Polylepis(Queñua)is a dominant woody plant genus in Andean Puna forests that occurs in a wide range of montane habitats and is ecologically diverse in endemism,which may be particularly threatened by climate chan...Polylepis(Queñua)is a dominant woody plant genus in Andean Puna forests that occurs in a wide range of montane habitats and is ecologically diverse in endemism,which may be particularly threatened by climate change.Wood anatomical traits are essential for understanding how plants adjust their ecophysiological requirements and maximize their resilience,resistance,and recovery to extreme climates.Although the effects of extreme climatic conditions in high altitude ecosystems have been studied extensively,our knowledge is relatively limited to quantitative differences in the main xylem tissues.To address this gap,we assessed the acclimation of wood anatomical traits in six Peruvian Andean Polylepis species with different water availability(semi-dry with high moisture and semiarid with dry winters).We selected hydraulic diameter,vessel density,vessel grouping index,solitary vessel index,vulnerability index,mesomorphy index,vessel element length,fiber length,fiber wall thickness,fiber lumen diameter,and total fiber diameter that can provide relevant eco-wood anatomical acclimation to hydric stress.We performed multivariate analysis to determine the leading dimensions of covariation among Polylepis species and climatic factors.Specific wood anatomical traits(vessel grouping index,vulnerability index,and fiber wall thickness)were dissimilar between xeric-and mesic-Polyelpis species.This study demonstrates that wood anatomical traits in Peruvian Andean Polylepis species provides high-resolution and long-term eco-wood anatomical signals on how climate oscillations drive the acclimation processes of fiber and vessel traits.Our findings underscore the significance of xylem hydraulic adjustment to various hydrological environments in Andean puna forests.By evaluating the effects of drought on wood anatomical characteristics and ecological function,we demonstrate the capacity of tree species to adapt and endure climate-related changes,thereby emphasizing their resilience and adaptability.展开更多
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 chronol...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.展开更多
Study on the basic anatomical characteristics of rattan canes will give great guidance to their classification, exploitation, utilization, processing and improvement. The basic anatomical characteristics and their var...Study on the basic anatomical characteristics of rattan canes will give great guidance to their classification, exploitation, utilization, processing and improvement. The basic anatomical characteristics and their variation in cane of three commercial rattans in South China, i.e. Calamus simplicifolius, Calamus tetradactylus and Daemonorops margaritae were investigated. Results show that: 1) The variation at the height of rattan canes is small, while the variation along the radius direction of rattan canes is significant. 2) The fiber length, fiber ratio and distributing density of vascular bundle in the cross section decrease from cortex to core, while the fiber width, vessel element length and width, parenchyma ratio, vessel ratio, vascular bundle size, metaxylem vessel diameter and fiber microfibrillar angle in the cross section increase from cortex to core. The cellulose crystallinity of stem core is bigger than that of the cortex. 3) All these three rattan possess the cane structure characteristics of good commercial rattan cane. As for the anatomical structure, C. simplicifolius is the best and C. tetradactylus is better than D. margaritae. 4) According to the anatomic study, the penetration approach of rattan cane is mainly the longitudinal axial passage around the core; it is an important research direction to improve the penetrability of rattan cane.展开更多
Microfibril angles of bamboo cell wall in different part of culm have been measured by using X ray diffraction(002)peaks. Its distribution shows that:(1)microfibril angle increases slightly along radial direction from...Microfibril angles of bamboo cell wall in different part of culm have been measured by using X ray diffraction(002)peaks. Its distribution shows that:(1)microfibril angle increases slightly along radial direction from the culm’s surface to its interior part. The Ansade Cortex consists of amorphous material.(2)The microfibril angles of the different parts along vertical direction in the same internode are the same.(3)The relationship between microfibril angle( θ ) and internode length( L) can be satisfactorily expressed as: L=b cos θ+a , in which \%a, b\% is constant respectively.展开更多
基金The authors are very grateful to park ranger the RPNYC,Eber Melgar Guerra Almerco for his support in sample collection and Cassiana Alves-Ferreira for his support in the Laboratorio de Anatomía e Identificación de Maderas,Universidad Continentalpartial funding provided by EJ Requena-Rojas and M Morales(047-2015-Fondecyt-DE and CONICET PIP 11220130100584 project)。
文摘Polylepis(Queñua)is a dominant woody plant genus in Andean Puna forests that occurs in a wide range of montane habitats and is ecologically diverse in endemism,which may be particularly threatened by climate change.Wood anatomical traits are essential for understanding how plants adjust their ecophysiological requirements and maximize their resilience,resistance,and recovery to extreme climates.Although the effects of extreme climatic conditions in high altitude ecosystems have been studied extensively,our knowledge is relatively limited to quantitative differences in the main xylem tissues.To address this gap,we assessed the acclimation of wood anatomical traits in six Peruvian Andean Polylepis species with different water availability(semi-dry with high moisture and semiarid with dry winters).We selected hydraulic diameter,vessel density,vessel grouping index,solitary vessel index,vulnerability index,mesomorphy index,vessel element length,fiber length,fiber wall thickness,fiber lumen diameter,and total fiber diameter that can provide relevant eco-wood anatomical acclimation to hydric stress.We performed multivariate analysis to determine the leading dimensions of covariation among Polylepis species and climatic factors.Specific wood anatomical traits(vessel grouping index,vulnerability index,and fiber wall thickness)were dissimilar between xeric-and mesic-Polyelpis species.This study demonstrates that wood anatomical traits in Peruvian Andean Polylepis species provides high-resolution and long-term eco-wood anatomical signals on how climate oscillations drive the acclimation processes of fiber and vessel traits.Our findings underscore the significance of xylem hydraulic adjustment to various hydrological environments in Andean puna forests.By evaluating the effects of drought on wood anatomical characteristics and ecological function,we demonstrate the capacity of tree species to adapt and endure climate-related changes,thereby emphasizing their resilience and adaptability.
基金supported by the Russian Science Foundation grant no. 23-44-00067the National Natural Science Foundation of China grant no.42261134537 in the framework of a joint Russian-Chinese project (fieldwork)by the Russian Ministry of Science and Higher Education,grant number FSRZ-2023-0007 (for data analysis)
文摘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.
文摘Study on the basic anatomical characteristics of rattan canes will give great guidance to their classification, exploitation, utilization, processing and improvement. The basic anatomical characteristics and their variation in cane of three commercial rattans in South China, i.e. Calamus simplicifolius, Calamus tetradactylus and Daemonorops margaritae were investigated. Results show that: 1) The variation at the height of rattan canes is small, while the variation along the radius direction of rattan canes is significant. 2) The fiber length, fiber ratio and distributing density of vascular bundle in the cross section decrease from cortex to core, while the fiber width, vessel element length and width, parenchyma ratio, vessel ratio, vascular bundle size, metaxylem vessel diameter and fiber microfibrillar angle in the cross section increase from cortex to core. The cellulose crystallinity of stem core is bigger than that of the cortex. 3) All these three rattan possess the cane structure characteristics of good commercial rattan cane. As for the anatomical structure, C. simplicifolius is the best and C. tetradactylus is better than D. margaritae. 4) According to the anatomic study, the penetration approach of rattan cane is mainly the longitudinal axial passage around the core; it is an important research direction to improve the penetrability of rattan cane.
文摘Microfibril angles of bamboo cell wall in different part of culm have been measured by using X ray diffraction(002)peaks. Its distribution shows that:(1)microfibril angle increases slightly along radial direction from the culm’s surface to its interior part. The Ansade Cortex consists of amorphous material.(2)The microfibril angles of the different parts along vertical direction in the same internode are the same.(3)The relationship between microfibril angle( θ ) and internode length( L) can be satisfactorily expressed as: L=b cos θ+a , in which \%a, b\% is constant respectively.
