Rapid elicitation of second messengers by nanomolar doses of triacontanol and octacosanol

Abstract

Triacontanol (TRIA) increases the dry weight and alters the metabolism of rice (Oryza sativa L.) seedlings within 10 min of application to either the shoots or roots. This activity is prevented if octacosanol (OCTA, C28 primary alcohol) is applied with the TRIA on the roots or shoots. Triacontanol activity is also stopped if the OCTA is applied at least 1 min before the TRIA on the opposite part of the seedling.Triacontanol rapidly elicits a second messenger that moves rapidly throughout the plant resulting in stimulation of growth (dry-weight increase) and water uptake. Octacosanol also produces a second messenger that inhibits TRIA activity. We have named the putative secondary messengers elicited by TRIA and OCTA, TRIM and OCTAM, respectively. The water-soluble TRIM extracted from plants treated with TRIA increases the growth of rice seedlings about 50% more than extracts from untreated plants, within 24 h of application. Both OCTAM and OCTA inhibit the activity of TRIA but not of TRIM.The TRIA messenger was isolated from rice roots within 1 min of a foliar application of TRIA. The TRIM elicited by TRIA will pass through a 4-mm column of water connecting cut rice shoots with their roots and can also be recovered from water in which cut stems of TRIA-treated plants have been immersed. Triacontanol applied to oat (Avena sativa L.) or tomato (Lycopersicon esculentum Mill.) shoots connected to rice roots by a 4-mm water column also results in the appearance of TRIM in rice roots.

Triacontanol: a potent plant growth regulator in agriculture

“…Ries and Houtz (1983) suggested that the hormonal effects of TRIA might be due to TRIA-induced alterations at the membrane level. TRIA-mediated activation of a number of membrane bound enzymes supports this assumption (Ries and Wert 1988;Ries 1991;Savithiry et al 1992). As per Ries et al (1990), TRIA treatment causes rapid elicitation of a specific second messenger, 9-b-L(') adenosine, which could induce extremely rapid physiological responses.…”

“…TRIA increased the dry weight as well as content of free amino acids, reducing sugars, and soluble protein of rice (Oryza sativa L.) and maize (Zea mays L.) plants within 5 min (Ries 1991). TRIA also elicited the appearance of L(')-adenosine in the roots of plants whose shoots were sprayed with its nanomolar concentrations within 1 min (Ries and Wert 1988). This was the first evidence that L(')-adenosine occurred in nature.…”

Rapid Induction of Ion Pulses in Tomato, Cucumber, and Maize Plants following a Foliar Application of L(+)-Adenosine

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Since the discovery of the plant growth-regulating properties of TRIA, a primary alcohol that is a natural constituent of plant waxes, and its second messenger L(+)-adenosine, the rapid response kinetics to these compounds have been enigmatic (Ries and Wert, 1988;Ries, 1991).TRIA increased the dry weight, free amino acids, reducing sugars, and soluble protein of rice (Oryza sativa L.) and maize (Zea mays L.) plants within 5 min (Ries, 1991). TRIA also elicited the appearance of L(+)-adenosine in the roots of plants whose shoots were sprayed with nanomolar concentrations within 1 min (Ries and Wert, 1988).

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“…TRIA applied to oat (Avena sativa L.) or tomato (Lycopersicon esculentum Mill.) shoots connected to rice roots by a 4-mm water column also resulted in the appearance of L(+)-adenosine (TRIM) in rice roots (Ries and Wert, 1988).In an attempt to determine other physiological responses to TRIA in addition to the elicitation of L(+)-adenosine, 20-to 25-d-old tomato seedlings were sprayed with water or TRIA, and after 1 min the plants were excised. Analysis of the diffusate from the excised shoots, as determined by HPLC and atomic absorption spectrophotometry, indicated large concentration differences in organic compounds and inorganic cations (unpublished data).…”

“…Since the discovery of the plant growth-regulating properties of TRIA, a primary alcohol that is a natural constituent of plant waxes, and its second messenger L(+)-adenosine, the rapid response kinetics to these compounds have been enigmatic (Ries and Wert, 1988;Ries, 1991).…”