Amitabha Chattopadhyay

Effect of Soil Sodicity on Growth, Yield, Essential Oil Composition, and Cation Accumulation in Rose‐Scented Geranium

Abstract The effect of soil sodicity [exchangeable sodium percentage (ESP)] on the growth, yield, essential oil composition, and cation accumulation of two cultivars (Bourbon and Cimpawan) of geranium (Pelargonium graveolens) were studied in a pot experiment. Irrespective of soil sodicity, two cultivars of geranium differed significantly in their plant height and herb and oil yield. Plant height was not significantly affected with increases in soil ESP from 0.7 (control) to 20.0 and 7.0, respectively, for cultivars (cv) Bourbon and Cimpawan, but further increase in soil ESP decreased the plant height. The herb yield of cv Bourbon significantly increased with increasing soil ESP to 16.0, and the oil yield increased with increasing ESP to 7.0. Further increase in soil ESP decreased the yield. The increase in yield of cv Bourbon was 13.1 and 15.1% in the herb and 40.0 and 15.2% in the oil over the control (ESP 0.7) at soil ESP of 7.0 and 16.0, respectively. Decreases in yield were 3.5, 4.9, 53.3, and 59.3% in the herb yield and 3.8, 5.7, 53.3, and 80.0% in the oil over control (ESP 0.7) at soil ESP of 20.0, 24.0, 28.0, and 30.0, respectively. The herb and oil yield of cv Cimpawan significantly decreased with increase in soil ESP. The decease in yield was 17.7, 20.2, 40.7, 53.1, 70.7, and 72.6% in the herb and 4.0, 6.8, 30.9, 45.4, 83.2, and 84.0% in the oil over control (soil ESP 0.7) at the soil ESP 7.0, 16.0, 20.0, 24.0, 28.0, and 30.0, respectively. The concentration of isomenthone, linalool, citronellyl formate, and geranyl formate in the essential oil increased at low levels of soil ESP (between 16.0 to 24.0) but decreased at high soil ESP (>28). The concentration of l‐citronellol, nerol, and geraniol gradually increased with increase in soil ESP. The increase in the soil ESP enhanced the concentration of sodium (Na) and decreased that of potassium (K) in shoot and root tissues of geranium as compared to control. The concentration of Ca in shoot tissues of cv Bourbon significantly decreased with increase in soil ESP, but in the cv Cimpawan, the Ca concentration was not significantly affected with increase in soil ESP from 0.7 to 16.0, and thereafter the Ca concentration significantly decreased with further increase in soil ESP. The concentration of Na, K, and Ca were relatively higher in shoot than in root tissues. The K/Na and Ca/Na ratios in shoot tissues of both cultivars of geranium decreased with increase in soil ESP. The K/Na and Ca/Na ratios in shoot were not found to be related to the differences in sodicity tolerance of the cultivars of geranium tested in this experiment. The concentration of zinc (Zn) in shoot tissues decreased with increase in soil ESP. The cv Bourbon maintained a higher concentration of Zn in shoot tissues at high sodicity than that of cv Cimpawan. The results suggest that the geranium is slightly to moderately tolerant of soil sodicity stress.

Heavy Metals Affect Yield, Essential Oil Compound, and Rhizosphere Microflora of Vetiver (Vetiveria zizanioides Linn. nash) Grass

The effects of heavy metals [chromoium (Cr), cadmium (Cd), lead (Pb) and nickel (Ni)] on the yield, khusimol content in the essential oil, accumulation of metals, and rhizosphere microflora of vetiver (Vetiveria zizanoides) were studied in a pot experiment. The shoot yield and khusimol content in oil of vetiver were enhanced by the application of moderate amount of metals to soils. The application of Cr, Pb, and Ni had deleterious effects on the root and essential oil yield. The application of high levels of metals to soil had harmful effects on the bacterial and fungal counts in the rhizosphere. The concentrations of metals such as Cr, Cd, Pb, and Ni in shoot and root tissues were significantly enhanced by the application of those metals to soils. It can be concluded that the vetiver could be used as a promising crop for revegetation, soil remediation, and production of better quality essential oil in metal-contaminated soils.

Response of Basil Species to Soil Sodicity Stress

Abstract Growth, yield, essential oil composition, and cation accumulation of two species of Ocimum (viz., O. basilicum and O. sanctum) in response to soil sodicity was studied in pot experiments. The herb yield of O. basilicum significantly decreased with increases in soil exchangeable sodium percentage (ESP). The oil yield of O. basilicum significantly increased with increase in soil ESP from 4.0 (control) to 16.0, and further increases in soil ESP decreased the yield. The decrease in the yield of O. basilicum was 4.7, 13.1, 13.6, 23.7, and 24.3% in herb and 3.8, 11.5, 15.4, 23.0, and 26.9% in oil yield the over the control (ESP 4.0) at soil ESP values of 24.0, 32.5, 36.0, 45.0, and 50.0, respectively. The herb and oil yield of O. sanctum significantly increased with an increase in the soil ESP from 4.0 (control) to 24.0, and further increases in soil ESP decreased the yield. The maximum increase in the herb and oil yield of O. sanctum was 18.2% over the control (ESP 4.0) at the soil ESP of 24.0. At high sodicity, the decrease in yield of O. sanctum was 12.4 and 23.2% in the herb and 12.7 and 20.9% in the oil yield over control (ESP 4.0) at soil ESP values of 45.0 and 50.0, respectively. The concentration of methyl chavicol in the essential oil of O. basilicum and that of eugenol in the essential oil of O. sanctum was significantly higher at moderate soil sodicity levels as compared to the control (ESP 4.0). Increases in soil ESP enhanced the concentration of sodium (Na) and decreased that of calcium (Ca) and magnesium (Mg) in shoot tissues of both the Ocimum species. The concentration of potassium (K) in shoot tissues of O. sanctum gradually decreased with increase in soil ESP, and that of K in the O. basilicum increased with increase in soil ESP from 4.0 (control) to 36.0. Further increases in soil ESP decreased the K content. These results indicate that both these Ocimum species are highly tolerant to soil sodicity stress.

Growth and Cation Accumulation of Mint Genotypes in Response to Soil Sodicity

Growth and cation accumulation of four mint species and four Japanese mint (Mentha arvensis) cultivars in response to soil sodicity was studied in pot experiments. The sprouting of all cultivars of Japanese mint was significantly inhibited by soil sodicity. The extent of inhibition in sprouting was greater in the cultivars Kalka and Himalaya than in the Shivalik and Koshi. A severe shoot injury symptom was exhibited in M. citrata, M. cardiaca, and M. arvensis after 50 days of transplanting at the soil ESP level 54.0 and in M. piperita after 50 and 70 days of transplanting at the soils ESP levels 25.0 and 54.0, respectively. Mentha piperita, grown on soils ESP of 25.0 and above, failed to survive after developing the shoot injury symptoms. Soil sodicity significantly restricted the herb yield of mint genotypes. At the ESP level of 54.0, the decrease in herb yield was 83.1, 92.2, 89.6, and 98.2% over control in M. citrata, M. cardiaca, M. arvensis, and M. piperita, respectively. The reduction in the yield of Japanese mint at the soil ESP level of 45.0 was 53.8, 81.4, 53.2, and 71.4 per cent over control in the cultivars Shivalik, Kalka, Himalaya, and Koshi, respectively. The oil yield of mint species was not significantly affected with increases in soil ESP level from 1.5 (control) to 25.0. Increases in soil sodicity enhanced the concentration of sodium (Na) and decreased that of potassium (K), calcium (Ca), and magnesium (Mg) in shoot tissues of mint genotypes as compared with control. The Na induced Ca nutrition imbalance had a greater impact on growth inhibition and shoot injury in M. piperita than K and Mg nutrition imbalance. Decreases in K/Na, and Ca/Na ratios in shoot tissues of Japanese mint were significantly and positively correlated with decrease in herb yield. The relatively lower increase in Na and the capacity to maintain high K/Na, Ca/Na and Mg/Na ratios in the cultivars Shivalik and Himalaya showed their greater tolerance to sodicity than that of Kalka and Koshi.

Influence of soil sodicity on the growth, alkaloid yield, and cation accumulation of Catharanthus roseus.

The effects of soil sodicity (exchangeable sodium percentage, or ESP) on the growth, alkaloid yield, and cation accumulation of two cultivars of Catharanthus roseus (Nirmal and Dhawal) was studied in a pot experiment. The leaves and stem yield of C. roseus significantly increased with an increase in soil ESP from 4.3 (control) to 16.9, but thereafter yield decreased with further increases in soil ESP. The severe leaf injury symptom from soil sodicity was exhibited in both cultivars at 32 weeks after transplanting into soil at ESP levels of 44.9 and above. Root yields of C. roseus were also significantly reduced with an increase in soil ESP. Total alkaloid yield in leaves increased with increases in soil at ESP levels of 32.0 and 16.9 for the cultivars Nirmal and Dhawal, respectively, but further increases in soil ESP the total alkaloid yield significantly decreased. The vindoline content in leaves of C. roseus significantly decreased with an increase in soil ESP. In the shoot and root tissues of C. roseus, the concentration of sodium significantly increased and that of potassium, and calcium decreased in plants grown in soil with high sodicity (ESP 44.9 and above) as compared with the control.

Influence of Gypsum and Farmyard Manure Application in Soil on Yield and Chemical Composition of Essential oil of Rose Scented Geranium (Pelargonium graveolens L'Herit.ex Ait.)

Abstract: A field experiment was conducted to evaluate the influence of farm yard manure (FYM) and gypsum application on the yield and chemical composition of essential oil of rose scented geranium. The herbage and essential oil yield of geranium was significantly increased (at 5 % level) by the combined application of FYM and gypsum along with recommended fertilizer application as compared to sole application of N, P and K fertilizer taken as control. The combined application of FYM and gypsum in soil was more effective to increase the herbage and essential oil yield of geranium by 35.4 % which was followed by the sole application of FYM (25.2 %) and gypsum (12.3 %) as compared to control. The chemical composition of the essential oil of geranium was affected differentially with the applied treatments. The content of citronellol, geraniol, linalool, citronellyl and geranyl formate in the essential oil of geranium were significantly increased by 48.9, 20.3, 62.3, 15.6 and 66.4 % respectively with the combined application of FYM and gypsum as compared to control but those were not significantly affected with the sole application of FYM and gypsum . The level of iso-menthone, trans-rose oxide were not affected but the content of cis-rose oxide was decreased and that of nerol and 10-epi-γ-eudesmol was increased in the essential oil of geranium with the application of FYM, gypsum and their combination as compared to control. The results suggest that the combined application of FYM and gypsum would be beneficial to obtain higher herb and essential oil yield of rose scented geranium with enhanced level of citronellol, geraniol along with their esters and other minor compounds like linalool, nerol, 10-epi-γ-eudesmol in the essential oil of geranium.