Unidirectional sodium fluxes in red beet storage tissue (Beta vulgaris L. cv. Platronde Egyptische): effects of the phytohormones indol-3yl-acetic acid and abscisic acid

Abstract

The influence of indol-3yl-acctic acid (IAA) and abscisic acid (ABA) on the capacities of the cytoplastn and vacuole and their elTects on unidirectiotial sodiutn fluxes across the plastnaletntna and the tonoplast of aged red beet storage tissue was investigated. After loading the tissue in a labelled NaCl solution the clllux of radio-activity was tneasured iti unlabelled NaCl. By tneatis of cotnparltncntal atialysis the capacities and fluxes were dctcrtnitied and cotnpated with those obtained after loading atid elution in the pteseticc of IAA or ABA.It was established thai both IAA and ABA alTect sodiutn transport across the principal cell tnetnbrancs. Both hormones inhibited the elUux across the plastnaletntna, possibly by alTecting a Na ' for H ' exchanging system. Elflux across the tonoplast was stitnttlatcd by IAA and influx across the satne tncmbtatic was enhanced by ABA. It was suggested that IAA stitnulated a proton putnp at this level while the influence of ABA tcmaitied diflicult to explain.

Occurrence of Localized Intense Cation Uptake Sites in the Vascular Rings of Red Beet Storage Tissue 2

“…Slices of storage tissue from red table beet (Beta vulgaris L.) subjected to a period of washing, usually referred to as ageing, are often used as model tissue for ion uptake studies (Sutcliffe, 1957;Briggs, Hope, and Pitman, 1958;Van Steveninck, 1975;Poole, 1976;Francois, Bogemans, and Neirinckx, 1982). A common feature of beet storage tissues is the presence of a series of concentric rings of small vascular cells (xylem and phloem) that are separated from one another by broader bands of highly vacuolated thin-walled parenchyma cells (Artschwager, 1926;Hayward, 1938).…”