Title

Regulation of tuber formation and ADP-glucose pyrophosphorylase (AGPase) in sweet potato ( Ipomoea batatas (L.) Lam.) by nitrate.

Authors

Kim, Sun-Hyung; Mizuno, Kouichi; Sawada, Shinichi; Fujimura, Tatsuhito

Abstract

The relationship between nitrate fertilization and tuber-bulking inroots from single-leaf explants was examined to clarify the mechanism of tuberformation. Cuttings of sweet potato leaves were grown on a medium containing 1,10, 30, and 50 mM nitrate and analyzed with regard tomorphologicaland biochemical traits. The cuttings grown on higher concentrations (≥10mM) showed inhibited root growth, with no apparent effect on leafgrowth or root length. The roots accumulated starch in a medium containing alower nitrate concentration (≤10 mM). Under this culturecondition, both the ADP-glucose pyrophosphorylase (AGPase) transcript level andthe starch content in the root decreased, while there was no decrease in thestarch content in the leaf. The greater AGPase transcript level in rootsgrowingwith a higher nitrate concentration (≥10 mM) might be caused bynitrogen-mediated signalling and/or changes in the levels of starch metabolism.Starch synthesis via AGPase and cell proliferation may work together for tuberformation in sweet potato root.

Publication

Plant Growth Regulation, 2002, Vol 37, Issue 3, p207

ISSN

0167-6903

Publication type

Academic Journal

DOI

10.1023/A:1020844418776