Wood anatomy chronologies of Scots pine in the foothills of the Western Sayan(Siberia)

Recent methodological advances in quantitative wood anatomy have provided new insights into the climatic responses of radial growth at the scale of cell structure of tree rings. This study considered long-term chronologies of tracheid measurements, indexed by a novel approach to separate their specific climatic responses from signal recorded in cell production(closely reflected in tree-ring width). To fill gaps in understanding the impact of climate on conifer xylem structure, Scots pine(Pinus sylvestris L.)trees > 200 years old were selected within the forest-steppe zone in southern Siberia. Such habitats undergo mild moisture deficits and the resulting climatic regulation of growth processes. Mean and maximum values of cell radial diameter and cell wall thickness were recorded for each tree ring.Despite a low level of climatogenic stress, components of cell chronologies independent of cambial activity were separated to obtain significant climatic signals revealing the timing of the specific stages of tracheid differentiation. Cell expansion lasted from mid-April to July and was impacted similarly to tree-ring width(stimulated by precipitation and stressed by heat), maximum cell size formed late June. A switch in the climatic responses of mean anatomical traits indicated transition to latewood in mid-July. Secondary wall deposition lasted until mid-September, suppressed by end of season temperatures. Generally, anatomical climatic responses were modulated by a less dry May and September compared with summer months.

Analysis of Wood Anatomy Characteristics by Fast Fourier Transfer Image Analysis

Fast Fourier Transfer Image Processing was widely applied to the analysis of wood anatomy structure in re-cent years. The cells in the wood transverse section have obviously periodicity and regularity. FFT power spectral patternscan extract the periodic characteristics so that they can be compared. identified and classified quaytitatively. This paperSummarizes the application of FFT image analysis in wood science and the general way to study wood anatomy by FFT.

Warming induced changes in wood matter accumulation in tracheid walls of spruce

The warming-driven increase of the vegetation season length impacts both net productivity and phenology of plants, changing an annual carbon cycle of terrestrial ecosystems. To evaluate this influence, tree growth along the temperature gradients can be investigated on various organization levels, beginning from detailed climatic records in xylem cells’ number and morphometric parameters. In this study, the Borus Ridge of the Western Sayan Mountains(South Siberia) was considered as a forest area under rapid climate change caused by massive Sayano-Shushenskoe reservoir. Several parameters of the xylem anatomical structure in Siberian spruce(Picea obovata Ledeb.)were derived from normalized tracheidograms of cell radial diameter and cell wall thickness and analyzed during 50 years across elevational gradient(at 520,960, and 1320 m a.s.l.). On the regional scale, the main warming by 0.42°C per decade occurs during cold period(November–March). Construction of the reservoir accelerated local warming substantially since 1980, when abrupt shift of the cold season temperature by 2.6°C occurred. It led to the vegetation season beginning 3-6 days earlier and ending 4-10 day later with more stable summer heat supply. Two spatial patterns were found in climatic response of maximal cell wall thickness:(1)temperature has maximal impact during 21-day period, and its seasonality shifts with elevation in tune with temperature gradient;(2) response to the date of temperature passing +9.5°C threshold is observed at two higher sites. Climate change yielded significantly bigger early wood spruce tracheids at all sites, but its impact on cell wall deposition process had elevational gradient: maximal wall thickness increased by 7.9% at the treeline, by 18.2% mid-range,and decreased by 4.9% at the lower boundary of spruce growth;normalized total cell wall area increased by 6.2%-6.8% at two higher sites but remained stable at the lowest one. We believe that these patterns are caused by two mechanisms of spruce secondary growth cessation: "emergency"induced by temperature drop versus "regular" one in warmer conditions. Therefore, autumn lengthening of growth season stimulated wood matter accumulation in tracheid walls mainly in cold environment,increasing role of boreal and mountain forests in carbon cycle.

Anatomical variations in wood among four native species of Leguminosae grown in arid areas of China

Morphological features and anatomical variations are described and illustrated in detail for four native species of Legnminosae grown in arid sandy regions in China, which are Hedysarum scoparium Fisch.et Mey., Caragana korshiskii Kom., Lespedeza bicolor Turcz. and Ammopiptanthus mongolicus （Maxim. ex Kom.） Cheng f. All species showed similar morphological features： distinct growth ring boundaries, ring to semi-ring-porosity, simple perforation plates, alternate intervessel pitting, nonseptate fibers, paratracheal confluent axial parenchyma, helical thickenings and heterocellular rays. However, the vessel arrangement and their quantitative features were different. A. mongolicus had smaller vessel diameters and larger vessel fi＇equency, while the values in the other three species were similar, but bigger than those in A. mongolicus. The variation of vessel lengths and fiber lengths along a horizontal direction showed an irregular tendency. There were significant differences in both fiber lengths and vessel element lengths among trees and within trees, except for A. mongolicus. The relationships between anatomical features of secondary xylem and the adaptability of these species to desert environments are also discussed.

Differences of Wood Elements of Prosopis laevigata from Two Areas of Northeast Mexico

Anatomical features of wood have a great variation among species as a result of genetic and environmental factors. The anatomical heartwood characteristics of Prosopis laevigata species from two areas with differences on temperature and rain precipitation on northeast Mexico were compared. Fibers length (μm), diameter of vessels (μm), and the area of the vessels (μm-2) were measured using light microscopy coupled with a digitized-image analysis system. The differences were statistically analyzed with analysis of variance. Statistical differences between fibers length (p 0.0001) and diameter of the vessels (p 0.001) from the two localities were found. The locality Linares, Nuevo León, Mexico, with higher precipitation and lower temperature, showed higher fiber length and higher diameter of the vessels than China, Nuevo León. Hard environmental conditions, where low precipitation values and high temperatures prevail, condition P. laevigata trees do reduce the risk of losing water.

Ecological Wood Adaptation and Horizontal Variations of Vessel Element and Fibre Length of Calligonum mongolicum

Wood anatomy of Calligonum mongolicum Turcz. was described from an ecological perspective. This species showed similar wood structure to that species published in the same genus. This species has distinct growth ring boundaries, ring-porosity, distinct helical thickenings, simple perforation plate, nonseptate fibre, axial parenchyma, uni- or 2-5-seriate heterogeneous rays, and alternate intervessel pitting. It was observed that there is a slightly increase of fibre length as the diameter from the pith increases. However, the vessel element length remains more or less constant from pith to bark. Furthermore, the relationships between anatomical features and adaptability to desert environments were discussed.

Drought effects on the plasticity in vessel traits of two endemic Magnolia species in the tropical montane cloud forests of eastern Mexico

Aims We aimed to evaluate how climatic fluctuations influence the plasticity of anatomical vessel traits and the width of annual tree-rings of two relict-endemic Mexican Magnolia species.Notwithstanding,few studies have assessed the drought effect on vessel traits in tropical montane cloud trees of eastern Mexico.Methods Through digital images of growth rings,we assessed the tree radial growth rate,age of the trees and plasticity in vessel traits regarding climatic fluctuations of the Mexican Magnolia species studied.We compared vessel density,hydraulic diameter and percentage of conductive area in drought years(DY)and non-drought years(NDY)in two Mexican Magnolia species.Important Findings For the first time,the plasticity that occurs in porous wood vessel traits to long-term climatic fluctuations was analysed for two endangered Magnolia species(Magnolia vovidesii and M.schiedeana)from two tropical montane cloud forests in Mexico.We found that temperature and precipitation were strongly associated with differences in tree-ring width when DY and NDY were compared.Our analyses revealed that a high plasticity in vessel anatomy of diffuse-porous wood was related to temperature and/or water availability for both Magnolia species studied.We concluded that anatomical adaptations to DY resulted in a substantial reduction in vessel traits when compared with NDY,and that the plastic adaptations played an essential role in water transport and safety for the survival of the studied species during stressful long periods.