Effects of Gibberellin and Gibberellin Biosynthesis Inhibitor (Paclobutrazol) Applications on Radish (Raphanus sativus) Taproot Expansion and the Presence of Authentic Hormones

Abstract

To cite this paper: Jabir, B. AbstractRadish (Raphanus sativus L), is a taproot plant that undergoes noticeable organ size modification during plant growth and development. Paclobutrazol (PBZ) inhibits gibberellin biosynthesis and stimulates the proliferation and expansion of plant root cells in growth and developmental stages. Our study aims to examine the effects of PBZ treatment on the storage organ of plant. Four treatments were applied at the pre-cortex splitting stage of "Nau-yh" radish plant. Foliar spray treatments including PBZ (50 mg/L), gibberellic acid (GA3, 150 mg/L) and a mix of GA3+PBZ (150+50 mg/L) were applied. The results revealed considerable improvement in taproot growth and decreases development in aerial parts after 48 days of the growth. Paclobutrazol treatment showed enhanced growth parameters, most notably, root weight was 33% higher than GA 3 treatment, 28% higher than the control (H2O), and 23% higher than the PBZ+GA 3 treatment. PBZ also significantly promoted xylem development in tuberous root of radish. In contrast, the GA3 treatment inhibited tuberous root growth and enhanced shoot growth in plants. Furthermore, mass spectrometry assay confirmed the absence of gibberellins in paclobutrazol-treated plants, whereas auxin was found in all treatments. Our study provides the first evidence on the applicability of PBZ in root size expansion of radish plant.

Morphogenesis, pigment content, phytohormones and productivity of eggplants under the action of gibberellin and tebuconazole

“…Therefore, the study of the effect of gibberellins and anti gibberellin preparations on the growth, development and productivity of cultivated plants deserves special attention (Jabir et al, 2017). Activation of growth processes and changes in the balance of endogenous hormones under the influence of exogenous gibberellins have been observed in organs of tomato plants (Khalloufi et al, 2017) and zucchini (Song et al, 2019).…”

“…A research paper (Jabir et al, 2017) reported that the use of gibberellic acid and triazole derivative of paclobutrazole, as well as their mixtures, affected growth, endogenous phytohormone content and productivity of Raphanus sativus L. Paclobutrazole inhibited the linear growth of radish plants, increased cell proliferation, increased root mass and size. Under the action of gibberellic acid, the growth of the aboveground part was activated and the underground was inhibited, the mass of the root crop remained practically unchanged.…”

Effect of Partial Excision of Early Taproots on Growth and Components of Hydroponic Carrots

“…Given that C5 taproots contained more wounded parts compared with C10 and C15 plants, continuous wound stress at a root cut site may trigger higher production of phenolic compounds in C5 plants. In root vegetables, sink development is regulated by a variety of plant hormones such as auxin, cytokinin, and gibberellic acid [30][31][32][33]. In carrots, gibberellic acids function as negative regulators of taproot enlargement [34,35].…”

Plant Vascular Tissues—Connecting Tissue Comes in All Shapes

“…GA induces xylem fibre differentiation in Arabidopsis , so exogenous GA treatment might reduce the tuber productivity, whereas treatment with the GA biosynthesis inhibitor paclobutrazol (PBZ) might elevate it. Several studies examined the effect of exogenous GA and PBZ treatment on storage organ development and showed that GA-treated carrot and radish are inhibited in storage organ secondary thickening whereas PBZ-treated carrot, radish and potato exhibited enhanced thickening [131,134,135,136]. It was shown that the exogenous GA facilitates the xylem differentiation and increases the lignin content in the carrot [131].…”

“…It was shown that the exogenous GA facilitates the xylem differentiation and increases the lignin content in the carrot [131]. In radish, it was shown that PBZ treatment increases the number of cells in the xylem area and the size of xylem vessels [135], suggesting that the suppression GA signalling can be used to increase storage organ productivity. In addition to applying knowledge gained from unravelling the networks regulating secondary growth in Arabidopsis , there have been approaches that characterize genome-wide transcriptomic changes during the tuberisation or comparisons between tuberous and non-tuberous roots to understand the bulking processes in the radish, cassava, and sweet potato [120,125,128,137].…”