S. Sharma

Herbage, oil yield and oil quality of patchouli [Pogostemon cablin (Blanco) Benth.] influenced by irrigation, organic mulch and nitrogen application in semi-arid tropical climate

A field experiment was conducted during 1999 and 2000 at Bangalore in the semi-arid tropical climate of South India, to study the influence of irrigation, organic mulch and nitrogen application on its growth, herbage, oil yield and quality of patchouli [Pogostemon cablin (Blanco) Benth.] grown on Alfisol. Irrigation at 1.0 IW:CPE ratio (irrigation water:cumulative pan evaporation), 5 t ha−1 distilled waste material of palmarosa, or 200 kg N ha−1 produced maximum herbage and oil yields. Organic mulch reduced weed biomass significantly. The oil content varied from 0.61 to 0.73%. The highest oil content was recorded with irrigation at 0.8 IW:CPE ratio, no mulch and 100 kg N ha−1. The quality of the essential oil with 50.66–54.31% patchouli alcohol, 9.86–10.26% α-bulnesene and 4.27% α-patchoulene was found to be good and readily accepted in the market.

Characteristics of menthol mint Mentha arvensis cultivated on industrial scale in the Indo-Gangetic plains

Abstract Mentha arvensis L. (menthol mint) oil is the source of commercial natural menthol. This industrial crop is now cultivated in about 0.145 million ha in the Indian state of Uttar Pradesh (UP) and several other states encompassing Indo-Gangetic plains. Considerable variation has been reported in the yield and quality of oil obtained from the crops of menthol mint varieties Himalaya and Kosi taken in the area. A follow up study was made to ascertain the cause(s) of such variation in many villages of selected districts of UP. The soils sampled from the fields were studied for variability in reaction, salinity, organic carbon content, the contents of the major nutrients nitrogen, phosphorous and potassium and micro-nutrients manganese, iron, copper and zinc and crops of mint on the concerned fields were characterized for the herb, essential oil and menthol yields. The observations made in 69 farmers’ fields have indicated variation in soil characteristics, as well as herb, essential oil and menthol yields from the crops taken on them. However, herbs harvested from different fields did not differ much in their oil content. Imbalance in N, P and K supplements to the field was observed; it seemed to arise from unnecessary emphasis on urea application without concomitant K and P supplementation. The fields were particularly deficient in Mn among the micronutrients. There was need for heavier application of K, Cu, Zn, and Mn together with sufficient amount of N and P to obtain better oil yields. To increase oil yield was inferred as the best means to increase menthol production from the fields of Indo-Gangetic plains.

An efficient in vitro procedure for micropropagation and generation of somaclones of rose scented Pelargonium.

Efficient protocols have been established for both direct and indirect regeneration of plants in Pelargonium graveolens Indian cultivar Hemanti (Algerian type). Murashige and Skoogs (MS) medium [T. Murashige, F. Skoog, A revised medium for rapid growth and bioassays with tobacco tissue cultures. Physiol. Plant. 15 (1962) 473-497] supplemented with 5.0 mg/l kinetin and 1.0 mg/l NAA was optimal for direct regeneration of plants from leaf explants while 8.0 mg/l kinetin and 1.0 mg/l NAA proved optimum for nodal explants for maximum number of shoots per explant. Callus induction was observed from nodal explants on MS medium supplemented with 10 mg/l kinetin and 1.0 mg/l NAA. Callus on further transfer to MS medium with 0.5 mg/l BAP and 0.1 mg/l NAA exhibited regeneration of maximum number of shoots. In vitro grown shoots of both direct and indirect origin rooted within 7-10 days following transfer to half strength MS medium with 1.0 mg/l IBA. Plantlets were acclimatized under glass house conditions with 90% survival. Randomly selected 85 individual Calliclones were subjected to field trial with 85-95% survival for two successive years along with control in randomized block design with three replicates. Screening of these calliclones revealed two distinct morphotypes, one with parental type highly dentated leaves (HDL) and the other with less dentated, round leaves (LDL). Only HDL calliclones flowered under field conditions. The LDL clones differed in several herb related agronomic characteristics such as plant height, herb yield, canopy size and number of branches per plant from the parental type as well as from the parent, which seems advantageous for commercial exploitation of such clones. The HDL clones closely resemble the parent in having higher content of citronellol than geraniol while the LDL clones contain almost equal contents of citronellol and geraniol in their essential oils as revealed by gas chromatography analysis. It is noticeable that the variability both in terms of agronomic characters and essential oil profiles among the clones were stable over 2 years of field trials.

Pattern of diversity for morphological and alkaloid yield related traits among the periwinkle Catharanthus roseus accessions collected from in and around Indian subcontinent

Thirty two accessions of periwinkle Catharanthus roseus collected from different semitemperate to tropical geographical areas of Indian subcontinent, Madagascar, Singapore and Malaysia were characterized under field conditions for 53 growth, development, morphogenesis and alkaloid yield related characters over a few seasons at Lucknow, India. Large differences were observed among the accessions for each of the characters examined. The differences among the accessions ranged 3, 80 and 15 fold for the alkaloid yield related traits – leaf dry matter yield and leaf vincristine and vinblastine concentration, respectively. Strong correlations were observed between leaf area and leaf yield with leaf alkaloid, root and root alkaloid yields, contents of dimeric alkaloid in leaves with yields of respective alkaloids, leaf number and root alkaloid content with leaf vinblastine yield and leaf vinblastine content with leaf vincristine and vinblastine yields. Multi-variate analyses allowed classification of the accessions into 5 to 7 morphologically and presumably genetically distinct groups. Generally, the accessions coming from tropical agro-climates tended to get separated from those having origins in subtropical to semi-temperate environments. Three clusters were observed to bear complementary characters for possibly cross-parenting high alkaloid yielding transgressive segregants. One of the accessions of C. roseus in which the leaf vincristine content was 5 fold and vinblastine content one and a half fold of the respective all accession means appeared suitable for the domesticated cultivation. It was proposed that accumulation of high amounts of total alkaloids and one or more dimeric alkaloids in leaves of certain accessions may be a reflection of reproductive fitness achieved under the biotic and abiotic stresses imposed on their parent populations, sometime in their evolutionary pathway.

Variation in Quality of Essential Oil Distilled from Vegetative and Reproductive Stages of Tagetes minuta Crop Grown in North Indian Plains

Abstract The essential oil yield and quality of Tagetes minuta was field tested in north Indian plain conditions of Lucknow, India in winter (rabi) season of November 1997 to April 1998. The shoot oil distilled from the crop of Banuri land race at full flowering stage was rich in dihydrotagetone (32.0%), (Z)-tagetone (16.7%) and (Z)-β-ocimene (133%). In comparison to the oils distilled from flower bearing plants, the oil from plants at vegetative stage(s) of growth contained (E)- and (Z)-tagetenones and (E)- and (Z)-tagetones at higher levels (27.1% and 31.2%, respectively) and dihydrotagetone and (Z)-β-ocimene at lower levels (13.6% and 6.1%, respectively). The oils obtained from the leaves of plants bearing flowers (capitula) at different stages of development were pre-eminent in dihydrotagetone, present in 50-60% concentration. The capitula oils were somewhat similar to leaf oils of reproductively mature plants in their monoterpenoid composition.

Herb yield and bacoside: A content of field-grown Bacopa monnieri accessions

ABSTRACT A field trial of five accessions of Bacopa monnieri (L.) Pennell was conducted during 1997 to 1998, at Lucknow, India, to standardize cultivation procedures for domestication of this medicinal herb. The accessions, monitored for growth and bacoside-A yields over 18 months, could be maintained as perennials, but growth properties were sensitive to the growing season. Loss of shoot biomass occurred in winter (December-February) and the growth rate was higher in the monsoon season (July-September) than in summer (March-June). Bacoside-A content of herb was high from September through March and in June. Suitable harvest times for high yields of bacoside-A were June and September through November. An accession from Guwahati in Assam state of India yielded more bacoside-A than all other accessions.

High economic returns from companion and relay cropping of bread wheat and menthol mint in the winter–summer season in north Indian plains

Abstract A total of 17 cropping schedules for the winter (rabi)–summer (zaid) season of north Indian plains were compared for the yield and economics of produce per hectare of land. In comparison to wheat, the sucker-planted mint crop was estimated to bring in a 32% higher income. The co-cultivation of wheat with sucker-planted mint gave 15% more productivity over wheat alone and 70% over mint alone. The relay cropping of wheat followed by transplanted mint had the highest productivity, 45% higher than that of co-cultivated wheat and mint. The cultivar HD 2285 of wheat ( Triticum aestivum L.) and Himalaya/Kosi cultivars of mint ( Mentha arvensis L.) were found to fit well in the co-cultivation and relay cropping schedules using wheat and mint crops. The results allowed recommendation of the following rotations for high yield together with resource conservation, permitting intensive agriculture by farmers with small holdings in Indo-Gangetic plains: (1) rice/greengram/blackgram, transplanted basil, wheat+mint, pigeonpea, chickpea, transplanted mint; and (2) pigeonpea, wheat, transplanted mint, rice, transplanted basil, wheat+mint.

Screening of genetic resources of the medicinal-vegetable plant Centella asiatica for herb and asiaticoside yields under shaded and full sunlight conditions

Summary Genetic resources of the medicinal and vegetable plant Centella asiatica, collected from different parts of India, were screened for their herb and asiaticoside yields under different levels of shading under sub-tropical field conditions of Indo-Gangetic plains at Lucknow in the winter (rabi) season. The 16 accessions studied were found to harbour wide differences in morphology and herb and asiaticoside yield-related characters. The herb and asiaticoside yields of accessions ranged from 470 to 2730 kg ha–1 and 1.0 to 9.8 kg ha–1 respectively. Considering all the accessions together, 50% shading of plants resulted in higher yields of herbage and asiaticoside. Thirteen out of the 16 accessions studied here had shading requirements for high yields of fresh and dry herb and asiaticoside. The accession CaShT, from Meghalaya, was identified as very high herbage and asiaticoside yielding but requiring a shading of about 50%. On the other hand accessions CaBp and CaCl from Orissa and West Bengal, respectively, gave high herb and asiaticoside yields under full light. It is concluded that triterpenoid saponin rich C asiatica for high yields can be cultivated in the field under shade or full light by selecting the genotype adapted to the respective growth conditions.

Utilization of Photosynthetically Fixed 14CO2 into Alkaloids in Relation to Primary Metabolites in Developing Leaves of Catharanthus roseus

Partitioning of current photosynthates towards primary metabolites and its simultaneous incorporation in leaf alkaloids was investigated in developing leaves of medicinally important Catharanthus roseus. Of the total 14CO2 assimilated, the leaves at positions 1–6 fixed 8, 22, 25, 19, 13, and 8 %, respectively, and stem 3 %. Leaf fresh mass, chlorophyll content, and CO2 exchange rate increased up to the third leaf. The total alkaloid content was highest in young actively growing leaves, which declined with age. Total 14C fixed and its content in ethanol soluble fraction increased up to the third leaf and then declined. The 14C content in primary metabolites such as sugars and organic acids was also highest in the 3rd leaf. The utilization of 14C assimilates into alkaloids was maximum in youngest leaf which declined with leaf age. Hence the capacity to synthesize alkaloids was highest in young growing leaves and metabolites from photosynthetic pathway were most efficiently utilized and incorporated into alkaloid biosynthetic pathway by young growing leaves.

Variation among commercial cultivars of Japanese mint ( Mentha arvensis L.) in the morphological and metabolite characters associated with essential oil yield

Summary Intraspecific variation in four widely cultivated cultivars of Japanese mint ( Mentha arvensis L.) was studied to understand the physiological basis of regulation of essential oil accumulation. The cultivars had the same oil biosynthetic route but differed in morphological/physiological characters. Oil content showed significantly positive correlations with yield traits like leaf and stem fresh and dry weights, relative growth rate and CO2 exchange rate. Leaf area per plant was positively associated with herb yield. Observation that leaf fresh and dry weights possessed higher significant genotypic correlation coefficients than phenotypic correlation coefficients indicated that these traits express a strong genetic influence on oil yield, as the latter incorporates the former. Photosynthetic efficiency measured by uptake and fixation of 14CO2 and 14C-sucrose showed differential utilization of these precursors. Sucrose was more efficiently utilized for oil biosynthesis than photoassimilated (14CO2) precursors. The levels of metabolites fixed through 14CO2 remained lower than those fixed via 14C-sucrose. Efficient cultivars translocated a greater portion of metabolite towards essential oil and also accumulated higher concentrations of nutrients. The concentrations of the micronutrients Fe, Mn, Cu, Zn varied significantly among cultivars with leaves showing higher concentrations than stems. It is evident that the physiological capability of mints in terms of leaf growth,nutrient uptake, photosynthetic capacity, partitioning and distribution of assimilated metabolites in leaf and stem, contribute significantly to biosynthesis and accumulation.