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Abstract

Potassium (K) influences the variables that determine quality of fruit and the concentration of phytonutrients to human health and therefore consumer preferences. The objective of this study was to evaluate the effect of different concentrations of K in the nutrient solution (5, 7, 9 and 11 mM of K) on yield and quality of Cantaloupe fruits under greenhouse conditions. The experiment was conducted in pots using a completely randomized design with 15 replications. Analysis of variance, correlation, regression and multiple comparisons among means (Tukey p<0.05) were performed. Results showed higher values of yield, average fruit weight, equatorial diameter, pulp thickness, fruit firmness, soluble solids content, phenolic content and antioxidant capacity of fruits at the concentrations of 9 and 11 mM of K. All variables, except equatorial diameter, increased their values as K concentrations increased, showing a lineal, positive and significant trend, which evidences that the optimal dose of K in muskmelon is higher than 11 mM, being suggested for future research, to evaluate concentrations above this value.
184
Research
Hortic. bras., Brasília, v.36, n.2, April - June 2018
The Cucurbitaceae family, which
includes cucumbers, pumpkins,
muskmelons, squash and pumpkins,
consists of hundreds of wild
and cultivated varieties. Of these,
muskmelon (Cucumis melo) is an
important horticultural crop in arid
and semi-arid regions, due to its good
adaptation to the soil and climatic
conditions (Kusvuran et al., 2012),
with a total annual production of 31.92
million tons (FAOSTAT, 2014).
However, production under field
conditions focuses in a few weeks,
mainly due to climatic factors, then, to
extend the availability of this product
in the market, it is necessary to use
other production methods (Arellano et
al., 2011).
In this situation, horticultural
production under protected systems is an
alternative to traditional eld production,
especially in highly profitable crops
(Pardossi et al., 2002). The development
of muskmelon plants under greenhouse
conditions compared to those developed
in eld, have many advantages such
as precocity, yield increases and water
use and fertilizer eciency (Preciado-
Rangel et al., 2011).
The low restrictive environment and
the increase of fertilization especially
nitrogen, allows high yields (Preciado-
Rangel et al., 2011); however, this
decreases the nutraceutical quality,
because of when there is no deficit
of nitrogen (N) the production of
compounds such as amino acids,
proteins, and alkaloids that contain N
increased (Hallmann & Rembiałkowska,
2012). Therefore, researches of the
factors that enhance the nutraceutical
PRECIADO-RANGEL, P; SALAS-PÉREZ, L; GALLEGOS-ROBLES, MA; RUIZ-ESPINOZA, FH; AYALA-GARAY, AV; FORTIS-HERNÁNDEZ, M;
MURILLO-AMADOR, B. 2018. Increasing doses of potassium increases yield and quality of muskmelon fruits under greenhouse. Horticultura Brasileira
36: 184-188. DOI: http://dx.doi.org/10.1590/S0102-053620180206
Increasing doses of potassium increases yield and quality of muskmelon
fruits under greenhouse
Pablo Preciado-Rangel1; Lilia Salas-Pérez2; Miguel Á Gallegos-Robles3; Francisco H Ruiz-Espinoza4; Alma
V Ayala-Garay5; Manuel Fortis-Hernández1; Bernardo Murillo-Amador6
1Instituto Tecnológico de Torreón, Coahuila, Mexico; ppreciador@yahoo.com.mx; fortismanuel@hotmail.com; 2Universidad Politécnica de
Gómez Palacio, Torreón, Mexico; lilia-nt@hotmail.com; 3Universidad Juárez del Estado de Durango, Durango, Mexico; garoma64@hotmail.
com; 4Universidad Autónoma de Baja California Sur, Baja California Sur, Mexico; fruiz@uabcs.mx; 5Instituto Nacional de Investigaciones
Forestales, Agrícolas y Pecuarias, Texcoco, Mexico; ayala.alma@inifap.gob.mx; 6Centro de Investigaciones Biológicas del Noroeste, Baja
California Sur, Mexico; bmurillo04@cibnor.mx; (autor para correspondencia)
ABSTRACT
Potassium (K) inuences the variables that determine quality of
fruit and the concentration of phytonutrients to human health and
therefore consumer preferences. The objective of this study was to
evaluate the eect of dierent concentrations of K in the nutrient
solution (5, 7, 9 and 11 mM of K) on yield and quality of Cantaloupe
fruits under greenhouse conditions. The experiment was conducted
in pots using a completely randomized design with 15 replications.
Analysis of variance, correlation, regression and multiple comparisons
among means (Tukey p<0.05) were performed. Results showed higher
values of yield, average fruit weight, equatorial diameter, pulp
thickness, fruit rmness, soluble solids content, phenolic content and
antioxidant capacity of fruits at the concentrations of 9 and 11 mM of
K. All variables, except equatorial diameter, increased their values as
K concentrations increased, showing a lineal, positive and signicant
trend, which evidences that the optimal dose of K in muskmelon is
higher than 11 mM, being suggested for future research, to evaluate
concentrations above this value.
Keywords: Cucumis melo, plant nutrition, nutraceutical quality.
RESUMO
Incremento de doses de potássio favorece a produtividade e
qualidade de melão em casa de vegetação
O potássio (K) inuencia as variáveis que determinam a qualidade
dos frutos e a concentração de tonutriente para a saúde humana e,
portanto, as preferencias do consumidor. O objetivo desse estudo foi
avaliar o efeito de diversas concentrações de K na solução nutritiva
(5, 7, 9 e 11 mM de K) sobre o rendimento e qualidade de frutos de
melão Cantaloupe em casa de vegetação. O experimento foi realizado
em vasos, em delineamento experimental completamente casualizado,
com 15 repetições. Foram analisadas a variância, correlação, regres-
são e comparação múltipla de médias (Tukey p<0,05). Obtiveram-se
valores maiores de produtividade, peso médio de frutos, diâmetro
equatorial, espessura da polpa, rmeza da polpa, teor de sólidos so-
lúveis totais, teor de compostos fenólicos e capacidade antioxidante
dos frutos nas concentrações de 9 e 11 mM de K. Todas variáveis, com
exceção de diâmetro polar dos frutos, tiveram seus valores aumen-
tados, com concentrações crescentes de K, evidenciando tendência
linear positiva e signicativa, indicando que a dose ótima de K em
melão é superior a 11 mM. Assim, sugere-se para pesquisas futuras,
avaliar concentrações acima de 11 mM..
Palavras chave: Cucumis melo, nutricão vegetal, qualidade
nutracêutica.
Received on November 9, 2016; accepted on December 10, 2017
185Hortic. bras., Brasília, v.36, n.2, April - June 2018
content of fruit were promoted (Navarro
et al., 2006). In particular, total phenols
have a high antioxidant capacity, highly
desirable nutraceutical characteristic
that can contribute to improved health
(Fischer et al., 2013; Rinaldi et al.,
2013). Therefore, a high content
of phenols and antioxidants, allow
greater competitiveness in domestic
and international markets; however,
studies using dierent K concentrations
in the nutrient solution and quality of
muskmelon were not found.
Muskmelon has low fat and sodium
(Na) content, no cholesterol and
provides many essential nutrients such
as potassium (K), besides being a rich
source of beta-carotene and vitamin C.
The factors that may aect quality of
fruits include genotype, environmental
conditions and fertilization (Beckles,
2012).
Regarding fertilization, in recent
years, to improve nutritional and
nutraceutical quality of vegetable
products for human consumption, the
bio-fortication programs consisting of
cultivation of species to increase their
nutritional value, include trace elements
such as micronutrients (Montoya et al.,
2013; Constán-Aguilar et al., 2014).
Concerning macronutrients, K is
the one that exerts greater inuence on
the characteristics that determine the
consumer’s preferences, the quality
of the fruits and the concentration of
phytonutrients of vital importance to
human health (Lester et al., 2010).
Under this perspective, the objective
of this study was to evaluate the eect
of dierent concentrations of K in the
nutrient solution applied during the
growth period of muskmelon plants and
their eect on yield and nutraceutical
quality of fruits.
MATERIAL AND METHODS
Study area
The study was conducted under
greenhouse conditions with automated
control system of environmental
conditions at Instituto Tecnológico
of Torreón, México (25°36’37”N,
103°22’32”W, altitude 1123 m).
During the growing season, minimum
and maximum temperatures inside
greenhouse fluctuated between 20
and 35°C, while the minimum and
maximum relative humidity ranged
from 60 to 80%.
Crop management
Sowing was done directly, placing
a seed of Expedition genotype (Harris
Moran®, USA) in black polyethylene
bags of 20 L, caliber 500 and nursery
type, which were used as pots and placed
in an arrangement called “quincunx”.
Density was of six plants per square
meter leaving one fruit per plant.
Prewashed and sterilized river sand
with a solution of 5% of NaClO was
used as substrate. The treatments were
designed from modifications of the
Steiner nutrient solution and consisted
of increasing levels of K (5, 7, 9 and 11
mM). Each treatment consisted of one
plant/pot, distributed in a completely
randomized design with 15 replications
(one pot per replication). All nutrient
solutions contained (in mM L-1) 8 Fe,
0.865 B, 1.6 Mn, 0.023 Zn, 0.11 Cu and
0.5 Mo and were adjusted to an osmotic
potential of -0.073 MPa and pH of 5.5.
The nutrient solutions were formulated
using high soluble commercial
fertilizers, available in the local market.
Three irrigations were applied daily,
using a drip irrigation system, whose
volume ranged from 0.750 L pot-1 from
sowing to the beginning of owering
(45 days after sowing) and 2.0 L
plant-1 were provided from owering
to harvesting stage, which began 85
days after sowing. Plants were pruned
to a stem and subsequently supported
with stakes which were placed using
raa thread, holding one extreme on the
stem base and the other to a metal wire
which was secured to the rm structure
of the greenhouse. Bees were used to
pollinate owers, introducing them to
the greenhouse during the owering
stage. Several fruits were set after
pollination with bees; however, only one
fruit per plant was left. After pollination,
fruits were pruned and the biggest one
selected, which remained on plant until
harvest. Harvest took place when the
fruits break of from peduncle.
Fruit average weight and quality
Fruits were harvested at full slip
phase, when stem was completely
separated. The fruit average weight was
expressed in kilograms per plant.
Fruit size (polar and equatorial
diameter in cm), pulp thickness (cm),
total soluble solids in Brix grades (°Brix)
were measured on each harvested fruit.
Brix grades were determined with a
hand refractometer with scale from 0
to 32% (Atago® Master 2311), on each
harvested fruit. Fruit pulp firmness
was measured using a penetrometer
(Extech®, FHT200) placing a plunger
of 8-mm diameter and a 2-cm2 portion
that was removed from the skin on
opposite sides of fruit, averaging the two
measurements in Newtons (N). Phenols
content was quantied according to the
methodology of Esparza-Rivera et al.
(2006) and antioxidant capacity by the
method of Brand-Williams et al. (1995).
Statistical analysis
Analysis of variance and multiple
comparisons (Tukey HSD, p<0.05) were
performed. All analyses were executed
using SAS statistical software v. 9.0.
Pearson correlation analysis (p<0.05)
and simple linear regression were
performed considering as independent
variable the K concentrations.
RESULTS AND DISCUSSION
Fruit average weight and quality
The results of this study indicate
that concentrations of K in the nutrient
solutions signicantly inuenced the
fruit average weight (p<0.05, Table 1);
obtaining the greatest yield those plants
treated with the highest concentrations of
K. These results were expected because
K plays a vital role in the lling of fruits.
There is an increase in requirement for
K during the plant’s production process;
so, when the muskmelon plants of this
experiment received enough K, the
eciency of water was improved by
increasing osmotic pressure of cells,
making them more turgid and increasing
the weight and size of fruits.
The report of Tuna et al. (2010)
indicate an increase in muskmelons fruit
average weight with high concentrations
of K, corroborating results of current
study, due to the deciency or excess
of this macroelement limiting growth
and crop yield (Tang et al., 2012; Hafsi
Increasing doses of potassium increases yield and quality of muskmelon fruits under greenhouse
186 Hortic. bras., Brasília, v.36, n.2, April - June 2018
et al., 2014). However, there is no dose
or unique concentration because of
dierences found in yield, due to dierent
varieties, soil and weather conditions,
crop management (Silva-Dias et al.,
2005), source and method of fertilizers
application (Lester et al., 2010). Fruit
weight showed signicant and positive
correlation with concentration of K in
the nutrient solution; this means that,
fruit weight increases with increasing
K concentrations (Table 2). This
correlation occurred due to the fact
that this element plays a fundamental
function in the lling of fruits, promoting
greater rmness and resistance of the
tissues since potassium is absorbed
in large quantities in crops such as
muskmelon. Similar results reported
Demiral & Köseoğlu (2005).
The fruit polar diameter did not
show significant differences among
concentrations of K, however, the values
varied from highest to lowest as follows:
9>11>7>5 mM of K (Table 1). Although
K increases the weight and size of
the fruits, the increase of fruit polar
diameter was slight with only 4.44% in
9 mM compared to 5 mM of K. The fruit
equatorial diameter showed signicant
dierences among the concentrations
of K (Table 1) and varied from highest
to lowest as follows: 11>9>(7=5). Polar
diameter was equal at 7 and 5 mM of K.
The fruit equatorial diameter increased
9.10% at 11 mM compared to 7 and 5
mM of K. The fruit polar and equatorial
diameters were greatest in those plants
treated with concentrations of 9 and 11
mM of K, respectively. The fruits size in
our study was similar to those reported
by Moreno-Resendez et al. (2010).
The fruit equatorial diameter showed
a signicant and positive correlation with
the concentration of K and increased as
the concentration of K increased (Table
2); nevertheless, correlation among fruit
polar diameter and K concentration was
not signicant. The fruit yield achieved
in those plants treated with 11 mM of
K, exceeds 41% of those obtained in
eld (Camberos & Rios, 2000). This
result confirms that under protected
conditions and using nutrient solutions,
the fruit average weight increases. The
results of present study are consistent
with Preciado-Rangel et al. (2002) who
reported that some muskmelon hybrids,
showed greatest demand of K and that
the dierent hybrids require dierent
nutritional conditions to show their full
potential.
Fruit pulp thickness showed
significant differences among the
dierent concentrations of K getting
the greatest values in those plants treated
with 9 and 11 mM of K (Table 1). Fruit
pulp thickness showed significant
and positive correlation with the
concentration of K in the nutrient
solution, displaying a linear relationship,
because of, increasing K concentrations
Table 1. Eect of potassium (K) concentrations in the nutrient solution, on fruit average weight, polar and equatorial diameter, pulp thickness,
total soluble solids, rmness, phenols content and antioxidant capacity of muskmelon fruits. Mexico, Instituto Tecnológico de Torreón, 2015.
K (mM) Fruit average
weight (kg)
Diameter (cm) Pulp
thickness (cm)
Firmness
(N)
TSS
(°Brix)
Phenols content (mg
equivalent Gallic acid
100 g FB-1)
Antioxidant capacity
(µM equiv
Trolox/100 g FB)
Polar Equatorial
51.01 b 13.50 11.10 b 2.95 b 18.11 b 11.90 b 31.46 b 114.90 c
70.95 b 13.51 11.10 b 2.95 b 18.58 b 11.90 b 30.79 b 162.90 b
91.11 a 14.10 11.70 ab 3.45 a 20.88 b 12.20 ab 33.22 b 191.40 ab
11 1.12 a 13.64 12.11 a 3.12 ab 23.92 a 12.70 a 39.27 a 213.10 a
CV (%) 4.66 3.46 3.84 6.70 4.45 2.87 7.79 8.95
1Data expressed as µM equivalent in Trolox per 100 g. FB= fresh base. Values in each column followed by the same letter(s) are not
signicantly dierent at p≤0,05 (Tukey HSD). TSS= total soluble solids. N= Newtons.
Table 2. Correlation coecient (Pearson), determination coecient and simple linear regression equation among potassium concentrations
(mM) and dependent variables, phenols content, antioxidant capacity, yield, fresh weight, equatorial diameter, pulp thickness, total soluble
solids and rmness of muskmelon fruits. Mexico, Instituto Tecnológico de Torreón, 2015.
Dependent variables Correlation
coefficient (r)
Determination
coefficient (R2)
Simple linear regression
equation
Phenols content 0.72** 0.52 PC=23.34+1.29×K**
Antioxidant capacity 0.93*** 0.86 AC=41.49+16.14×K***
Fresh weight 0.63** 0.39 FW=0.89+0.02×K**
Yield 0.67*** 0.46 Y=5.30+0.13×K***
Equatorial diameter 0.59** 0.34 ED=10.41+0.14×K**
Pulp thickness 0.62** 0.38 PT=2.49+0.08×K**
Total soluble solids 0.67*** 0.45 TSS=11.06+0.13×K***
Firmness 0.90*** 0.81 F=12.49+0.98×K***
Signicance level (p)= **p<0.01; ***p<0.001.
P Preciado-Rangel et al.
187Hortic. bras., Brasília, v.36, n.2, April - June 2018
resulted in fruit pulp thickness increase
(Table 2). These results do not match
with those reported by Silva et al. (2014)
who found a quadratic response for
fruit pulp thickness and a linear trend
in the fruit size caused by increased
fertilization with K.
Pulp firmness showed significant
dierences between K concentrations,
exhibiting greatest value in the
concentration of 11 mM of K (Table
1). Pulp rmness showed signicant
and positive correlation with the
concentration of K in the nutrient
solution, increasing as the concentration
of K increased (Table 2). Also, fruit
firmness showed significant and
positive correlation with total soluble
solids content, because of, as fruit
rmness increases, total soluble solids
content also increase. In this regard,
Lester et al. (2010) indicate that fruit
rmness is correlated with the pressure
potential (ψp) because K increases the
accumulation of sugars (solutes) in
fruits (Ribas et al., 2003). Similarly,
Demiral & Köseoğlu (2005) reported
this positive relationship among fruit
rmness and total soluble solids. From
the commercial viewpoint, when fruit
rmness increases, acceptance of the
muskmelon fruits by the consumer is
improved, because they prefer fruits
with rm pulp instead of soft and watery
(Ribas et al., 2003) being 23.6 Newtons
the optimal value for fruit rmness in
muskmelon (Silva-Dias et al., 2005).
Potassium concentrations in the
nutrient solution, stimulated signicant
differences (p<0.05; Table 1) in the
soluble solids content, getting the
greatest values those fruits from plants
treated with 11 mM of K, validating
the positive eect of K on fruit quality
(Demiral & Koseoglu, 2005; Tang et al.,
2012; Silva et al., 2014). Furthermore,
the content of total soluble solids showed
signicant and positive correlation with
the concentration of K in the nutrient
solution, revealing a linear relationship
caused of increasing K concentrations,
also the content of total soluble solids
increased (Table 2).
The concentration of soluble solids
of fruits harvested from plants treated
with the concentrations of K exceeded
the minimum value (9° Brix) (Table 1)
reported as acceptable in market (Mata
& Mendez, 2009). This conrms that
transport of sugars to fruits was eective
since K has an important role in the
transport of solutes through phloem
(White & Karley, 2010) and these fruits
are considered marketable because total
soluble solids are one of the main quality
criteria for muskmelon fruits (Budiastuti
et al., 2012).
The results showed that the increase
of K concentration, exhibited an increase
in phenols content and antioxidant
capacity, both characteristics showed
greatest values in the concentration of
11 mM of K (p<0.05, Table 1); which
is an advantage since the fruits with
greatest phytonutrients content have
great interest because their consumption
is associated with a lower risk of
cardiovascular diseases and certain
cancers types (Llacuna & Mach, 2012).
The antioxidant compounds are essential
in the nutritional quality of fruits and are
rated an essential factor in determining
their price in the market (Frusciante et
al., 2007). Lester et al. (2010) found that
muskmelon fruits from plants treated
with dierent sources of K had greatest
content of antioxidants compared with
untreated fruits.
The benecial eects of K supplement
to the plant were presumably result of
a combination of an improvement
in the assimilation of CO2, higher
photosynthetic activity and greatest
translocation of photoassimilates
from leaves to fruits, improved water
relations, greater enzyme activity and
substrate availability for the biosynthesis
of bioactive compounds; so the amount
of antioxidants of a plant is also a good
indicator of stress tolerance (Kusvuran
et al., 2012).
Phenols content and antioxidant
capacity showed signicant and positive
correlation with the concentration of K
in the nutrient solution, with a linear
relationship caused by the concentration
of K increased in the nutrient solution;
the values of both variables also
increased (Table 2), demonstrating
that K contributes significantly to
the antioxidant capacity and phenols
content in muskmelon fruits. The
current study demonstrated that the
concentrations of 9 and 11 mM of K
positively influenced the increased
yield and fruit quality of muskmelon.
The best concentration to maximize
yield and quality of muskmelon fruits
was 11 mM of K. Given the linear
trend of all characteristics (except fruit
polar diameter) to increase their values
as concentrations of K increased, it
evidences that the optimal dose of K
in muskmelon is greater than 11 mM,
suggesting, for future research, to
evaluate concentrations of K above 11
mM.
ACKNOWLEDGEMENTS
Thanks to Lidia Hirales-Lucero,
Pedro Luna-García and Manuel Salvador
Trasviña-Castro for technical support.
Diana Dorantes-Fischer for English
edition is gratefully acknowledged.
The corresponding author is grateful
to Consejo Nacional de Ciencia y
Tecnología (Mexico) by supporting
the modality of sabbatical stays abroad
within the framework of the national
call support for sabbatical stays related
to the consolidation of research groups
and/or strengthening of the national
postgraduate program (2017-I).
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... Yam et al. (2020) reported that nutrient composition directly enhances the quality of melon fruit sweetness in a hydroponic system. Specifically, potassium positively correlates with melon fruit's increasing sugar content, as Rangel et al. (2018) reported. In hydroponic systems, Johnson & Mirza (2020) stated that plants are required to supply essential nutrients, such as nitrogen (N), phosphate (P), and potassium (K), to complete the plant life cycle optimally. ...
... It indicated a very high correlation. Potassium has a vital role in several plant physiological functions, such as carbohydrate metabolism, enzyme activity, osmotic regulation, water use efficiency, nitrogen element absorption, protein synthesis, and assimilate translocation (Dreyer et al., 2017;Rangel et al., 2018;Ho et al., 2020;Mostofa et al., 2022;Wang et al., 2023). Furthermore, Wang et al. (2024) explained that potassium is also crucial in the sugar synthesis process in leaves because it can influence the expression of genes that regulate sugar metabolism and assimilate transport. ...
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The fruit sweetness is the main target in melon plant production. The highest criterion of sweetness is excellent, with 16% of total sugar content. Modification of essential plant nutrients is the alternative to reach that category. So, this study aims to obtain optimum NPK doses using a simple regression method. The experiment was conducted in a greenhouse with a soilless culture hydroponic system from August until November 2023 using a completely randomized design (CRD) with five treatments and four replications. The parameters included leaf area, plant dry matter, leaf nutrient uptake, fruit weight, and fruit sugar content. Pearson correlation analysis showed that the total sugar content in fruit has a significantly positive correlation with potassium in NPK fertilizer treatments such as K2O dose and K2O uptake at 7 WAP, i.e., 0.932 and 0.973, respectively. According to the regression model y = -50.7 + 1.079 N + 0.251 P2O5 + 0.528 K2O, the NPK formula fertilizer containing 31.56 g N, 23.99 g P2O5, and 50.42 g K2O can be used by grower to produce excellent fruit sugar content.
... O potássio é um nutriente essencial ligado ao transporte de solutos, aumentando o teor de sólidos solúveis. (PRECIADO-RANGEL et al., 2018). ...
... O mesmo foi observado por Duarte et al. (2017), em que pitaias submetidas à adubação orgânica na temperatura de 13ºC apresentaram maior firmeza devido ao teor de cálcio que o fertilizante proporcionou às plantas. Outro nutriente encontrado na composição da urina que tem relação positiva com a firmeza é o potássio (PRECIADO-RANGEL et al., 2018). ...
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... The uptake and assimilation of N by the plants can be influenced by both the source and the doses of N applied [104,105]. Plants acquire inorganic N from the soil, mainly in the ammonium (NH 4 + ) and nitrate (NO 3 − ) forms [106]. When NH 4 + is only applied as a unique N source, it increases the internal ammonia (NH 3 ) levels, which can be highly toxic for the plant cells [107,108]. ...
... Likewise, when strawberries were treated with three levels of nitrate NO 3 − , the highest dose (15 M m −3 ) produced the maximum fruit yield. However, the nutraceutical quality, such as the antioxidant capacity and phenolic compounds, significantly declined [106]. Under a N deficiency, the increased phenolic compounds and antioxidant activity have also been reported in mustard, sweet basil, and lettuce [126][127][128]. ...
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Southern Chile has experienced a strong increase in sweet cherry production in recent years. However, there are climatic gaps that negatively reduce the fruit quality and yield of exportable fruit, such as the high incidence of rains during flowering and pre-harvest. The use of roof covers has become an agronomic solution that offers protection from weather events, such as rain, which will significantly increase the exportable fruit. However, the use of plastic covers can cause negative impacts on the fruit, such as a loss of firmness and acidity. Currently, the incidence of internal (pulp) browning has reduced the quality of cherries produced in Southern Chile, although research on this subject is largely under explored. Some studies reported that a high content of antioxidants in the fruit, both phenolic and non-phenolic (e.g., ascorbic acid), could reduce the incidence of the physiological disorder of browning. The soils of Southern Chile are characterized by the high content of organic matter, which implies high levels of available nitrogen (N) and a high phosphorus (P) content. Some studies, however, have shown that fertilization with N and P would significantly improve the postharvest quality, shelf life, and the accumulation of antioxidant compounds in fruits, even better than other strategies, including selenium and chitosan applications. However, there needs to be more detailed information on this aspect of the sweet cherry fruit production. The quality attributes and postharvest life of cherries are closely associated with the antioxidant levels of fruits, which could be related to either the soil acidity level of the Chilean Andisols or the levels of P and N in soil or plant tissues. Therefore, the objective of this review was to discuss the role of the N and P supply on the internal browning incidence in sweet cherries and relate it to what is known in other fruits.
... The average pulp thickness observed in the present study is higher than those obtained by Andrade et al. (2022) and Rangel et al. (2018), who evaluated the performance of Cantaloupe melon in greenhouse and observed averages of 3.76 and 3.45 cm, respectively. ...
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The need for studies that allow the use of brackish water in irrigated agriculture and the socioeconomic importance of melon cultivation in Brazil, especially for the Northeast region, which concentrates most of the national production and faces problems with the availability of good quality water for irrigation, motivated the present study. In this context, the objective of present study was to evaluate the growth, production and fruit quality of the ‘Goldex’ (yellow-type hybrid F1) melon under salt stress conditions. The experiment was performed in a completely randomized design, with two salinity levels of irrigation water (0.8 and 4.0 dS m⁻¹) and eight evaluation times (52, 54, 56, 58, 60, 62, 64, and 66 days after transplanting). Variables of plant growth and development, production and quality of melon fruits were evaluated throughout the cycle. Plants had delayed growth characteristics and less development with the increase in irrigation water salinity, showing reductions of more than 20% in shoot dry weight, leaf area, number of branches and length of secondary branches and 16.7% in length of the main branch. In addition, salinity caused a delay in fruit development and a 16% reduction in final fruit weight, without significantly modifying carbohydrate and total soluble solids contents. Along the development, there was an increase in the total soluble solids content of the fruits, especially due to the increment of sucrose at the final stages of development. Key words: growth inhibition; irrigation; salinity; post-harvest
... Tingginya unsur Kalium dalam tanaman dapat meningkatkan translokasi fotosintat dari daun ke bagian sink atau penyimpanan sehingga menyebabkan berat buah meningkat. Menurut pernyatan Preciado-Rangel et al. (2018), menyebutkan bahwa buah melon yang menerima cukup K, menyebabkan efisiensi air ditingkatkan dengan meningkatkan tekanan osmotik sel, membuat sel membesar dan meningkatkan berat dari buah melon. Namun peningkatan berat buah melon tidak berbanding lurus dengan diameter melon yang didapatkan hasil tidak berbeda nyata. ...
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... In the case of a closed hydroponic system, proper nutrient solution management in the plant is the first consideration for the adoption of the plants. [7] stated that rock melon growth was affected by different strength of nutrient solutions. The present finding was consisted with the findings of [10]. ...
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... Calcium interacts with pectin and helps preserve fruit firmness by maintaining cell wall integrity (Mohebbi et al., 2020). Regarding the effect of K, Preciado-Rangel et al. (2018) observed that it promotes greater firmness and resistance of melon tissues. ...
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The effect of different potassium (K) rates on yield, fruit quality, and chemical composition of greenhouse-grown melon (Cucumis melo L., cv. Galia) was investigated. The experiment was carried out in a greenhouse similar to that used by farmers in the coastal Mediterranean region of Turkey. Control and three rates of potassium (0, 200, 400, 600 mg L) were applied to cv. Galia in a randomized complete block design with 3 replications. Leaf and fruit quality analyses were carried out and yield was determined. Different rates of potassium had no effect on yield. However, fruit number and fruit firmness were higher than the control at the 400 and 600 mg L rates. Total soluble solids were higher than the control at the 600 mg L rate. Average fruit weight was lower than the control at the 600 mg L rate. Treatments did not affect nitrogen (N), phosphorus (P), calcium (Ca), magnesium (Mg), and zinc (Zn) contents of leaves, but leaf K content was higher than the control at all three rates. Iron (Fe) content was lower than the control at the 600 mg L rate and manganese (Mn) content was lower at the 400 and 600 mg Lrates. The data from our study indicate that 300 mg L K in the root zone was sufficient for optimum yield of greenhouse-grown Galia melons. In terms of total yield, it is not necessary to apply higher rates of K. However, results show that it is possible to improve fruit quality by applying as much as 600 mg L additional K to the plants without a reduction in yield.