红树族植物次生木质部附物纹孔的电镜观测

应用扫描电子显微镜详细观察了红树族4属、10种、1变种植物次生木质部管状分子附物纹孔的分布和形态, 应用Carnoy 2.0软件和扫描电镜下采集的照片, 测定了管间梯状附物纹孔丰富度指标和管间梯状纹孔数量特征指标。结果显示, 红树族植物次生木质部管状分子侧壁具附物纹孔。所观察的植物附物纹孔的分布和形态变化大。附物纹孔丰富度指标与管间梯状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随纹孔口面积百分比的增大而增大。据此推测, 红树族植物附物纹孔丰富度与纹孔几何构造及数量特征有关。附物纹孔是红树族植物稳定存在的一个木材解剖性状。综合生态-系统演化的观点, 红树族植物具附物纹孔可能是受系统演化关系控制的生态适应结果。

SEM Observations and Measurements of Vestured Pits of the Secondary Xylem in the Tribe Rhizophoreae

We used SEM to investigate the distribution and micromorphology of vestured pits in the secondary xylem of 10 species and one variety representing all 4 genera within the tribe Rhizophoreae. Richness indexes of intervascular vestured pits and quantitative features of scalariform intervascular bordered pits were measured on SEM images by use of Carnoy 2.0. Vestured pits were present in vessel elements and tracheary elements of secondary xylem of the specimens and varied considerably in distribution and micromorphology. Stepwise regression analysis of richness indexes and quantitative features of scalariform intervascular bordered pits indicated increased richness indexes, including frequency of vestured vessel inner aperture, outer aperture and pit chamber with increasing aperture fraction, which suggests that richness of intervascular vestured pits was associated with the geometric structure of scalariform intervascular bordered pits. We demonstrate consistent occurrence of intervascular vestured pits in the tribe Rhizophoreae from the common presence of intervascular vestured pits in our specimens. In terms of ecophylogeny, vestured pits occurring in the vessel elements and tracheary elements of the secondary xylem of the tribe Rhizophoreae might be an ecologically adaptive character controlled by phylogeny.