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Responses to Root‐Zone CO 2 Enrichment and Hypoxia of Wheat Genotypes Differing in Waterlogging Tolerance
Author(s) -
Huang Bingru,
Johnson Jerry W.,
NeSmith D. Scott
Publication year - 1997
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci1997.0011183x003700020026x
Subject(s) - photosynthesis , shoot , biology , stomatal conductance , waterlogging (archaeology) , hypoxia (environmental) , nutrient , horticulture , botany , agronomy , zoology , oxygen , chemistry , ecology , wetland , organic chemistry
Knowledge of wheat ( Triticum aestivum L.) responses to CO 2 and O 2 in the root environment could improve understanding of the mechanisms of waterlogging tolerance and thus help develop waterlogging tolerance wheat plants. This experiment was designed to investigate the responses to elevated CO 2 and hypoxia of two wheat genotypes, Bayles and Savannah, which differ in waterlogging tolerance. Plants were grown in a growth chamber in nutrient solutions. Nutrient solutions were bubbled with ambient air (control), N 2 containing 5 kPa O 2 and ambient CO 2 (hypoxia), N 2 containing 10 kPa CO 2 and ambient O 2 (high CO 2 , ambient O 2 ), and N 2 containing 10 kPa CO 2 and 5 kPa O 2 (high CO 2 , low O 2 ). Hypoxia alone had adverse effects on net photosynthesis (P n ), stomatal conductance (g s ), water relations, chlorophyll (chl) content, and shoot and root growth. The effects were greater for waterlogging‐sensitive Bayles. When compared with the aerated control, the combination of elevated CO 2 and hypoxia caused significant reductions in P n , g s , leaf water potential, and leaf chl content for Bayles, and in shoot and root growth for both Bayles and Savannah. Photosynthetic rate and leaf chi content of Savannah were increased when roots of hypoxic plants were exposed to elevated CO 2 , but this was not true for Bayles. Root‐zone CO 2 enrichment at ambient O 2 had no significant effects on shoot growth, but reduced root growth in both genotypes. The results showed that CO 2 enrichment under root hypoxia can alleviate some negative effects of hypoxia on P n , leaf chi content, and shoot growth, the effect being larger for waterlogging tolerance Savannah.