TY - JOUR

T1 - Regulation of K+ channels in maize roots by water stress and abscisic acid

AU - Roberts, Stephen K.

PY - 1998/1

Y1 - 1998/1

N2 - Root cortical and stelar protoplasts were isolated from maize (Zea mays L.) plants that were either well watered or water stressed, and the patch-clamp technique was used to investigate their plasma membrane K+ channel activity. In the root cortex water stress did not significantly affect inward-or outward-rectifying K+ conductances relative to those observed in well-watered plants. In contrast, water stress significantly reduced the magnitude of the outward-rectifying K+ current in the root stele but had little effect on the inward-rectifying K+ current. Pretreating well-watered plants with abscisic acid also significantly affected K+ currents in a way that was consistent with abscisic acid mediating, at least in part, the response of roots to water stress. It is proposed that the K+ channels underlying the K+ currents in the root stelar cells represent pathways that allow K+ exchange between the root symplasm and xylem apoplast. It is suggested that the regulation of K+ channel activity in the root in response to water stress could be part of an important adaptation of the plant to survive drying soils.

AB - Root cortical and stelar protoplasts were isolated from maize (Zea mays L.) plants that were either well watered or water stressed, and the patch-clamp technique was used to investigate their plasma membrane K+ channel activity. In the root cortex water stress did not significantly affect inward-or outward-rectifying K+ conductances relative to those observed in well-watered plants. In contrast, water stress significantly reduced the magnitude of the outward-rectifying K+ current in the root stele but had little effect on the inward-rectifying K+ current. Pretreating well-watered plants with abscisic acid also significantly affected K+ currents in a way that was consistent with abscisic acid mediating, at least in part, the response of roots to water stress. It is proposed that the K+ channels underlying the K+ currents in the root stelar cells represent pathways that allow K+ exchange between the root symplasm and xylem apoplast. It is suggested that the regulation of K+ channel activity in the root in response to water stress could be part of an important adaptation of the plant to survive drying soils.

KW - PATCH-CLAMP

KW - PLASMA-MEMBRANE

KW - ION-TRANSPORT

KW - BARLEY ROOTS

KW - XYLEM PARENCHYMA

KW - GROWTH

KW - CELLS

KW - INWARD

KW - PROTOPLASTS

KW - PLANTS

U2 - 10.1104/pp.116.1.145

DO - 10.1104/pp.116.1.145

M3 - Journal article

VL - 116

SP - 145

EP - 153

JO - Plant Physiology

JF - Plant Physiology

SN - 0032-0889

IS - 1

ER -