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Effect of root perturbation and excision on nitrate influx and efflux in barley ( Hordeum vulgare ) seedlings
Author(s) -
Aslam Muhammad,
Travis Robert L.,
Rains D. William,
Huffaker Ray C.
Publication year - 1996
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1996.tb00499.x
Subject(s) - efflux , hordeum vulgare , stimulation , nitrate , chemistry , biology , biophysics , poaceae , horticulture , botany , biochemistry , endocrinology , organic chemistry
The effects of perturbation and excision on net NO ‐ 3 , uptake, influx and efflux in roots of 8‐day‐old barley ( Hordeum vulgare L.) seedlings induced with NO ‐ 3 or NO ‐ 2 were determined. Perturbation was simulated by mechanically striking the intact roots with a glass rod. Perturbation or excision of roots and subsequent division into small segments had little effect on NO ‐ 3 influx, but briefly inhibited net uptake which recovered within a few min. While in perturbed roots net uptake rates recovered to the same level as in control roots, full recovery did not occur in excised roots. Inhibition of net uptake was due to stimulation of NO ‐ 3 efflux. The recovery time and level of inhibition of net NO ‐ 3 uptake and/or stimulation of efflux were a function of extent of perturbation, or the number of segments following excision, and root NO ‐ 3 concentration. NO ‐ 3 efflux was further stimulated when roots were perturbed after cytoplasmic NO ‐ 3 had been depleted, indicating that both the plasmalemma and tonoplast may be affected. In excised roots both NO ‐ 3 influx and efflux decreased with age due to depletion of energy sources. The results indicate that root perturbation and excision had no effect on NO ‐ 3 influx but inhibited net uptake by stimulating efflux.