马尾松正常木与应压木的比较解剖

用光学显微镜和扫描电镜观察比较了马尾松(Pinus massoniana)正常木与应压木的结构差异。研究结果表明:马尾松应压木从早材到晚材呈缓变,管胞在横切面上除生长轮分界处的两侧外均为圆形,管胞之间具明显的胞间隙;管胞的次生壁仅有 S_1和 S_2两层;次生壁上螺纹间隙和螺纹裂隙都很明显,并与 S_2层微纤丝平行。此外,还初步讨论了应压木形成的可能机理。     

WOOD ANATOMY AND RELATIONSHIPS OF LACTORIDACEAE

Mature wood of Lactoris, not previously available for study, reveals ten distinctive characters: vessels with simple perforation plates; vessels in pore multiples; vessel-to-axial parenchyma pits scalariform or transitional, vessel-to-vessel pits alternate; fiber-tracheids with vestigial pits; fiber-tracheids, vessels, and axial parenchyma storied; axial parenchyma vasicentric scanty; axial parenchyma either not subdivided or, if subdivided, with thin nonlignified walls between the cells (like the septa in septate fibers); rays wide and tall, little altered during ontogeny; ray cells upright; and ray cells taller adjacent to fascicular areas. All of these features occur in woods of Piper and other Piperaceae. The systematic position of Lactoris is therefore reassessed. Evidence available to date is consonant with placement of Lactoridaceae in Piperales, in which it would be more primitive than Piperaceae or Saururaceae. Features cited as evidence for alternative placements of Lactoridaceae are reviewed.     

广西蒜头果属及青皮木属木材解剖研究

本文报道蒜头果、青皮木和华南青皮木的木材解剖特征以及对它们的三种木材分子进行研究的结果。     

WOOD ANATOMY OF THE AMERICAN FRANKENIAS (FRANKENIACEAE): SYSTEMATIC AND EVOLUTIONARY IMPLICATIONS

Results of a comparative wood anatomical survey of the American frankenias are presented. The eleven species examined are woody perennials occurring almost exclusively in arid and semiarid regions and on saline and gypseous soils. The secondary xylem of all species is highly specialized and is characterized by libriform fibers, vessel elements with simple perforation plates, and the absence of rays. Axial elements of all species are quite small. A number of unusual features, e.g., anomalous secondary growth and formation of interxylary cork, were observed in some species. Nonfibrous woods have evolved independently in two species of reduced stature and contrast markedly with the highly fibrous woods of most species. Woods of the American frankenias are compared with those of the Tamaricaceae. The systematic and evolutionary implications of interspecific variation in both qualitative and quantitative features are discussed. There is a general tendency for dimensions of the axial wood elements to be positively associated and to decrease with decreasing plant height. In general, differences in wood anatomy more strongly reflect differences in plant growth form and size than phylogeny.     

构树形成层的活动周期及其淀粉贮量的变化

在构树（Ｂｒｏｕｓｓｏｎｅｔｉａ ｐａｐｙｒｉｆｅｒａ （Ｌ．） Ｖｅｎｔ．）形成层活动周期中,每年７月末以后,未成熟的木质部和韧皮部逐渐减少,成熟的木质部和韧皮部急剧增多。８月初开始分化晚材。进入９月后木质部的形成逐渐停止,而一个半月以后才停止形成韧皮部。淀粉贮量的消长与形成层的活动周期有很强的相关关系。早春形成层恢复活动后,淀粉贮量逐渐减少直至消失。尔后,形成层活动减慢,特别是木质部分化停止后,淀粉又开始积累。当韧皮部分化也停止后,淀粉又消失,直至翌年１月才重新积累,这似乎与两个休眠期的转化有关     

长白松的木材解剖及其分类问题

关于长白松的分类问题一直有争议^[6-11],根据作者对吉林省安图县二道白河产的长白松的木材解剖研究,发现其木材的射线管胞内壁具深锯齿,颇与欧洲赤松(Pinus sylvestris Linn.)相近^{[14] [15]},但以其木射线薄壁组织细胞水平壁无纹孔和晚材最后数列管胞弦壁上存在着排列成轴向单行小形具缘纹孔来看,这又显属赤松(Pinus densiflora Sieb.et Zucc.)的特征。因此,作者认为长白松的木材结构是处于欧洲赤松与赤松之间而更偏于赤松^[10],故确认其当归属于赤松的种群范围。     

WOOD ANATOMY OF ILLICIUM (ILLICIACEAE): PHYLOGENETIC,ECOLOGICAL, AND FUNCTIONAL INTERPRETATIONS

Quantitative and qualitative features are reported for 23 collections of ten species of Illicium, sole genus of Illiciaceae. Vessel elements are long, thin-walled, and angular; perforation plates are scalariform and range from long to moderately long; vessel-ray pitting is scalariform to opposite. Tracheids bear fully bordered pits. Axial parenchyma is sparse, abaxial to vessels with some diffuse cells also present. Rays are both multiseriate and uniseriate; the former are lacking near the pith in some species. No erect sheathing cells are present on multiseriate rays, and procumbent cells become more abundant as stems increase in size. Four species from montane subequatorial highlands lack growth rings and helical sculpture in vessels; the remainder of Illicium species have these features. Notably narrow vessels and large numbers of vessels per sq. mm characterize the temperate species from northern limits for the genus, I. anisatum, I. floridanum, and I. parviflorum. Greater vessel density offers redundancy and greater safety and is correlated with greater frost and possibly greater fluctuation in moisture availability. These two ecological features are probably also related to the narrow vessel diameter, which may retard entry of air embolisms (lowered air entry values) in accord with the physiological considerations of Slatyer. Reduction of number of bars per perforation plate within Illicium is also correlated with the more northerly climates. An additional hypothesis for evolution of shorter vessel elements in dicotyledons is introduced: if, as claimed by Slatyer, air embolisms in vessels tend to stop at ends of vessel elements and thus do not disable entire vessels, shorter vessel elements would maximally localize air embolisms. Presence of helical sculpture and other forms of relief within vessels has been difficult to explain in conifers and dicotyledons; such features might help resist cavitations by increasing adhesion of water molecules to cell walls (hydration).     

WOOD ANATOMY OF TREMANDRACEAE: PHYLOGENETIC AND ECOLOGICAL IMPLICATIONS

Stems of four species of the Australian family Tremandraceae furnished sufficient material for analysis of wood anatomy. Presence of simple perforation plates on vessel elements, occurrence of libriform fibers (some septate), tendency toward vasicentric parenchyma, presence of crystalliferous axial parenchyma strands, presence of crystals singly in ray cells, and occurrence of amorphous deposits in parenchyma are all features in which Tremandraceae resemble Pittosporaceae. Wood anatomy tends to support a “rosoid” rather than a sapindalean, rutalean, or polygalalean affinity for Tremandraceae, although wood is only a preliminary indicator. By the use of numerical indices as well as such indicators as helical thickening and presence of vascular tracheids, wood of Tremandraceae is shown to be highly xeromorphic. The genus Tremandra may represent a secondary entrant into wet forests of southwestern Australia; it clearly is not relict from mesic ancestry.     

EFFECT OF ISOLATION OF BARK ON CAMBIAL ACTIVITY AND DEVELOPMENT OF XYLEM AND PHLOEM IN TREMBLING ASPEN

Circular patches of bark were surgically isolated on the sides of trembling aspen (Populus tremuloides Michx.) trees at breast height at various times during the dormant and growing seasons. Subsequently, samples of wood and attached bark were taken from isolated and control sites to determine the effects of isolation of the bark on cambial activity and xylem and phloem development. In control trees cambial activity and xylem and phloem development occurred normally. Isolation of bark during the dormant season (in November, February, or March) did not prevent initiation of cambial activity and of phloem differentiation in spring but continued normal cambial activity and phloem developmented were prevent. Xylem differentiation was essentially prevented by isolation of tissues during the dormant season. The ultimate effect of isolation of the bark on the cambium, either during the dormant season or during the growing season, was subdivision of all fusiform cambial cells into strands of parenchymatous elements; the ultimate effect on the newly formed phloem was early death of the sieve elements. The most conspicuous effect of isolation of the bark after xylem differentiation had begun was the curtailment of secondary wall formation. Shortening of cells of the cambial region was reflected in the length of the vessel members which differentiated from such cells. These results indicate that normal cambial activity and xylem and phloem development require a supply of currently translocated regulatory substances from the shoots.     

ANATOMY OF A LIGNITIZED WOOD FROM SENFTENBERG

A piece of lignitized wood from the Miocene of Senftenberg, Germany, was identified as a type of compression wood, and was studied anatomically, as groundwork, in an investigation on cell wall cellulose and lignin. The wood showed affinity to modern Cryptomeria and Taxodium. In each growth ring the early wood was compacted. By contrast, cellular structure in the late wood had been retained to a high degree. Massive compaction of the early wood most likely occurred during the initial stages of sedimentation prior to mineralization. Numerous cell wall deformations in late wood tracheids apparently originated from compressive forces applied to the wood during sedimentation.     

EVOLUTIONARY AND GEOGRAPHIC TRENDS IN ADAPTIVE WOOD ANATOMY IN ERIASTRUM DENSIFOLIUM (POLEMONIACEAE)

Anatomical features of Eriastrum densifolium populations in southern California show variation that correlates well with ecological setting and geographical distribution. Vessel element size and density in shoots suggest strong adaptation among different subspecies to efficient water movement in different habitats. Indices of mesomorphy, devised by Carlquist to indicate relative adaptivity of wood, likewise show considerable variation among populations, suggesting that different subspecies have anatomical components that can define them. Relationships among the five subspecies of E. densifolium may be explored through MI value relationships.