Conditions for the development of the Pinus pumila zone of Hokkaido,northern Japan

The development of the Pinus pumila zone of Hokkaido, northern Japan is discussed on the basis of an examination of the Warmth Index (WI). The Pinus pumila zone is developed on deforested areas in the boreal subalpine belt, and is characterized by strong wind and heavy snow accumulation in winter, and by the presence of rocky fields. It is concluded that in Japan, including Hokkaido, this high mountain zone generally is intrazonal, belonging mainly to the subalpine belt, and that such zones are not common in Europe and North America. Its formation is due mainly to present-day wind, snow and substrate conditions and partly to conditions prevailing during the glacial period.     

Δ13C and tree-ring width reflect different drought responses in Quercus ilex and Pinus halepensis

Holm oak (Quercus ilex L.) and Aleppo pine (Pinus halepensis Mill) are representative of two different functional types of trees extensively found in the Mediterranean: evergreen sclerophyllous and drought-adapted conifers. The former is considered a partially drought-tolerant species, whereas the latter is a typically drought-avoiding, water-saving species. We postulated that contrasting strategies in response to water deficits in Q. ilex and P. halepensis would lead to a differential sensitivity to changes in water availability. To test this hypothesis, we compared the response of both species in growth rate (measured as radial increments) and intrinsic water use efficiency [WUE_i, as inferred from carbon isotope discrimination (¹³C) in wood samples] among sites from different provenance regions in NE Spain. We found significant differences in ¹³C and growth among provenance regions, partly explained by contrasting water availability. Wood ¹³C was positively related with precipitation and the ratio between precipitation and potential evapotranspiration (P / E). However, these relationships were stronger in P. halepensis (for P / E, r ²=0.67, P <0.001) than in Q. ilex (r ²=0.42, P <0.01). In addition, radial growth was positively related with precipitation and ¹³C in P. halepensis (r ²=0.32 and r ²=0.35, respectively, P <0.01), but not in Q. ilex. We concluded that P. halepensis was more sensitive than Q. ilex to water availability, showing faster increase in WUE_i in response to water stress. We also found that the effect of north/south aspect on ¹³C and growth was site-specific, and unrelated to climatic variables.Due to an error in the citation line, this revised PDF (published in December 2003) deviates from the printed version, and is the correct and authoritative version of the paper.     

Comparative study of the effects of temperature on net photosynthesis and respiration in lichens from the antarctic and subalpine zones in Japan

Photosynthetic activity and dark respiration were measured in some species of lichens,Umbilicaria, Cladonia, Stereocaulon, Usnea, etc. sampled in the Antarctic and subalpine zones of central and northern Japan. On the basis of the responses of their activities to thallus temperature, the response patterns were divived into three groups, and further, each group was subdvided into some adaptation types for net photosynthesis and repiration. Lichens collected in the Antarctic were adapted to cool condition and some species collected in subalpine zones were adapted to warm condition. For exmaple, the optimal temperatures for net photosynthetic rates in Antarctic lichens were lower than 5 C and those in lichens which lived on rock surface at a southern slope in mountains of Japan were higher than 20 C.     

Temperature versus species-specific influences on the stable oxygen isotope ratio of tree rings

Stable isotopic ratios integrate ecosystem variability while reflecting change in both environmental and biological processes. At sites, where climate does not strongly limit tree growth, co-occurring trees may display large discrepancies in stable oxygen isotopic ratios (δ¹⁸O) due to the interplay between biological processes (competition for light and nutrients, individual tree physiology, etc.) and climate. For a better quantification of the isotope variability within and among trees, the climatic and/or individual tree effects on seasonal δ¹⁸O variations in precipitation, soil water, leaf water and leaf organic material (whole leaf, cellulose and starch) and annual δ¹⁸O variations in tree-ring cellulose for Fagus sylvatica (Fs), Quercus robur (Qr), Carpinus betulus (Cb) and Pinus sylvestris (Ps) were studied in a mature temperate forest in Switzerland, using a mixed linear regression model technique. Furthermore, the influence of environmental factors on δ¹⁸O was assessed by means of three common isotope fractionation models. Our statistical analysis showed that except for Ps, a greater portion of δ¹⁸O variance in leaf compounds can be explained by individual tree effects, compared to temperature. Concerning tree-ring cellulose, only Fs and Ps show a significant temperature signal (maximum 12% of the variance explained), while the individual tree effect significantly explains δ¹⁸O for all species for a period of 38 years. Large species differences resulted in a limited ability of the isotope fractionation models to predict measured values. Overall, we conclude that in a diverse mixed forest stand, individual tree responses reduce the potential extraction of a temperature signal from δ¹⁸O.     

Developing tree ring chronologies from New Zealand matai (Prumnopitys taxifolia (D.Don) Laub.) for archaeological dating: Stable isotope dendrochronology

Aotearoa New Zealand has a rich cultural heritage but dating wooden objects using classic dendrochronology is challenging due to a paucity of master tree-ring width chronologies for species commonly identified in the archaeological record. This paper explores the potential for using a stable isotopic approach to dendrochronology for matai (Prumnopitys taxifolia (D.Don) Laub.). A total of six annual stable oxygen isotope (δ¹⁸O) series for matai growing in the Pureora Forest Reserve, were analysed and their oxygen isotopes found to exhibit a level of coherence that enabled cross-dating. A provisional chronology covering the period 1930–2018 CE was developed and tested against a sample of matai from the Kauaeranga Valley (200 km to the north of Pureora) and a sample of miro (Prumnopitys ferruginea (D.Don) Laub.). Miro is another species common in the cultural archive, but also difficult to date using ring-width dendrochronology. Both the Kaueranga matai and Pureora miro samples cross matched against the site chronology at the correct position, but with weaker dating statistics (Student’s t: 4.26 and 4.11 respectively) compared to the results obtained for two (non-2019) sampled Pureora matai analysed in this study (Student's t: 6.80 and 5.66). These results nevertheless demonstrate the presence of a regional-scale dating signal which may be developed for future use as a precision dating tool.     

Foraminiferal oxygen and carbon isotopes during the last 34 kyr off northern Japan, northwestern Pacific

Oxygen and carbon isotopes of foraminifera were analyzed in core PC4, water depth 1366 m, off northern Japan, near the east side of the Tsugaru Strait (130 m depth) between the open northwestern Pacific Ocean and the Japan Sea. At present, the site is at the confluence of the Tsugaru Warm Current which flows eastwards out of the Sea of Japan through the Tsugaru Strait, the subarctic Oyashio Current and the subtropic Kuroshio Current. During the Last Glacial Maximum (LGM), the Oyashio Current penetrated further to the South and outflow from the Japan Sea was restricted by glacio-eustatic sea level lowering.The isotopic values of the planktic foraminifer Neogloboquadrina pachyderma (sinistral) and the benthic foraminifer Uvigerina akitaensis reflect rapid millennial-scale paleoceanographic changes between 34 and 6 ka. Hydrographic changes during deglaciation were related to events at high northern latitudes, but Holocene hydrographic changes were dominated by local effects, such as the development of the outflow of the Tsugaru Warm Current. High values of planktic δ¹⁸O during the LGM reflect the southward advance of the Oyashio Current. These values decreased by 0.3‰ from 19.4 to 18.9 ka, then increased by 0.5‰ at 18 ka, with highest values between 17.5 and 15 ka. The δ¹⁸O oscillations between 19.4 and 15 ka may reflect millennial-scale warm–cold oscillations during Heinrich event 1. Planktic microfossil data indicate that cold Oyashio waters flowed from the northwestern Pacific into the Japan Sea via the Tsugaru Strait between 17 and 16 ka, consistent with the occurrence of the highest planktic δ¹⁸O values in core PC4. Planktic δ¹⁸O values rapidly decreased by 0.9‰ at 15 ka, possibly reflecting the effects of both a rapid increase in fresh water flux and rising temperatures in the subarctic North Pacific. During the Younger Dryas, cold event planktic δ¹⁸O values increased by 0.5‰, followed by a gradual decrease by 1‰ from the early to middle Holocene, reflecting a gradual increase in eastward outflow via the Tsugaru Strait with sea level rise. Both planktic and benthic foraminiferal δ¹³C values oscillated between 34 and 10 ka, at relatively large amplitudes (about 0.5‰), then remained relatively stable during the last 10 kyr. Several negative planktic and benthic ( − 0.7‰) δ¹³C excursions were present in sediment dated between the precipitation of secondary carbonates during episodic methane release possibly associated with methane release from continental margin sediments.     

Influence of water flow on skeletal isotopic composition in the coral Pocillopora damicornis

Fragments of branching Pocillopora damicornis coral colonies were grown in experimental flumes under two water flow regimes. Colony size and buoyant weight increased most rapidly in the fast-flow regime. Branch tips from the upper and outer parts of the colonies showed the lowest and most consistent skeletal oxygen isotope ratios. Flow regime had little influence on the lowest oxygen isotope ratios, which were at least 3.5‰ lighter than the calculated oxygen isotopic equilibrium. These “kinetic” isotope effects are comparable to those observed in Porites corals. Relatively more branch tips showed extreme ¹⁸O depletions under low-flow conditions, and among small coral colonies. Isotopic variability was greater among branch tips from the lower and inner parts of the colonies and at high flow. Skeletal oxygen and carbon isotope ratios generally showed positive correlations. Despite the particularly large offsets from isotopic equilibrium, the isotopically lightest branches showed the greatest isotopic consistency and therefore would make the best isotopic thermometers. Isotopic variability within the colony may provide an indication of flow regime.     

Volcanic activity signals in tree-rings at the treeline of the Popocatépetl,Mexico

The Popocatépetl volcano resumed its eruptive activity in 1994 and is still active. The largest eruption recorded during this new stage of activity occurred in December 2000. We traced the volcanic activity signal in tree-rings from Pinus hartwegii trees located in the north slope of the volcano, located at ∼3 km from the volcanic cone. Annually resolved tree-ring widths, elemental and stable δ¹³C and δ¹⁸O isotope composition were measured during the period 1989–2014 to study the effects of the volcanic activity on trees. Our results indicate a high increase in the concentration of metal elements (Co, Cr, Cu, Fe, Li, Mo, Ni, Pb, Rb, Sr, Ti, Zn) in tree rings following the major 2000 volcanic eruption, compared to the pre-eruption period from 1989 to 1993. Other chemical elements such as Al, K and S peaked 2 years later, in the 2003 tree ring, that matched with the formation of a very narrow ring that year. This sharp reduction of growth was probably driven by a combination of harsh climatic conditions (drought) with the lagged negative effects of the 2000 eruption. Carbon isotope discrimination (Δ¹³C) and δ¹⁸O increased from 1995 to 2006, suggesting reduced stomatal conductance, photosynthetic activity and water use efficiency due to the large dust veil covering the study zone. The variation of relevant elements (Ca, Mn) showing significant correlations with tree growth, Δ¹³C and δ¹⁸O can be attributed to the selective availability of elements following the soil acidification caused by the volcanic activity. Our findings suggest that the recent activity of the Popocatépetl might have increased tree vulnerability, as reflected in the sharp reduction of growth following the drought recorded 2 years after the large eruption of December 2000. Our results warn about the cumulative negative effects of volcanic activity and harsh climatic conditions on tree growth and functioning.     

Limited uptake of summer precipitation by bigtooth maple (Acer grandidentatum Nutt) and Gambel's oak (Quereus gambelii Nutt)

Winter and spring precipitation that saturates to deep soil layers precedes summer droughts in the Intermountain West. Occasional summer convection storms relieve summer drought, but are infrequent and unreliable from year to year, leading to the hypothesis that dominant tree species might not invest limited carbon reserves to surface roots to take up summer precipitation in these regions. We compared the hydrogen (D) and oxygen (¹⁸O) isotope ratios of winter, spring and summer precipitation to that of xylem sap water in Acer grandidentatum and Quercus gambelii, two dominant trees of this region. By this method we could identify water sources utilized throughout the growing season. Xylem D and ¹⁸O values changed significantly when each species leafed-out; this change was not associated with changes in either soil or plant water status (as measured by predawn and midday water potentials). This shift is apparently related increased transpirational flux, which may flush out residual stem water from the previous growing season. D values of xylem sap of both species matched winter precipitation input values throughout most of the summer, indicating a reliance on deep-soil moisture sources throughout the growing season. Mature Q. gambelii did not take up summer precipitation, whereas A. grandidentatum responded slightly to the largest summer rain event. Small trees of both species, particularly A. grandidentatum, showed a limited uptake of summer rains.     

滇西北亚高山针叶林带的外生菌根调查

本文报道了滇西北亚高山针叶林带的外生菌根调查工作。对一些亚高山针叶树种的外生菌根及其形态学和解剖学等方面进行了比较。调查结果表明,该地主要树种如长苞冷杉(Abies georgeiOrr.)、丽江云杉(Picea likiangensis Pritz.)、高山松(Pinus densata Mast.)、垂枝云杉(Picea brachytyla(Fr.)Pritz.)以及少数大果红杉(Larix potaninii Batal.)与担子菌类真菌形成外生菌根。长苞冷杉根系所形成的菌根形态多为棍棒型;丽江云杉的菌根形态多为单轴式分枝型;高山松的菌根形态都是二叉状分枝型。     

针叶树体细胞无性系研究和应用进展

针叶树体细胞无性系的建立是加速其品种改良和良种繁育的基础,在无性系林业的发展、园林绿化和环境保护等方面也有十分重要的作用。本文从形态发生的不同途径全面综述了目前国内外有关针叶树体细胞胚胎发生、器官发生和腋芽增殖植株再生的研究进展,概括了每一形态发生途径的培养过程、影响因素及其在实际生产中的应用前景。同时对不同形态发生途径的树种及其在外植体来源和分化与再生结果的不同等的文献报道进行了详尽的统计和收录,为我国充分开展这一方面的研究提供了有价值的资料 。     

Induction of a virulence response in Agrobacterium tumefaciens by exudates of Pinus pinea cotyledons

As a preliminary step in efforts to develop a successful protocol for Agrobacterium-mediated transformation of cotyledonary explants of Pinus pinea L. embryos, we tested the ability of embrionary exudates of this species to induce the expression of the virulence genes virA, virB, virC, virD, virE and virG in Agrobacterium tumefaciens containing vir: lacZ fusion constructs. The results obtained in the vir induction assay indicated the absence of bactericidal or bacteriostatic plant compounds affecting A. tumefaciens growth, and showed that cotyledonary and embrionary exudates of P. pinea are able to induce all virulence genes studied, except virG. The data suggest that A. tumefaciens can be used for gene transfer into this important forest and fruit species. This revised version was published online in June 2006 with corrections to the Cover Date.     

不同含湿率及加载条件对人皮质骨纳米压痕测试的影响

目的:探讨不同含湿率及加载条件对人皮质骨纳米压痕测试的影响。方法:采用美国Hysitron纳米压痕仪,设定不同加载模式(高峰载荷分别为300、400、500 nm;加载速度分别为6、8、10 nm/s)对不同含湿率(20‰、30‰、40‰、50‰、60‰)人皮质骨进行弹性模量及硬度测量。结果:在同一加载模式下,不同含湿率标本的测试值随着含湿率增高,弹性模量及硬度值均显著降低(P0.01);三种不同加载模式对含湿率为20‰标本测试值无明显变化;对含湿率60‰标本测试值有显著性影响(P0.02)。结论:纳米压痕仪测试骨微观力学特性时,测试值不仅受标本本身含湿率的影响,当测试条件改变,对湿润标本测试结果也完全不同。当使用纳米压痕技术时,通常采用脱水包埋处理的标本测试出的机械性能,对我们在微观层面认识人体骨在湿润的生理环境下的机械性能是不够全面的。     

Gene trees and species trees – mutual influences and interdependences of population genetics and systematics

Both population genetics and systematics are core disciplines of evolutionary biology. While systematics deals with genealogical relationships among taxa, population genetics has mainly been based on allele frequencies and the distribution of genetic variants whose genealogical relations could for a long time, due mainly to methodological constraints, not be inferred. The advent of mitochondrial DNA analyses and modern sequencing techniques in the 1970s revolutionized evolutionary genetic studies and gave rise to molecular phylogenetics. In the wake of this new development systematic approaches and principles were incorporated into intraspecific studies at the population level, e.g. the concept of monophyly which is used to delineate evolutionarily significant units in conservation biology. A new discipline combining phylogenetic analyses of genetic lineages with their geographic distribution ('phylogeography') was introduced as an explicit synthesis of population genetics and systematics. On the other hand, it has increasingly become obvious that discordances between gene trees and species trees not only result from spurious data sets or methodological flaws in phylogenetic analyses, but that they often reflect real population genetic processes such as lineage sorting or hybridization. These processes have to be taken into account when evaluating the reliability of gene trees to avoid wrong phylogenetic conclusions. The present review focuses on the phenomenon of non-phylogenetic sorting of ancestral polymorphisms, its probability and its consequences for molecular systematics.     

The potential contribution of conifer plantations to the UK Biodiversity Action Plan

Summary

The detrimental effects of conifer plantations on open ground habitats have been well catalogued and discussed, but the potential contribution of planted forests to the conservation of woodland biodiversity has not been quantified to the same extent. This quantification is needed urgently to help forest managers fulfil commitments to biodiversity enhancement as outlined in the UK Biodiversity Action Plan, the UK Forestry Standard and the UK Woodland Assurance Scheme (UKWAS). Results are presented from a five-year programme of research aimed at obtaining baseline information on biodiversity in planted forests and evaluating the contribution of planted forests to the conservation of native flora and fauna. Fifty-two plots were surveyed in total, covering a range of different tree crops (Scots pine Pinus sylvestris L., Sitka spruce Picea sitchensis (Bong.) Carr., Norway spruce Picea abies L. and Corsican pine Pinus nigra var maritima (Aitón) Melville) and stand ages (pre-thicket, mid-rotation, mature and over-mature) in three contrasting bioclimatic zones (upland, foothills and lowlands) throughout Britain. Additional plots were established in semi-natural woodland to allow comparisons between the biodiversity of plantations and native stands. Over 2000 species were recorded in total, including 45 Red Data Book species. Planted stands had similar or richer fungal and invertebrate communities to those of the native stands but poorer lichen and vascular plant communities. The latter were strongly affected by shading, dense, mid-rotation Sitka spruce stands having the lowest species counts. In contrast, these stands had a high diversity of mycorrhizal fungi, including a number of rare and threatened species normally associated with native pine wood. Bryophyte species-richness was related more to climate than woodland type, with the wetter upland spruce and native oak stands having the most diverse communities. Compared to the younger planted stands, over-mature planted stands had a higher proportion of species characteristic of semi-natural woodland stands. This related to greater structural diversity and higher deadwood volumes in the over-mature stands. It is concluded that conifer plantations make a positive contribution to biodiversity conservation in the UK and hence to the UK Biodiversity Action Plan. No single stand or crop type provides ‘optimal’ conditions for biodiversity, but the habitat value of plantations could be enhanced by increasing the area managed under alternative systems to clear-felling, such as ‘continuous cover’ and/or non-intervention natural reserves.