels of genetic diversity should be selected for germplasm preservation and monitored during the conservation phase by using molecular markers.In situandex situstrategies for the preservation of germplasm of the redwoods are discussed in this study. A holisticin situgene conservation strategy calls for the regeneration of a large number of diverse redwood genotypes that exhibit adequate levels of neutral and adaptive genetic variability, by generative and vegetative methods for their preservation and maintenance in their endemic locations. At the same time, it would be desirable to conserve the redwoods in newex situreserves, away from their endemic locations with similar as well as different environmental conditions for testing their growth and survival capacities. In addition, otherex situstrategies involving biotechnological approaches for preservation of seeds, tissues, pollen and DNA in genebanks should also be fully exploited in the face of global climate change.

The role of bioactive substances in controlling foodborne pathogens derived from Metasequoia glyptostroboides Miki ex Hu

The mechanisms regulating spring phenology have been extensively studied in angiosperm species. However, given that gymnosperms and angiosperms diverged 300 million years ago, phenology may be triggered by different cues in gymnosperm species. The regulatory mechanisms of phenology in subtropical regions remain largely unknown. In combination, it remains untested whether subtropical gymnosperm species have chilling requirements and are photosensitive. We conducted a climate chamber experiment with three chilling and three photoperiod treatments to investigate budburst during an 8-week forcing period. We tested whether budburst of eight gymnosperms species (Cryptomeria japonica, Cunninghamia lanceolata, Cupressus funebris, Ginkgo biloba, Metasequoia glyptostroboides, Pinus massoniana, Pseudolarix amabilis and Podocarpus macrophyllus) was photoperiod sensitive or has strong chilling requirements and whether photoperiod or chilling was more important for advancing budburst. Chilling advanced budburst and increased the percentage of budburst for gymnosperm species. Gymnosperm species required moderate chilling days to advance budburst. Interestingly, the forcing requirement for gymnosperm species was higher than that for angiosperms in the same forest, suggesting that gymnosperms may need more cumulative forcing to initiate budburst than do angiosperms. Compared with temperate gymnosperm species in Germany (194–600 °C days), the subtropical species studied here had a much higher forcing requirement (814–1150 °C days). The effects of photoperiod were minor, suggesting that chilling outweighs photoperiod in advancing budburst of gymnosperm species in this subtropical region. These results reveal that increased winter temperatures with continued global warming may impact not only angiosperms but also gymnosperms, leading to their delayed spring budburst.

Succession of soil macro-faunal biodiversity in forests converted from croplands after long-term coastal reclamation

Effect of urban pavement on nutrient strategies of common greening tree species in northern China

AFTER its discovery in the interior of China at latitude 30° N in 1941, Metasequoia glyptostroboides was introduced to Britain in 1948, and has been propagated by cuttings and established in botanical gardens and parks throughout the country. Although there are now specimens up to 16 m high, flowering has been confined to occasional female cones, which in the absence of pollen have not produced viable seeds1. Male cones do not seem to have been recorded here2 although both seedlings and cuttings growing in the Crimea at 45° N have produced them after an interval of 7 yr3. Flowers of both sexes have been induced in Japan by strangulation4 and by treatment with gibberellic acid5–7.

How does forest fine root litter affect the agricultural soil NH3 and N2O losses?

Metasequoia glyptostroboides Hu et W.C. Cheng, known as a living fossil species, is planted in parks, gardens, and streets in many temperate regions worldwide. Adequate branch pruning is necessary to grow the plants in these locations, and pruning generates a large amount of waste. In this study, allelopathic activity of pruned-branch waste was investigated to search for beneficial applications of the waste. The leaves of M. glyptostroboides obtained from pruned branches were extracted, and the extracts showed growth-inhibitory activity on four weed species, namely, Vulpia myuros, Lolium multiflorum, Echinochloa crus-galli, and Phleum pretense. The inhibition was extract-concentration dependent. The roots of P. pretense were the most sensitive, and the coleoptiles of E. crus-galli were the least sensitive to the extracts among all roots and coleoptiles of these weed species. Two allelopathic substances in the extracts were isolated and identified as umbelliferone and (+)-rhododendrol. Both compounds showed inhibitory activity on the growth of V. myuros, although the inhibitory activity of (+)-rhododendrol was much greater than that of umbelliferone. The leaves may also contain some other allelopathic substances. These allelopathic substances, including umbelliferone and (+)-rhododendrol, may work as growth-inhibitory substances of leaf extracts. Therefore, the leaves of M. glyptostroboides obtained from pruned branches are allelopathic and potentially useful for weed control in certain agricultural settings such as foliar spray and soil additive, to decrease synthetic herbicide application in crop production pursuant to developing ecofriendly agriculture.

【Purpose】Urban green spaces mitigate carbon emissions, boost carbon sinks, and address environmental risks. Analyzing their types, carbon stocks, and key tree species' sequestration capacity aids in improving green space management. This advances the "Carbon Peak, Carbon Neutral" strategy, guiding greening industry development and robust ecosystem construction.【Method】A systematic survey was conducted at representative urban green space sites, establishing observation plots to study species composition and woody plant populations. The carbon sequestration capacity of major tree species was evaluated considering baseline carbon stock and a latitude correction parameter.【Result】The total carbon stock in Suqian's urban green spaces stands at 136,285.47 tons, with regional green spaces contributing the most, followed by parks and protective green spaces, while subsidiaries account for the least. Analysis reveals that the arbor layer is the primary carbon pool, surpassing soil, shrub, and herb layers. Notably, different arbor species exhibit significant variations in carbon sink capacity. There is an obvious difference in the carbon sink capacity of different tree species, and among the 30 major tree species in Suqian City, there is an obvious difference in the carbon sink capacity of different tree species, and there is an obvious difference in the carbon sink capacity of different tree species，Populus adenopoda, Populus × canadensis, Cedrus deodara, Triadica sebifera, Celtis julianae, Celtis sinensis, Liquidambar formosana, Malus spectabilis, Ligustrum lucidum, Acer buergerianum, Osmanthus fragrans, Metasequoia glyptostroboides, Ginkgo bilobaet al. Carbon sink capacity is weaker, and the carbon sink capacity of species will not be insignificantly related to the length of the time interval, but will be affected by the latitudinal zonal space。【Conclusion】 For urban green space management, trees are pivotal, dominating carbon sequestration potential compared to shrubs and herbs. Thus, studying carbon sequestration and oxygen release of tree communities is crucial. Additionally, attention should be given to tree configuration and species selection, prioritizing locally adapted, high-carbon sequestration trees while considering landscape aesthetics and biodiversity conservation, for efficient urban green space management.

Metaseol, a symmetrical diphenylmethane from Metasequoia glyptostroboides

previously known from fossil material was discovered as a living tree in the early 1940s in southeast China. The first seeds were received in 1948 in the Netherlands and the first plants were planted in 1957. The research on this species started in the beginning of the 1960s. The aim of the research was to investigate its possible use in forestry as a good alternative for other species. In 1967 an overview of the first experiences on Metasequoia glyptostroboides in the Netherlands was given. Research on the growth and habitus of the different clonals was done in 1992. In this study, the wood was examined regarding anatomical characteristics, physical-mechanical and chemical properties as well as durability. A total of 23 trees from two different stands was selected for this purpose. The data of the different properties were compared with those of Metasequoia glyptostroboides grown in other countries and other commercial softwood species. The average fibre length proved to be longer than the British data but shorter than the fibres measured on a specimen of Metasequoia from China. Strength properties and density gave lower values compared to data of Metasequoia from other countries and commercial species. The tangential swelling and shrinkage was relatively high. With respect to the chemical composition, the difference in the extractive substances of heartwood and sapwood was remarkable. The durability tests showed higher durability for Metasequoia heartwood than for Scots pine and Douglas fir. Presently, timber of the young plantation-grown Metasequoia is not of high commercial interest in the Netherlands. However, considering its production and good silvicultural treatment, the species might be of interest as a source of plantation grown softwood.

21 - Experimental evaluation of photosystem parameters and their role in the evolution of stand structure and deciduousness in response to palaeoclimate seasonality in Metasequoia glyptostroboides (Hu et Cheng)

The liquefaction of wood (Metasequoia glyptostroboides) has been studied in two imidazole-based ionic liquids: IL1, 3,3′-ethane-1,2-diylbis(1-methyl-1H-imidazol-3-ium) dichloride; and IL2, 3,3′-ethane-1,2-diylbis(1-methyl-1H-imidazol-3-ium) dichloroaluminate. Rapid and complete liquefaction was obtained in IL2 without residue at 120°C for 25 min, in contrast to liquefaction in phenol/H2SO4 (liquid/wood ratio 20:1) with 25.9% residue. Temperature- and time-dependent studies indicate that the performance of the reagents investigated is IL2>IL1> phenol/H2SO4. The liquid/wood ratio and the amount of AlCl3 as catalyst affect the liquefaction rate. In the course of liquefaction with IL2, AlCl3 plays a dual role as a catalyst and a liquefaction reagent. Ionic liquids separated from the liquefied product can be recycled at least five times to maintain a good liquefaction rate.