UPTAKE AND TRANSPORT OF RADIOCHLORIDE AND TRITIATED WATER BY VARIOUS ZONES OF ONION ROOTS OF DIFFERENT CHLORIDE STATUS

Journal Article · Wed Jan 01 04:00:00 EST 1964 · Plant Physiology (U.S.)

DOI:https://doi.org/10.1104/pp.39.1.104· OSTI ID:4107602

Hodges, T K; Vaadia, Y

The uptake and transport of radiochloride and tritiated water by different root zones of individual exuding onion (Allium cepa) roots of different chloride status was determined. The terminal 3 cm of the root was most active in Cl/sup 36 accumulation and transport to the exudate. The net rate of Cl/sup 36/ accumulation by the root tissue initially decreased with time, whereas the rate of Cl/sup 36/ transport to the exudate remained constant over a 12 hour period. It was suggested that the transport of ions into vacuoles also occurs at a constant rate which is accompanied by progressively increasing rates of ion efflux from vacuoles. The reoccupation of active transport sites by ions moving from vacuoles to cytoplasm would account for the decreasing rate of net accumulation with time and also the reduced uptake and transpont of Cl/sup 36/ in high chloride roots. Exudate concentrations of Cl/sup 36/ exceeded tissue concentrations of Cl/sup 36/ when tracer absorption occurred at the 3 to 6 cm zone of high chloride roots. This result was obtained even though water absorption from the 1 to 3 cm and 6 to 9 cm zones would have caused dilution of the xylem steam. Movement of Cl/sup 36/ from the treated zones to untreated zones was negligible as was movement from the xylem into the untreated zones. The uptake and movement of tritiated water (THO) to root exadates was unaffected by the chloride status of the tissue. The 6 to 9 cm zone appeared to absorb THO most rapidly. Adjacent root zones had only a trace of THO. (auth)

• Research Organization: Univ. of California, Davis
• Sponsoring Organization: USDOE
• NSA Number: NSA-18-011607
• OSTI ID: 4107602
• Journal Information: Plant Physiology (U.S.), Journal Name: Plant Physiology (U.S.) Vol. Vol: 39; ISSN PLPHA
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

ALLIUM
BIOLOGY AND MEDICINE
CHLORIDES
CHLORINE 36
DIFFUSION
HEAVY WATER
IONS
PLANT CELLS
PLANTS
ROOTS
TRITIUM
TRITIUM COMPOUNDS
WATER