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Convergent tip‐to‐base widening of water‐conducting conduits in the tallest bryophytes
Author(s) -
Bok Erin C. P. M.,
Brodribb Timothy J.,
Jordan Gregory J.,
Carriquí Marc
Publication year - 2022
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.1002/ajb2.1795
Subject(s) - electrical conduit , photosynthesis , biology , vascular plant , botany , moss , water transport , vascular bundle , ecology , water flow , environmental science , soil science , mechanical engineering , species richness , engineering
Premise Tip‐to‐base conduit widening is considered a key mechanism that enables vascular plants to grow tall by decreasing the hydraulic resistance imposed by increasing height. Widening of hydraulic anatomy (larger conducting elements toward the base of the vascular system) minimizes gradients in leaf‐specific hydraulic conductance with plant height, allowing uniform photosynthesis across the crown of trees. Tip‐to‐base conduit widening has also been associated with changes in conduit number. However, in bryophytes, despite having representatives with internal water‐conducting tissue, conduit widening has been scarcely investigated. Methods Here, we examined the changes in hydroid diameter and number with distance from plant tip in Dawsonia superba and D. polytrichoides , two representatives of the genus containing the tallest extant bryophytes. Results The position of these moss species on the global scale of conduit size and plant size was consistent with a general scaling among plants with internal water transport. Within plants, patterns of conduit widening and number with distance from plant tip in endohydric mosses were similar to those observed in vascular plants. Conclusions This study demonstrated that land plants growing upward in the atmosphere show analogous conduit widening of hydraulic structures, suggesting that efficient internal water transport is a convergent adaptation for photosynthesis on land.