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Enhancing the Quality of Monoterpenes in (Cymbopogon nardus (L.) Rendle) Through Rhizobacteria Application Toward Sustained Soil Health

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Cymbopogon nardus is an aromatic plant which produces essential oil. Citronellal, citronellol, and geraniol as well-known as monoterpenes. The component of monoterpenes in this research were triggered by organic matter, such as organic manure and rhizobacteria. Organic fertilizers are used for environmentally friendly by maintaining soil and plant health and it’s necessary to achieve agricultural sustainability. Rhizobacteria are beneficial microorganisms for plants and soil for environmental management of both soil, plants, and soil micro biodiversity. Rhizobacteria contributes to soil fertilization through bio-fixation and bio-solubilization of essential nutrients along with the production of growth regulators. Microorganisms regulate the mechanism of absorption and mobility of nutrients in soil. The objective of this research is to investigate the effects of rhizobacteria and organic manure on the component of monoterpenes as well as the content of citronellal, citronellol, and geraniol. The results research show that C. nardus treated with rhizobacteria accumulating of nitrogen 1% and geraniol 5% in leaves which is more than those without rhizobacteria. Interestingly, content of citronellal and citronellol in leaves increased reach at 10% treated by without rhizobacteria and it higher than those supplied with rhizobacteria. In that case, citronellal, citronellol, geraniol formed from the carbon which was seems supplied by organic manure. Furthermore, rhizobacteria treatment shows a stable content of oil components in various rates of organic manure, but able to increase the oil yield at about 30% of C. nardus . Meanwhile, without supply of rhizobacteria, the result of oil yield relatively similar in various rates of organic manure. Regarding to the results, found that application of rhizobacteria able to increase the fresh weight, dry weight, and oil content. As consequently, contribution of rhizobacteria and organic manure to the mechanism of mineralization and improve soil health indirectly. Hence, plant able to uptake and accumulation nutrients in particular nitrogen, phosphorous and potassium.
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Enhancing the Quality of Monoterpenes in
(Cymbopogon nardus (L.) Rendle) Through
Rhizobacteria Application Toward Sustained Soil
Health
To cite this article: Sudiarso
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2024
IOP Conf. Ser.: Earth Environ. Sci.
1299 012007
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1st International Conference on Tropical Agroforestry in Indonesia
IOP Conf. Series: Earth and Environmental Science 1299 (2024) 012007
IOP Publishing
doi:10.1088/1755-1315/1299/1/012007
1
Enhancing the Quality of Monoterpenes in (Cymbopogon
nardus (L.) Rendle) Through Rhizobacteria Application
Toward Sustained Soil Health
Sudiarso1, Ferota Larasati1, Mochammad Roviq1, Andi Kurniawan1, Salvia
Salsabila1, Nunun Barunawati1*
1 Department of Agronomy, Faculty of Agriculture, Brawijaya University. Jl. Veteran,
Ketawanggede, Malang City, East Java, Indonesia. Tel. (0341) 565845,
E-mail: nnbarunawati.fp@ub.ac.id
Abstract. Cymbopogon nardus is an aromatic plant which produces essential oil. Citronellal,
citronellol, and geraniol as well-known as monoterpenes. The component of monoterpenes in
this research were triggered by organic matter, such as organic manure and rhizobacteria.
Organic fertilizers are used for environmentally friendly by maintaining soil and plant health and
it’s necessary to achieve agricultural sustainability. Rhizobacteria are beneficial microorganisms
for plants and soil for environmental management of both soil, plants, and soil micro
biodiversity. Rhizobacteria contributes to soil fertilization through bio-fixation and bio-
solubilization of essential nutrients along with the production of growth regulators.
Microorganisms regulate the mechanism of absorption and mobility of nutrients in soil. The
objective of this research is to investigate the effects of rhizobacteria and organic manure on the
component of monoterpenes as well as the content of citronellal, citronellol, and geraniol. The
results research show that C. nardus treated with rhizobacteria accumulating of nitrogen 1% and
geraniol 5% in leaves which is more than those without rhizobacteria. Interestingly, content of
citronellal and citronellol in leaves increased reach at 10% treated by without rhizobacteria and
it higher than those supplied with rhizobacteria. In that case, citronellal, citronellol, geraniol
formed from the carbon which was seems supplied by organic manure. Furthermore,
rhizobacteria treatment shows a stable content of oil components in various rates of organic
manure, but able to increase the oil yield at about 30% of C. nardus. Meanwhile, without supply
of rhizobacteria, the result of oil yield relatively similar in various rates of organic manure.
Regarding to the results, found that application of rhizobacteria able to increase the fresh weight,
dry weight, and oil content. As consequently, contribution of rhizobacteria and organic manure
to the mechanism of mineralization and improve soil health indirectly. Hence, plant able to
uptake and accumulation nutrients in particular nitrogen, phosphorous and potassium.
Keywords: C. nardus., Monoterpene, Nitrogen, Organic Manure, Rhizobacteria
1. Introduction
Cymbopogon nardus (L.) Rendle is a herbal plant that produce essential oil. C.nardus contains of main
oil components to determine quality and purity, such as citronellal, citronellol, and geraniol. These
components are secondary metabolites categorized to terpenoid group, which are synthesized through
1st International Conference on Tropical Agroforestry in Indonesia
IOP Conf. Series: Earth and Environmental Science 1299 (2024) 012007
IOP Publishing
doi:10.1088/1755-1315/1299/1/012007
2
monoterpene pathway. The essential oil contains monoterpene such as citral, geraniol, citronellol,
citronellal, linalool, elemol, 1,8 cineole, limonene, β caryophyllen, methyl heptonone, geranyl acetate,
and geranyl format from several species of Cymbopogon such kind C.nardus, C. citratus, and C. martinii
[1]. Monoterpenes accumulation in leaves can be induced by an organic material such as organic manure
and rhizobacteria. Organic manure is mineral sources contain essential nutrients for plant growth and
affects soil quality as well-known physical, chemical and biological properties. Nutrient availability in
soil can be improved through rhizobacteria supply. Earlier study by Leountidou [2], rhizobacteria
contribute to several mechanisms in the rhizosphere such as nutrient cycling, degradation of organic
matter, increasing soil fertility hence it encourages plant growth. The combination of organic manure
and rhizobacteria able to induce growth-promoting hormones in roots and the availability of nutrients
to stimulate plants growth and content of essential oil particularly in citronellal, citronellol, and geraniol.
Previous study by Liao [3] stated that rhizobacteria have positively correlates to plant biomass. Organic
manure in various rates on Cymbopogon martini shows that the total of biomass and essential oil
significantly increased [4]. The metabolism of medicinal plants can be increased by application of
organic manure which affect plant morphology and biomass [5].
Nutrient management through application organic material is one of the agricultural practices to
enhance essential oil components. The induction of monoterpene in C.nardus strongly depends on
growth phase and the availability of soil nutrients. Biosynthesis of essential oil from Cymbopogon
species is accumulating in young leaves, which are deeply influenced by the plant's development stage,
and environment factors like the nutrient availability. Converting the nutrients availability and
partitioning carbon as result of photosynthesis product into biomass and synthesis into secondary
metabolism [6]. The availability of main components of secondary metabolism gained from
photosynthesis directly affects essential oil synthesis. This research objectives is to investigate the
effects of rhizobacteria and organic manure on monoterpenes and obtain the optimal rate of organic
manure for C. nardus growth hence produce high quality of essential oil. Based on these considerations,
the management of environmental between C. nardus, rhizobacteria, and organic manure are expected
to improve the quality particularly in component of citronellal, citronellol, and geraniol.
2. Materials and Methods
The research was conducted from August 2021 to March 2022 in Experimental Garden of Agricultural
Faculty, Brawijaya University, Jatimulyo, Malang, with the altitude at about 460 meters above sea level.
The soil type at experimental locations is Andisols that the correct type of soil to C. nardus optimal
growth. The research method used Randomized Factorial Design with three-time repetitions. The first
factor is PGPR which contain some of microbes there are Rhizobium sp., Lactobacillus sp., Trichoderma
sp., Aspergillus sp., and Penicillium sp. Rhizobacteria treatment arranged with two different levels: P0:
Without Rhizobacteria dan P20: Supply of 20 mL plant-1 Rhizobacteria. The second factor is organic
manure with five levels there are K10: 10 t ha-1, K15: 15 t ha -1, K20: 20 t ha-1, K25: 25 t ha-1, K30: 30 t h-1.
The data was analysed using the variance analysis (F Test) with 5% level. If there is a significant effect,
then continue to use the DMRT test with 5% level.
The data observed in sixth month after planting, there is a dry weight parameter (g plant-1) because
of the separation process between leaves and roots, was placed in an oven at 80°C for 2 x 24 hours until
dry-stable weight. Fresh weight (g plant-1) was measured using a digital scale. Then, the oil yields was
observed by weighing 500 g of dry C.nardus at 6 months after planting and putting it into a distillatory
for 6 hours for each treatment. Afterward, the distilled oil was put into a bottle, recorded the results, and
calculated using the following formula below :
Oil Yield (%) = Oil Weight (kg)
Distilled Leaves Weight (kg) x 100%
Leaves area (cm2) was measured at first until sixth month after planting using LAM (Leaf Area
Meter) tools by putting each leaf in the device and recording the value of the leaves area displayed on
the device. Meanwhile, the measurement of nitrogen was carried out destructively at harvest in 6 MAP
by weighing 1 g of leaves, putting them into a Kjeldahl flask with a mixture of 1 g selenite and 5 mL
1st International Conference on Tropical Agroforestry in Indonesia
IOP Conf. Series: Earth and Environmental Science 1299 (2024) 012007
IOP Publishing
doi:10.1088/1755-1315/1299/1/012007
3
H2SO4, and destructed them at 300ºC. After the mixture was done, diluted it with 50 mL of H2O, added
20 mL of 40% NaOH, distilled it, and contained it with 20 mL of boric acid. The distillation was stopped
when the storage volume reached the limit of 50 mL, and the mixture turned green. The next step was
titration of the mixture with H2SO4 until burgundy color marked the titration endpoint and calculated
the total of nitrogen using the following formula:
Total N (%) = 𝑠𝑎𝑚𝑝𝑙𝑒 𝑚𝑙−𝑏𝑙𝑎𝑛𝑘 𝑚𝑙
𝑠𝑎𝑚𝑝𝑙𝑒 𝑤𝑒𝑖𝑔ℎ𝑡 x 0.14 x N. H2SO4 x 100 x Water Content
The observation of carbon was measureated in 6 MAP by weighing 1 g of C. nardus for every
treatment and putting it into Erlenmeyer tube to be mixed with 5 mL of K2Cr2O7 1 N solution before
shaking it. Afterward, 5 mL H2SO4 was added to the solution before being shaken again and set aside
for 30 minutes. Then 15 mL of aquadest and 5 mL of H3PO4 were added to the sample. Next, 1 drop of
diphenylamine was added. The sample underwent titration using FeSO4 1 N until the solution became
light blue. The following formula measures the C-organic content.
C-Organic= (𝑁 𝐾2𝐶𝑟2𝑂7 𝑥 𝑉 𝐾2𝐶𝑟2𝑂7)−(𝑁 𝐹𝑒𝑆𝑂4 𝑥 𝑉 𝐹𝑒𝑆𝑂4)
𝑠𝑎𝑚𝑝𝑙𝑒 𝑤𝑒𝑖𝑔ℎ𝑡 𝑥 0,77 x 0,33
Explanation:
N FeSO4 = FeSO4 concentration
N K2Cr2O7 = K2Cr2O7 concentration
V FeSO4 = FeSO4 volume
V K2Cr2O7 = K2Cr2O7 volume
The essential oil observation at harvest i.e. 6 MAP through distillation of leaves then extracted oil
use the oil dilution added N-Hexane as the diluent for oil composition analysis by GC-MS instrument
(QP-2010 Ultra/Shimadzu). C. nardus’s components test was done 6 months after the planting at Institut
Atsiri, Brawijaya University, Malang, using the steam distillation method. The C. nardus’s components
to test were citronellal, citronellol, and geraniol, and other component.
3. Result
3.1. The Biomass of Root and Shoot Ratio C. nardus
Ratio of C. nardus shoot and roots at 6 MAP presents in Figure 1. In general, without-rhizobacteria
(P0) and with-rhizobacteria (P20) present the ratio of dry weight of shoot (65%) and roots (35%) have
relatively same trend in both treatments. On treatment without rhizobacteria (P0), the shoot roots ratio
at K15, K25, and K30 have the same average range about at 45% to 55%. On the other hand,
rhizobacteria (P20) treatment on K25 and K30 show a higher percentage between shoot (45%) than roots
(55%) than other dosage of organic manure. In comparison, the ratio of shoot at K10, K15, and K20
show a lower percentage reach at about 60% and roots by 40% in average.
3.2. The Fresh Weight, Dry Weight, and Oil Yield
The average of fresh weight and dry weight (Figure 2) and oil yield of C. nardus presented in Figure 3
were measured at 6 MAP. Fresh weight (1970 g) and dry weight (508 g) without rhizobacteria (P0)
treatment shows relatively similar pattern at all various levels of manure. Supply of organic manure at
P0 treatment shows remind stable of dry weight as the biomass of plant, however the treatment of
rhizobacteria (P20) is able to increase dry weight and fresh weight by 30%, respectively. The maximum
dry weight 862 g and fresh weight 3185 g was reached at both K25 and K30 by 2 fold at 6 MAP.
The oil yield was produced at 6 MAP by C. nardus on rhizobacteria (P20) at K10 (1.94%) hold down
to K15 (1.62%), and the pattern was increased at K20, K25, and K30 at about 1.9%. While, without
rhizobacteria (P0) at K10 shows that minimum point of oil yield at 0.5% while 3-fold of oil yield reached
at K15, K20, and K30. Furthermore, the oil yield relatively reminds stable at P20 (K10, K20, and K25)
were reached 2.1%. The enhancement of fresh weight and dry weight were followed by increasing oil
yield trend on maximum rate of K25 and declined with adding 5 t ha-1 organic manure.
1st International Conference on Tropical Agroforestry in Indonesia
IOP Conf. Series: Earth and Environmental Science 1299 (2024) 012007
IOP Publishing
doi:10.1088/1755-1315/1299/1/012007
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Figure 1. The Percentage of Biomass on C. nardus’s Shoot and Root Ratio at 6 MAP
Figure 2. Fresh Weight and Dry Weight at 6 MAP of C. nardus
Figure 3. Oil Yield at 6 MAP of C. nardus
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
K10 K15 K20 K25 K30 K10 K15 K20 K25 K30
The Biomass of Root and Shoot
Ratio (%)
P0 P20
Root DW 6 MAP Leaf DW 6 MAP
0
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
K10 K15 K20 K25 K30 K10 K15 K20 K25 K30
Fresh and Dry Weight (g)
P0 P20
FW 6 MAP
DW 6 MAP
0
0.5
1
1.5
2
2.5
K10 K15 K20 K25 K30 K10 K15 K20 K25 K30
Oil Yield (%)
P0 P20
1st International Conference on Tropical Agroforestry in Indonesia
IOP Conf. Series: Earth and Environmental Science 1299 (2024) 012007
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doi:10.1088/1755-1315/1299/1/012007
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3.3. Leaves Area and Nitrogen Content of C. nardus
The observation of leaves area and nitrogen content in C. nardus at 6 MAP are present on Figure 4 and
5. In general, rhizobacteria treatment (P20) shows that increasing leaves area is followed by nitrogen
accumulation. Enhancing of leaves area at about 30.000 cm2 and nitrogen at 1.7% reach at K20 to K30
in respectively. Meanwhile, nitrogen content of K10 and K15 show a relatively remind stable at around
1.3%. Moreover, without rhizobacteria (P0), the leaves area reached at K25 and gradually enhance by
K10, K15, K20, and K30.
Nitrogen content in leaves is presented in Figure 5. Interestingly, rhizobacteria (P20) able to enhance
10% of nitrogen content reached by K30. Meanwhile, the rate of organic manure K10, K15, K20, and
K25 had the similar trend of nitrogen content with P0 in average 1.3%.
3.4. Carbon
Figure 6 presents of carbon content on C. nardus's leaves. The carbon content without rhizobacteria (P0)
shows that the application of various levels of organic manure incline at about 30% carbon in leaves
compared to P20. While the treatment of rhizobacteria (P20) shows the same pattern of carbon content
particularly 1.50% in average. Interestingly, the treatment of K10, K25, and K30 are two folds increase
compared to the treatment rate of K15 and K20 at about 30%.
3.5. Oil Components
The C. nardus oil components, such as citronellal, citronellol, and geraniol are presented in Figure 7. In
general, both of treatments without-rhizobacteria (P0) and with-rhizobacteria (P20) have a higher
citronellal 20% compared to the other components. Furthermore, the citronellol component have the
same range of 15.95-16.83% with rhizobacteria (P20) or without rhizobacteria (P0). By contrast,
rhizobacteria (P20) produces the oil components relative stable at all various rates of organic manure.
Interestingly, citronellal level gradual increases with adding 5 t ha-1 of organic manure reach at 40,38%
in K30.
Figure 4. Leaves Area (cm2) C. nardus at 6 MAP
0
5000
10000
15000
20000
25000
30000
K10 K15 K20 K25 K30 K10 K15 K20 K25 K30
Leaf Area (cm2)
P0 P20
1 MAP
2 MAP
3 MAP
4 MAP
5 MAP
6 MAP
1st International Conference on Tropical Agroforestry in Indonesia
IOP Conf. Series: Earth and Environmental Science 1299 (2024) 012007
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doi:10.1088/1755-1315/1299/1/012007
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Figure 5. Nitrogen Content (%) in C.nardus leaves at 6 MAP
Figure 6. Carbon Content of C.nardus at 6 MAP
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
K10 K15 K20 K25 K30 K10 K15 K20 K25 K30
Carbon Content (%)
P0 P20
1st International Conference on Tropical Agroforestry in Indonesia
IOP Conf. Series: Earth and Environmental Science 1299 (2024) 012007
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Figure 7. Citronellal, Citronellol, and Geraniol Oil Levels in Citronella
4. Discussion
The measurement of nitrogen content has the same trend under rhizobacteria (P20) and increased while
supplying of organic manure. It was showing an increasing nitrogen content followed by expand of
vegetative plant, such as leaves area, fresh weight, and dry weight. By contrast, without rhizobacteria
(P0), present in fluctuated trends of leaves area obtains under all dosages of organic manure. The
nitrogen in leaves is required and converted to form of vegetative organs immediately during 3 and 4
MAP, hence, the leaves formed completely to formulate secondary metabolites. The organic manure
indirectly affects to observation variables in this research which have a role in nutrients availability.
However, organic manure provides nutrients is relatively slow availability, hence rhizobacteria can take
role nutrients uptake by plant through produce some hormones. Address to Hasan [7], stated that
rhizobacteria colonization trigger plant development, such as hormones indole-3-acetate, cytokinin, and
gibberellin by the roots. Furthermore, higher rhizobacteria population tend to enrich mineralization and
nutrition availability much earlier in rhizosphere by dissolved phosphates, oxidation of sulphur, and
availability of ammonium. Refers to Bhardwaj [8] stated that inoculation of rhizobacteria directly on
rhizosphere affect to nutrients absorption mechanism through several mechanisms, such as nitrogen
fixation, mineralization of organic compounds, and dissolution of mineral nutrients. Meanwhile, it
supported and triggered by the ion absorption system, accessibility, and concentration of nutrients in
the roots [9] as well as plant growth and productivity [10]. The result of research present that the
biomass significantly increased under treatment of organic manure at 6 MAP. It might be occurred due
to the primary metabolism closely related to carbohydrate formed in leaves and it converted to organ
of plant. Based on El-Sayed [11], mentioned that the influence of organic manure enhances plant height
due to the nitrogen level may be a precursor of hormones to formed protein synthesis for cell elongation.
Regard to Nandapure [12], C. nardus is a kind of plant which able to produce and accumulate biomass
rapidly five months after planting, even though nutrients uptake reach maximum around at ten months.
It was clearly that increasing biomass following by the carbon accumulation which continue to synthesis
monoterpenes as secondary metabolites. The application of organic manure encourages the proliferation
of soil microbes and inducing root lateral hence increases the biomass of the root system which
following by carbon content accumulation [13]. Rhizobacteria simultaneously involves in various
stages of plant growth, such as germination until harvest phase [14]
The cultivation of aromatic plants with organic fertilizers can improve soil health and determine
factor for quality of essential oils [15]. Rhizobacteria was added to roots contained bacteria and fungi,
there are Rhizobium sp., Lactobacillus sp., Trichoderma sp., Aspergillus sp., and Penicillium sp.
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
K10 K15 K20 K25 K30 K10 K15 K20 K25 K30
Oil Content (%)
P0 P20
Citronellal Citronellol Geraniol
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IOP Conf. Series: Earth and Environmental Science 1299 (2024) 012007
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Microorganism in rhizobacteria play a role the mechanism of absorption and mobility of nutrients. In a
previous study conducted by Kutlu [16], PGPR inoculation with various bacterial strains increased such
kind fresh weight, dry weight, and essential oil yields in (Origanum onites L.). Based on our research,
we also found the same results, fresh weight, dry weight, and oil content increased after PGPR added
compared without PGPR. Nurzynska-Wierdak [15], states the availability of essential nutrients N, P, K,
Ca, and Mg effect on composition of essential oils particular like citronellal, citronellol, and geraniol.
The role of rhizobacteria support the dissolution of nutrients, especially Nitrogen and Phosphorus in the
soil thus it impacts on growth and induction of oil components in aromatic plants. Nutrient absorption
in aromatic plants will trigger oil biosynthesis and affect to plant growth characteristics [17,18].
The accumulation of macronutrients N, P, K are limiting factors which had a role particular on plant
metabolism, as well known forming of tissue, organs, and converting primary products to secondary
metabolism. Indeed, nutrient status such as nitrogen content in leaves and accumulation of
monoterpenes, such as citronellal, citronellol, and geraniol, were influenced by the availability of soil
nutrients and nutrient accumulation in leaves [19]. In this case, the nutrients include an essential macro
nutrient, as nitrogen. The average accumulation of nitrogen reached at about 10% in leaves by
rhizobacteria (P20) at all dosage levels. Carbon and nitrogen regulate on modulating plant growth and
development, as organic manure compound which is required rhizobacteria form to be energy. Organic
matter had manipulated and provide condition in term storage of water, which induce vegetative plant
growth as well as secondary metabolites such kind monoterpenes [20]. Internal factors of plant
morphology such leaves area, clearly contributes in biomass accumulation. It assumed that there is
interrelationship between carbohydrates and monoterpenes as secondary metabolism [21]. Therefore,
much higher accumulation of biomass result substrate availability for monoterpenes biosynthesis [22].
The secondary metabolite pathway involves precursors, co-factors, energy (ATP), (NADPH) from
primary metabolism [23]. The glycolysis of carbohydrates leads to the production of ATP and reduce
nucleotides, and substrates for monoterpene biosynthesis as well as the abundant carbon, thus will be
synthesized into secondary metabolism such kind citronellal, citronellol, and geraniol. Therefore,
regards to Santoro [24], the availability of nutrients obtained from rhizobacteria inoculation enhance
indirectly photosynthetic efficiency and primary metabolism accumulation, which results to enrich
secondary metabolite concentrations such kind of essential oils.
The low percentage of oil yield closely related to density of C. nardus oil. By contrast, the high oil
component of C. nardus was not correlated by the percentage of oil yield. Deeply stated by Rochim
[25], the higher production of oil yield causes lacks quality of C. nardus oil. Metabolism and synthesis
of essential oils are rapid during early growth and development of young leaves in C. nardus. Based on
Mukkaram [26], research clearly that young plant tissues had more essential oils compared to old leaves.
Moreover, plant phase development affects to biosynthesis and accumulation of essential oils. In
previous research conveyed by Gershenzon [27], the trend of monoterpenes accumulation in Peppermint
increases rapidly in young leaves for 21 days at the stage of leaf development. In addition Cymbopogon
sp. monoterpenes patterns accumulation enhanced in young leaves as well as in the Lamiaceae family
[28]. Address to another investigation by Gupta and Ganjewala [29], a large amount of essential oil in
lemongrass plays a role by actively biogenetic young leaves and leaves position include anabolic and
catabolic processes. Therefore, the role of monoterpenes metabolism regards to Moser and Pichler [30],
induced by the formation of terpenoid isopentenyl diphosphate (IPP) and dimethylallyl diphosphate
(DMAPP) as precursor through carbon sources. It was triggered by the esterase enzyme which can
convert geranyl acetate. Thus, two biosynthetic pathways by Abdallah and Quax [31], involve the 2C-
methyl-D-erythritol-4-phosphate (MEP) pathway which is known well as the 1-deoxy pathway-D-
xylulose-5-phosphate (DXP) pathway and mevalonate pathway (MVA). In MVA pathway, the
formation of IPP precursors is obtained and delivered to the formation of monoterpenes higher in young
leaves. Meanwhile, the acetate pathway enzyme MVA mevalonate-5pyrophosphate (MVAPP and
PMD) decarboxylase occurs strongly influenced by environmental conditions such as soil microbes’
population. Supply of organic manure and rhizobacteria in C. nardus indirectly trigger mineralization
in soil, hence the large uptake of nutrient by plants. Furthermore, plants are able to absorb nutrients
1st International Conference on Tropical Agroforestry in Indonesia
IOP Conf. Series: Earth and Environmental Science 1299 (2024) 012007
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doi:10.1088/1755-1315/1299/1/012007
9
rapidly during growth and development while rhizobacteria supply. Evidently, in this result research
shows that monoterpenes remain stable in leaves under rhizobacteria application. Carbon and
macronutrients are used in two kinds of metabolism as well-known primary and secondary metabolism.
During the plant growth phase, nitrogen and carbohydrates initiate monoterpenes biosynthesis, and those
depend on resources and utilization by partitioning of primary secondary metabolism. Address to
Anggraini [32], that the production of primary and secondary metabolites used carbon and
macronutrients such as nitrogen, phosphorus, and potassium in plants are closely interlinked. This result
is supported by Thirumurugan [33] and Cui [34], that sufficient nutrients, particularly carbon and
nitrogen, clearly induce the synthesis of primary and secondary metabolites.
Obviously, monoterpene components namely citronellal, citronellol, and geraniol, were found to be
like this research results, which were observed under the same conditions. Supported by Ganjewala and
Gupta [35], stated that the MEP (Methyl erythritol) pathway, IPP in plastids will be synthesized into
components of citronella, namely citronellall, citronellol, and geraniol. Indeed, besides being formed
into oil components, IPP is formed into other products such as chlorophyll, carotenoids, and growth
regulators. Therefore, plant secondary metabolites tend to be the same and deeply influenced by carbon
content in leaves and nutrient availability in rhizosphere
Acknowledgements
The authors would like to grateful the Professor Grant Project 2021, Faculty of Agriculture, Brawijaya
University, Malang for the research grant.
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ResearchGate has not been able to resolve any citations for this publication.
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