Search

Blast disease caused by Magnaporthe grisea has emerged as a serious threat to pearl millet cultivation in India. Most of the hybrids being grown in India are susceptible to blast as not much efforts have been made to breed for blast resistance in pearl millet. In the absence of host plant resistance, the disease can be effectively managed with chemical fungicides. Therefore, nine fungicides, chlorothalonil, tricyclazole, hexaconazole, kasugamycin, benomyl, carbendazim, tebuconazole + trifloxystrobin, propiconazole and metalaxyl + mancozeb were tested for their efficacy to manage blast disease on a blast susceptible pearl millet line ICMB 95444. Different combinations of seed treatment and foliar sprays were tested: seed treatment alone, seed treatment + one spray, seed treatment + two sprays, seed treatment + three sprays. None of the fungicides was found effective when used as seed treatment. Results of this study clearly demonstrated that the disease can be effectively managed with three sprays of tebuconazole + trifloxystrobin (Nativo) or propiconazole (Tilt).

TiAlN/AlCrN and AlCrN/TiAlN bilayer coatings were deposited on tungsten carbide cutting inserts using the plasma enhanced physical vapour deposition process. Their thermal stability was varied by annealing the specimens at different temperatures and time durations. The thermal stability was evaluated from hardness measurement, oxygen absorption and X-ray diffraction (XRD) patterns. TiAlN/AlCrN coating initially shows an increase in hardness, but it decreases when the annealing temperature is increased. A high hardness of 46 GPa is measured in the TiAlN/AlCrN coating annealed at 600 °C for 08 h. But, AlCrN/TiAlN coating displays a decrease in hardness after annealing at 600 °C, and the hardness increases to 47 GPa on increasing the annealing temperature further (1000 °C for 6 h). From weight measurements, it is clear that the TiAlN/AlCrN bilayer coating results in weight reduction initially, but it increases with a further increase in the annealing temperature. In contrast, in the AlCrN/TiAlN coating, the weight increases monotonically, but gradually, with increasing temperature of annealing. The XRD results are discussed with reference to the different oxide phases formed in the two bilayer coatings during annealing.

Rice blast, incited by Pyricularia oryzae Cavara, is an important fungal disease of rice (Oryza sativa L.) worldwide. To understand the resistance mechanisms of rice to P. oryzae, we studied metabolic responses of rice suspension-cultured cells to treatment with an elicitor prepared from the mycelial walls of P. oryzae. Suspension-cultured cells of blast- resistant (Usen) and -susceptible (CO39) rice genotypes were profiled for differential metabolic responses at 1, 3, 5 and 7 days after elicitor treatment using gas chromatography coupled to electron impact ionization-time of flight-mass spectroscopy (GC/EI–TOF–MS). A total of 99 metabolites were identified by mass spectral and retention index match to the reference data of the Golm Metabolome Database (GMD). Of the 99 metabolites, 66 metabolites were classified into different chemical classes representing mostly primary metabolites. The remaining 33 metabolites are yet non-identified but are frequently observed metabolites that are part of the GMD reference data and are designated with a unique GMD identifier. Multivariate analysis revealed that the suspension-cultured cells of susceptible and resistant genotypes differ in regard to primary metabolism. Differential responses to the P. oryzae elicitor included significant changes among aromatic amino acids, phenylpropanoids, polyamines and sugars of major carbohydrate metabolism.

Injection profile enhancement has been one of the primary objectives for an operator in Kuwait. Stimulation interventions in injector wells directly affect the enhancement of oil recovery in producer wells. This paper presents the application of a verifiable stimulation intervention in a water injector well to help achieve the operator's objectives. The intervention presented several challenges. There was limited information available for the newly drilled carbonate formation under consideration in the Greater Burgan Field. Additionally, the fiberglass well tubing required significant attention before running in hole (RIH) with coiled tubing (CT). A high concentration of H2S was identified in Formation A; therefore, gas returns were also a potential issue. This paper discusses the methods used to help address these challenges. During this case study, real-time fiber-optic cable CT (RTFOCT) technology was applied in the fiberglass tubing injector well to determine initial well injection profile and adjust treatment accordingly. This technology includes a fiber-optic cable integrated into the CT pipe and a modular sensing bottomhole assembly (BHA). RTFOCT technology allows for rigless operations and performs interval diagnostics, stimulation treatment, and evaluation in a single CT run. During this case study, the well injectivity increased by more than 100%. Diagnostics and evaluation were performed by analyzing the well thermal profile using fiber-optic distributed temperature sensing (DTS). The BHA helped ensure accurate fluid placement during the treatment using real-time pressure, temperature, and depth-correlation sensors. The RTFOCT technology provided real-time downhole information that was used to analyze reservoir parameters, help ensure accurate fluid placement, and enable quick and smart decisions regarding the stimulation treatment stages based on the fluid intake in different zones. During injection, the heterogeneous fluid flow became homogeneous along the interval confirmed with the thermal-hydraulic model (THM). This helped reliably complete the intervention operations and delay possible water breakthrough in the producer wells and extended reservoir recovery.

This paper reports the development of a cutting tool insert prepared by consolidation, followed by Spark Plasma Sintering (SPS) of TiB2 (Titanium diboride) particles processed through an in-situ reaction and AlN (Aluminium nitride) manufactured by the direct nitridation process. In-situ TiB2 particles, formed during reaction of KBF4 (Potassium tetra Fluoroborate) and K2TiF6 (Potassium Fuorotitanate) with Al alloy, are obtained by dissolving the Al-TiB2 composite in an acidic medium. The extracted TiB2 (30%) particles are blended with AlN and Al2O3 in the weight ratio of 67%-3% and sintered (SPS) at 1440°C with a compaction load of 50 MPa and a total sintering time of 8 minutes. The sintering is carried out in vacuum. The sintered ceramic displays high hardness of nearly 15.5 GPa and extraordinary toughness of 7MPa.m1/2. The inserts are manufactured according to SNGN (Square Double-sided ceramic) configuration. To study its performance, machining is carried out on hardened steel (EN 24). The developed AlN based inserts show increased wear resistance and provide good surface finish when compared with commercially available ceramic inserts (70%Al2O3+30%TiC). Cutting forces are recorded with a Kistler® dynamometer to correlate them with the tool wear. Methods of preparation and comparison of wear resistance and surface finish of the machined material with those pertaining to commercial ceramic inserts are also presented. SEM images are displayed, which support the results.

The objective of the study is to develop an adsorbent which is abundant with economical and environmental friendly characteristics to remove reactive dye from its aqueous solution. The municipal solid waste modified by H3PO4 activated carbon (MSWAC) was prepared and characterised. The adsorption capacity of the activated carbon was tested towards reactive red M5B (RR), a representative of industrial effluent at varied operational conditions by using batch method. Langmuir, Freundlich and Temkin adsorption isotherm models were applied to describe the characteristics of adsorption behaviour. Kinetic data were fitted to pseudo-first-order, pseudo-second-order and intra-particle diffusion models. The virgin characteristics of MSWAC were studied using BET surface area, scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) studies. The result indicated that MSWAC as a low cost adsorbent and it can be effectively used for treating textile industry effluent.

This is an account of a process that has led to an application for a patent of relevance to the metal cutting industry and the paper examines the scientific aspects like the influence of process parameters of aluminothermic reaction synthesis of in-situ Al-TiB 2 metal matrix composites on their microstructure and mechanical properties. The reaction between the salts potassium fluoborate (KBF 4 ) and Potassium hexafluorotitanite (K 2 TiF 6 ) in the aluminium melt leads to the formation of TiB 2 particles. The process parameters of reaction time (Rh), reaction temperature (Rt) and weight percentage of precursors (W) were carefully controlled in order to regulate the volume fraction of TiB 2 formation in the aluminium melt. Detailed microstructure analysis at different processing conditions revealed that particle clustering was present in the reinforcement and that this changes the hardness and density of the resultant composites. Addition of cryolite, which is a surface-active salt, prevented agglomeration and emulsification at high temperatures and also facilitated the uniform distribution of the particles in the matrix. The prepared Al-TiB 2 composites were tested for their tensile properties, density and hardness. Both hardness and yield strength are found to increase with an increase in the percentage of reinforcement. The percentage elongation decreases due to an increase in TiB 2 ceramic particle content in the matrix. It is found that the reaction time plays a major role in TiB 2 growth and the distribution of TiB 2 particles within the matrix.

Synthesis of nine Task Specific Ionic liquids (TSILs), their characterization using1H NMR spectral studies and other physical properties and potential applications in the removal of certain heavy metals such as Nickel, Iron, Zinc, Copper and Lead has been studied. The removal of these heavy metals from the industrial effluents / contaminated water bodies using these ionic liquids has been proved to be more successful than conventional methods such as precipitation, cementation, reverse osmosis, ion exchange and adsorption.

Recent estimates suggest that turtlegrass ( Thalassia testudinum) can persist while being heavily grazed by smaller herbivores (e.g., sea urchins and bucktooth parrotfish) in many areas of the western North Atlantic. Based on studies conducted in terrestrial and aquatic ecosystems, we hypothesized that seagrasses compensate for grazer-induced losses of aboveground production by (1) increasing the uptake of growth-limiting nitrogen from the surrounding environment and (2) translocating this newly acquired nitrogen to grazed tissues. We tested our hypotheses by comparing the activity levels of nitrogen metabolizing enzymes (nitrate reductase (NR) and glutamine synthetase (GS/T)) and the distance of nitrogen translocation, in the roots and leaves of mechanically damaged and undamaged plants. These experiments were repeated along a seasonal productivity gradient (in mid summer, early fall, and late fall). Significantly greater enzyme activity (GS/T) was measured in the roots of clipped plants in all months. NR and GS/T activity was also significantly higher in partially clipped leaves than in unclipped outer leaves in two of three months. The degree of leaf damage had no impact on the enzyme activity of inner (i.e., younger) leaves. Nitrogen-15, as either ammonium or nitrate, was translocated up to 50 cm away from the application point within 48 h. Defoliation, however, did not lead to increased 15 N accumulation in clipped segments, suggesting

Reactivity of Zn(BH4)2 was modified by adding cyclohexene to achieve the reduction of aromatic esters to alcohols which reaction was not possible previously because of the mild nature of the reagent. Functional groups like Cl and nitro were tolerated.

Zinc borohydride reduces secondary amides to the corresponding N-ethyl amines in excellent yields. The reduction requires only stoichiometric quantities of hydride and does not require the addition of any Lewis acid. The amides are isolated by simple hydrolysis of the reaction mixture.

Zinc borohydride reduces amino acids with only stoichiometric amounts of hydride to the corresponding chiral alcohols in excellent yields in the absence of any Lewis acid.

Nitrogen and deuterium kinetic isotope effects were measured in the Menshutkin reaction between methyl iodide and a series of para-substituted N,N-dimethylanilines in ethanol. The nitrogen kinetic isotope effect increases for the more electron-donating substituents [0·9989, 1·0032, and 1·0036 for 4-C(O)Me, H and 4-Me, respectively], in agreement with the Hammond postulate. The secondary deuterium isotope effect, however, exhibits the reverse trend (1·045, 0·989, 0·975 per deuterium, for the respective substituents). This discrepancy is rationalized in terms of solvent molecule participation in the transition state.

Calcium borohydride is found to hydroborate unsaturated systems in the presence of ethyl acetate. The reaction exhibits remarkable selectivity towards terminal double bonds. Several Z-11-alken-1-ol pheromones are synthesized using this method.

The aim of this study was to evaluate antibacterial activity of the leaves of Bauhinia tomentosa Linn. In the current study, aqueous and ethanolic extracts of leaves of Bauhinia tomentosa were tested against some human pathogenic bacteria. In vitro antibacterial test was performed by disc diffusion method on Mueller Hinton agar medium. Ethanolic extract showed significantly higher inhibitory effect compared to aqueous extract on tested organisms. Key words : Bauhinia tomentosa leaves, aqueous and ethanol extracts, antibacterial activity.

The nonallelic sweetclover (Melilotus alba Desr.) mutants U371 (ch10/ch10 genotype) and U372 (ch11/ch11 genotype) are derived from the U389 (+/+ genotype) parental strain. Growth of the U389 strain at a temperature of 17 or 26[deg]C results in plants normally green in appearance. The U371 and U372 mutant plants grown at 26[deg]C are slightly to moderately chlorophyll (Chl) deficient and have decreased Chl b/a ratios. Growth of the mutants at 17[deg]C results in plants severely deficient in Chl a, with markedly reduced levels of carotenoids except for violaxanthin, and with negligible amounts of Chl b or apoproteins for the light-harvesting complex of photosystem II. If mutant plants grown at 17[deg]C are transferred to 26[deg]C, during the next 20 d the amount of Chl per fresh weight will increase 5-fold and both the Chl b/a ratio and the expression of the light-harvesting complex apoproteins will progressively increase. Studies of the U371 mutant during the temperature-induced greening demonstrate progressive changes in chloroplast ultra-structure and leaf carbon isotope fractionation that parallel the increases in Chl. Changes observed in the leaf carbon isotope fractionation in the mutant suggest that, in addition to the already known effects of various abiotic factors, structural and metabolic internal factors can also influence whether the limitation in CO2 fixation is at the level of diffusion or carboxylation. Such temperature-initiated progressive greening in these and similar mutants may make them useful tools to elucidate not only the biosynthesis and assembly of the photosynthetic apparatus, but also physiological phenomena such as the influence of light-driven energy production on the overall carbon isotope fractionation during photosynthesis.

Electrochemical oxidation of dibenzocarbazole was carried out galvanostatically at a graphite electrode in acetonitrile containing 0.1 mol dm–3 tetrabutylammonium perchlorate in a laser interferometric microcell at current densities of 0.23, 0.34 and 0.59mA cm–2. Fringe shifts were produced immediately at both electrodes. At the anode, dibenzocarbazole is oxidized to produce an insoluble film. The formation of the film does not inhibit further oxidation of dibenzocarbazole. Cyclic voltammetric studies of dibenzocarbazole show an anodic peak at Epa= 1.30 V vs. Ag with a complementary peak at 0.37V. Repetitive sweeping between 0 and 2V produces a dark coloured film and this film exhibits interesting apparent electrocatalysis for the oxidation of 9,10-diphenylanthracene (DPA).

Using semi-empirical self-consistent field molecular orbital (SCF-MO) quantum chemical calculations, structures of putative intermediates of the desaturation pathway for both cis- and trans- carotene biosynthesis have been optimized. It was observed that the cis isomers of the early biosynthetic intermediates are more stable than corresponding trans isomers. Both desaturation and cyclization steps confer increased stability on these carotenes. The results also argue for phytofluene, rather than the earlier suggested phytoene or ζ-carotene, as the energetically favored branch point for poly-cis-carotene biosynthesis.

Naturally-occurring variations in the abundances of the stable isotopes of carbon and other elements can be used to understand the dynamics of natural processes in chemistry, biochemistry, biology, medicine, ecology and other fields. The use of carbon-13 isotopic abundances as an indicator of photosynthetic function in plants has become common. The purpose of this article is to describe the physical and chemical processes that contribute to the abundances of carbon-13 in plant materials, and to provide a framework for understanding how those processes control the isotopic contents of natural materials.

Furfural Analysis and Degree of Polymerisation measurements give a measure of the degradation of paper insulation in transformers. These in turn relate to the ageing of transformers. Independent analysis of each of these chemical parameters gives an idea of the residual age of a transformer. But there have been no specific standards established to determine the ageing in transformers. In this paper, there is an attempt to estimate/predict the Degree of Polymerisation and the residual age of a transformer using Artificial Neural Networks given the Furfural component in oil.

The soybean aphid, Aphis glycines Matsumara, was discovered in the United States in the summer of 2000. Since that initial discovery, the aphid has spread across northern soybean production regions. In 2001, we examined the physiological responses of soybeans to low aphids densities (fewer than 50 aphids/leaf). In this study, we determined photosynthetic rates, leaf fluorescence responses, and photosynthetic responses to variable carbon dioxide and light levels. In addition, analyses for chlorophyll content and stable carbon isotope ratios were used to differentiate potential differences in stomatal versus mesophyll limitations to photosynthesis. We observed rate reductions of up to 50% on infested leaflets, including lealets with no apparent symptoms of aphid injury (such as chlorosis). Differences in fluorescence data indicated that photoelectron transport was not impaired. These results indicate that substantial physiological impact on soybean is possible even at low aphid densities. Also, the conventional view of aphid injury acting through reductions in chlorophyll content and light-harvesting reactions of photosynthesis is not supported by our findings in this system.

Known high nitrogen utilization efficiency (NUE1, biomass per unit plant N) China lines of sorghum, China 17 and San Chi San, were compared with relatively low NUE1 U.S. lines, CK60 and Tx623, for both their physiological and biochemical adaptations to tolerate an imposed N stress in the greenhouse. Assimilation efficiency indices (ACi) were significantly greater for the China lines than the U.S. lines at both low and high soil nitrogen levels by about two-fold. Chlorophyll levels in leaves of high NUE1 lines were lower at both soil N treatments. Immunoblots of leaf extracts of sorghum subjected to N stress indicated reduced levels of both phosphoenolpyruvate carboxylase (PEPcase) and ribulose 1,5-bisphosphate carboxylase (Rubisco) while NADP-malic enzyme levels, in general, appear not to be affected. However, NUE1 China line, China 17, retained a significantly greater PEPcase activity than the less-NUE1 U.S. lines, and also the NUE1 China line San Chi San, when grown under N stress conditions. This suggests that PEPcase and enzymes associated with phosphoenolpyruvate synthesis, perhaps, are significant factors in maintaining relatively high photosynthesis under N stress. Carbon isotope ratios of leaves from sorghum genotypes, as indicated by δ13C values, became less negative when sorghum plants were grown under N stress, but a genotypic variation either at a low or high N was not observed.

Washed rubber particles isolated from stem homogenates of Parthenium argentatum Gray by ultracentrifugation and gel filtration on columns of LKB Ultrogel AcA34 contain rubber transferase which catalyzes the polymerization of isopentenyl pyrophosphate into rubber polymer. The polymerization reaction requires Mg(2+) isopentenyl pyrophosphate, and an allylic pyrophosphate. The K(m) values for Mg(2+), isopentenyl pyrophosphate, and dimethylallyl pyrophosphate were 5.2 x 10(-4) molar, 8.3 x 10(-5) molar, and 9.6 x 10(-5) molar, respectively. The molecular characteristics of the rubber polymer synthesized from [(14)C]isopentenyl pyrophosphate were examined by gel permeation chromatography on three linear columns of 1 x 10(6) to 500 Angstroms Ultrastyragel in a Waters 150C Gel Permeation Chromatograph. The peak molecular weight of the radioactive polymer increased from 70,000 in 15 minutes to 750,000 in 3 hours. The weight average molecular weight of the polymer synthesized over a 3 hour period was 1.17 x 10(6) compared to 1.49 x 10(6) for the natural rubber polymer extracted from the rubber particles. Over 90% of the in vitro formation of the rubber polymer was de novo from dimethylallyl pyrophosphate and isopentenyl pyrophosphate. Treatment of the washed rubber particles with 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate solubilized the rubber transferase. The solubilized enzyme(s) catalyzed the polymerization of isopentenyl pyrophosphate into rubber polymer with a peak molecular weight of 1 x 10(5) after 3 hours of incubation with Mg(2+) and dimethylallyl pyrophosphate. The data support the conclusion that the soluble preparation of rubber transferase is capable of catalyzing the formation of a high molecular weight rubber polymer from an allylic pyrophosphate initiator and isopentenyl pyrophosphate monomer.

Electrochemical oxidation of dibenzocarbazole was carried out galvanostatically at a graphite electrode in acetonitrile containing 0.1 mol dm–3 tetrabutylammonium perchlorate in a laser interferometric microcell at current densities of 0.23, 0.34 and 0.59mA cm–2. Fringe shifts were produced immediately at both electrodes. At the anode, dibenzocarbazole is oxidized to produce an insoluble film. The formation of the film does not inhibit further oxidation of dibenzocarbazole. Cyclic voltammetric studies of dibenzocarbazole show an anodic peak at Epa= 1.30 V vs. Ag with a complementary peak at 0.37V. Repetitive sweeping between 0 and 2V produces a dark coloured film and this film exhibits interesting apparent electrocatalysis for the oxidation of 9,10-diphenylanthracene (DPA).

Applications of 2-(3,4-dichlorophenoxy)-triethylamine (DCPTA) to guayule plants (Parthenium argentatum) increase the enzymatic polymerization of isopentenyl pyrophosphate (IPP) to polyisoprene. The purpose of this study was to determine the effectiveness of DCPTA in increasing polyisoprenoid rubber synthesis at the end of the winter period of rubber synthesis in plants expressing a high level of polymerization activity. Guayule seedlings were transplanted to desert field plots in May, 1987 and treated with DCPTA. The polymerization activity in the stems was monitored throughout the year and the rubber content of the stems was determined in April, 1988. Treatment of plants with DCPTA increased the enzymatic polymerization activity in stem homogenates. The polymerization activity in control plants increased from 4 nmol h−1 g fresh wt.−1 in July to 183 nmol h−1 g fresh wt.−1 in January and the activity in plants with 1000 ppm DCPTA increased from 7 nmol h−1 g fresh wt−1 in July to 340 nmol h−1 g fresh wt.−1 in January. The high mol.wt. rubber polymer in the stems was determined by solvent extraction and 13C-NMR spectroscopy. Applications of different concentrations of DCPTA to guayule plants resulted in a statistically significant increase of 7–33% of the rubber content of the stems. The application of DCPTA to guayule seedlings stimulates the synthetic pathway for the production of secondary products in mature plants.

Photolysis of the metalmetal bonded dimer [(η 5 C 5 H 5 ) Fe(CO) 2 ] 2 in the presence of a variety of potential hydrogen atom donors leads to net hydrogen abstraction only in the case of benzaldehyde, for which (η 5 C 5 H 5 )Fe(CO) 2 (C 6 H 5 ) is the only product formed. Photolysis in acetonitrile gives the monosubstitution product (η 5 C 5 H 5 ) 2 Fe 2 (CO) 3 (CH 3 CN).

The substituted tertiary amine 2-(4-methylphenoxy)triethylamine (MPTA) induces a synthesis of phytofluene and lycopene in the flavedo of lemons ( Citrus limon Burm. f.). Treatment of lemon pieces with 500 ppm MPTA results in the synthesis of 8.4 μg phytofluene · g fresh wt. −1 · 72h and 29.6 μm lycopene · g fresh wt. −1 · 72 h −1 . The untreated lemons do not accumulate any detectable lycopene during this period. Treatment of lemon pieces with MPTA and amanitin, cordycepin, anisomycin or cycloheximide (CH) significantly reduced the MPTA induction of the carotenes. These results support the conclusion that the induction of phytofluene and lycopene by MPTA requires gene expression, polyadenylation of the gene transcript and translation of the poly A + RNA on 80 S ribosomes. MPTA may regulate the synthesis of isoprenoids by controlling the expression of genes coding for the enzymes in the carotene pathway. Treatment of lemons with MPTA increases the partitioning of glucose into the mevalonic acid (MVA) pathway to provide carbon for the synthesis of phytofluene and lycopene.

The electrochemical oxidation of carbazole in acetonitrile containing tetra-n-butyl ammonium perchlorate produces a green film on the electrode; this film is electrocatalytic to the oxidation of 9,10-diphenylanthracene, or perylene or 9,10-dimethylanthracene or ferrocene. The spectral features of the film reveal a N-N-coupling with a total absence of—NH stretching band. It is soluble in N,N-dimethylformamide. The polymer is structurally modified compared to the film produced by carbazole oxidation in N,N-dimethylformamide.

The application of 2-(3,4-dichlorophenoxy)-triethylamine to guayule (Parthenium argentatum Gray var 593) plants results in a 2-fold stimulation of rubber synthesis and a 1.5- to 3-fold increase in mevalonic acid kinase, isopentenyl pyrophosphate isomerase, and rubber transferase. The increase in these enzymic activities accounts in part for the chemical induction of rubber synthesis.

Electron micrographs of the mesophyll cells of guayule Parthenium argentatum Gray leaves show deposits of cis-polyisoprene (rubber) in the cytoplasm in the vicinity of mitochondria and chloroplasts and demonstrate that the rubber-synthesizing enzymes are present in guayule leaves. The terminal step in the synthesis of cis-polyisoprene from isopentenyl pyrophosphate (IPP) catalyzed by isopentenyl pyrophosphate cis-1,4-polyisoprenyl transferase has been demonstrated in crude leaf extracts by the enzymic incorporation of [(14)C]isopentenyl pyrophosphate into the polymer and the recovery of [(14)C]levulinic acid following ozonolysis. The rubber transferase activity in the crude extracts of guayule leaves was 5.8 nanomoles isopentenyl pyrophosphate incorporated per milligram protein per hour. This is the first description of the rubber transferase from a nonlaticiferous plant.The specific activity (in units of nanomoles IPP converted per milligram protein per hour) of the partially purified enzyme following chromatography on diethylaminoethyl-cellulose columns was 41.7 units and contained 0.29 units of IPP isomerase activity and 0.08 units of farnesyl pyrophosphate synthetase activity. The rubber transferase requires reduced glutathione and Mg(2+) for maximal activity. There was no incorporation of IPP into cis-1,4-polyisoprene in the absence of rubber particles as primer, and Langmuir isotherm plots showed that the specific activity of the enzyme was proportional to the concentration of the enzyme on the surface of the rubber particles. For a given rubber particle distribution, enzyme activity was proportional to time, IPP concentration, and rubber concentration. The addition of 0.4 millimolar dimethylallyl pyrophosphate to the rubber transferase reaction resulted in a 2-fold increase in the incorporation of IPP into rubber. A comparison was made of the relative activities of rubber transferase in different species of Parthenium, Ficus, and Euphorbia.