Photosynthetica

, Volume 44, Issue 4, pp 536–541

Awn contribution to gas exchanges of barley ears

Original Papers

Abstract

The effects of awn removal on ear gas exchange in four barley lines (Morex, Harrington, Steptoe, and TR306) were studied under a controlled environment using a Before-After Control-Impact Paired (BACIP) experimental design. From ear emergence to grain maturity, plants were grown in pots at either 60 or 90 % of soil water holding capacity. Gas-exchange measurements of ears were made 9 and 10 d after anthesis (DAA). On 11 DAA, awn removal was performed on half of the ears in each pot, followed by measurements on both intact and de-awned ears on 12 and 13 DAA. Net photosynthetic (PN) and transpiration (E) rates decreased significantly with awn removal, but dark respiration (RD) rate was not affected. We estimated for each ear a temperature-adjusted respiration rate (Ra) from RD. When we corrected PN with Ra, we found that rates of spikelet photosynthesis were largely underestimated. Moderate water stress had minimal effect on gas exchange of bracts and awns of the barley ear. Barley lines did not differ for any individual gas-exchange parameter.

Additional key words

BACIP design Hordeum net photosynthetic rate respiration rate transpiration 

Abbreviations

BACIP

Before-After Control-Impact Paired

DAA

days after anthesis

E

transpiration rate

iWUE

instantaneous water-use efficiency

PN

net photosynthetic rate

PG

gross photosynthetic rate

PPFD

photosynthetic photon flux density

Ra

temperature-adjusted respiration rate

RD

dark respiration rate

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Copyright information

© Institute of Experimental Botany, ASCR 2006

Authors and Affiliations

  1. 1.Department of Plants, Soils and BiometeorologyUtah State UniversityLoganUSA
  2. 2.Ecology CenterUtah State UniversityLoganUSA

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