TY - JOUR

T1 - A shift in sensitivity to auxin within development of maize seedlings

AU - Shishova, Maria

AU - Yemelyanov, Vladislav

AU - Rudashevskaya, Elena

AU - Lindberg, Sylvia

PY - 2007/10/19

Y1 - 2007/10/19

N2 - The auxin-induced changes in cytosolic concentrations of Ca2+ and H+ ions were investigated in protoplasts from maize coleoptile cells at 3rd, 4th and 5th day of development of etiolated seedlings. The shifts in [Ca2+]cyt and [H+]cyt were detected by use of fluorescence microscopy in single protoplasts loaded with the tetra[acetoxymethyl]esters of the fluorescent calcium binding Fura 2, or pH-sensitive carboxyfluorescein, BCECF, respectively. Both the auxin-induced shifts in the ion concentrations were specific to the physiologically active synthetic auxin, naphthalene-1-acetic acid (1-NAA), and not to the non-active naphthalene-2-acetic acid (2-NAA). Regardless of the age of the seedlings, the rise in [Ca2+]cyt was prior to the acidification in all investigated cases. The maximal acidification coincided with the highest amplitude of [Ca2+]cyt change, but not directly depended on the concentration of 1-NAA. Within aging of the seedlings the amplitude of auxin-induced [Ca2+]cyt elevation decreased. The shift in auxin-induced acidification was almost equal at 3rd and 4th day, but largely dropped at 5th day of development. The acidification was related to changes in the plasma membrane H+-ATPase activity, detected as phosphate release. The decrement in amplitude of both the tested auxin-triggered reactions well coincided with the end of the physiological function of the coleoptile. Hence the primary auxin-induced increase in [Ca2+]cyt, which is supposed to be an important element of hormone signal perception and transduction, can be used as a test for elucidation of plant cell sensitivity to auxin.

AB - The auxin-induced changes in cytosolic concentrations of Ca2+ and H+ ions were investigated in protoplasts from maize coleoptile cells at 3rd, 4th and 5th day of development of etiolated seedlings. The shifts in [Ca2+]cyt and [H+]cyt were detected by use of fluorescence microscopy in single protoplasts loaded with the tetra[acetoxymethyl]esters of the fluorescent calcium binding Fura 2, or pH-sensitive carboxyfluorescein, BCECF, respectively. Both the auxin-induced shifts in the ion concentrations were specific to the physiologically active synthetic auxin, naphthalene-1-acetic acid (1-NAA), and not to the non-active naphthalene-2-acetic acid (2-NAA). Regardless of the age of the seedlings, the rise in [Ca2+]cyt was prior to the acidification in all investigated cases. The maximal acidification coincided with the highest amplitude of [Ca2+]cyt change, but not directly depended on the concentration of 1-NAA. Within aging of the seedlings the amplitude of auxin-induced [Ca2+]cyt elevation decreased. The shift in auxin-induced acidification was almost equal at 3rd and 4th day, but largely dropped at 5th day of development. The acidification was related to changes in the plasma membrane H+-ATPase activity, detected as phosphate release. The decrement in amplitude of both the tested auxin-triggered reactions well coincided with the end of the physiological function of the coleoptile. Hence the primary auxin-induced increase in [Ca2+]cyt, which is supposed to be an important element of hormone signal perception and transduction, can be used as a test for elucidation of plant cell sensitivity to auxin.

KW - Acidification

KW - Auxin

KW - Cytoplasmic calcium

KW - Fluorescence microscopy

KW - Sensitivity

UR - http://www.scopus.com/inward/record.url?scp=34548709113&partnerID=8YFLogxK

U2 - 10.1016/j.jplph.2006.09.005

DO - 10.1016/j.jplph.2006.09.005

M3 - Article

C2 - 17074416

AN - SCOPUS:34548709113

VL - 164

SP - 1323

EP - 1330

JO - Journal of Plant Physiology

JF - Journal of Plant Physiology

SN - 0176-1617

IS - 10

ER -