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Root Growth of Winter Wheat under Elevated Carbon Dioxide and Drought
Author(s) -
Chaudhuri U. N.,
Kirkham M. B.,
Kanemasu E. T.
Publication year - 1990
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/cropsci1990.0011183x003000040017x
Subject(s) - loam , carbon dioxide , dry weight , horticulture , biology , winter wheat , agronomy , crop , carbon dioxide in earth's atmosphere , silt , soil water , botany , ecology , paleontology
With the atmospheric concentration of CO 2 increasing, it is important to know how this will affect crop growth. The objective of this study was to determine the effect of enriched CO 2 on root growth of winter wheat ( Triticum aestivum L. ‘Newton’) under both wellwatered and dry conditions. The wheat was grown for 3 yr in 16 plastic chambers (121 by 92 by 168 cm) in the field under ambient CO 2 (340 μL L −1 ) and elevated levels of CO 2 (485, 660, and 825 μL L −1 ). Each chamber was placed over an underground box (77 by 37 cm at the top; 180 cm deep) containing a Muir silt loam (fine‐silly, mixed, mesic Cumulic Haplustoll). The boxes could be pulled out of the ground for observation of roots. Half of the boxes were maintained at field capacity (0.38 m −3 m −3 ) (well‐watered or not stressed plants) and half between 0.14 to 0.25 m3 m 3 (drought‐stressed plants). At harvest, root dry weights at different depths and stem dry weight were determined. Roots of plants grown under the three elevated levels of CO 2 penetrated to the maximum depth of observation (176 cm) before roots of plants grown under the ambient level. At harvest, the difference in root growth between elevated and ambient levels of CO 2 was most pronounced at the top level (0‐ to 10‐cm depth). Roots of drought‐stressed plants grown with 825 μL L −1 CO 2 had a greater dry weight than roots of well‐watered plants grown with ambient CO 2 . The ratio of root to stem weight usually showed no trend (neither increase or decrease) with increasing CO 2 concentration. Total dry weight at harvest of well‐watered root grown at ambient CO 2 (3‐yr mean: 118 g m −2 ) was similar to that of drought‐stressed roots grown at the highest level of CO2 (3‐yr mean: 123 g m −2 ). The results indicated that high CO 2 (825 μL L −1 ) can compensate for restrictions in root growth by drought.