The alkaline tolerance in Lotus japonicus is associated to a mechanism of iron acquisition and a modification of the root architectural pattern

CAMPESTRE M.P; ANTONELLI C.J.; CALZADILLA P.I.; MAIALE S.J.; RODRIGUEZ A.A.; RUIZ O.A.

JOURNAL OF PLANT PHYSIOLOGY

ELSEVIER GMBH

Lugar: BERLIN; Año: 2016 vol. 206 p. 40 - 48

0176-1617

The response of multiple Lotus japonicus ecotypes, fifty-four initially and six selected ecotypes later on, was investigated under alkaline conditions. The sensitive, but not the tolerant ecotypes, grown in sand substrate, showed internerval chlorosis under all alkalinity conditions and high mortality under extreme alkalinity. This phenomenon was associated with Fe deficiency, observing a reduced Fe2+ shoot content in all sensitive ecotypes. In addition, some of them showed a decline in the photosynthesis rate and the PSII performance, with respect to the control. On the contrary, some tolerant ecotypes did not change these parameters between treatments. Alkaline tolerance could be explained by a mechanism of Fe acquisition, related to Strategy I, and a root structural modification. This conclusion was based on the fact that all tolerant, but not the sensitive ecotypes, presented high ferric reductase oxidase activity under alkaline stress, with respect to the control, and a Herringbone root pattern modification. Therefore, the analysis of these mechanisms of alkaline tolerance could be used in screening programs for the selection of new tolerant genotypes in the Lotus genus.