An ignored anatomical variable: pore shape shows a nonrandom variation pattern in xylem cross sections

Abstract

Anatomical characteristics of vessels have a profound impact on the hydraulic conductivity of the xylem. However, pore shape, the cross‐section shape of a vessel, has been ignored in previous hydraulic architecture studies. In this study, we examined whether pore shape tended to be circular, and whether variation in pore shape may be affected by water flow path‐length and cambial age. The circularity of pores in Betula platyphylla Roth and Quercus mongolica (only earlywood) were analyzed from the pith to the bark along the water flow path. It was found that although there were very few pores with perfectly circular shape, solitary pores did tend to be regularly circular. The pore shape of sequentially formed vessels in the xylem was influenced by cambial age and flow path‐length. Pore shape tended to be more circular as flow path‐length increased or cambial age decreased. Circular pore shape appears to be an important morphogenetic mechanism for hydraulic architecture development, and studies of it expand our understanding of the structure–function relationships of the xylem.

Morpho-Anatomical and Physiological Responses Can Predict the Ideal Period for the Transplantation of Hydroponic Seedlings of Hymenaea courbaril, a Neotropical Fruit Tree

“…Thangthong et al [ 52 ] showed that plants under water stress have xylemic vessels of a smaller diameter and area. A reduction in the diameter of the xylemic vessels reduces the response to the high negative pressure generated by the transpiration of the leaves [ 53 ]. As we recorded the largest mean RVE diameter in the plants evaluated at 120 DAT, and thus the highest transpiration rate, the reduction in the RVE diameter observed at 150 DAT and 180 DAT, together with the reduction observed in the SD and PP, may be associated with the adjustments adopted by the plant to optimize the efficiency of its water use.…”

Response of vessel features to witches’‐broom disease in Zizyphus Jujuba branches

“…It should be noted that the means of vessel features measured here were collected from branchwood of the Z. Jujuba trees, and the values differed greatly to that from trunkwood studied by Zhu et al., (2015) with large average vessel size. Some studies reported that the sample position in a tree affected the vessel features of the tree (Dadzie et al., 2018; Kotowska et al., 2015; Zhao et al., 2019; Zhao, et al., 2019). In this case, the variation of vessel features would be discussed later following the description of branch level impacts.…”

“…One hundred and twenty vessels were randomly selected from each transverse section to count the vessels and groups (a solitary pore is also considered as one group), and measure the circumference, area, tangential and radial diameter of each vessel lumen. The circularity of vessel lumen was calculated based on the circumference and area of the vessel lumen (Zhao et al., 2019). The vessel frequency was calculated using the total number of vessels in an observed image area and then dividing by that area.…”

A systems genetic analysis identifies putative mechanisms and candidate genes regulating vessel traits in poplar wood

“…However, greater vessel grouping indices have also been related to decreased vulnerability to embolism ( Lens et al., 2011 ; Smith et al., 2013 ), likely due to the presence of alternate pathways that can bypass embolism blockage ( Carlquist, 1984 ). The cross-sectional shape of vessels (termed vessel circularity) can also affect transport efficiency, as deviations from perfect circularity can decrease the volumetric flow rate of water through a conduit ( Zhao et al., 2019 ). Vessel width and frequency scale with tree height and diameter; taller and thicker trees have wider and less numerous vessels than shorter and thinner trees at the same sampling height ( Olson et al., 2014 ; Olson et al, 2020 ).…”