Effects of elevated atmospheric CO[sub 2] on soybean and sorghum root growth

Conference · Sat May 01 00:00:00 EDT 1993 · Plant Physiology; (United States)

OSTI ID:6280034

Rogers, H H; Prior, S A; Runion, G B ^[1]

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1. National Dynamics Lab., Auburn, AL (United States)

Aboveground plant responses to elevated CO[sub 2] concentration are well documented. However, very little is known about crop root responses to CO[sub 2] enrichment, especially under field environments. This study evaluates the effects of increased serial CO[sub 2] concentration on root systems of a C[sub 3] [soybean (Glycine max (L>) Merr.)] and C[sub 4] [sorghum (Sorghum bicolor (L.) Moench.)] crop. Plants were grown in open top field chambers under two levels of CO[sub 2]. Root systems were sampled at physiological maturity by uprooting the plant from the soil while concurrently measuring vertical pull resistance. Root variables (length, dry weight, and tissue density), except for number of roots, were significantly increased under elevated CO[sub 2]. The positive effects of extra CO[sub 2] on soybean roots partitioned into taproot and lateral roots were similar to patterns previously described. The number of soybean nodules increased under CO[sub 2]-enriched conditions, but no effect on nodule dry weight was seen. Elevated CO[sub 2] increased root dry weight more so than root length. The larger root systems observed under CO[sub 2] enrichment was reflected in an overall increase in vertical pull resistance. Several root variables exhibited significant CO[sub 2] X species interactions (except root number) with differences between CO[sub 2] levels seen with sorghum. Fine root data obtained from soil cores (30 cm) also showed that extra CO[sub 2] influenced root dry weight density more so than root length density. Under elevated CO[sub 2] conditions, root dry weight density more so than root tissue density values tended to be greater in the top 15 cm of the soil profile, but not lower in the profile (i.e., 15-30 cm). The fine root data exhibited few CO[sub 2] X species interactions. Results from this study indicate that additional atmospheric C[sub 2] will affect crop root systems.

• OSTI ID: 6280034
• Report Number(s): CONF-9307119-; CODEN: PLPHAY
• Journal Information: Plant Physiology; (United States), Vol. 102:1; Conference: 1993 joint annual meeting of the American Society of Plant Physiologists (ASPP) and the Canadian Society of Plant Physiologists (CSPP), Minneapolis, MN (United States), 31 Jul - 4 Aug 1993; ISSN 0032-0889
• Country of Publication: United States
• Language: English

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63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
CARBON DIOXIDE
BIOLOGICAL EFFECTS
ECOLOGICAL CONCENTRATION
ROOTS
GROWTH
PLANTS
SORGHUM
SOYBEANS
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