Lemon Basil Research Articles

In Vitro Culture-An Alternative Method for The Enhanced Production of Some Volatile Components of Ocimum Citriodorum Vis.

Ocimum plants are highly valued for their effective antibacterial, anti-fungal, antioxidant and therapeutic activities. These properties are attributed to some active metabolites. In order to enhance and develop an alternative source for the production of such active components, a comparative study was carried out. Composition of volatile organic compounds emitted by in vitro shoots, calli derived from leaf and nodal explant of Ocimum citriodorum Vis. were studied using Gas Chromatography-Mass Spectroscopy (GC-MS) and compared to those emitted by mother plants. Solvent extraction method was used for obtaining essential oils from the samples. Total 18 volatile compounds from the leaf extract of mother plant, 14 volatile compounds from the leaf extract of in vitro regenerated plants, 5 volatile compounds from the calli derived from leaf and 10 volatile compounds from the calli derived from nodal explant were identified. The content of nerol (2.44%) and geranylacetate (1.53%) was greater in in vitro regenerated plantlets than in comparison to mother plant (nerol- 0.88% and geranylacetate- 0.32%). Seven new compounds (isocaryophyllene, b-farnesene, b-himachalene, globulol, geranylformate, b-citronellylacetate, citronellylisobutyrate) were identified from the in vitro regenerated plants while six and three new compounds were identified from the calli derived from nodal explant (geraniol, trans-b-bergamotene, b-longipinene, bergamotene, geranylformate and b-citronellyacetate) and leaf (b-curcumene, trans-b-bergamotene, b-citronellol) respectively. From the present study, it can be concluded that in vitro propagated plants as well as calli derived from leaf and nodal segment may be used as an alternate source for the increased production of bioactive compounds.

Hydroponic Greenhouse Basil Production: Comparing Systems and Cultivars

Basil (Ocimum sp.) is the most popular fresh culinary herb. However, there is a lack of data characterizing the effect of hydroponic production systems and cultivars on the yield of hydroponically produced basil. Our objectives were to quantify productivity and characterize growth of basil cultivars grown in two hydroponic production systems. Thirty-five basil cultivars, including selections of sweet basil (O. basilicum), holy basil (O. tenuiflorum), and lemon basil (O. ×citriodorum and O. basilicum) were chosen. Seedlings were transplanted into nutrient film technique (NFT) or deep flow technique (DFT) systems and grown for 3 weeks. There was no interaction between basil cultivars and hydroponic production system. Fresh weight of plants grown in DFT systems was 2.6 g greater compared with plants grown in NFT systems. Basil cultivars differed greatly in fresh weight. In general, holy, lemon, and sweet basil cultivars produce moderate to high fresh weight, but vary greatly. Dissimilarly, bush (O. basilicum var. minimum), cinnamon (O. basilicum), large-leaf (O. basilicum), and thai basils (O. basilicum var. thyrisiflorum) produce moderate fresh weight and purple basil (O. basilicum) cultivars produce the least fresh weight. The yield of basil seems to be affected more by cultivar selection than hydroponic production system. Therefore, hydroponic basil producers should select basil cultivars based on flavor and yield, while hydroponic systems should be selected based on operational preferences.

Complete Chemo Type of Three Species of Basils (Ocimum basilicum) Grown in Indonesia

The three species of basil (Ocimum basilicum) i.e. lemon basil (O. citriodorum), purple basil (O. canum) and green basil (O. violaceum) had been analyzed to derived their complete chemo type. Ten series of time difference in wilting of aerial part of basil were plotted in different harvesting period. Each accession of Ocimum species underwent air dried preparations varying from 0 day (fresh) to 4 months (very dry), respectively. Steam distillation was subjected in each process to collect an essential oil state. The analysis of chemical components was conducted using Gas chromatography/Mass spectrometry (GC-MS). Results was obtained by analysis of similar compounds that found during series of wilting time. The frequence (in percentage) of their appearance used as a basis of complete chemo type determination. The complete chemo type of lemon basil, purple basil, and green basil suggested to be listed as major compound followed by minor constituents set in descending order of concentrations. The complete chemo type of lemon basil could be written as : trans-citral > cis-citral>cis-α-bisabolene>(-)-caryophyllene oxide>trans-caryophyllene>α-bergamotene >(E)-β-farnesene > germacrene D>β-bisabolene>β-sesqui phellandrene; also for purple basil : methyl eugenol>1,8-cineole>germacrene-D>β-elemene>δ-guaiene>camphor>germacrene-B>l-linalool>α-guaiene>α-humulene>α- copaene>bornyl acetate; and for green basil : methyl chavicol>methyl eugenol>1,8-cineole>α-amorphene > β-elemene>trans-caryophyllene>α-bergamotene. This result could be used as accomplished of chemo taxonomy or solving a taxonomical problem in basils.

Physicochemical properties and biological activities of Thai plant mucilages for artificial saliva preparation

Context: Plant mucilages can be found in various parts of several Thai plants, which can be used as thickening, moisturizing, and lubricating agents in artificial saliva formulations.Objective: The objective of this study was to evaluate the physicochemical properties, biological activity, and cytotoxicity of Thai plant mucilages.Materials and methods: The mucilages from Thai plants were extracted by various processes (temperature and pH variation, microwave oven, steam, and Tris-HCl buffer extraction). The viscosity and the rheology were evaluated using viscometer. Antioxidative activities including DPPH radical scavenging and metal chelating activities were investigated. The mucilages were determined for cytotoxicity on normal human gingival fibroblasts and anti-adherent activity of Streptococcus mutans.Results: Mucilages from Ocimum citriodorum Vis. (Lamiaceae), Artocarpus heterophyllus Lam. (Moraceae), Abelmoschus esculentus (Linn.) Moench. (Malvaceae), and Basella alba Linn. (Basellaceae) exhibited pseudoplastic non-Newtonian rheology. The highest DPPH radical-scavenging and metal-chelating activities were observed in the mucilages from B. alba (microwave, 3 min) and A. esculentus (microwave, 1 min) with the SC50 and MC50 values (50% of scavenging activity and 50% of metal chelating activity, respectively) of 0.71 ± 0.32 and 1.11 ± 0.52 mg/ml, respectively. Most mucilages exhibited no cytotoxicity to normal human gingival fibroblasts. The mucilage from A. esculentus (microwave, 5 min) gave the shortest wetting time of 2.75 ± 0.51 min. The highest S. mutans adhesion inhibition was observed in A. esculentus (pH 11) of 5.39 ± 9.70%.Discussion and conclusion: This study has indicated the suitable physicochemical and biological properties and the potential application of mucilages from Thai plants for artificial saliva preparation.

Ecotype and Foliar Fertilization with Florovit Affect Herbage Yield and Quality of Greenhouse-Grown Basil (Ocimum basilicum L.)

Basil is usually grown in 0.5-0.7 dm3 pots, at 25 plants per pot. However, potted basil plants wilt and die easily due to high plant density, low substrate volume, insufficient moisture and nutrient depletion. The aim of this study was to determine the herbage yield and nutritional value of greenhouse-grown basil. A two-factorial experiment was performed in a randomized block design with three replications, in 2012-2013. A two-factorial experiment was performed in a randomized block design with three replications, in 2012-2013 Six basil (Ocimum basilicum L.) ecotypes were analyzed: sweet basil, ‘Queen of Siam’ basil, purple basil, cinnamon basil, lemon basil and ‘Minette’ basil. The second experimental factor was foliar fertilization with Florovit at a concentration of 0.5% and 1%. Basil yield was significantly affected by the ecotype and the interaction between the experimental factors. ‘Minette’ basil fertilized with 1% Florovit solution was characterized by the highest fresh herbage yield. A statistical analysis revealed that Florovit had no significant effect on basil yield. The concentrations of dry matter, total sugars, L-ascorbic acid and nitrates(V) in basil herbage varied across ecotypes. Foliar fertilization had a significant effect on the organic acid content of basil leaves. The accumulation of the analyzed components in basil herbage was significantly affected by the interaction between the experimental factors. Basil yield was significantly affected by the ecotype. ‘Minette’ and ‘Siam Queen’ basil was characterized by the highest fresh herbage yield. The fresh herbage of ‘Minette’ basil contained the lowest concentrations of dry matter, total sugars, L-ascorbic acid, organic acids and nitrates(V).

Chilling injury alleviation and quality maintenance of lemon basil by preharvest salicylic acid treatment

The purpose of this study was to alleviate chilling injury (CI) of lemon basil during storage by using preharvest salicylic acid (SA) treatment. The basil was sprayed with SA at the concentration of 0, 1, 5 or 10 mM before harvesting 24 h and was then stored at 7 °C for 4 days. Weight loss, CI score, malondialdehyde (MDA) content, electrolyte leakage (EL), superficial colour, pigments and bioactive compounds were determined. SA treatments alleviated CI and reduced the increase in EL and MDA content which the best result alleviating CI was 5 mM SA. The greenness and total chlorophyll content were maintained by SA application. After 24 h of treatment, antioxidants, total phenols and flavonoids were enhanced. During storage, SA treatment reduced the loss of bioactive compounds in the lemon basil. In conclusion, preharvest SA treatment at 5 mM alleviated CI and maintained quality of lemon basil during cold storage.

Screening for Anticandidal and Antibiofilm Activity of Some Herbs in Thailand

Purpose: To evaluate the anticandidal activity of the ethanol extracts of 12 herbs from Thailand. Methods: The herbs studied were Alpinia galanga, Curcuma longa, Curcuma zedoaria, Mentha cordifolia, Ocimum africanum, Ocimum basilicum, Ocimum sanctum, Piper betle, Piper chaba, Piper nigrum, Piper sarmentosum and Zingiber officinale. Various Candida spp. were examined for minimal inhibitory concentration (MIC) and minimal fungicidal concentration (MFC) using microdilution method; time-kill assay was also used to assess the plants. Antibiofilm activity was investigated using a 3-[4, 5dimethyl-2-thiazolyl]-2, 5-diphenyl-2H-tetrazolium-bromide (MTT assay). Gas chromatography mass spectrometry (GC-MS) analysis, thin layer chromatography (TLC) fingerprinting and TLC-bioautography were used to determine the active anticandidal compounds. Results: All tested herbs, except extracts of P. nigrum and Limiaceae family, showed varying zones of inhibition against Candida albicans ATCC 90028. P. betle revealed the strongest anticandidal activity against all tested strains with MIC ranging from 1.56 to 3.13 mg/ml, and MFC from 3.13 to 8.33 mg/ml. Killing activity depended on time and concentrations of the extract. The concentration of P. betle extract required to inhibit ≥ 90 % biofilm formation of C. albicans ATCC 90028 was 3.13 ± 0.15 mg/ml, while that to remove ≥ 90 % biofilm growth was 12.50 ± 0.69 mg/ml. The result of GC-MS analysis showed the major compound of P. betle extract responsible for anticandidal activity as 4-chromanol. Conclusion: P. betle extract contains 4-chromanol which is a good potential anticandidal agent for the treatment of oral infectious diseases caused by certain Candida spp.

Ocimum L. (Lamiaceae) in Australia and Papua New Guinea

A review of the genus Ocimum (Lamiaceae) in the Papua New Guinea and Australia reveals the presence of five species and the natural hybrid, Ocimum africanum. Ocimum caryophyllinum F.Muell. is reinstated for much of the Australian plants previously included in the widespread O. tenuiflorum L. The other species recognized for Papua New Guinea and Australia are O. americanum, O. basilicum and O. gratissimum. An identification key, brief descriptions and distribution maps are provided for these taxa. An enumeration of collections examined is included.

The relationship between growth stages and aroma composition of lemon basil Ocimum citriodorum Vis

Volatiles from infusions of lemon basil Ocimum citriodorum Vis were evaluated by SPME-GC/MS. Citral, linalool and estragole were the major constituents. Citral, the major contributor to the lemony flavour, was significantly higher in post-flowering (79%) and full-flowering (65%), it was reduced to 42% at pre-flowering. Linalool was consistent throughout the growth cycle (2–3%). Estragole was higher in pre-flowering representing 15% of the total volatiles present. Linalool levels dropped sharply during the full-flowering and post-flowering stages to 2% and 0.4%, respectively. Volatiles from different parts of lemon basil were evaluated to determine the parts that influence the flavour. The percentage composition of citral for leaves and flowers was 64.5% and 58% for the branches. Linalool was much higher in flowers (13%), followed by 11% in branches and 3% in leaves. The flavour attributes of lemon basil infusions can be improved by incorporating aerial branches and flowers in the tea.

Antioxidant property of selected Ocimum species andtheir secondary metabolite content

In this study, chemical composition and antioxidative properties of eight selected Ocimum species (Ocimum gratissimum, Ocimum americanum, Ocimum minimum, Ocimum citriodorum, Ocimum kilimandscharicum, Ocimum grandiflorum, Ocimum lamiifolium, and Ocimum selloi) was investigated. Leaves of these plants were extracted using methanol. The quantitative analysis of phenolic constituents was determined using high-performance liquid chromatography. Total phenolic content was estimated using Folin-Ciocalteu reagent and antioxidant activity was assessed using iron (III) reduction,
-carotene–linoleic acid bleaching, 1,1-diphenyl-2-picrylhydrazyl and superoxide anion free radical scavenging assays. Phenolic acids, hydroxycinnamates, and flavonoids were identified and quantified within each extracts based on the area of each peaks with an external standards. The extracts of Ocimum species exhibited activity in all the in vitro antioxidant assays but it was not as potent as butylated hydroxyl anisole (BHA). The phytochemicals found in each extract are rich antioxidants and these extracts can be used as an effective preservative in food industry. Key words: Ocimum species, antioxidant activity, free radicals, total phenols, HPLC, secondary metabolites

Plantlet regeneration from nodal explants of Ocimum citriodorum Vis.

A protocol for multiple shoot induction and plant regeneration from nodal explants of Ocimum citriodorum has been developed. Nodal explants inoculated on Murashige and Skoog (MS) medium supplemented with 1.0 mg/l Benzyl adenine (BAP) and 0.025 mg/l indole -3- acetic acid (IAA) showed better growth response (80%) and produced 15.2 ± 1.28 shoots per explant with an average length of 6.17 ± 0.29 cm after 35 days. Roots were induced after transfer to half strength MS medium supplemented with 0.5 mg/l Indole -3- butyric acid (IBA) produced 6.0 ± 1.0 roots with an average height of 4.9 ± 0.26 cm after 30 days. Plantlets with well developed root and shoot systems were successfully acclimated (80 %) and established in earthen pots containing mixture of soil, vermiculite and farm yard manure (1:1:1). Bangladesh J. Sci. Ind. Res. 47(4), 433-436, 2012 DOI: http://dx.doi.org/10.3329/bjsir.v47i4.8547

Effects of chicken manure and vermicompost teas on herb yield, secondary metabolites and antioxidant activity of lemon basil (Ocimum x citriodorum Vis.)

Effects of chicken manure tea (CMT) and vermicompost tea (VCT) as soil drench on vegetative growth, herb yield, essential oil content, total phenolics, total flavonoids and antioxidant activity of lemon basil (Ocimum × citriodorum Vis.) was evaluated in a two-year field experiment. The greatest plant height and number of leaves and flowers, shoot fresh and dry weight and leaf chlorophyll content were obtained using CMT at either 1:5 or 1:10 dilutions with no significant differences. The highest number of lateral branches and flavonoid content were obtained when CMT at 1:5 dilution was applied. Essential oil content was at its highest level (0.618%) when CMT or VCT were used at 1:10 dilution, while the greatest total phenolic content and total antioxidant activity were obtained at 1:5 dilution of VCT. The results emphasize the possibility of using organic-based compost teas for enhancing herbal yield and important secondary metabolites in aromatic medicinal plants.

Transmission of the Mycopathogen,Hirsutellaspp., to Nymphs and Adults of the Glassy-Winged Sharpshooter,HomalodiscaVitripennis(=Coagulata), in the Greenhouse

The mycopathogen Hirsutella spp. produces regular epizootics in Florida populations of the glassy-winged sharpshooter (GWSS), Homalo disca vitripennis, a polyphagous, xylem-feeding cicadellid native to the southeastern U.S. and northeastern Mexico (Boucias et al. 2007). The GWSS transmits a lethal phytopathogenic bacte rium, Xylella fastidiosa, and thereby threatens the production of economically important plants (Redak et al. 2004). Recent introduction of GWSS into southern California, French Polynesia, Tahiti and Hawaii has stimulated interest in identifying potential biocontrol agents against invasive pop ulations (Boucias et al. 2007; Hunnicutt et al. 2008). During a field survey in Quincy, FL, a new species of Hirsutella, H. homalodiscae nom. prov., was detected in -50% of mycosed sharpshooters (Boucias et al. 2007). Virtually nothing is known about the transmission of Hirsutella within GWSS populations. Our field observations have shown that Hirsutella-infected sharpshooters at tach via rhizoids to the plant bark in the summer and often remain attached throughout the winter. Placed in a moist environment, overwintered ca davers produce conidiospores suggesting they serve as microhabitats protecting Hirsutella and facilitating transmission to the new generation of GWSS. This study examined potential transmis sion routes of Hirsutella under greenhouse condi tions. Experimental treatments included topical spore application and choice-exposure to sporu lating cadavers on host plants. For insect rearing, field-collected, healthy adults without hyphal bodies (HBs) in their hemolymph were identified by non-destructive antennal bleeding (Breaux 2005) and maintained on caged, potted plants (soybean, Glycine max, cotton, Gossypium hirsutum, and cowpea, Vigna unguiculata) in a greenhouse (temperature 26 30°C, 14:10 h light:dark photoperiod). Leaves with egg masses were removed and hatching neo nates were transferred to caged lemon basil (Oci mum basilicum). Soil was watered to saturation once daily. In each bioassay replicate, individual cotton or basil plants housing groups of 10-20 adults or nymphs, respectively, were covered with clear, gauze-covered acryl cylinders (15 cm diam eter x 45 cm high). Mortality and infection were recorded daily by removing dead individuals from the soil surface and examining their hemolymph for HB propagation. Cadavers were maintained on water agar to record mycosis. After 3 weeks, each plant was examined for mycosed cadavers, and surviving GWSS were subjected to hemolymph examination. Statistical analyses were conducted using the Proc Genmod procedure and Ls means statement of the Statistical Analy sis System (SAS) for Windows to compare mortal ity or infection responses by logistic regression (Neter et al. 1990; SAS 2004). For topical application of Hirsutella spores, healthy adults were treated in three replicate as says by touching their ventral surface to either sporulating in vitro colonies of strain 3A (main tained at the UF Entomology/Insect Pathology lab, Gainesville, FL) (total n = 46 adults), to GWSS cadavers displaying spores of Hirsutella (n = 33), or to a nutrient agar plate (control, n = 35). Mortality in control, in vitro, and cadaver treat ments was similar with 56 ± 11%, 74 ± 12%, and 60 ± 8%, respectively (x2= 2.48, P = 0.1155). Con tac with agar, in vitro colonies or cadavers pro duced 0%, 13 ± 6% and 42 ± 5% infection, respec tively, and only the latter treatment produced my cosis (28 ± 6%). Infection transmitted from cadav ers was significantly higher than that transmitted from in vitro colonies (x2 = 8.02, P = 0.0046). To examine whether co-existence of healthy and mycosed GWSS on a plant would result in disease tr nsmission, either overwintered cadav ers collected in Jan (stored at -80°C) or new ca davers collected in Jul/Aug were pinned to plants (10 per plant) and groups of healthy nymphs or adults were maintained on each plant for up to 3 weeks. Controls were conducted on plants with out cadavers. The majority of pinned cadavers displayed sporulating Hirsutella mycelium within one week. New cadavers developed an un usually thick, white mycelium overgrowing the entire insect (Fig. 1A). Disease transmission was observed to varying degrees (Table 1). Dead ex posed nymphs and adults (Fig. IB and C), at tached to the plant and displaying Hirsutella-in duced mycosis, were seen as early as 7 and 12 d after exposure, respectively. Hemolymph-borne HBs were detected as early as 8 d after exposure. New cadavers were more efficient in disease transmission when compared with overwintered cadavers (Table 1). When nymphs were exposed to new cadavers, no survivors were found and all dead insects were overgrown with thick mycelium

FUNCTIONAL GENOMICS FOR THE DISCOVERY OF GENES AFFECTING LEMON BASIL AROMA AND THEIR USE IN FLAVOR ENGINEERING OF TOMATO

Aromatic, medicinal and spice plants have been valued since antiquity as food supplements, preservatives and sources of flavors, aromas, medicinal drugs and essential oils. We have embarked on a long-term project to identify and isolate genes that encode key enzymes in aroma formation in plants. Lemon basil (Ocimum basilicum L. Lamiaceae) is known to accumulate essential oils rich in monoterpenes such as citral (geranial and neral) and sesquiterpenes, such as germacrene D, β-caryophyllene, α-bisabolene and α-zingiberene in glandular trichomes localized on the surface of the aerial parts of the plant. We have isolated mRNA from such glandular trichomes and produced a database of the genes that are expressed in them. Information on three basil lines with different chemical compositions was thus generated. Bioinformatic analysis of these databases yielded genes encoding key enzymes involved in mono- and sesquiterpene formation. cDNAs of these genes were functionally expressed in E. coli to validate their biochemical role. They include geraniol synthase (GES), a gene encoding the enzyme that converts geranyl diphosphate into the rose-scented compound geraniol, and α-zingiberene synthase (ZIS), a gene that encodes a multifunctional enzyme able to produce 13 monoterpenes from geranyl diphosphate and 15 sesquiterpenes from farnesyl diphosphate. To test the potential of metabolic engineering to effectively modify aroma and taste properties of tomato, we diverted the tomato terpenoid pathways by expression the lemon basil GES and ZIS genes. Expression of GES in tomato fruit caused elevated levels of geraniol and several other geraniol derivatives, resulting in dramatic changes in the aroma and overall flavor of the transgenic fruits, as judged by a panel of untrained taste panelists. Expression of the lemon basil ZIS gene in tomato fruit resulted in the enhanced accumulation of mono- and sesquiterpenes, bringing about improved aroma characteristics of the fruits. Our data clearly indicate that the utilization of genes originating in lemon basil for the genetic engineering of tomato fruit aroma and taste is feasible and that this approach has the potential for modifying the aroma and taste of other carotenoid-accumulating vegetables and fruits.

Overexpression of the lemon basil α‐zingiberene synthase gene increases both mono‐ and sesquiterpene contents in tomato fruit

alpha-Zingiberene synthase (ZIS), a sesquiterpene synthase gene that was isolated from lemon basil (Ocimum basilicum L.), encodes an enzyme that catalyzes the formation of alpha-zingiberene, and other sesquiterpenes, from farnesyl diphosphate. Transgenic tomato fruits overexpressing ZIS under the control of the fruit ripening-specific tomato polygalacturonase promoter (PG) accumulated high levels of alpha-zingiberene (224-1000 ng g(-1) fresh weight) and other sesquiterpenes, such as alpha-bergamotene, 7-epi-sesquithujene, beta-bisabolene and beta-curcumene, whereas no sesquiterpenes were detected in non-transformed control fruits. The ZIS-transgenic fruits also produced monoterpenes, such as alpha-thujene, alpha-pinene, beta-phellandrene and gamma-terpinene (1-22 ng g(-1) fresh weight), which were either not detected or were found only in minute concentrations in control fruits. Recombinant ZIS overexpressed in Escherichia coli catalyzed the formation of these monoterpenes from geranyl diphosphate. As the ZIS protein apparently lacks a transit peptide, and is localized in the cytosol, the production of monoterpenes in the transgenic tomatoes suggests that a pool of geranyl diphosphate is available in the cytosol. The phenotype of the ZIS-transgenic tomatoes was the same as that for wild-type tomatoes, with regard to plant vigor and shape, but transgenic plants exhibited a small decrease in lycopene content. This study thus showed that the synthesis of both mono- and sesquiterpenes can be enhanced by the ectopic expression of a single transgene in tomato fruit, and it further demonstrated the interconnection between the pools of terpenoid precursors in the plastids and the cytosol.

Research Article: Cultivation of Lemon Basil, Ocimum americanum, in two different hydroponic configurations supplemented with various concentrations of Tilapia aquaculture green water

Abstract It was deemed important to determine whether Tilapia fish green water would allow increased lemon basil plant growth when added to a hydroponic nutrient solution. Since Tilapia effluent is known to contain beneficial microorganisms, it was hypothesized that it would enhance hydroponic plant growth. In the initial study, fish green water was added at varying concentrations (8.3%, 4.2%, and 0%) in three different plastic pool “cultures” (six feet in diameter containing 60 gallons of nutrient solution and 51 culture cups per pool). In the subsequent experiment, the size of the culture containers was decreased in order to obtain additional culture replicates (three replicates in each of the four groups which each contained 19 gallons of nutrient solution and seven culture cups). Nutrient solutions were monitored once a week for pH, temperature, electronic conductivity (EC), and total dissolved solutes (TDS). Also, plants were enumerated and their relative health noted. After eight or nine weeks of cu...

The relationship between chilling injury and membrane damage in lemon basil ( Ocimum × citriodourum) leaves

Leaves of lemon basil ( Ocimum × citriodourum) were stored in sealed polyethylene bags at 4 °C and 12 °C. At 4 °C, leaf browning, the visible symptom of chilling injury, occurred earlier and was more severe in mature leaves than in young leaves. No positive correlation was found, when comparing young and mature leaves stored at 4 °C, between browning and either substrate levels (free phenolics) or the activities of peroxidase or catechol oxidase, which might catalyse these reactions. The levels of saturated and unsaturated fatty acids differed only slightly and were not correlated with chilling injury. Compared to young leaves, mature ones showed higher lipoxygenase activity throughout the period of low temperature storage. This might indicate more degradation of membrane unsaturated fatty acids. In addition, mature leaves exhibited lower catalase activity than young ones. This suggests lower protection against membrane oxidation in mature leaves. The data thus suggest a correlation between lipoxygenase activity, antioxidant defense, and chilling injury.

Chromosome Number Variation in Ocimum basilicum L.

Meiotic analysis documented variation in chromosome number in Ocimum basilicum L. (family: Lamiaceae) in the form of 2n=72 chromosomes in O. basilicum var. citriodorum (lemon basil) and 2n=52 chromosomes (a new number in Ocimum) in variety crispum. Persistent presence of secondary association of chromosomes in 87.88% and 69.39% metaphase I cells of var. citriodorum and var. crispum respectively suggested secondary polyploid nature of the species. Statistical analysis of cytological data revealed x=12 as basic chromosome numbers for the varieties studied and polyploidy as well as aneuploidy might have been operative at different levels to give variable chromosome numbers within O. basilicum.

Agrobacterium tumefaciens -mediated transformation of Ocimum basilicum and O. citriodorum

Transgenic basil (Ocimum spp.) was produced for the first time using an Agrobacterium tumefaciens-mediated transformation system. β-Glucuronidase (GUS) transient expression experiments showed a 96% or higher infection rate using Agrobacterium strains GV3101 and EHA105. Inoculated leaf explants were regenerated on Murashige and Skoog medium supplemented with thidiazuron, naphthaleneacetic acid and kanamycin. Two sweet basil (cvs SBA28 and Purple Ruffles, O. basilicum) and two lemon basil (cv Sweet Dani, O. citriodorum) plants were regenerated after in vitro cultivation. Stable transformation of both species was verified by polymerase chain reaction amplification (PCR) of both the gus (697 bp) and nptII (320 bp) gene fragments and by Southern blot analysis for the gus gene. Inheritance of the transgenes was verified by the GUS colorimetric assay and PCR analysis of the T1 generation of Ocimum transgenic plants, and the observed segregation ratio (3:1) indicated a single gene for GUS. Transgenic T1 plants exhibited identical phenotypic characteristics and accumulated high concentrations of linalool (118.98 µg g–1), 1.8-cineole (20.86 µg g–1), eugenol (69.3 µg g–1), neral (468.61 µg g–1) and geraniol (649.1 µg g–1) in volatile oil profiles similar to those of the non-transgenic controls.

Ultra-High Carbon Dioxide Levels Enhances in vitro Shoot Growth and Morphogenesis in Labiatae

ABSTRACT The growth and morphogenetic development in shoot cultures of lemon basil (Ocimutn basilicum), oregano (Origanum vulgare), peppermint (Mentha × piperita), spearmint (Mentha spicata), and thyme (Thymus vulgaris) shoots on MS salts and 0.8 percent agar containing 0 or 3 percent sucrose were determined under 350, 1,500, 3,000, 10,000, and 30,000 μl Co2/liter of air were determined after 8 weeks growth. High CO2 levels, especially the ultra-high levels (≥ 3,000 μl CO2/liter of air), substantially increased fresh weight and leaf and root numbers in all cultures, whether or not the basal media contained sucrose, as compared with cultures grown on the same basal media under ambient air (350 μl CO2/liter of air). Ultra-high CO2 levels, also, enhanced the formation of aerial adventitious roots from the shoots of all species tested. A photosynthetic photon flux density of 180 μmole m−2.s−1 using a 16 h light/8 h dark photoperiod consistently provided better growth than lower light levels.