Rose-scented geranium - CIMAP Staff - Central Institute of Medicinal ...

220 Plant Cell Tiss Organ Cult (2007) 90:215–223Fig. 2 Comparativeaccount of variousmorphological characters oftransgenic and controlplants of Pelargoniumgraveolens cv. Hemanti8070605040302010Control Plants TransgenicPlants0Plant height (cm)No. of branchesNodes/branchLeaves/branchMorphologicalcharactesrRoots/plantRoot length (cm)One of the 11 transgenic plants, LZ-3, producedflowers in 3 months with two inflorescences, eachbearing four flowers could be seen during the entirecultivation period and the flower size was smallerwith reduced petals and abnormality in their shape(Fig. 1G and H). The small flower size in thetransgenic plant in comparison to control was alsoreported in tobacco (Tepfer 1984). A hundred percentpollen sterility could be recorded through acetocarminestaining technique. The cuttings were usedfor maintaining and further multiplication of transgenicplants for three successive years.All the 11 transgenic plants along with theircontrol were subjected to quantitative and qualitativeanalysis of their essential oils after 5 months oftransfer to the pots. It was observed that all the plantsshowed stable behaviour in this duration. The oilcontents of all the transgenics were comparativelylower than the wild type (Table 4) in contrast to anearlier report (Pellegrineschi et al. 1994). Taking intoconsideration the number of leaves and branches, anoverall increase in the oil yield can be predicted fromthe transgenics since higher herb yield normally has astronger correlation with the oil yield per plant(Saxena et al. 2000). The analysis showed that theoils of nine transgenic plants (A6, 2TG, 5TG, 6TG,10TG, 12TG, 13TG, 15TG and 20TG) had compositionsimilar to that of the control Hemanti type(Table 4) which represents Chinese geranium oil inhaving higher amounts of citronellol and loweramounts of geraniol (Saxena et al. 2000). Theconcentrations of citronellol and geraniol as well astheir esters were found to be at par in thesetransgenics with those of the wild type oil. Amongthese nine transgenics, the oil of A6 was unique inhaving very low concentration of 10-epi-c-eudesmol(0.2%) which signifies better odour value (Teisseire1987). As compared to the oils of the other eighttransgenics and the control, the oil of 6TG was foundto contain lower concentration of isomenthone.Unaltered oil profiles of these transgenics mightrepresent the fact that the insertion sites of Ri TDNAin these plants do not interfere with the secondarymetabolites biosynthetic pathway as is mostly notedin majority of medicinal plants (Jung and Tepfer1987; Banerjee et al. 1998; Zehra et al. 1999).The RAPD analysis of these transgenics alsorevealed similarity at genetic level with that of thewild type in terms of most of the primers used.However, the primer OPT 1 revealed distinct differencesbetween the wild type and A6 in terms of thepolymorphic bands (Fig. 3) which might account forthe distinctiveness of A6 in terms of its unique oilprofile in having very low concentrations of 10-epi-ceudesmol.On the other hand, the difference inpolymorphic bands between the 15TG and controlwith regard to the same primer could not be corelatedwith any biochemical or morphologicalparameters in consideration, however changes inother physiological characters cannot be ruled out.Besides the above nine transgenics, the transgenicsLZ-3 and 14TG were found to differ in their oil123