Table 1. Changes in number of air-filled xylem vessels and xylem fibers in the stem of intact C. dentata saplings during the winter period

After the initial microCT scan in September, saplings were maintained well-watered and subjected to a rescan after 5 months. Saplings dropped their leaves during the winter period at the beginning of December (i.e. nontranspiring). Sapling-3 (Fig. 1) and -6 were initially subjected to drought stress (Ψstem at −3.0 MPa and −2.1 MPa, respectively); Sapling-7 was not subjected to drought.

SampleXylem RegionNo. of Air-Filled VesselsNo. of Air-Filled Fibers
InitialAfter 5 MonthsInitialAfter 5 Months
Sapling-3Current-year40423530
Older4251101,7623,478
Sapling-6Current-year18758460
Older3016792,4675,806
Sapling-7Current-year381200
Older3263056,4002,863