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EFFECTS OF SIMULATED DROUGHT ON SHOOT DEVELOPMENT IN LIRIODENDRON SEEDLINGS
Author(s) -
DOLEY D.
Publication year - 1970
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.1970.tb02453.x
Subject(s) - xylem , shoot , parenchyma , apex (geometry) , botany , biology , horticulture , humidity , plant growth , physics , thermodynamics
S ummary Shoot extension, leaf growth, xylem radial growth, and xylem structure in i‐year old Liriodendron tulipifera L. seedlings maintained in a growth chamber were affected more by reduction of atmospheric relative humidity from about 95 to about 45% than by simultaneous reduction of the root medium water potential (Ψ so i) from – 0.4 to about –11 bars. For plants subjected to the same minimum Ψ sol , the rate of change of Ψ sol during the imposition and relief of simulated drought had no apparent effect on growth. Xylem formed near the stem base during a period of simulated drought resembled that characteristic of the terminal stage of seasonal growth under normal conditions; vessel elements, fibres and ray parenchyma cells were narrower in the radial direction, vascular rays increased in width, and more vertical parenchyma was evident than under conditions of rapid growth. The differences between the structure of xylem formed at high and low plant water potentials diminished towards the apex of the stem, and it is suggested that these differences may be due chiefly to an impairment of synthesis and translocation of growth factors.