Variability in mesophyll conductance between barley genotypes,and effects on transpiration efficiency and carbon isotope discrimination |
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| Authors: | MARGARET M BARBOUR CHARLES R WARREN GRAHAM D FARQUHAR GUY FORRESTER HAMISH BROWN |
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| Institution: | 1. Landcare Research, PO Box 40, Lincoln 7640, New Zealand,;2. Faculty of Agriculture, Food and Natural Resources, The University of Sydney, NSW 2567, Australia,;3. School of Biological Sciences, University of Sydney, NSW 2006, Australia,;4. Environmental Biology Group, Research School of Biology, The Australian National University, Canberra, ACT 2601, Australia and;5. The New Zealand Institute for Plant and Food Research, Private Bag 4704, Christchurch, New Zealand |
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| Abstract: | Leaf internal, or mesophyll, conductance to CO2 (gm ) is a significant and variable limitation of photosynthesis that also affects leaf transpiration efficiency (TE). Genotypic variation in gm and the effect of gm on TE were assessed in six barley genotypes (four Hordeum vulgare and two H. bulbosum). Significant variation in gm was found between genotypes, and was correlated with photosynthetic rate. The genotype with the highest gm also had the highest TE and the lowest carbon isotope discrimination as recorded in leaf tissue (Δp). These results suggest gm has unexplored potential to provide TE improvement within crop breeding programmes. |
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| Keywords: | Hordeum vulgare leaf internal conductance photosynthesis stomatal conductance water use efficiency |
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