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Not Sci Biol, 2011, 3(1):46-50
Print ISSN 2067-3205; Electronic 2067-3264
Notulae Scientia Biologicae
Light Absorption and Carotenoid Synthesis of Pot Marigold (Calendula
officinalis L.) in Response to Phosphorous and Potassium Varying Levels
Mohammad SEDGHI1 , Alireza PIRZAD2 , Bahman AMANPOUR-BALANEJI3
1University of Mohaghegh, Faculty of Agriculture, Department of Agronomy and Plant Breeding; firstname.lastname@example.org
2University of Urmia, Faculty of Agriculture, Department of Agronomy and Plant Breeding, Urmia, Iran; email@example.com
3Young Researchers Club of Islamic Azad University, Urmia branch, Urmia, Iran; firstname.lastname@example.org
In order to provide additional information on the effects of elemental deficiency on factors that affect plant production in medicinal
plants, a factorial field experiment as randomized complete block design was conducted on Calendula officinalis. Treatments were four
phosphorus levels (P2O5) including 0, 40, 80 and 120 Kg ha-1 and four potassium levels (K2O) as 0, 50, 100 and 150 Kg ha-1. Results
showed that applied treatments had significant effects on petal carotenoids and the highest amount of β - carotene obtained at 80 and
150 Kg ha-1 P2O5 and K2O, respectively. Effect of K2O on light interception and light use efficiency was significant and the highest
radiation use efficiency achieved by applying 150 Kg ha-1 K2O. The highest yield of grain and dry flowers was recorded in the mixture of
80 and 150 Kg ha-1 P2O5 and K2O, respectively. In conclusion, using of K2O had greater effects on studied traits than P2O5.
Keywords: carotenoids, light extinction coefficient, light interception efficiency, pot marigold
Calendula officinalis (pot Marigold), belongs to Aster-
aceae family, is an annual herb with yellow to orange flow-
ers, native to Mediterranean region (Gazim et al., 2008).
Pot Marigold is cultivated for its flowers with receptacle
or flowers without receptacle (Varban et al., 2008) which
are used as the medical raw material. The flower contains
essential oils which are used for high blood-fat and treat-
ment of inflammation intestine organs (Mrda et al., 2007).
It strengthens the organism immunity. Active ingredient
contents reported previously for C. officinalis flowers are:
flavonoids, carotenoids, ethereal oils, triterpenic saponos-
ins, calenduloside, phytoncids, tannins, resins, slime, gly-
cosides, C vitamin and organic acids (Mrda et al., 2007).
Cultivation of medical plants has advantages in rela-
tion to assembling the medical plants from the nature.
There is the production of the pure, flat rate and quality
medical raw material. It can be accomplished by choosing
the right plant species, right cultivars, soil, with the appro-
priate practical measures, with the optimal sowing date,
the right plant nutrition, harvest, drying and etc. There are
more advantages, like the high yield, possibility of the pro-
fessionally supervision, obtaining the quality row material
without additive and impurity (Mrda et al., 2007).
At the present time, fertilizers are applied to almost
every crop that is grown commercially. Most of the stud-
ies investigating fertility and plant nutrition have focused
on nitrogen, and its requirements as well as it effects in
the plants response to increased nitrogen rates are well
known (Everet and Subramaya, 1983; Jones et al., 1988).
Few studies examining phosphorus and potassium fertil-
ity in pot Marigold have been conducted, but they are not
specific to the medicinal use of this plant. Potassium is one
of the three major essential nutrient elements required
by plants. Unlike nitrogen and phosphorus, potassium
does not form bonds with carbon or oxygen, so it never
becomes a part of protein and other organic compounds
(Hoeft et al., 2000). Phosphorus functions cannot be per-
formed by any other nutrient, and an adequate supply of P
is required for optimum growth and reproduction. Phos-
phorus is classified as a major nutrient, meaning that it is
frequently deficient for crop production and is required
by crops in relatively large amounts. It is a part of several
key plant structure compounds and as catalysis in the con-
version of numerous key biochemical reactions in plants.
Phosphorus is noted especially for its role in capturing and
converting the sun’s energy into useful plant compounds.
Phosphorus is a vital component of ATP, the “energy unit”
of plants. ATP forms during photosynthesis, has phospho-
rus in its structure, and processes from the beginning of
seedling growth through to the formation of grain and ma-
turity. Thus phosphorus is essential for the general health
and vigor of all plants. Some specific growth factors that
have been associated with phosphorus are: stimulated root
development, increased stalk and stem strength, improved
flower formation and seed production, more uniform and
earlier crop maturity, improvements in crop quality, and
increased resistance to plant diseases (Taiz and Zeiger,
Received 07 November 2010; accepted 11 February 2011
Sedghi, M. et al. / Not Sci Biol, 2011, 3(1):46-50
That “I0” is the light intensity (µmol photon m-2 min-1)
at the canopy surface and “I” is the light intensity at soil
Light extinction coefficient (K) was calculated based
on Lambert- Beer law as fallow:
I/I0 = e –K(LAI)
Which, “e” is the natural logarithm.
Radiation use efficiency (RUE) was calculated as be-
low (Rosenthal et al., 1993):
RUE = DM / I
That, DM is the dry matter of canopy.
Petal cartenoids were measured by gas chromatography
(GC) model G890N (Agilent Technologies, USA).
Element absorption affinity (Km) was calculated ac-
cording to Thomaz et al. (2007) by modified Michaelis-
Petal yield was determined at flowering by harvesting
the 0.5 m-2 of each plot, and drying at 45°C for 24 h.
Collected data was subjected to normality test before
analysis of variance (ANOVA). ANOVA procedure was
performed by SAS 9.1 and mean comparison was done us-
ing Duncan’s Multiple Range Test (DMRT).
Results and discussion
Light Interception Efficiency (LIE)
Analysis of variance showed that only the simple effect
of K2O is significant on LIE as shown in Tab. 2. LIE is the
amount of light absorbance by specific leaf area that is ca-
pable to do work. The higher LIE (0.64) achieved by using
150 kg ha-1 K2O (Fig. 1).
Vijay et al (2009) investigated the effects of different
dosages of NPK fertilizers on growth and constituents
of Asparagus racemosus. They found that P and K at the
highest concentration had the maximum effect on dry
matter, carbohydrate, protein and sapogenin increasing in
this plant root tubers. They concluded that NPK had the
positive effect on photosynthesis and increasing of pho-
tosynthates which were stored in root tubers. Mandal et
al. (2008) studied the effect of NPK on Isabgol (Plantago
ovata) seed yield and leaf phenols. Results showed that
only N and K had significant effects on leaf phenols, but
seed yield only affected by Thomaz et al. (2007) studied
the effect of phosphorus and nitrogen amendments on the
growth of Egeria najas. They concluded that both N and
P has sharp effects on relative growth rate of this aquatic
plant and N uptake was more crucial than P.
As the combining effect of P and K has been rarely
studied in the literature especially in pot Marigold and on
the base of best of our knowledge there are no reports in
this area, an experiment conducted to determine the ef-
fects of P and K on light use and metabolite production in
pot Marigold and invigorative effects of these elements on
Materials and methods
Field experiment carried as factorial based on complete
block design arrangement with three replications at the re-
search farm of university of Mohaghegh Ardabili, Ardabil,
Iran. Seeds of C. officinalis obtained from the Pakan Bazr
Company, Isfahan, Iran. Soil analysis result for this region
was presented in Tab. 1. Treatments were phosphorus
(P2O5) levels as control, 40, 80 and 120 kg ha-1 and potas-
sium fertilizer (K2O) with four levels as control 50, 100
and 150 kg ha-1.
Radiation intensity at canopy and soil surfaces was
measured by Sun Scan instrument (model BF3, Delta-T
devices, UK). Leaves area was measured by portable leaf
area meter and leaf area index was calculated by the for-
LAI = LA/S
That “LA” is the leaves area and “S” is the ground sur-
face that covered by leaves.
Light interception efficiency (LIE) was calculated with
the formula proposed by Board and Harville (1992), as
LIE = LI/LAI
“LI” is the light interception by canopy that was calcu-
lated according to Purcell et al (2002):
LI = 1- (I/I0)
Tab. 1. Physiochemical properties of the soil in experimental field
7008.20 silty loam
Fig. 1. Effect of different potassium rates on the percentage of
light interception efficiency (LIE) in C. officinalis
Sedghi, M. et al. / Not Sci Biol, 2011, 3(1):46-50
LIE is low just before canopy closure and then will
reach to maximum rate. In this point increasing leaf area
has negative effect on LIE, because to shading of downer
leaves (Fig. 2). There was a negative relation between LAI
and LIE, so with increasing LAI, LIE was decreased. In-
creasing LAI, to about 4.5 did not decrease LIE, but it is
expected that in higher LAI than 4.5, there will be a reduc-
tion in LIE.
Radiation use efficiency (RUE)
Simple effect of K2O was significant on RUE (Tab. 2).
RUE is the explanatory parameter of dry matter produc-
tion per intercepted radiation unit (Purcell et al., 2002).
Comparison of means showed the highest RUE (1.64) by
applying 150 kg ha-1 K2O (Fig. 3). It means that each MJ
light energy m-2 can produce 1.64 g of dry matter. Agele et
al. (2007) demonstrated that RUE for many plants is 1.2-
1.7 g MJ-1 m-2. Likely, applying K2O enhanced the LAI and
this can increase RUE. Relation between LAI and RUE
(Fig. 4) indicates that increasing LAI to 4.5 can raise RUE,
but more LAI may cause a sharp decline in RUE.
Light extinction coefficient (K)
Effect of K2O on “K” was significant (Tab. 2). The
highest value of “K” was associated with 150, and 100 kg
ha-1 (respectively, 0.73 and 0.71) that were not significantly
Tab. 2. Analysis of variance for the effects of potassium and phosphorus on the studied traits of C. officinalis in the field
Mean of squares
Flower dry yield
K β -carotene
* and ** indicating the significant differences at 5 and 1 percent probability levels
Fig. 2. Regression relation between leaf area index (LAI) and
light interception efficiency (LIE) in C. officinalis
Fig. 3. Effect of different potassium rates on radiation use effi-
ciency (RUE) in C. officinalis
Fig. 5. Effect of different potassium rates on light extinction co-
efficient (K) in C. officinalis
Fig. 4. Regression relation between leaf area index (LAI) and
radiation use efficiency (RUE) in C. officinalis
Sedghi, M. et al. / Not Sci Biol, 2011, 3(1):46-50
different (Fig. 5). K2O had positive and invigorative effect
on LAI development so, light transmittance to soil surface
decreased. In other words, only 27 and 29 percent of up
canopy light reach to the soil surface. Fig. 6, indicates the
relation between “K” and LAI.
Light intensity decreases from up layers of canopy to
soil surface due to absorbance and reflectance of light by
leaves. This reduction is described by Lambert-beer law.
Accordingly, each layer with the same thickness can ab-
sorb the equal light that it transmits.
Element absorption affinity (km)
The highest relative growth rate (RGR) in the absence
of K2O, was recorded in 120 kg ha-1 P2O5 (RGR=0.127).
From Michaelis-Menten equation, the value for “km” in
presence of P2O5 was 11.27 mg g-1, while this value in the
presence of K2O was 3.48 mg g-1. It is concluded that pot
Marigold has more affinity to K2O than P2O5. “Km” is an
indicator of plant growth with each unit of nutritional ele-
ment, or it is the affinity of plant to absorb a specific nutri-
ent. If plant requires an element, it will absorb that with
great rate from soil solution. The higher affinity is associ-
ated with the smaller “km” (Thomaz et al., 2007).
Simple effects of K2O and P2O5 and their interaction
were significant on petal carotenoids (Tab. 2). The highest
amount of carotenoids was obtained by the application of
80 and 150 kg ha-1 P2O5 and K2O, respectively (Tab. 3).
Biochemical analysis of petals for carotenoids showed that
flavenoxanthin had the highest percent then followed by
luteoxanthin. K2O was more effective than P2O5 in caro-
Borna-Nasrabadi (2006) demonstrated that mixture
of NPK fertilizer increased essential oils of Silybum mari-
anum, but higher amounts of these elements had negative
effects. Naguib et al. (2005), found an increase in essential
oils of pot Marigold with different micronutrients. Man-
dal et al. (2008) showed that potassium can increase the
amount of phenols in Plantago.
Dry flower yield
Interaction between P2O5 and K2O on dry flower yield
of pot Marigold was significant (Tab. 2). The highest yield
(0.16 kg m-2) achieved by 120 kg ha-1 P2O5 + 100, and 150
kg ha-1 K2O that was not different from 80 kg ha-1 P2O5 +
100, and 150 kg ha-1 K2O (Tab. 3).
Tab. 3. Comparison of means for essential oils and yield of pot marigold as affected by interaction of K and P using Duncan’s
multiple range test (p≤0.05)
(kg m -2)
means with different letters in each column are different significantly at p<0.05
Fig. 6. Regression relation between leaf area index (LAI) and
light extinction coefficient (K) in C. officinalis
Sedghi, M. et al. / Not Sci Biol, 2011, 3(1):46-50 Download full-text
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