Chin J Plant Ecol ›› 2021, Vol. 45 ›› Issue (9): 1024-1032.DOI: 10.17521/cjpe.2021.0083

• Methods and techniques • Previous Articles    

Using Strauss-Hardcore model to detect vessel spatial distribution in angiosperms with various vessel configurations

ZHENG Jing-Ming(), LIU Hong-Yu   

  1. Beijing Key Laboratory for Forest Resources and Ecosystem Processes, Beijing Forestry University, Beijing 100083, China
  • Received:2021-03-10 Accepted:2021-05-19 Online:2021-09-20 Published:2021-11-18
  • Contact: ZHENG Jing-Ming
  • Supported by:
    Second Tibetan Plateau Scientific Expedition and Research (STEP) Program(2019QZKK0305)


Aims Spatial patterns of vessel in xylem are diverse and closely related with water transportation functions in angiosperms. However, the pattern was generally described qualitatively in anatomy, which were unable to reveal their links to xylem functions and to species distribution. We used point pattern analysis to study vessel spatial pattern in xylem cross-sectional images to quantify their features.

Methods Images of 17 types of vessel configurations were selected in terms of wood porosity, vessel arrangement, and vessel grouping. Optimum Strauss-Hardcore models for coordinates in the images were fitted. Correlations among vessel variables and model coefficients were tested.

Important findings We found that (1) Strauss-Hardcore model fitted all the data well and its three parameters, i.e., hardcore distance, local aggregation distance, and point-pair interaction or point aggregation index, and had apparent biological significance. (2) Classifications of wood xylem by traditional anatomical indices could not precisely present the spatial pattern of vessels compared to spatial point analysis, and local aggregation index from Strauss-Hardcore model was mainly influenced by vessel grouping, especially frequency of radial multiples and vessel clusters. (3) Among the 17 vessel patterns analyzed, diffusive or semi-ring species with xylem consisting of solidary vessels showed negative point-pair interaction and aggregation index was less than 0.4, whereas species with obvious vessel arrangement and multiple or clusters of vessel grouping in xylem owned positive point-pair interaction and bigger aggregation index. (4) The former group of species demonstrated inhibition- inhibition-random pattern at three local scales while the latter species showed inhibition-aggregation-random pattern according to the fitted Strauss-Hardcore models. The findings showed that point process modeling could precisely describe vessel distribution features in 2-D xylem sections and provide insights on vessel development. Therefore, this method may support 3-D vessel system simulation and experimental studies on structure-function of angiosperm xylem.

Key words: xylem vessel, spatial point pattern, Ripley's K function, Strauss-Hardcore model