Radial section: five axial parenchyma strands and one septate fiber; pits on cross-walls of axial parenchyma are numerous and bordered, c-e Solmsia calophylla Baill., McPherson 5511 (MO), c, d SEM images of cross-walls of axial parenchyma strands in radial section, to show a single
bordered pit in each, e Transverse section, outer face of cross-wall of axial parenchyma; all pits are bordered, f Gnetum gnemon, Carlquist 8088 (RSA).
Bordered pit pairs control movement of water from one tracheary element to the next in the wood of vascular plants (Zimmermann, 1983; Pittermann et al., 2005).
polystachyum Ho + - Podocarpus costaricensis Ho - - Podocarpus guatemalensis Ho - - Podocarpus macrostachys Ho - - Prioria copaifera Ht - - Prumnopitys standleyi Ho - - Qualea paraensis Ho-Ht - S(+)v Sclerolobium costaricense Ho - - Sideroxylon capari Ht - U+ P(-) Swietenia humilis Ht +- U+ P(-) Swietenia macrophylla Ht +- U+ (-) Tabebuia guayacan Ho + - Tachigali versicolor Ho - S(+) Vantanea barbourii Ht - - Fiber: FL=Fiber or tracheids length (mm), LD=lumen or tracheids diameter (um), WCT=wall cell thick (um), FC=Fibers crystals, SF=Septate fibers, GTF=ground tissue fiber, SBD=simple to minutely
bordered pits, BD=Fibers with distinctly
bordered pit, T=tracheids, PFRT=Fiber pits common in both radial and tangential, FS=Fibers stored.
Yuzou Sano's chapter on
bordered pit structure and resistance to cavitation is worthy of a wide audience, because it covers structures and processes basic to the successful functioning of wood.
Many studies have shown that the increased permeability occurring during water storage of logs is a result of the decomposition of
bordered pit membranes, ray parenchyma cells, and resin canals by bacterial action (Knuth and MeCoy 1962, MacPeak 1963, Greaves 1969).
Bordered pit pairs connect water-conducting tracheary elements of vascular plants and allow water transport from one element to the next.
Effect of
bordered pit torus position on permeability in Chinese Yezo spruce.
Frequently, the pit membrane is aspirated and the torus blocks one of the apertures of a given
bordered pit pair (compare Figs.
Thus,
bordered pit pairs provide passageways for water moving from cell to cell.
1), and it is the pits between tracheary elements (the so-called
bordered pit pairs, Fig.
However, below 25 percent MC, drying rates of untreated samples were lower than steam-treated samples because steam treatments enhanced vapor permeability of wood by damaging
bordered pits, aspirated pits, and chemical structure of the cell-wall.