Use of High Performance Liquid Chromatography for the Determination of Endogenous Hormone Levels in Solanum tuberosum L. Subjected to Carbon Dioxide Enrichment of the Root Zone

Abstract

Changes in cytokinin, auxin, and abscisic acid levels were determined by high performance iquid chromatography following CO2 enrichment of the root zone. Both trans zeatin and zeatin riboside signifcandy decreased in the roots 6 days after treatment with CO. In the leaves zeatin riboside increased whereas trans zeatin showed no significant difference from the control. Indoleacetic acid in the leaves increased dramatically for 6 days following CO2 treatment; however, indoleacetic acid levels in the roots increased slHghdy after 2 days and remained higher than the control. Abscisic acid increased shortly after CO2 treatments; after 6 days this difference was no longer evident. levels of several plant hormones after treatment of potato root zones with CO2. Plant hormones were determined in order to evaluate whether CO2 applications were directly involved in dry matter accumulation and tuberization reported earlier or was the CO2 treatment coupled with changes in hormone levels involved in this phenomenon. MATERIALS AND METHODSPotato plants (Solanum tuberosum L. var. Russet Burbank) were propagated by taking 1-cm plugs within the "eye" area (in the apical end) of the tuber. The plugs were arranged in holes bored in styrofoam sheets floating on water with continuous aeration in the dark. After 2 weeks, rooted sprouts 6-8 cm in length were detached from the plug and surface sterilized in 10%o NaOCl. Plants were then transferred to full-strength Hoagland solution (5) Recently we have shown (1) that a single 12-h CO2 treatment to the root zones of potato plants increased dry matter content as well as the production and translocation of C4 acids from the roots to the shoots. We have also shown (1) that CO2 enrichment of the root zones of potato plants causes dramatic changes in the tuberization response. This is in agreement with the findings of Patterson (16) who showed that a single 12-h treatment with CO2 to the roots of potato plants grown in sand culture resulted in significantly more tubers than controls. In addition, CO2 has been shown to stimulate tuberization of isolated potato stolons cultured in vitro (12).It has been shown that cytokinins enhance tuberization of sprout sections cultured in vitro (14,15). Also, it has recently been reported that zeatin riboside is the principle cytokinin in potato plant tissue and that there is an increase in zeatin riboside under conditions which induce tuberization (10). Auxin, on the other hand, may accelerate tuber formation (4, 7); however, conflicting reports by Booth (2) and Okazawa (13) indicate that auxin is probably involved in stolon growth rather than tuber initiation. Applications of ABA as a foliar spray have been shown to increase tuberization (3), probably due to a general depression in growth.Because of the wide range of physiological events under hormonal control (8), our objective was to determine changes in the ' Scientific Paper No. 5238.

Effect of IAA produced by Klebsiella oxytoca Rs-5 on cotton growth under salt stress

“…The extraction and purification of IAA in cotton root tissue followed the method of Arteca et al (1980). One gram frozen and powdered root samples with liquid nitrogen was extracted with 10 ml cold 80% aqueous methanol (MeOH) containing 200 mg/L butylated hydroxytoluene as an antioxidant for 24 h in darkness at 4 C and then centrifuged at 6,000 g for 15 min.…”

Effect of abscisic acid on endogenous IAA, auxin protector levels and peroxidase activity during adventitious root initiation in Vigna radiata cuttings

“…The tissues were reextracted twice for 4 h each. The combined extracts were reduced to the aqueous phase in vacuo at 30 °C using a rotary evaporator and centrifuged at 48,000 g for 30 rain (Arteca et al 1980). Supernatants were evaporated to about 0.5 mL, then 0.5 mL of MeOH was added and the extracts were passed through an activated C 18 Sep-Pak cartridge (Purves and Hollenberg 1982), followed by elution with 9 mL 90 % MeOH.…”

“…Supernatants were evaporated to about 0.5 mL, then 0.5 mL of MeOH was added and the extracts were passed through an activated C 18 Sep-Pak cartridge (Purves and Hollenberg 1982), followed by elution with 9 mL 90 % MeOH. Aliquots equal to 3 g FW were analyzed by high performance liquid chromatography (HPLC) for free IAA by a modification of the method of Arteca et al (1980). The remainder of the sample was used lbr analysis of total (free+ ester+ amide) IAA according to the method described by Cohen et al (1988).…”

Plant Growth Substances

“…There have been several reports showing that there are elevated levels of cytokinins in response to conditions which promote tuberization (Forsline and Langille 1975;Okazawa 1970;Langille and Forsline 1974;Mauk and Langille 1978;Arteca et al 1980). The major cytokinin found in potato leaves is zeatin riboside (Mauk and Langille 1978;Arteca et al 1980), although, zeatin has also been found in potato tubers (Okazawa 1970), leaves and roots (Arteca et a1.…”

“…The major cytokinin found in potato leaves is zeatin riboside (Mauk and Langille 1978;Arteca et al 1980), although, zeatin has also been found in potato tubers (Okazawa 1970), leaves and roots (Arteca et a1. 1980).…”