Fig. 5

Auxin regulated PIN1 expression in the root tip. a and b Immunostaining of PIN1 expression in wild type plants treated with low (0.1 μM) and high (1 μM) NAA dosage for 24 h. a The effect of exogenous low-level auxin on PIN1 upregulation in the meristem and at the sites of lateral primordia outgrowth. b Modulation of PIN1 expression domain under low and high NAA treatments, compared to control. The variation in length of the expression domains for different cell lineages is shown by coloured triangles. CSC—columella stem cell, c2—the second columella tier, c3- the third columella tier, epid—epidermis, c—cortex, en—endodermis, prc—pericycle, vsc—vasculature. Anti-PIN1 staining is in green, DAPI is in the blue channel. Bars = 50 μm. c and d Quantitative estimates of the changes in PIN1 domain length (c) and PIN1 maximal expression intensity (d) under exogenous IAA treatments with different dosages. The experimental images were analysed in ImageJ (See Methods). Green line—estimates for PIN1pro:PIN1-GFP plants; blue line—for PIN1pro:GUS plants. The measured values for each IAA dosage and for each reporter line were normalized to controls. Statistics differences were identified by t-test: * p-value < 0.05; ** p-value < 0.01; *** p-value < 0.001