How are leaves plumbed inside a branch? Differences in leaf-to-leaf hydraulic sectoriality among six temperate tree species

The transport of water, sugar, and nutrients in trees is restricted to specific vascular pathways, and thus organs may be relatively isolated from one another (i.e. sectored). Strongly sectored leaf-to-leaf pathways have been shown for the transport of sugar and signal molecules within a shoot, but not previously for water transport. The hydraulic sectoriality of leaf-to-leaf pathways was determined for current year shoots of six temperate deciduous tree species (three ring-porous: Castanea dentata, Fraxinus americana, and Quercus rubra, and three diffuse-porous: Acer saccharum, Betula papyrifera, and Liriodendron tulipifera). Hydraulic sectoriality was determined using dye staining and a hydraulic method. In the dye method, leaf blades were removed and dye was forced into the most proximal petiole. For each petiole the vascular traces that were shared with the proximal petiole were counted. For other shoots, measurements were made of the leaf-area-specific hydraulic conductivity for the leaf-to-leaf pathways (k(LL)). In five out of the six species, patterns of sectoriality reflected phyllotaxy; both the sharing of vascular bundles between leaves and k(LL) were higher for orthostichous than non-orthostichous leaf pairs. For each species, leaf-to-leaf sectoriality was determined as the proportional differences between non-orthostichous versus orthostichous leaf pairs in their staining of shared vascular bundles and in their k(LL); for the six species these two indices of sectoriality were strongly correlated (R2=0.94; P <0.002). Species varied 8-fold in their k(LL)-based sectoriality, and ring-porous species were more sectored than diffuse-porous species. Differential leaf-to-leaf sectoriality has implications for species-specific co-ordination of leaf gas exchange and water relations within a branch, especially during fluctuations in irradiance and water and nutrient availability.     

Comparative wood anatomy of Andromedeae s.s., Gaultherieae, Lyonieae and Oxydendreae (Vaccinioideae, Ericaceae s.l.)

The wood anatomical structure of 11 out of 13 genera from four tribes of the Vaccinioideae, namely Andromedeae s.s. , Gaultherieae, Lyonieae and Oxydendreae (Ericaceae s.l. ), is described using light and scanning electron microscopy. Several features of the secondary xylem support the tribal classification based on molecular data: arrangement of vessel-ray pitting, height of multiseriate rays and the shape of the body ray cells. Oxydendreae are clearly defined from the other representatives by various wood anatomical features. Gaultherieae can be distinguished from Lyonieae by differences in vessel perforation plates, vessel-ray pitting, height and structure of multiseriate rays, and occurrence of prismatic crystals, but the wood of Andromedeae s.s. is similar to Gaultherieae. Moreover, Andromedeae s.s. , Oxydendreae and Vaccinieae are characterized by their pith structure, whereas considerable variation in the pith cells is found in Lyonieae and Gaultherieae.  © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society , 2004, 144 , 161–179.     

The major veins of mesomorphic leaves revisited: tests for conductive overload in Acer saccharum (Aceraceae) and Quercus rubra (Fagaceae)

Many leaves survive the severing of their major veins in apparently excellent health. According to the classical explanation, the leaf minor veins provide "conductive overload," an excess of parallel conductive paths, rendering the major veins hydraulically dispensable. Whether such an excess of conductive paths exists has important implications for vascular design and for leaf response to vascular damage. We subjected leaves of Acer saccharum and Quercus rubra to cutting treatments that disrupted the major vein system and determined leaf survival, stomatal conductance (g), quantum yield of photosystem II (Φ(PSII)), and leaf hydraulic conductance (K(leaf)). For A. saccharum, the cuts led to the death of distal lamina. For Q. rubra, however, the treated leaves typically remained apparently healthy. Despite their appearance, the treated Q. rubra leaves had a strongly reduced K(leaf), relative to control leaves, and g and Φ(PSII) were reduced distal to the cuts, respectively, by 75-97% and 48-76%. Gas exchange proximal to the cuts was unaffected, indicating the independence of lamina regions and their local stomata. Analogous results were obtained with excised Q. rubra leaves. These studies demonstrate an indispensable, vital role of the major veins in conducting water throughout the lamina.     

Logistic regression in comparative wood anatomy: tracheid types, wood anatomical terminology, and new inferences from the Carlquist and Hoekman southern Californian data set

Despite collecting copious amounts of data, wood anatomists rarely perform appropriate statistical analyses, especially in the case of categorical variables. Nevertheless, anatomists have succeeded in identifying strong ecological trends. We show that, with only a slightly more sophisticated analysis, the strength and significance of 'well-known' associations can be quantified, and new associations pinpointed. Using logistic regression to reanalyse the classic Carlquist and Hoekman data set for the southern Californian flora, we show strong support for the notion that true tracheid presence lowers vessel grouping; in contrast, vasicentric tracheids are associated with a diversity of vessel grouping strategies. We show that statistical models can refine anatomical interpretations by identifying unusual species. For example, Fremontodendron californicum and Baccharis salicifolia (=  B. glutinosa ) were identified as unusual in lacking vasicentric tracheids; a consultation of preparations revealed that they are indeed present. For purposes of ecological wood anatomy, anatomical terminology should reflect cell function; we suggest that terminological systems that yield better predictive power in statistical models such as ours are preferable. Finally, we make recommendations ranging from the statistical, e.g. the need to check assumptions and the need for the inclusion of phylogeny, to the biological, e.g. gathering data expressly designed to test functional hypotheses rather than all of the information in standardized lists.  © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society , 2007, 154 , 331–351.     

Caryophyllales: a key group for understanding wood anatomy character states and their evolution

Definitions of character states in woods are softer than generally assumed, and more complex for workers to interpret. Only by a constant effort to transcend the limitations of glossaries can a more than partial understanding of wood anatomy and its evolution be achieved. The need for such an effort is most evident in a major group with sufficient wood diversity to demonstrate numerous problems in wood anatomical features. Caryophyllales s.l., with approximately 12 000 species, are such a group. Paradoxically, Caryophyllales offer many more interpretive problems than other ‘typically woody’ eudicot clades of comparable size: a wider range of wood structural patterns is represented in the order. An account of character expression diversity is presented for major wood characters of Caryophyllales. These characters include successive cambia (more extensively represented in Caryophyllales than elsewhere in angiosperms); vessel element perforation plates (non‐bordered and bordered, with and without constrictions); lateral wall pitting of vessels (notably pseudoscalariform patterns); vesturing and sculpturing on vessel walls; grouping of vessels; nature of tracheids and fibre‐tracheids, storying in libriform fibres, types of axial parenchyma, ray anatomy and shifts in ray ontogeny; juvenilism in rays; raylessness; occurrence of idioblasts; occurrence of a new cell type (ancistrocladan cells); correlations of raylessness with scattered bundle occurrence and other anatomical discoveries newly described and/or understood through the use of scanning electron microscopy and light microscopy. This study goes beyond summarizing or reportage and attempts interpretations in terms of shifts in degrees of juvenilism, diversification in habit, ecological occupancy strategies (with special attention to succulence) and phylogenetic change. Phylogenetic change in wood anatomy is held to be best interpreted when accompanied by an understanding of wood ontogeny, species ecology, species habit and taxonomic context. Wood anatomy of Caryophyllales demonstrates problems inherent in binary character definitions, mapping of morphological characters onto DNA‐based trees and attempts to analyse wood structure without taking into account ecological and habital features. The difficulties of bridging wood anatomy with physiology and ecology are briefly reviewed. © 2010 The Linnean Society of London, Botanical Journal of the Linnean Society, 2010, 164 , 342–393.     

Genetic variation and clonal diversity in island Cephalanthera rubra populations from the Biebrza National Park, Poland

Three populations of the orchid species Cephalanthera rubra localized on neighbouring mineral islands in the Biebrza National Park (north-east Poland) were examined using 16 allozyme loci. The percentage of polymorphic loci in these C. rubra populations ranged from 25 to 31.3% and the mean number of alleles per polymorphic locus from 1.25 to 1.31. The levels of observed heterozygosity at polymorphic loci were higher than expected for all populations. The overabundance of heterozygotes was noted in every population. The values of fixation indices were highly negative. The genetic differentiation among the three populations was small ( F _ST = 0.0173), albeit statistically significant ( P  < 0.001). The level of gene flow varied from 13 to 16. Fourteen multilocus genotypes were found among the 401 ramets sampled from the populations. Only four of them were common for all populations. The frequency of genotypes was different in these three populations of C. rubra . Some of the multilocus genotypes dominated in the given populations, others were found sporadically. Genetic variation within C. rubra populations is mainly the result of small population sizes and reflects the influences of breeding system and type of reproduction. On the other hand, these properties are also connected with habitat conditions.  © 2003 The Linnean Society of London, Botanical Journal of the Linnean Society , 2003, 143 , 99–108.     

Population divergence in the amphicarpic species Amphicarpaea edgeworthii Benth. (Fabaceae): microsatellite markers and leaf morphology

Comparative analyses of the genetic differentiation in microsatellite markers ( F _ST) and leaf morphology characters ( Q _ST) of Amphicarpaea edgeworthii Benth. were conducted to gain insight into the roles of random processes and natural selection in the population divergence. Simple sequence repeat analyses on 498 individuals of 19 natural populations demonstrate that a significant genetic differentiation occurs among populations (mean F _ST = 0.578), and A. edgeworthii is a highly self-fertilized species (mean selfing rate s  = 0.989). The distribution pattern of genetic diversity in this species shows that central populations possess high genetic diversity (e.g. population WL with H _E = 0.673 and population JG with H _E = 0.663), whereas peripheral ones have a low H _E as in population JD (0.011). The morphological divergence of leaf shape was estimated by the elliptical Fourier analysis on the data from 11 natural and four common garden populations. Leaf morphology analyses indicate the morphological divergence does not show strong correlation with the genetic differentiation ( R  = 0.260, P  = 0.069). By comparing the 95% confidence interval of Q _ST with that of F _ST, Q _ST values for five out of 12 quantitative traits are significantly higher than the average F _ST value over eight microsatellite loci. The comparison of F _ST and Q _ST suggests that two kinds of traits can be driven by different evolutionary forces, and the population divergence in leaf morphology is shaped by local selections.  © 2009 The Linnean Society of London, Biological Journal of the Linnean Society , 2009, 96 , 505–516.     

Wood anatomy of Krameriaceae with comparisons with Zygophyllaceae: phylesis, ecology and systematics

Wood of nine species of Krameria (including all clades proposed within the genus) reveals a few characters related to infrageneric systematics; most relate primarily to ecology and habit. Wood of Krameria closely fits quantitative data reported for desert shrubs. Lack of vessel grouping correlates with the presence of densely pitted tracheids. Wood xeromorphy in Krameria may relate in part to hemiparasitism. Tracheid presence may also account for relatively low vessel density. Wood anatomy of six species of Zygophyllaceae (including both genera of Morkillioideae) is compared with that of Krameriaceae because recent phylogenies propose that these two families comprise the order Zygophyllales. Several wood characters appear to represent synapomorphies reflecting this relationship. Differences in wood anatomy between Krameriaceae and Zygophyllaceae are believed to represent autapomorphies. Notable among these include Paedomorphic Type II rays (Krameriaceae), storying (Zygophyllaceae), presence of vestured pits (Zygophyllaceae), and differentiation into vasicentric tracheids and fibre-tracheids (Zygophyllaceae). The latter feature is referable to the concept of fibre-tracheid dimorphism. Recognition of Krameriaceae as separate from Zygophyllaceae is supported by wood characters. Wood of Zygophyllales does not conflict with the idea that the order belongs to rosids, with Malpighiaceae as the outgroup of Zygophyllales.  © 2005 The Linnean Society of London, Botanical Journal of the Linnean Society , 2005, 149 , 257–270.     

Changes in leaf organisation, photosynthetic performance and wood formation during ex vitro acclimatisation of black mulberry (Morus nigra L.)

Changes in anatomical organisation of the leaf, photosynthetic performance and wood formation were examined to evaluate the temporal and spatial patterns of acclimatisation of micropropagated slow-growing black mulberry ( Morus nigra L.) plantlets to the ex vitro environment. Leaf structure differentiation, the rates of net photosynthesis (P_n), transpiration (E) and stomatal conductance (g_s), and secondary xylem growth were determined in the course of a 56-day acclimatisation. Differentiation of palisade parenchyma was observed 7 days after transfer. At this stage, the rates of P_n, E and g_s reached maximum values, after which the rates of all three gas exchange parameters gradually decreased. The highest proportion of woody area occupied by vessels was also observed 7 days after transfer. An important feature of developing woody tissue is the difference in patterns of vessel distribution from the characteristic differentiation patterns of earlywood and latewood vessels in mature wood of ring-porous trees. Vessels with lumen areas over 3000 μm² were only differentiated in acclimatised plantlets, whereas vessels in stems sampled on days 0 and 7 had very small lumen areas of up to 560 μm². Full acclimatisation, observed 56 days after transfer to the ex vitro environment, was associated with the rapid growth of new in vivo formed leaves, very low rates of E and g_s, and much increased secondary xylem tissue within the stem area.     

KLEINODENDRON AND XYLEM ANATOMY OF CLUYTIEAE (EUPHORBIACEAE)

Kleinodendron, a new genus of Euphorbiaceae, was assigned by Smith and Downs to the tribe Cluytieae. A xylem anatomical survey indicates that there are no objections to this placement. Woods of Cluytieae are diverse but may be characterized generally by having pores which average less than 80 μ in diameter and which are well divided between solitary and radial multiple distributions in the same species; simple vessel perforations; alternate intervascular pitting; fiber-tracheids and libriform wood fibers; exclusively uniseriate, or uniseriate and biseriate heterocellular vascular rays in the same species; uniseriate “bridges” linking superposed biseriate ray segments; diffuse, diffuse-in-aggregates, and scanty vasicentric axial parenchyma, sometimes in the same species; and crystal rhomboids. That Microdesmis and Pogonophora diverge sharply from these generalizations in having scalariform vessel perforations and broad vascular rays, is an indication that they may not be closely related to other genera in Cluytieae.     

Wood anatomy of Polygonaceae: analysis of a family with exceptional wood diversity

Quantitative and qualitative data are presented for woods of 30 species of woody Polygonaceae. Wood features that ally Polygonaceae with Plumbaginaceae include nonbordered perforation plates, storeying in narrow vessels and axial parenchyma, septate or nucleate fibres, vasicentric parenchyma, pith bundles that undergo secondary growth, silica bodies, and ability to form successive cambia. These features are consistent with pairing of Plumbaginaceae and Polygonaceae as sister families. Wood features that ally Polygonaceae with Rhabdodendraceae include nonbordered perforation plates, presence of vestured pits in vessels, presence of silica bodies and dark-staining compounds in ray cells, and ability to form successive cambia. Of the features listed above, nonbordered perforation plates and ability to form successive cambia may be symplesiomorphies basic to Caryophyllales sensu lato . The other features are more likely to be synapomorphies. Wood data thus support molecular cladograms that show the three families near the base of Caryophyllales s.l. Chambered crystals are common to three genera of the family and may indicate relationship. Ray histology suggests secondary woodiness in Antigonon, Atraphaxis, Bilderdykia, Dedeckera, Eriogonum, Harfordia, Muehlenbeckia, Polygonum , and Rumex . Other genera of the family show little or no evidence of secondary woodiness. Molecular data are needed to confirm this interpretation and to clarify the controversial systematic groupings within the family proposed by various authors. Vessel features of Polygonaceae (lumen diameter, element length, density, degree of grouping) show an extraordinary range from xeromorphy to mesomorphy, indicating that wood has played a key role in ecological and habital shifts within the family; the diversity in ecology and habit are correlated with quantitative wood data.  © 2003 The Linnean Society of London. Botanical Journal of the Linnean Society , 2003, 141 , 25−51.     

阳桃次生木质部导管分子及侵填体的研究

运用细胞图象分析系统和显微照相的方法对阳桃次生木质部导管分子进行了观察研究。次生木质部导管分子类型有两端具尾导管、一端具尾导管和无尾导管。导管分子穿孔板存在着2种类型:两端均为一个单穿孔板;一端为一个单穿孔板,另一端为具两个单穿孔的复穿孔板。48%的导管分子具有囊状侵填体;管间纹孔式为互列纹孔式。     

Large variations in the ratio of effective breeding and census population sizes between two species of pond-breeding anurans

The viability of wild populations is frequently assessed by monitoring adult census sizes ( N _c). This approach is particularly useful for pond-breeding amphibians, because assemblages during the breeding season are relatively easy to detect and count. However, it is the genetic effective population size ( N _e) or surrogates such as effective breeding population size ( N _b) that are of primary importance for long-term viability. Although N _c estimates of one anuran amphibian ( Bufo bufo ) in Britain were much larger than those of another ( Rana temporaria ) at the same sites, the ratios of N _b to N _c were much smaller in B. bufo than in R. temporaria. These differences were sufficiently great as to reverse the effective size order at one site, such that N _b for R. temporaria was larger than that for B. bufo. Differences in adult sex ratios at breeding sites probably contributed to lower N _b values in B. bufo populations compared with those of R. temporaria . The relationship of N _b to N _c can therefore vary dramatically even between similar species, to the extent that just monitoring N _c can give misleading impressions of relative effective breeding sizes and thus of population viability. It will be increasingly important to estimate N _e or N _b in wildlife populations for assessment of conservation priorities.  © 2006 The Linnean Society of London, Biological Journal of the Linnean Society , 2006, 89 , 365–372.     

Ecophysiological responses to simulated canopy gaps of two tree species of contrasting shade tolerance in elevated CO2

1. One-year-old seedlings of shade tolerant Acer rubrum and intolerant Betula papyrifera were grown in ambient and twice ambient (elevated) CO₂, and in full sun and 80% shade for 90 days. The shaded seedlings received 30-min sun patches twice during the course of the day. Gas exchange and tissue–water relations were measured at midday in the sun plants and following 20 min of exposure to full sun in the shade plants to determine the effect of elevated CO₂ on constraints to sun-patch utilization in these species.
2. Elevated CO₂ had the largest stimulation of photosynthesis in B. papyrifera sun plants and A. rubrum shade plants.
3. Higher photosynthesis per unit leaf area in sun plants than in shade plants of B. papyrifera was largely owing to differences in leaf morphology. Acer rubrum exhibited sun/shade differences in photosynthesis per unit leaf mass consistent with biochemical acclimation to shade.
4. Betula papyrifera exhibited CO₂ responses that would facilitate tolerance to leaf water deficits in large sun patches, including osmotic adjustment and higher transpiration and stomatal conductance at a given leaf-water potential, whereas A. rubrum exhibited large increases in photosynthetic nitrogen-use efficiency.
5. Results suggest that species of contrasting successional ranks respond differently to elevated CO₂, in ways that are consistent with the habitats in which they typically occur.     

Water stress induced cavitation and embolism in some woody plants

A comparison was made of the relative vulnerability of xylem conduits to cavitation and embolism in three species [ Thuja occidentalis L., Tsuga canadensis (L.) Carr. and Acer saccharum Marsh.]. Waterlogged samples of wood were air dehydrated while measuring relative water loss, loss of hydraulic conductance, cumulative acoustic emissions (= cavitations) and xylem water potential. Most cavitation events and loss of hydraulic conductance occurred while water potential declined from – 1 to –6 MPa. There were differences in vulnerability between species. Other people have hypothesized that large xylem conduits (e.g. vessels) should be more vulnerable to cavitations than small conduits (e.g. tracheids). Our findings are contrary to this hypothesis. Under water stress, the vessel bearing wood retained water better than tracheid bearing wood. However, within a species large conduits were more prone to cavitation than small conduits.     

Comparing the estimation properties of different statistics for measuring sexual isolation from mating frequencies

Sexual isolation is a key component of reproductive isolation, involving mate choice among mature adults. While there are various statistics for estimating sexual isolation from mating frequencies, their ability to produce unbiased estimates varies considerably, depending on the particular situation. We investigated, under different biological scenarios, the estimation properties (statistical bias, efficiency, root mean square, statistical test) of 12 statistics commonly used in the literature for measuring sexual isolation. Yule's Q , V , YA (and related indices) and I _PSI are revealed to be the most efficient, with the smallest biases and root mean square deviations. Yule's Q , YA and I _PSI show better estimation properties when using infinite sample sizes, while I _PSI is preferable using smaller sample sizes. Other statistics investigated should be avoided, at least within the range of conditions considered. Regarding the parametric test of hypothesis, the best alternative is YA . We discuss the advantages and drawbacks of the various estimators, and propose I _PSI as the safest for biological sample sizes.  © 2005 The Linnean Society of London, Biological Journal of the Linnean Society , 2005, 85 , 307–318.     

Stem wood properties of mature Norway spruce after 3 years of continuous exposure to elevated [CO2] and temperature

The objective of the study was to investigate the interactive effects of elevated atmospheric carbon dioxide concentration, [CO₂], and temperature on the wood properties of mature field-grown Norway spruce ( Picea abies (L.) Karst.) trees. Material for the study was obtained from an experiment in Flakaliden, northern Sweden, where trees were grown for 3 years in whole-tree chambers at ambient (365 μmol mol⁻¹) or elevated [CO₂] (700 μmol mol⁻¹) and ambient or elevated air temperature (ambient +5.6 °C in winter and ambient +2.8 °C in summer). Elevated temperature affected both wood chemical composition and structure, but had no effect on stem radial growth. Elevated temperature decreased the concentrations of acetone-soluble extractives and soluble sugars, while mean and earlywood (EW) cell wall thickness and wood density were increased. Elevated [CO₂] had no effect on stem wood chemistry or radial growth. In wood structure, elevated [CO₂] decreased EW cell wall thickness and increased tracheid radial diameter in latewood (LW). Some significant interactions between elevated [CO₂] and temperature were found in the anatomical and physical properties of stem wood (e.g. microfibril angle, and LW cell wall thickness and density). Our results show that the wood material properties of mature Norway spruce were altered under exposure to elevated [CO₂] and temperature, although stem radial growth was not affected by the treatments.     

Two early Eocene vines from south-east England

Small diameter pyritized axes, commonly referred to as 'twigs', of fossil vitaceous and menispermaceous wood from the Lower Eocene, London Clay Formation of south-east England are described here for the first time. The vitaceous twigs, which represent the earliest known occurrence of fossil Vitaceae wood, are characterized by large diameter, solitary vessels, tall wide rays which dilate in the phloem region, scalariform intervessel pits and simple perforation plates. The wood anatomy supports a close relationship to the Vitaceae and in particular the genus Rhoicissus Planch. The menispermaceous twigs are characterized by medium to moderately large vessels, simple perforation plates, alternate intervascular pitting and very broad and high rays. The anatomical characters support a close relationship to the Menispermaceae and in particular the genera Tinomiscium Miers and Coscinium Colebr. However, as these fossil twigs are not exactly similar to any particular genus they have been placed in the organ genus, Vitacexoylon Wheeler and LaPasha and Menispermoxylon Vozenin-Serra, Privé-Gill & Ginsburg, with which, respectively, they have the greatest similarity. These specimens were studied using reflected light- and scanning electron microscopy.     

A review of the platanaceous woods from the Eocene paratropical rainforest of south-east England

Small diameter pyritized axes, commonly referred to as 'twigs', of fossil platanaceous wood are described from the Lower Eocene London Clay Formation of south-east England. These twigs are characterized by solitary vessels with scalariform perforation plates, opposite intervessel pits, and tall, multiseriate rays that dilate in the phloem region. The wood anatomy supports close relationship to members of extant Platanaceae and the material is placed in the organ genus Plataninium Unger erected for fossil woods with close anatomical similarity to Platanus L. This material supplements the fossil record of platanaceous type wood from the Eocene London Clay and documents the first record of Plataninium decipiens Brett in the twig flora.  © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society , 2002, 139 , 181–191.     

梣属11种植物次生木质部附物纹孔的电镜观测

应用扫描电镜对梣属11种植物次生木质部导管附物纹孔的分布和形态进行了详细的观察,应用Carnoy2.0软件和扫描电子显微镜采集的照片,测定了附物纹孔丰富度指标和纹孔数量特征指标。电镜观察表明,梣属11种研究植物次生木质部导管分子侧壁附物纹孔的分布和形态变化较大,附物纹孔丰富度指标的统计描述进一步证实附物纹孔的分布变化大;3个附物纹孔丰富度指标分别与管间具缘纹孔数量特征指标的逐步回归分析表明,导管侧壁附物纹孔丰富度2个指标,即导管外纹孔口附物频率与导管纹孔腔附物频率随纹孔口面积百分比的增大而增大,推测梣属植物附物纹孔丰富度与纹孔几何构造及数量特征有关。研究认为,附物纹孔在梣属植物稳定存在,是可界定梣属植物的木材解剖性状。