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Version 3.21
Publication Type J
Authors Khan, M. A., B. Gul and D. J. Weber
Title Temperature and high salinity effects in germinating dimorphic seeds of Atriplex rosea
Source Western North American Naturalist
Author Keywords Atriplex rosea; halophyte; salinity; seed germination; temperature; dimorphic seeds triangularis willd; polymorphic seeds; growth-regulators; suaeda-fruticosa; salt tolerance; responses; stress; halophytes; desert; canada
Abstract Atriplex rosea L (Chenopodiaceae; tumbling orach), an annual herb, is a widely established weedy species of disturbed sites in all Counties of Utah. Seeds of Atriplex rosea were collected from a salt marsh in Faust, Utah, and are dimorphic, light brown, and 2-2.5 mm wide, or black and 1-2 mm wide. Seed germination responses of the black and brown seeds were studied over a range of salinity and temperature. Both brown and black seeds germinated at 1000 mM NaCl, and the optimal temperature for germination of both types was 20degrees-30degreesC. Variation in temperature, however, affected germination of black seeds more than brown seeds. At lower thermoperiod only 40%-50% black seeds germinated in nonsaline control, and germination was almost completely inhibited with the inclusion of salinity However all brown seeds germinated in control at temperatures above 5degrees-15degreesC, and inhibition caused by salinity was comparatively lower. Brown seeds had a higher germination rate than black seeds at all temperature and salinity treatments. The highest rate of germination of both seeds occurred at the temperature regime of 5degrees- 15degreesC. Recovery of germination for black seeds when transferred to distilled water after being in various salinity treatments for 20 days was quite variable. Recovers: decreased with increase in salinity at lower temperature regimes, increased with salinity at optimal thermoperiod, and had no effect at 20degrees-30degreesC. Brown seeds recovered poorly from salinity at all thermoperiods except 5degrees-15degreesC, where recovery decreased with in increase in salinity Brown seeds are adapted to germination in the early part of the growing season, whereas black seeds are capable of surviving harsher conditions and can germinate in later time periods. Characteristics of the dimorphic seeds increase chances for survival in the harsh saline desert environment.
Author Address Brigham Young Univ, Dept Bot & Range Sci, Provo, UT 84602 USA Brigham Young Univ, Dept Bot & Range Sci, Provo, UT 84602 USA Univ Karachi, Dept Bot, Karachi 75270, Pakistan Weber DJ Brigham Young Univ, Dept Bot & Range Sci, Provo, UT 84602 USA
29-Character Source Abbreviation West. North Am. Naturalist
Publication Date Apr
Year Published 2004
Volume 64
Issue 2
Beginning Page 193-201
Unique Article Identifier ISI:000221395500006
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