ibclogo XVI International Botanical Congess

Abstract Number: 2465
Poster No. = 2154


PLANT NATRIURETIC PEPTIDE HORMONE MODULATES K+, Na+ AND H+ FLUXES IN ZEA MAYS


M Pharmawati1, SN Shabala2, IA Newman2, CA Gehring1. 1Deakin University, School of Biol & Chem Sciences, Geelong, Vic 3217, Australia, 2University of Tasmania GPO Box 252, Hobart, Tas 7001, Au


In plants, as in vertebrates, biologically active natriuretic peptide hormones (NP) may regulate homeostasis. NP analogues (irPNP) were immunoaffinity purified from ivy. The irPNP increased cGMP levels in corn root stele. Ion-selective microelectrodes were used to measure net fluxes in corn root conductive tissue. The irPNP caused immediate H+ influx. Increases in K+ and Na+ uptake were observed only after 30 min. Delayed increase in K+ influx also occurs in response to 8-Br-cGMP, but is not accompanied by significant change in H+ flux. Do irPNP and cGMP stimulate a cation channel with PK > PNa? We propose an NP role in plant homeostasis and that some NP effects are mediated by the second messenger cGMP.

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