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Effects of Osmotic Stress on the Growth of Etiolated Mung Bean Seedlings
Author(s) -
Passos L. P.
Publication year - 2003
Publication title -
journal of agronomy and crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.095
H-Index - 74
eISSN - 1439-037X
pISSN - 0931-2250
DOI - 10.1046/j.1439-037x.2003.00010.x
Subject(s) - turgor pressure , hypocotyl , osmotic shock , etiolation , osmotic pressure , elongation , biology , horticulture , osmoregulation , botany , water stress , osmosis , agronomy , biochemistry , salinity , ecology , materials science , membrane , ultimate tensile strength , metallurgy , gene , enzyme
The alterations in growth and water status of dark‐grown mung bean tissues following sudden osmotic stress were investigated. Photographic measurements of hypocotyl elongation revealed that stress (−0.2 to −0.8 MPa) induced growth cessation within one minute, with resumption occurring at lower rates after a latent period; periods which tended to increase in accordance with whether the seedlings were 4, 5 or 6 days old. Tissue water status was related to growth as water and osmotic potentials were highest in the expanded root region and the lowest in the growing hypocotyl region. These rankings were not verified under osmotic stress, and values were reduced in the course of 24 h. Turgor levels were similar in all tissues and were not altered by stress. The responses were not caused by substantial water loss, which was detected only after 24 h of stress, and could have resulted from the accumulation of osmotic solutes. The results indicate that plants exposed to sudden osmotic stress, besides exhibiting rapid growth cessation, show growth resumption at lower rates and no subsequent short‐term changes in any water status measure of the growing region. Because growth resumes without further detectable turgor increments, water status alterations are unlikely to be the cause of the observed immediate growth stoppage.