Effect of micronutrients application on morpho-physiological, biochemical parameters and essential oil yield of mentha (Mentha arvensis L.)

Introduction

Japanese mint a member of the Lamiaceae family, is a widely used aromatic plant in the food, sanitary and cosmetic industries. It is typically found in temperate and sub-temperate areas all around the globe. Mentha produce monoterpene-rich essential oils that are widely used in the food, flavour, cosmetics and pharmaceutical industries. It is a sterile natural hybrid of M. aquatica L. (2n=96) and M. spicata L. (2n=48) that is tetraploid (2n=4x=72). Pepper mint essential oil contains between 1 to 2.5% menthol (50%), menthone (10 to 30%), menthyl esters (up to 10%) and other monoterpene derivatives and is mostly made up of menthol (50%), menthone (10 to 30%), menthyl esters (up to 10%) and other monoterpene derivatives (Ali et al., 2018) [1] . The state of Chhattisgarh, with its diverse geography and climate, serves as a storehouse for the region's unique medicinal and aromatic plant wealth. The "Herbal State" of Chhattisgarh is blessed with huge resources, including a rich and diversified flora of medicinal and aromatic plants, particularly on the Bastar Plateau and Northern Hills. Zn has been discovered to boost menthol content and current research efforts are focused not just on encouraging plant growth for increased herb harvest, but also on increasing oil yield (Johri et al., 1991) [3] . Cu is required for a variety of metabolic activities in plants, including cell wall metabolism. Sulphur shortage on the other hand, produces a significant shift in the balance between soluble and insoluble nitrogen in favour of the soluble fraction (mainly glutamine and asparagine's as protein synthesis is halted, sulphur deprivation is characterised by arginine and amide build up (Patro et al., 2010) [8] . Nitrogen, Phosphorus and Potash concentrations and their uptake of barley plants increase by increasing application of zinc. About 140 enzymes that catalyze specific biological reactions require iron (FeSo 4 ) as a cofactor (George et al., 1994) [2] .

Materials and Methods

The experiment was carried out during Rabi season 2020-21 at Instructional cum Herbal Garden and Department of Plant Physiology, Agricultural Biochemistry, Medicinal and Aromatic Plants, CoA, IGKV, Raipur (C.G). The experiment were laid out in randomized block design with tenth treatments and three replication considered as FeSo 4 different ppm levels as factor A and CuSo 4 as a factor B. ZnSo 4 is a factor C. The treatment such as T 1 (Control), T 2 300 ppm (FeSo 4 ), T 3 500 ppm (FeSo 4 ), T 4 700 ppm (FeSo 4 ), T 5 300 ppm (CuSo 4 ), T 6 500 ppm (CuSo 4 ), T 7 700 ppm (CuSo 4 ), T 8 300 ppm (ZnSo 4 ), T 9 500 ppm (ZnSo 4 ) and T 10 700 ppm (ZnSo 4 ). Nursery was raised in pro tray coco peat and FYM were used as media for growing menta cutting. Koshi variety of mint plant consists of shoot having stem and suckers. The transplanting was done on 25th February, 2021. Transplanting were done as per requirement, healthy seedlings were transplanted horizontally in furrows about 2.5 to 3 cm deep at the spacing of 15×45 cm distance and covered with thin layer of the soil.

Results and Discussion

Morphological parameters

The observations were recorded before the treatment and 15 days after the treatment. Recorded data was analyzed using the standard statistical tools. From the results it can be inferred that the plant height ranged from 29-38 cm. T 9 (ZnSo 4 @ 500 ppm) showed the maximum plant height 38 cm, while T 7 (CuSo 4 @ 700 ppm) showed the minimum plant height 29 cm. Similar result were obtained by Mehrab et al., 2017.

Number of leaves plant -1

Maximum number of leaves plant -1 87.08 was observed in T 6 (CuSo 4 @ 500 ppm). Similar observations were obtained by Zahra et al., 2018 [10] .

Number of branches plant -1

Maximum number of branches plant -1 7.58 was observed in T 6 (CuSo 4 @ 500 ppm) which was followed by T 9 (ZnSo 4 @ 500 ppm) 7.54, Number of branches plant -1 recorded in T 2 (FeSo 4 @ 300 ppm) 7.05 and T 5 (CuSo 4 @ 300 ppm) 6.76 was at par with the T 6 , while the minimum was recorded in T 1 Control 5.42. Similar observation was obtained by Zehtab et al., 2008 [11] .

Fresh weight

Maximum fresh weight 8.28 was observed in T 6 (CuSo 4 @ 500 ppm) which was followed by T 9 (ZnSo 4 @ 500 ppm) 8.15.

Number of branches plant

Number of branches plant -1 recorded in T 2 (FeSo 4 @ 300 ppm) 8.08, T 5 (CuSo 4 @ 300 ppm) 8.05 and T 10 (ZnSo 4 @ 700 ppm) 8 was at par with the T 6 , While the minimum was recorded in T 1 control 6.48.

Dry weight

Maximum dry weight 2.16 was observed in T 6 (CuSo 4 @ 500 ppm) which was followed by T 9 (ZnSo 4 @ 500 ppm) 2.14. Dry weight recorded in T 2 (FeSo 4 @ 300 ppm) 2.09, T 5 (CuSo 4 @ 300 ppm) 2 and T 10 (ZnSo 4 @ 700 ppm) 1.95 was at par with the T 6 , While the minimum was recorded in T 1 Control 1.61. Similar results were obtained by Pandey et al., 2015 [7] .

Leaf area plant -1

Maximum leaf area plant 622.65 was observed in T 6 (CuSo 4 @ 500 ppm) which was followed by T 9 (ZnSo 4 @ 500 ppm) 582.95, while the minimum was recorded in T 1 Control 429.50.

Leaf area index

Maximum leaf area index 10.90 was observed in T 6 (CuSo 4 @ 500 ppm), while the minimum was recorded in T 1 Control 7.79.

Specific leaf area

Maximum specific leaf area 522.67 was observed in T 6 (CuSo 4 @ 500 ppm), while the minimum was recorded in T 1 control 320.36.

Specific leaf weight

Maximum specific leaf weight 0.53 was observed in T 6 (CuSo 4 @ 500 ppm), while the minimum was recorded in T 1 Control 0.36.

Biochemical parameters

Data recorded for biochemical parameters before and after treatments as impacted by various concentrations of micronutrients.

Chlorophyll a

Maximum chlorophyll a 0.81 was observed in T 9 (ZnSo 4 @ 500 ppm) which was followed by T 2 (FeSo 4 @ 300 ppm) 0.80. Chlorophyll a recorded in T 1 control 0.79, T 10 (ZnSo 4 @ 700 ppm) 0.78 and T 6 (CuSo 4 @ 500 ppm) 0.77 was at par with the T 9 . While the minimum was recorded in T 3 FeSo 4 @ 300 ppm) 0.65.

Chlorophyll b

Maximum chlorophyll b T 9 0.32, was observed in (ZnSo 4 @ 500 ppm) which was followed by T 2 (FeSo 4 @ 300 ppm) 0.26, Chlorophyll b recorded in T 6 (CuSo 4 @ 500 ppm) 0.24 was at par with the T 9 . While the minimum was recorded in T 7 (CuSo 4 @ 700 ppm) 0.20.

Total chlorophyll

Maximum total chlorophyll T 9 (1.12) was observed in (ZnSo 4 @ 500 ppm) which was followed by T 2 (FeSo 4 300 ppm) (1.06), Total Chlorophyll recorded in T 1 control 1.02, T 6 (CuSo 4 @ 500 ppm) 1.01 and T 10 (ZnSo 4 @ 700 ppm) 1.00 was at par with the T 9 . While the minimum was recorded in T 3 (FeSo 4 @ 500 ppm) 0.86. Similar result found by Pandey et al., 2015 [7] . After treatment data revealed that all treatment was significantly differed to each other. Results indicate that the variation in total chlorophyll significant within treatments.

Yield parameters

The maximum herbage yield was recorded in T 6 (20.18 ton ha -1 ) herbage yield in T 9 (19.43 ton ha -1 ) was statistically at par with T 6 and the minimum herbage yield was observed in T 1 (16.06 t ha -1 ). Similar result found by Pejhman et al., 2018 [9] essential oil (%) ranged from 0.64-0.78%. The highest essential oil (%) was obtained in T 9 (0.78%) which was at par with T 6 (0.77%) and the lowest essential oil (%) was recorded in T 7 (0.64%). Similar result found by Kumar et al., 2010 [4] .

Summary

The experiment was conducted at Department of Plant Physiology, Agricultural Biochemistry, Medicinal and Aromatic Plants, IGKV, Raipur (C.G.) in Mentha during the 2020-21 Rabi season. Randomized block design was used to conduct the experiment with three replications. There was 10 treatments T 1 (Control, Water Spray), T 2 (FeSo 4 @ 300 ppm), T 3 (FeSo 4 @ 500 ppm), T 4 (FeSo 4 @ 700 ppm), T 5 (CuSo 4 @ 300 ppm), T 6 (CuSo 4 @ 500 ppm), T 7 (CuSo 4 @ 700 ppm), T 8 (ZnSo 4 @ 300 ppm), T 9 (ZnSo 4 @ 500 ppm), T 10 (ZnSo 4 @ 700 ppm). Herbage yield ranged from 16.06-20.18 t ha -1 . The maximum herbage yield was recorded in T 6 (20.18 ton ha -1 ) herbage yield in T 9 (19.43 ton ha -1 ) was statistically at par with T 6 and the minimum herbage yield was observed in T 1 (16.06 t ha -1 ). Essential oil (%) ranged from 0.64-0.78%. The highest essential oil (%) was obtained in T 9 (0.78%) which was at par with T 6 (0.77%) and the lowest essential oil (%) was recorded in T 7 (0.64%).

Table 1: Effect of micro nutrients on fresh herbage yield of Mentha

Treatments

Fresh herbage yield Kg plot -1 Ton ha -1 T1 control 2.89 16.06 T2 FeSo4 @ 300 ppm 3.47 19.28 T3 FeSo4 @ 500 ppm 3.13 17.36 T4 FeSo4 @ 700 ppm 3.07 17.05 T5 CuSo4 @ 300 ppm 3.42 19.00 T6 CuSo4 @ 500 ppm 3.63 20.18 T7 CuSo4 @ 700 ppm 3.23 17.96 T8 ZnSo4 @ 300 ppm 3.24 18.00 T9 ZnSo4 @ 500 ppm 3.50 19.43 T10 ZnSo4 @ 700 ppm 3.31 18.37 SE (m) 0.13 0.73 CD (0.05%) 0.39 2.15

Conclusion

It is concluded from the study that T 6 (CuSo 4 @ 500 ppm) is the best treatment for morpho-physiological growth of mentha for getting higher herbage yield. Treatment T 9 (ZnSo 4 @500 ppm) is found to be superior for obtaining higher essential oil yield and economic value.

References

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