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Free‐Air Carbon Dioxide Enrichment of Cotton: Root Morphological Characteristics
Author(s) -
Prior S. A.,
Rogers H. H.,
Runion G. B.,
Kimball B. A.,
Mauney J. R.,
Lewin K. F.,
Nagy J.,
Hendrey G. R.
Publication year - 1995
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq1995.00472425002400040019x
Subject(s) - taproot , carbon dioxide , evapotranspiration , lateral root , lysimeter , environmental science , root system , dry weight , agronomy , horticulture , chemistry , soil water , biology , soil science , ecology , biochemistry , organic chemistry , arabidopsis , gene , mutant
The response of plants to rising global CO 2 concentration is of critical research interest but one neglected aspect is its effect on roots. Root morphological changes in cotton [ Gossypium hirsutum (L.) ‘Delta Pine 77’] were examined in a 2‐yr field study. The test crop was grown under two water regimes (wet, 100% of evapotranspiration [ET] replaced and dry, 75% [1990] and 67% [1991] of ET replaced) and two atmospheric CO 2 concentrations (ambient = 370 µmol mol −1 and free‐air CO 2 enrichment [FACE] = 550 µmol mol −1 ). A FACE technique that allows for CO 2 exposure under field conditions with minimal alteration of plant microclimate was used. Excavated root systems were partitioned into taproot and lateral roots at two growth phases (vegetative and reproductive). Vertical root‐pulling resistance was determined at the second sampling; this measure was higher because of CO 2 enrichment but was unaffected by water stress. Water stress affected root variables only at the second sampling; water stress reduced taproot variables more than lateral variables. The larger diameter taproots seen at all sample dates under FACE exhibited large increases in dry weight and volume. FACE often increased lateral root number and lateral dry weights were higher at all sample dates. The development of more robust taproot systems in CO 2 ‐enriched environments may allow for greater carbohydrate storage for utilization during periods such as boll filling and to ensure root growth for continued exploration of the soil profile to meet nutrient and water demands during peak demand periods.