Potassium uptake by onion roots characterized by potassium/rubidium ratio

Journal Article · Sat Jul 01 04:00:00 EDT 1978 · Soil Sci. Soc. Am. J.; (United States)

DOI:https://doi.org/10.2136/sssaj1978.03615995004200040017x· OSTI ID:5775590

Baligar, V C; Barber, S A

A common belief is that plant roots absorb cations from the solution phase of the soil. Experiments with corn (Zea mays L.) using K/Rb ratio to evaluate the source of K and Rb absorbed indicated the plant roots absorbed these ions in the ratio of exchangeable K and Rb. The objective of this research was to study the source of K and Rb absorbed from soil by onion (Allium cepa) roots since they do not have root hairs and this may influence the uptake mechanism. Onions absorbed K/Rb with a ratio which was intermediate between the ratio of exchangeable K and Rb and the ratio of these cations in solution. In comparison with corn, onions absorbed K at one-third the rate, but absorbed water three times faster so that mass flow contributed a greater proportion of K absorbed by onions than that by corn. This, rather than differences in root hairs may be the reason for the observed differences in K uptake between corn and onions.

• Research Organization: Purdue Univ., West Lafayette, IN
• OSTI ID: 5775590
• Journal Information: Soil Sci. Soc. Am. J.; (United States), Journal Name: Soil Sci. Soc. Am. J.; (United States) Vol. 42:4; ISSN SSSJD
• Country of Publication: United States
• Language: English

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54 ENVIRONMENTAL SCIENCES
ALKALI METALS
CEREALS
ELEMENTS
FOOD
GRAMINEAE
GRASS
ION EXCHANGE
MAIZE
METALS
ONIONS
PLANTS
POTASSIUM
ROOT ABSORPTION
ROOTS
RUBIDIUM
SOIL MECHANICS
SOILS
UPTAKE
VEGETABLES