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Calcium and Strontium Transport to Plant Roots
Author(s) -
Elgawhary S. M.,
Malzer G. L.,
Barber S. A.
Publication year - 1972
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1972.03615995003600050030x
Subject(s) - strontium , diffusion , chemistry , relative humidity , calcium , humidity , volumetric flow rate , zoology , horticulture , botany , analytical chemistry (journal) , environmental chemistry , biology , physics , organic chemistry , quantum mechanics , thermodynamics
Mass‐flow and diffusion of Ca and Sr to tomato ( Lycopersicon esculentum ) roots were studied in two exchange resin rooting media. Six harvests were made from plants grown over a 26‐day period under low and high humidities in a growth chamber. With low humidity, the rate of supply of Ca and Sr by mass‐flow exceeded uptake rate during the entire growth period. Under high humidity, the rate of mass‐flow supply exceeded uptake only until the second harvest, thereafter diffusion became the dominant supply mechanism. The Ca/Sr ratio of uptake was compared with the Ca/Sr ratios on the resins and in solutions to determine the source of Ca and Sr. Supply by mass‐flow came from the solution, where‐as supply by diffusion apparently came mainly from the exchangeable fraction indicating exchange diffusion was important. Both log of root length and log of water uptake were linearly correlated with time for the 26‐day growth period investigated. The rate of water absorption ranged from 1.1 × 10 ‐7 to 6.0 × 10 ‐7 cm 3 /cm of root per sec. The root uptake coefficient for Ca uptake varied between 1.43 × 10 ‐6 and 2.72 × 10 ‐6 cm/sec and for Sr 1.0 × 10 ‐6 to 2.38 × 10 ‐6 cm/sec where an average root radius of 0.015 cm was used in the calculations.