Response of maize and rice to 9-β-L(+) adenosine applied under different environmental conditions

The increase in growth, determined by dry weight gain, of rice (Oryza sativa L.) and maize (Zea mays L.) caused by foliar applications of 9--L(+) adenosine, a putative second messenger elicited by triacontanol, was studied under different environmental conditions. Maize seedlings cultured in the greenhouse under approximately 100 mol m^–2s^–1 of light prior to treatment with L(+) adenosine did not respond unless they received supplemental light (250–300 mol m^–2s^–1) after treatment. Exposure of rice seedlings growing for 16 h at 150 mol m^–2s^–1 to short periods of 450 mol m^–2s^–1 (< than 20 min) had no effect on the positive response of rice to L(+) adenosine; however, exposure for 60 min or more increased the growth of rice and obviated the effect of L(+) adenosine. Rice seedlings treated with L(+) adenosine at different times during the day responded only when treated 9 to 12h after initiation of the photoperiod. Normal growing temperatures under different light intensities had little or no direct effect on the response of plants to L(+) adenosine.     

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

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.Abbreviations OCTA octacosanol - OCTAM second messenger elicited by OCTA - TAS tallow alkyl sulfate - TRIA triacontanol - TRIM second messenger elicited by TRIA Michigan Agricultural Experiment Station Journal Article No. 12001     

Specificity of 1-triacontanol as a plant growth stimulator and inhibition of its effect by other long-chain compounds

The effect of several analogs of 1-triacontanol (TRIA), differing in C-chain length (16–32), the position of the hydroxyl group and the terminal functional group, were tested alone and in combination with TRIA on the growth of rice (Oryza sativa L.), maize (Zea mays L.) and tomato (Lycopersicon esculentum Mill.) seedlings. Applied alone, none of the compounds caused an increase in growth; thus, chain length (30 C) and presence and position (terminal) of the hydroxyl group appear to be specific for the growth-promoting activity of TRIA. When applied simultaneously with TRIA, all analogs inhibited the response to the latter in all three test plants, whether applied in the nutrient solution, as foliar spray or by seed soaking. 1-Octacosanol inhibited the response of rice seedlings to 2.3 x 10^-8 M TRIA at concentrations as low as 2.4 x 10^-12 M. Thus preparations of TRIA and application equipment must be free from trace amounts of other long-chain compounds if they are to be used to increase plant growth.Abbreviation TRIA 1-triacontanol     

Influence of 9-β-l(+)-adenosine on malate dehydrogenase activity in rice

The activity of malate dehydrogenase (MDH, EC 1.1.1.37) in rice ( Oryza sativa L. cv. California M-201) roots was increased within 25 min by a foliar application of 37 n M of 9-β- l (+)-adenosine [ l (+)-adenosine]. A similar concentration of 9-β- d (-)-adenosine [ d (-)-adenosine] did not affect MDH. Triacontanol (2.7 n M ) which elicits l (+)-adenosine in plants also increased MDH activity in roots of rice seedlings. whereas neither octacosanol nor a mixture of equimolar concentrations of triacontanol and octacosanol had any effect on MDH activity. l (+)-Adenosine increased MDH activity of rice seedlings grown at 10.20 and 40°C. The effect was measurable 24 h after application at 10 and 20°C, but not 6 h after treatment at 40°C. Ninety minutes after l (+)-adenosine was applied to the foliage of plants grown at 10, 20 and 40°C, MDH activity in the roots was 40, 30 and 9% more, respectively, than in the untreated controls. The concentration of water soluble protein was also increased by l (+)-adenosine and was positively correlated with MDH activity. When measured 90 min after application of l (+)-adenosine at different times of day, MDH activity and dry weight were increased most when l (+)-adenosine was applied 9 and 12 h after the lights came on in a 16-h photoperiod. The optimum light intensity for the response of rice to l (+)-adenosine, as measured by MDH activity, was 450 μmol m⁻² s⁻¹.     

Photosynthesis response to triacontanol correlates with increased dynamics of mesophyll protoplast and chloroplast membranes

The effects of a long chain aliphatic alcohol 1-triacontanol (TRIA) on the photosynthesis and membrane properties of mesophyll protoplasts and chloroplasts isolated from pea leaves were studied. In vitro treatments of isolated protoplasts caused a large enhancement (166% ) of the CO2-fixation rate after 60 min of TRIA (10^-6 M) application as compared to the control. An enhanced photosynthetic response was observed in in vitro treated leaf pieces. Application of octacosanol (OCTA) under the same experimental conditions did not result in any stimulating effects. In vivo treatments of pea seedlings also resulted in a significant increase of the net CO2 uptake to 109% and 119% in 10^-8 M and 10^-6 M TRIA-treated plants respectively. It was demonstrated that the incubation of both protoplasts and chloroplasts with TRIA resulted in a rise of the excimer/monomer (I_E/I_M ) ratio of pyrene (Py) fluorescence, thus indicating remarkable fluidization and/or disordering of the lipid matrix of their membranes. This effect depended on the incubation time and became evident at very low concentrations of TRIA (0.3 M). The increase of membrane fluidity was accompanied by TRIA-induced alterations in the dielectric environment in the membrane regions where Py molecules are situated. The results are discussed in terms of specific concentration dependent TRIA-induced alterations of the dynamic properties of protoplast and chloroplast membranes and their possible involvement in the initiation of the integral physiological response to exogenous application of TRIA.     

Effect of triacontanol and chlormequat on growth,plant hormones and artemisinin yield in Artemisia annua L.

Artemisinin and herbage yield of Artemisia annua plants were determined after application of triacontanol (tria.) and chlormequat (2-chloroethyltrimethylammonium chloride). Tria. at 1.0 and 1.5 mgl^–1 produced a statistically significant positive effect on artemisinin level as well as on plant height, leaf and herbage yield. Chlormequat at 1000 and 1500 mgl^–1 also increased artemisinin level, decreased the plant height at higher concentrations and increased the leaf and herbage yield at lower concentrations. Tria. application enhanced GA-like activity, but ABA levels decreased, while chlormequat increased ABA but reduced GA-like substances. The effect of Tria. on artemisinin yield seems to be mediated through its effect on plant growth.CIMAP Publication.     

Chemical Constituents of Lac Host,Acacia suma

Six crystallin compounds were isolated from the stem bark of Acacia surna BuchHam. ex. Wall. Based on spectral and chemical evidences, four of them were demonstrated as triacontanol, β-sitosterol, daucosterin and lupeol heptylate. All were firstly reported from the plant. Among them lupeol heptylate was a new compound.     

Effect of triacontanol on the lipid composition of cotton (Gossypium hirsutum L.) leaves and its interaction with indole-3-acetic acid and benzyladenine

Application of triacontanol (TRIA), a long chain aliphatic alcohol (C-30), to cotton (Gossypium hirsutum L.) leaves resulted in an increase in dry weight and an alteration in lipid composition. A significant increase in monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol (DGDG) was attained 24 h after TRIA treatment. However, no significant change in any of the individual phospholipids was observed. Benzyladenine (BA) treatment increased only phosphatidylcholine (PC) levels without having any effect on either glycolipids or other phospholipids. Indole-3-acetic acid (IAA) initiated no significant change in the lipid composition. Combined treatment with TRIA and BA resulted in an increase of MGDG, DGDG and PC, indicating that the individual effects of these two growth regulators were not altered.The combined treatment of IAA and TRIA did not bring about any change in the levels of MGDG and DGDG indicating that the effect of TRIA was nullified by IAA. MDGD is known to be involved in the packaging of photosystem I proteins. Whether TRIA-induced increase in dry weight which is due to the enhanced photosynthetic rate, is related to increased MGDG levels is not yet discernible.Abbreviations BA benzyladenine - DGDG digalactosyldiacylglycerol - IAA indole-3-acetic acid - MGDG monogalactosyldiacylglycerol - PC phosphatidylcholine - PE phosphatidylethanolamine - PG phosphatidylglycerol - PI phosphatidylinositol - PS phosphatidylserine - SQDG sulfoquinovosyldiacylglycerol - TRIA triacontanol     

The effect of triacontanol on micropropagation and on secretory system of Thymus mastichina

Shoot multiplication of Thymus mastichina L. was achieved on media containing 0.1 mg l^–1 6-benzyladenine and/or 0.1 mg l^–1 indole-3-butyric acid, or in hormone-free medium (control). The growth of plantlets, the production and composition of the essential oil, the density and secretory stage of glandular hairs have been evaluated in the presence and absence of growth regulators and triacontanol. We observed a positive effect of triacontanol on the growth of micropropagated plantlets using different conditions. Media with different levels of BA, IBA and TRIA resulted in no differences in the composition of the essential oil produced by plantlets. The major components of the oil were 1,8-cineole and linalool. An increase in the oil yield was observed especially when triacontanol was added to hormone-free medium. There was no correlation between changes in the oil yield and glandular hairs density, but the yield was dependent on the secretory stage of the glands.