Effect of Cobalt on Growth and Chemical

Australian Journal of Basic and Applied Sciences, 5(11): 628-633, 2011 ISSN 1991-8178

Effect of Cobalt on Growth and Chemical Composition of Peppermint Plant Grown in Newly Reclaimed Soil 1

Eman E. Aziz, 2Nadia Gad and 2Khaled S.M.

1

Medicinal and Aromatic Plants Research Department, National Research Centre (12622), Dokki, Cairo, Egypt. 2 Plant Nutrition Department, National Research Centre, Cairo, Egypt.

Abstract: The biosynthesis and metabolism of essential oil in mint are strongly influenced by environmental factors. Mint is a plant that can become easily adapted to a variety of climate and soil conditions. Cobalt is a promising element in the newly reclaimed soils. Thus, the aim of this investigation was to study the effect of cobalt(0, 7.5, 15.0, 22.5 and 30.0 ppm) on herb yield, essential oil production as well as macro and micronutrients contents of peppermint plant grown in the Experimental Station of National Research Centre at Nubaria, Behira governorate, West of Nile Delta of Egypt under drip irrigation system. The data showed that cobalt at 15 ppm gave the greatest fresh and dry herb yield, the highest essential oil yield as well as improve the status of macro (N, P and K) and micro (Mn, Zn and Cu) nutrient content. The highest level of cobalt (30.0ppm) increased the principal components of menthone (37.84%), and isomenthone (15.19%) and this effect was companied with decreasing the relative content of L-(-)-menthol (20.54%). While low level (7.5 ppm) of cobalt recorded the highest content of L-(-)-menthol (28.54%) as compared with other treatment and control. Thus, the relatively high level of menthol in the peppermint oil suggests that a marketable peppermint essential oil could be successfully produced in newly reclaimed land of Egypt. Key words: Cobalt, peppermint, essential oil, newly reclaimed soil, macro and micro nutrient. INTRODCTION Mentha x piperita commonly known as peppermint is a popular medicinal plant. The major active constituent is volatile oil, which contains (-)-menthol (40%), (-)-menthone (20%) and (-)-menthyl acetate (10%) (Bauer et al., 1997). A relatively low level of salt in the growth media increased concentration of menthol in the peppermint oil (Aziz et al., 2008). As well as Aziz and Craker ( 2009) stated that the major components of peppermint essential oil grown in desert agro system were menthol (34.29%), isomenthyl acetate (30.47%), and ρ-menthone (15.61%). Mentha piperita L. is used for medicinal and food purposes (Lorenzi and Matos, 2002). Its cultivation has economic importance, peppermint essential oil ranks high in terms of total sales volume (Moraes, 2000). The main constituent is menthol, used in oral hygiene products, pharmaceuticals, cosmetics, and foods. Menthol also has high antifungal and antibacterial potentials, thus becoming one of the most demanded substances by the scents and essences industry (Souza et al., 1991). Menthol stimulates cold receptors in the respiratory tract, which inhibits cough and improves nasal airflow (Shah and Mello, 2005). The biosynthesis and metabolism of essential oil in mint species are strongly influenced by environmental factors (Piccaglia et al., 1993), such as temperature (Fletcher et al., 2005), photoperiod (Maffei and Codignola, 1990), nutrition (Zheljazkov and Margina, 1996), and salinity (Tabatabaie et al., 2007 and Aziz et al., 2008) . Cobalt is considered a beneficial element for higher plants in spite of the absence of evidence for direct role in their metabolism .It is an essential element for the synthesis of vitamin B, which is required for human and animal nutrition (Young, 1983 and Smith, 1991). Unlike other heavy metals, cobalt is saver for human consumption up to 8 mg can be consumed on a daily basis without health hazard (Young, 1983). It is known that certain inorganic trace elements such as vanadium, Zinc chromium, copper, iron, potassium, sodium and nickel play an important role in the malignance of normologycemia by activing the beta-cells of the pancreas. Thus the elemental composition in leaves of Murraya koeningii, Mentha piperita, Bcimum Sanctum, and Aegle marmelos widely used in treatment of diabetes-related metabolic disorders (Narendhirakannan et al., 2005). Maryam Mirza et al., (2004) stated that trace elements (Cu, Zn, Mn, Fe, Co, Ni, Cd, Pb, Cr, Ag, Na and K) in indigenous medicinal diuretic plants (Cymbopogon citrates, Raphanus sativus and Zea mays) have possible role in human health and disease. Pan Zuewu et al., (2004) reported that the addition of microelements (BO3 --- - MoO4 --, Co++, Cu++, Fe++ and Zn++ have important roles on the biosynthesis of comptothecin and growth of suspension cultures of comptotheca acuminate.

Corresponding Author: Eman, E. Aziz, Medicinal and Aromatic Plants Research Depertment, National Research Center(12622), Dokki, Cairo, Egypt. E-mail: [email protected]

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Aust. J. Basic & Appl. Sci., 5(11): 628-633, 2011

Mint is a plant that can become easily adapted to a variety of climate and soil conditions (Scora and Chang (1997)). However, Veronese et al., (2001) mentioned that mint and mint oil yield are modified by biotic and abiotic factors. Cobalt is a promising element in the newly reclaimed soils. Thus, the aim of this investigation was to study the effect of cobalt (0, 7.5, 15.0, 22.5 and 30.0 ppm ) on herb yield, essential oil production as well as macro and micronutrients contents of peppermint plant grown in newly reclaimed Soil. MATERIALS AND METHODS Soil Analysis: Physical and chemical properties of Nubaria Soil at Research and Production Station, National Research Centre was determined. Particle size distribution along with soil moisture of the soil sample were determined as described by Blackmore (1972). Soil pH, EC, cations and anions, organic matter, CaCO3, total nitrogen and available P, K, Fe, Mn, Zn, Cu were run according to Black et al., (1982). Determination of soluble, available and total cobalt was determined according to method described by Cottenie et al., (1982). Some physical and chemical properties of Nubaria soil are shown in Table (1) Plant Material and Experimental Works: Two field experiments were conducted during two successive seasons of 2008-2009 and 2009-2010 at Research and Production Station National Research Centre, Nubaria, Behira governorate, West of the Nile Delta of Egypt to evaluate the effect of different cobalt levels on growth, yield, essential oil content and composition as well as nutrient status of peppermint plants. On 15 on August, healthy rooted seedlings (45day old) of peppermint (Mentha piperita) were transplanted to the Experimental filed under drip irrigation system. Drip lines with 2 liter h-1 discharge rate at a spacing of 50 cm apart in 1 m wide beds at about 5 cm from each dripper were put directly on surface of each soil bed. The seedlings were planted in one row parallel to the drip lines at adjacent to water sources on the irrigated beds. The layout of the Experiment was randomized complete block design with three replicates. The experiment was consisting of 5 treatments i.e. 00, 7.5, 15.0, 22.5 and 30.0 ppm. Each treatment was represented by three plots. Each plot area was 5X3 meter, consisting of three rows. After one month from transplanted the seedlings were irrigated once with cobalt sulphate at the different levels. Organic manure, at 40 m3 ha-1, calcium super phosphate at 300 kg ha-1 and potassium sulfate at 150 kg ha-1 were added prior to planting as is customary for the region. The plants were harvested two times (in June and October) during two successive seasons. At each harvesting time, fresh and dry weights of herb (gm plant -1 and ton ha-1) were recorded. The obtained data were statistically analyzed according to to Snedcor and Conchran (1982). Table 1: Some physical and chemical properties of Nubaria soil. Physical properties Particle size distribution % Sand Silt Clay Soil texture 70.8 25.6 3.6 Sandy loam Chemical properties Soluble cations (meq-1L) pH EC Mg++ K+ Na+ CaCO3 OM Ca++ 1:2.5 (dS m-1) % % 8.49 1.74 3.4 0.20 0.8 0.5 1.6 1.80 Cobalt ppm

Total Available mg 100 g-1 soil Soluble Available Total N P K 0.35 4.88 9.88 15.1 13.3 4.49 FC (Field capacity), WP (Welting point), AW (Available water).

Fe 4.46

Soil moisture constant % Saturation FC WP 32.0 19.2 6.1

AW 13.1

Soluble anions (meq-1L) HCO3CO3 ClSO4= 0.3

-

1.9

Available micronutrients ppm Mn Zn 2.71 4.52

0.5

Cu 5.2

The essential oils percent of the fresh herbage were extracted by hydrodistillation in a Clevenger-type apparatus for 3 according to the Egyptian Pharmacopeia (1984). The essential oil extracted were dried over anhydrous sodium sulfate and analyzed by gas chromatography using a model Delsi 121C gas chromatograph (GC) fitted with a CPWA X 52 CB column (30 m x 0.32 mm; film thickness 0.25 µm). The oven temperature was programmed to rise from 50 °C to 300 °C at 4 °C/min and the injector and detector temperatures were set at 240 °C and 255 °C, respectively. The carrier gas was nitrogen at a flow rate of 1 mL min-1. Constituents were identified by coupling gas chromatography with mass spectrometry (GC/MS), using a Sigma 300 apparatus attached to a HP 5970 300 mass spectrometer. Macro (N, P and K) and micronutrients (Fe, Mn, Zn and Cu) along with cobalt were determined according to Cottenie et al., (1982).

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RESULTS AND DISCUSSION Vegetative Growth: Data presented in Table (2) showed that the addition of different Cobalt doses to the plant media had a significantly promotive effect on all growth parameters i.e. fresh and dry weights of peppermint herb (gm plant-1 and ton ha-1) for the two harvests compared to the control. Cobalt at 15.0 ppm gave the greatest fresh and dry herb yield (11.81 and 3.12 ton ha-1). Increasing cobalt more than 15.0 ppm gave the adverse effect. These data are harmony with those obtained by Nadia Gad (2005) who found that low level (7.5ppm) of cobalt may attributed to catalase and peroxidase activities which were enzymes are known to induce plant respiration, so superior resulting in successive consumption for products of photosynthesis and consequently reduced in plant growth. Moreover, low cobalt levels being with positive effect due to several induced endogenous hormonal (Auxins and Giberllens) synthesis and metabolic activity (Atta-Ali et al., 1991). While the higher cobalt doses were found to increase the enzymes activity such as peroxidase and catalase in plant and hence increasing the anabolism rather than catabolism (Nadia Gad, 1989). Yagodin and sablina (1989) showed improvement in the number and size of chloroplasteds as well as growth and area of cucumber leaves by application of low cobalt the rate of 0.5 ppm in solution culture. Liala Helmy and Nadia Gad (2002) found that cobalt at 25 mg kg-1 soil significantly increased fresh and dry weights of parsley leave. On the other hand, relatively high cobalt concentration reduced the growth of wheat plants and decreased chlorophyll content in the new leaves. Table 2: Effect of cobalt on vegetative growth of peppermint plants grown in newly reclaimed soil (mean of two seasons). Dry weight Total fresh Total dry Fresh herb Cobalt treatments Fresh weight gm plant-1 weight weight yield ppm gm plant-1 gm plant-1 gm plant-1 ton ha-1 1 cut 2 cut 1 cut 2 cut Control 113.40 329.57 25.52 84.72 442.97 110.24 9.57 7.5 118.40 385.80 34.27 97.77 504.20 132.03 10.89 15.0 142.50 404.37 41.65 102.94 546.87 144.59 11.81 22.5 135.23 391.57 31.59 99.40 526.80 130.99 11.38 30.0 131.57 387.93 29.57 96.53 519.50 126.09 11.22 LSD 5 % 0.40 1.54 0.53 0.66 1.73 0.74 0.04

Dry herb yield ton ha-1 2.38 2.85 3.12 2.83 2.72 0.02

Essential Oil Content: It was evident from data illustrated in Table (3) that the essential oil percent and the yield (ml plant-1 and l ha-1) were significantly affected with the application of different cobalt levels. Cobalt at 15 ppm recorded the highest values of the essential oil percent and yield (1.80 ml plant-1 and 38.95 lha-1), while increasing cobalt to 22.5 and 30 ppm caused significant reduction (31.55 and 26.65 lha-1, respectively) in the essential oil yield. Liala Helmy and Nadia Gad (2002) found that cobalt at 25 mg kg-1 soil significantly increased essential oil content of parsley leaves, moreover Nadia Gad et al., (2006) pointed that, cobalt is a promising element in the newly reclaimed soils such as Rass Seder, Egypt. Cobalt had a significant promotive effect on olive trees (Manzanello and Arbicon) growth, yield, fruits quality, endogenous hormones, and oil percent especial with organic fertilization. Table 3: Effect of cobalt on the essential oil content of peppermint plant grown in newly reclaimed soil (mean of two seasons). Oil yield Cobalt Treatment 1 cut 2 cut Total oil yield l ha-1 ppm ml plant−1 Oil% ml plant-1 Oil% ml plant-1 Control 0.17 0.19 0.21 0.69 0.88 19.03 7.5 0.21 0.24 0.24 0.91 1.16 25.01 15.0 0.31 0.44 0.34 1.36 1.80 38.95 22.5 0.25 0.34 0.29 1.12 1.46 31.55 30.0 0.23 0.30 0.24 0.93 1.23 26.65 LSD 5 % 0.01 0.02 0.02 0.07 0.08 1.68

Essential Oil Composition: Data illustrated in Table (4) showed that the essential oil of peppermint were characterized by a high content of menthone (35.39 - 37.84%), L-(-)- menthol (20.54% - 28.54 ), isomenthone (8.13% -15.19 ), and 1,8cineol (8.36 - 10.92) which represented about 80-83% of the peppermint oil. The data showed that the highest level of cobalt (30.0ppm) increased the principal component of menthone (37.84%), and isomenthone (15.19 %) and this effect was a companied with decreasing the relative content of L-(-)-menthol (20.54%). While low level (7.5 ppm) of cobalt recorded the highest content of L-(-)-menthol (28.54%) as compared with other treatments and control. During essential oil synthesis in M. piperita L., the isoprenoid pathway leads to the formation of geranil pyrophosphate, from which limonene is originated, next forming piperitenone which, in turn, forms pulegone, which can form menthone and/or menthofuran (Dey and Harbone, 1997, Croteau et al., 2000). Menthone forms neomenthol and menthol, which may undergo esterification and thus be converted into menthyl acetate (Murray,

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1972). Scora and Chang (1997) reported that menthone as a major component in M. piperita L. plants grown in soil with high Cd levels. Zheljazkov and Margina (1996), studying the application of increasing levels of N, P, and K fertilizers in M. piperita L., verified that the second highest essential oil component, after menthol, was menthyl acetate in all cultivars studied, with a mean percentage of 27.3%. An earlier greenhouse study demonstrated that salinization could affect the essential oil of peppermint plants subjected to a relatively low level of salt in the growth media increased concentration of menthol in the oil, but a relatively high level of salt in the media decreased the concentration of menthol in the oil (Aziz et al. , 2008). As well as Aziz and Craker (2009) stated that the major components of peppermint essential oil grown in desert agro system were menthol (34.29%), isomenthyl acetate (30.47%), and ρ-menthone (15.61%). Table 4: Effect of cobalt on the essential oil constituents of peppermint plant grown in newly reclaimed soil. Cobalt Concentration (ppm) Essential Oil Constituents Control 7.5 15.0 22.5 Myrcene 1.09 0.95 0.84 0.85 Linalool 2.24 2.54 2.07 2.41 1,8 cineol 10.92 9.44 8.48 8.36 Linalool oxid 0.25 0.22 0.40 0.26 Linalool trans 0.27 0.34 0.35 0.37 α terpinolene 0.43 0.44 0.40 0.40 Menthone 36.31 35.39 37.78 37.73 Isomenthone 10.96 8.76 8.13 10.86 Neo-menthol 0.19 0.24 0.35 0.25 L-(-)- menthol 24.65 28.54 26.06 26.26 Polegone 8.08 8.14 9.47 6.96 Piperitone oxide 0.63 0.68 0.89 0.77 Isomenthyl acetate 0.95 0.70 0.35 0.27 Nementhyl acetate 0.38 0.37 0.40 0.34 Caryophyllen oxid 0.39 0.34 0.36 0.33 Total identified 97.74 97.09 96.37 96.42

30.0 0.90 2.23 10.23 0.15 0.24 0.37 37.84 15.19 0.22 20.54 7.58 0.72 0.22 0.29 0.27 96.99

Nutritional Status in Plants: Macronutrients Content(N, P and K): Results presented in Table (5) show the effect of cobalt on the macronutrients content of peppermint herb. Data revealed that all cobalt levels significantly increased the content of N, p and K compared with the control plants. Confirm these results Basu et al., (2006). The highest values of N, P and K content were obtained by using cobalt dose at 15.0 ppm, as compared with other used levels. While, increasing cobalt concentration more than 15.0 ppm decreased the content of N, P and K in pepperment herbs compared with the control. These data are agreement with those obtained by Nadia Gad and Abd El and Moez (2011) who stated that cobalt had a promotive effect on N, P and K content of brocooli plants. While increasing cobalt dose gave the adverse effect. Cobalt Content: Increasing cobalt concentration in plant media increased cobalt content in peppermint herbs for two harvests as compared with untreated plants (Table 5). These results clearly indicated that cobalt content goes along with the concentration of added cobalt. The obtained results are in harmony with those obtained by Nadia Gad (2010) how found that increasing cobalt in plant media increased cobalt content in canola plants. Iron Content: Results presented in Table (5) indicated that, increasing cobalt concentration in the plant media resulted in a progressive depression effect on iron content in the peppermint herbs for two harvests. This may be explained on the basis of obtained results by Blaylock (1993) who showed certain antagonistic relationships between the two elements (Fe and Co). Manganese, Zn and Cu Content: Presented data in Table (5) revealed that cobalt at 15.0 ppm gave the highest values of Mn, Zn and Cu of peppermint herbs compared with the control and other cobalt levels. Conferm these results Laila Helmy and Nadia Gad (2002) indicated that addition of low Co level had a significant promotive effect for better status of Mn, Zn and Cu in coriander herbs. Aziz et al., (2007) stated that low cobalt dose (20mg kg-1 soil) posses a synergistic effect on the status of Mn, Zn and Cu in leaves and calyces of roselle plants. They added that higher cobalt dose had a hazardous effect. Finally, El- Kobbia and Osman (1987) added that, increasing cobalt level in the growth media increased cobalt content in both shoots and roots of tomatoes. They stated the there was an evidence that when plant roots absorb water soil solution containing cobalt moves from the non and rhizosphere soil towards roots by mass flow.

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Table 5: Effect of cobalt on mineral content of peppermint plants plant grown in newly reclaimed soil. Cobalt treatment (ppm) Macronutrients (%) Micronutrients (ppm) N P K Mn Zn Cu 1 cut Control 1.68 0.93 1.39 27.5 22.5 17.8 7.5 1.72 0.98 1.74 31.0 25.6 18.9 15.0 2.12 1.16 1.91 33.6 28.8 20.5 22.5 1.98 1.07 1.66 36.2 30.5 19.3 30.0 1.69 0.95 1.41 32.1 28.2 18.7 LSD 5 % 0.04 0.04 0.03 1.02 0.14 0.20 2 cut Control 1.85 0.84 0.78 25.1 20.5 18.8 7.5 1.94 1.00 1.38 29.3 23.8 20.9 15.0 2.36 1.17 1.89 32.6 26.4 22.6 22.5 1.88 0.83 1.32 35.4 29.1 21.0 30.0 1.62 0.65 0.98 33.0 25.3 19.4 LSD 5 % 0.06 0.01 0.02 2.14 0.26 0.60

Fe

Cobalt (ppm)

229 211 195 181 167 0.09

1.50 3.01 8.01 12.0 16.5 0.62

225 207 198 183 170 0.14

1.71 3.14 7.94 12.3 17.0 0.46

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