© 1995 Heron Publishing—Victoria, Canada
Physiological, morphological and anatomical responses of Fraxinus mandshurica seedlings to flooding
Fukuju Yamamoto (1), Tsutomu Sakata (1) and Kazuhiko Terazawa (2)
1. Department of Forestry Science, Faculty of Agriculture, Tottori University, Koyama, Tottori 680, Japan / 2. Hokkaido Forestry Research Institute, Higashiyama, Koshunai, Bibai, Hokkaido 079-01, Japan / Received March 17, 1994
Summary
Two-year-old Fraxinus mandshurica Rupr. var. japonica Maxim. seedlings were flooded to 8 cm above soil level for 70 days. The flooding treatment altered the growth, morphology,
stem anatomy and ethylene production of the seedlings. Although flooding did not affect height growth, it stimulated diameter
growth of the submerged stems by increasing both the number and size of wood fibers produced; however, the thickness of the
cell walls of the wood fibers was reduced by flooding. In response to the flooding treatment, the seedlings formed abundant
hyperhydric tissues, originating from the vicinity of lenticels on the surface of the flooded stems, and adventitious roots,
which grew through the hyperhydric tissues. Aerenchyma tissues were observed in the bark of the adventitious roots. The flooding
treatment did not affect dry weight increment of leaves and stems, but it reduced the total dry weight increment of the root
system even though it promoted adventitious root formation. Flooding also enhanced ethylene production in the submerged portions
of stems. The potential roles of flood-induced ethylene in cambial growth and adventitious root formation in flooded plants
are discussed.
Keywords:
adventitious roots, cambial growth, diameter growth, dry weight increment, ethylene, height growth.
