Scented Geranium Research Articles

Metal Tolerance of Scented Geranium (Pelargonium sp. ‘Frensham’): Effects of Cadmium and Nickel on Chlorophyll Fluorescence Kinetics

ABSTRACT The ability of scented geraniums (Pelargonium sp. Frensham) to tolerate metal stress was assessed using chlorophyll a fluorescence kinetics. The effects of various concentrations of cadmium and nickel in the culture solution on photosynthetic efficiency in scented geranium was evaluated in comparison to two well-established metal accumulators, the Indian mustard (Brassica juncea), and the sunflower (Helianthus annuus), under greenhouse conditions. The efficiency of the photosynthetic apparatus was affected to varying degrees at all metal concentrations for the plants tested. High concentrations of cadmium (1000 mg L-1) did not significantly affect the efficiency of photosystem II activity, expressed as the ratio of variable fluorescence to maximal fluorescence (Fv/Fm), which remained high (0.738) in scented geraniums, but decreased significantly (P < 0.05) in Indian mustard (0.089) and sunflower (0.026) plants following 4 days of metal exposure. Similar trends were observed for nickel treatments. Also, the number and size of active photosynthetic reaction centers, as measured by the Fv/Fo ratio, was not significantly affected by metal exposure in scented geranium plants, while the ratio significantly decreased in Indian mustard and sunflower seedlings. The results suggest that scented geranium plants were able to overcome metal stress through (1) maintaining an efficient photosystem II activity, which is required for plant metabolism and physiological functions, as well as to overcome metal ion mediated stress, and (2) restricting damage to the photosynthetic apparatus (reaction centers) by metal ions.

Resistance to Botrytis cinerea in scented geranium transformed with a gene encoding the antimicrobial protein Ace -AMP1

Scented geranium (Pelargonium sp. `Fren-sham') was transformed with a gene encoding an antimicrobial protein (Ace-AMP1) from onion through an Agrobacterium-mediated transformation system. The binary vector pFAJ3033 contained the coding region of the Ace-AMP1 preproprotein-encoding cDNA. Transformants were verified by polymerase chain reaction and Southern blot analysis. Transgenic plants expressing high levels of Ace-AMP1 were identified by immunoblots and those plants were shown to have increased resistance to Botrytis cinerea leaf infection.

Structure-Fungitoxicity Relationships of the Monoterpenoids of the Essential Oils of Peppermint (Mentha piperita) and Scented Geranium (Pelargonium graveolens)

The fungitoxicity of essential oil of peppermint (Mentha piperita) and its primary monoterpene constituents, namely menthol, neomenthol, linalool, menthyl acetate and menthone was assayed. Median effective concentrations (EC50) of these constituents for the mycelial growth inhibition of Colletotrichum gloeosporioides were determined and were compared with those of geraniol and citronellol which are the chief constituents of the oil of scented geranium (Pelargonium sp.). Structure-activity relationship studies revealed that alcoholic group is necessary for activity and that primary alcoholic group is the most potent followed by secondary alcoholic, while the tertiary alcoholic group is the least potent.

Somatic embryogenesis and Agrobacterium -mediated transformation system for scented geraniums ( Pelargonium sp. `Frensham')

Plant regeneration via somatic embryogenesis was achieved from leaf petioles of Pelargonium sp. `Frensham' cultured on Murashige and Skoog medium containing 15 μM N6-benzyladenine, and 5 μM α-naphthaleneacetic acid (NAA). More than 80% of these somatic embryos converted into plants when isolated and cultured on Murashige and Skoog medium supplemented with 15 μM NAA. Stable transgenic plants were obtained by co-cultivation of the petioles (prior to culture) with Agrobacterium tumefaciens strains LBA4404 (harbouring a binary vector pBI121 carrying the nptII and gus genes) and LBG66 (harbouring a binary plasmid pJQ418 carrying the gus/int:nptII fusion gene). Transformants were selected using kanamycin and transformation was verified by β-glucuronidase histochemical assay and polymerase chain reaction. Southern analysis further confirmed the integration of these genes into the genome of transgenic plants. We report here for the first time, an Agrobacterium-mediated model transformation system coupled with regeneration via somatic embryogenesis for production of transgenics in Pelargonium sp.

Agrobacterium rhizogenes-mediated transformation of scented geranium

A method is described for producing genetically transformed plants from explants of three scentedPelargonium spp. Transgenic hairy root lines were developed fromPelargonium spp leaf explants and microcuttings after inoculation withAgrobacterium rhizogenes strains derived from the agropine A4 strain. Hairy root lines grew prolifically on growth regulator-free medium. Transgenic shoots were regenerated from hairy roots and the plants have been successfully transferred to soil. The phenotype of regenerated plants has been characterized as having abundant root development, more leaves and internodes than the controls, short internodes and highly branched roots and aerial parts. Southern blot analyses have confirmed the transgenic nature of these plants.

Seasonal Variation in Oil Content and Its Composition in Two Chemotypes of Scented Geranium (Pelargoniumsp.)

ABSTRACT Variations in oil content and the chemical composition of the oil of two chemotypes (G-1 and G-2) of scented geranium were investigated in different seasons in a semiarid tropical climate in south India. The results showed that weather parameters such as atmospheric temperatures and rainfall have influenced the oil content and its chemical composition. Increases in maximum temperatures reduced oil content in G-1, increased citronellol in G-1 and G-2, and increased citronellyl formate in G-1. Rainfall increased geraniol in G-2. Geraniol and citronellol in G-1 were highly negatively correlated.

Analysis of Essential Oils from Selected Cultivars ofPelargonium quercifoliumby GC/MS

ABSTRACT Essential oils from four scented geranium [all cultivars of Pelargonium quercifolium (L.F.) L'Herite.] were distilled annually and analyzed by GC/MS over a period of three years. The cultivars studied were: ‘Giant Oak,’ ‘Staghorn Oak,’ ‘Sharptooth Oak’ and ‘Skeletons Unique.’ More than 120 components were detected in each oil with partial or complete identifications made on 57 to 72 constituents per oil. Considerable quantitative variation in composition occurred in the oils over the three-year period. The major components in the oil of ‘Giant Oak,’ ‘Sharptooth Oak’ and ‘Staghorn Oak’ were α-phellandrene (12.8–24.9%) and p-cymene (18.7–22.5%). The oils of ‘Sharptooth Oak’ and ‘Staghorn Oak’ differed from the ‘Giant Oak’ by also containing substantial amounts of hexyl butyrate (4.5–10.7%) and trans-2-hexenyl butyrate (16.0–19.4%). The major components in the cultivar ‘Skeletons Unique’ were: α-guaiene (15.7%) and geranyl butyrate (19.4%).

Essential Oil Profiles and their Possible Use in Hybridization of Some Common Scented Geraniums

ABSTRACT The essential oil profiles of some common scented geraniums were investigated using GC/M S. These include the following Pelargonium species and cultivars in the family Geraniaceae: P. graveolens, L'Herit., P. radens H. E. Moore, P. capitatum (L.) L'Herit. ex Aiton, P. tomentosumjacq., ‘Mabel Grey’, ‘Frensham’, ‘Citronella’, ‘Rober's Lemon Rose’, ‘Camphor Rose’ and ‘Godfrey's Pride’. There was a strong correlation between the odor of the main essential oil components and that of the overall odor of the Pelargonium studied. There was also a correlation between the essential oil profile of the hybrids and that of parents, indicating its potential taxonomic viability. This indicates that a hybridization program could be suggested by the essential oil profiles of different species in order to produce a commercially viable hybrid for the perfumery or food industry. Variations are found when the present data are compared with the published data. These could be due to the proliferation of hybrid and cult...

Phyllotaxy Variability in Pelargonium1

Abstract Phyllotaxy (the arrangement of leaves on the stem) in scented geranium is typically 2/5, i.e., in order to reach a leaf directly above another, it is necessary to maneuver 2 complete turns around the stem and pass 5 other leaves. We have observed variable phyllotaxy of certain clones of Pelargonium. For instance, in ‘Rober’s Lemon Rose’ (RLR) (Pelargonium graveolens L’Heritier ex. Ait on) nearly all plants change their phyllotaxy from 2/5 to 1/2 (Fig. 1, 2) (3) on either the main axis or lateral shoots. Most plants show: a) a region of 2/5 (usually the oldest growth near the base of the plant), b) a region of 1/2 (the newest growth), and c) a variable (1/2 + 2/5) region between these two (Table 1). The 2/5 phyllotaxy is associated with vegetative growth, while the 1/2 or 1/2 + 2/5 phyllotaxy is associated with flowering. The phyllotaxy switch was reversible. Lateral buds developing within a phyllotactic region could segregate all 3 patterns (Table 1).

Comparison of in vitro and in vivo tissue culture systems in scented geranium

Comparison of in vitro and in vivo tissue culture systems in scented geranium

Tissue Culture-induced Variation in Scented Pelargonium spp.1

Abstract In vitro techniques were developed to regenerate plantlets (calliclones) from callus of scented geraniums (Pelargonium spp.). Calliclones were compared to plants derived from stem, root, and petiole cuttings of 5 cultivars. Plants from stem cuttings of all cultivars were uniform and identical to the parental clone. Plants from root and petiole cuttings were more variable with the amount of variation dependent upon cultivar. High variability was associated with calliclones. Aberrant types included changes in plant and organ size, leaf and flower morphology, essential oil constituents, fasciation, pubesence, and anthocyanin pigmentation. Calliclone variation was dependent upon clone and age of callus. Variability in calliclones was due to segregation of chimeral tissue, euploid changes, and heritable changes which may involve individual chromosomal aberrations or simple gene mutations. Variability of calliclones might be exploited for improvement of vegetatively propagated crops especially highly polyploid, sterile lines.

‘Velvet Rose’ Pelargonium, a Scented Geranium1

Abstract ‘Velvet Rose’ is a high polyploid, tissue culture-derived line (calliclone) from ‘Rober's Lemon Rose’, a scented geranium (Pelargonium graveolens L’Heritier ex. Alton) released for its sturdy plant type, general attractiveness, and vigor.