Effects of Arbuscular Mycorrhizal Fungi on the Heat Resistance of
Dianthus hybridus Seedlings
Yunxin Tang
1,#
, Jia Huang
1,#
, Yunjian Guo
2
, Yongliang Luo
2
, Chunwen Li
3
, Zhongqun He
1,*
,
and Xiaoting Zhou
1,*
1
College of Horticulture, Sichuan Agricultural University, Chengdu, Sichuan, 611130, China
2
People’s Government of Pidu District, Chengdu, Sichuan, 611730, China
3
Chengdu Jinping Flower Seedling Limited Liability Company, Chengdu, Sichuan, 611730, China
#
These authors contributed equally to this work
Keywords:
Dianthus hybridus, Arbuscular Mycorrhizal Fungi, High Temperature Stress.
Abstract:
In order to explore whether AMF can inoculation enhance heat resistance of Dianthus hybridus seedlings
under high temperature, growth indexes and gas exchange parameters chlorophyll fluorescence parameters as
well as the main heat resistance evaluation indexs were tested. The results showed that the plant height and
stem diameters of AMF-inoculated plants were significantly greater than those of non-inoculated plants. AMF
treatment also increased the net photosynthetic rate. Under high temperature stress, AMF treatment plants
decreased the MDA content, while it increased the activities of SOD, POD and CAT as well as proline content.
Under high temperature stress, AMF treatment plants suppressed the decrease of Fv'/Fm', Y(II) and qP to the
control level, and also reduced NPQ. Thus, application of AMF inoculation can promote both the plant growth
and heat resistance in Dianthus hybridus seedlings.
1 INTRODUCTION
Dianthus hybridus is an important material for
arranging flower beds and flower borders. To ensure
the production of Dianthus hybridus around the year,
seedling raising is often used. However, high
temperature is one of the limited factors of seedling
raising in Dianthus hybridus in summer, due to its
sensitivity to heat. Under high temperature stress, the
combination of strong sunlight and rapid
transpiration will lead to plant protoplast dehydration
and protein solidification, plant growth weakening,
leaf color fading, wilting and yellow, and lead to the
increase of deformed flowers. Therefore, it is
important to carry out the research on the Dianthus
hybridus of heat resistance. Therefore, it is important
to carry out the research on the Dianthus hybridus of
heat resistance. Arbuscular mycorrhizal fungi (AMF)
is a kind of soil microorganism (Liu 2009), which can
form a symbiotic relationship with more than 90%
plant (Ma 2015). Studies have shown that AMF
inoculation can promote growth of plant (Liu 2015,
Ma 2014), improve the ability of plants to resist
continuous cropping obstacles (Chen 2013), and
enhance plant stress resistance (Liu 2011, Zhang
2016, Guo 2011, Sun 2012, Ye 2019). AMF can
regulate the formation of secondary metabolites in the
host plant by changing the root morphology of the
plant, so as to improve the physical and chemical
properties of the root environment. It also changes the
microbial community structure around the root,
activates and induces a variety of mechanisms in the
process of infecting the host, increase the regulation
of plant defensive enzyme activity and gene
expression, as a result of improving plant abiotic
stress tolerance. However, the effect of AMF
inoculation on the heat resistance of Dianthus
hybridus has not been reported.
This study was based on the inoculated AMF,
measuring the growth indexes and gas exchange
parameters of the leaves of Dianthus hybridus. The
effect of AMF on the heat resistance of Dianthus
hybridus seedlings under high temperature stress
were also discussed. This authors tried to explore the
effect of AMF inoculation on the growth of Dianthus
hybridus, so as to provide a theoretical basis for the
popularization and application of AMF in the
production practice of Dianthus hybridus.
1260
Tang, Y., Huang, J., Guo, Y., Luo, Y., Li, C., He, Z. and Zhou, X.
Effects of Arbuscular Mycorrhizal Fungi on the Heat Resistance of Dianthus hybridus Seedlings.
DOI: 10.5220/0011507800003443
In Proceedings of the 4th International Conference on Biomedical Engineering and Bioinformatics (ICBEB 2022), pages 1260-1263
ISBN: 978-989-758-595-1
Copyright
c
2022 by SCITEPRESS Science and Technology Publications, Lda. All rights reserved
2 MATERIALS AND METHODS
2.1 Materials
Dianthus hybridus cv. Fanxing was used in this work,
the seeds were provided by Jinping flower seedling
limited liability company. AMF products (including
mixed bacterial agents such as Glomus mosseae,
Acaulospora morrowiae and Gigaspora gigantean)
were provided by Huai'an chaimihe agricultural
science and technology development limited
company. A commercial substrate was used for
seedling raising, with pH5.5-6.5.
2.2 Experimental Design
The experiment was conducted in the laboratory of
college of horticulture, Sichuan Agricultural
University from January 2021 to September 2021.
Before inoculation, the flowerpots were disinfected
with 75% ethanol and ventilated to dry. Two
treatments were set up: (1) CK: without adding AMF
in the substrate; (2) AMF: adding AMF in the
substrate. The Arbuscular mycorrhizal fungal agent
(spore concentration of 120 per gram) was mixed
with the seedling substrate and loaded them into 50-
well plates, with an average dosage of 50 g per plate.
Then the plates were placed in artificial climate
chamber with the temperature of 25℃/18℃
(day/night), and photoperiod 12h/12h (day/dark)
simultaneously, with Hogland nutrition solution
every three days. As for heat stress experiment, the
Dianthus hybridus seedlings were moved into the
artificial climate box for pretreatment (25℃/ 18℃
(day/night)) after 50 days of inoculation, with
photoperiod of 12h/12h (light/dark), and the relative
humidity was 70%. After 3 days, the temperature of
the artificial climate box was changed into 35℃/30℃
(day/night), the light intensity and air humidity
remained unchanged. The mature leaves of the same
growth part of each plant were sampled on the fifth
day after heat stress.
Plant height and stem diameter were measured by
using vernier caliper. The methods described by Lu
et al (Lu 2009) were used for the determination of free
proline, and the methods of measurement of
antioxidant enzyme activities and malondialdehyde
(MDA) content were described by Wang et al (Wang
2021). Gas exchange parameters were measured by
LI-6400XT Portable Photosynthesis System.
Photosynthetic fluorescence parameters were
measured by portable fluorescence parameter meter
(PAM2500).
2.3 Statistical Analyses
Statistical analysis was carried out by using SPSS
18.0 statistical software. The data were analyzed by
one-way ANOVA, with the least significant
difference at the 5% confidence level.
3 RESULTS AND DISCUSSION
3.1 Effects of AMF on Growth Indexes
and Gas Exchange Parameters in
Dianthus hybridus
After 50 days of AMF inoculation, compared with no
inoculation (CK), the AMF treatment significantly
increased the plant height of Dianthus hybridus. At
the same time, after AMF inoculation, the net
photosynthetic rate, stomatal conductance,
intercellular carbon dioxide concentration and
transpiration rate of Dianthus hybridus leaves were
significantly improved. Previous studies have shown
that arbuscular mycorrhizal can improve the strong
seedling index of wheat (Ma 2014). This study found
that AMF treatment also promoted the growth of
Dianthus hybridus, which was consistent with the
research results in Poncirus trifoliata by Zuo et al
(Zuo 2014).
Table 1: Effects of AMF on growth indexes and gas exchange parameters in Dianthus hybridus.
Treatments Plant height
(cm)
Stem
diameter
(
cm
)
Pn
(μmol·co
2
m
-
2
·s
-1
)
Gs
(mol H
2
O·m
-
2
s
-1
)
Ci
(μmol·co
2
·mol
-
1
)
Tr
(mmol
H
2
O·m
-2
s
-1
)
CK 15.60±1.09b 0.06±0.01b 2.03±0.38b 0.08±0.02b 336.19±1.61b 1.44±0.38b
AMF 20.83±2.86a 0.12±0.02a 6.12±1.07a 0.16±0.02a 355.63±7.93a 3.83±0.78a
Value are means ± standard errors. Means with the same letter within each column are not significantly different at p < 0.05
.
Effects of Arbuscular Mycorrhizal Fungi on the Heat Resistance of Dianthus hybridus Seedlings
1261
3.2 Effects of AMF on Proline,
Malondialdehyde (MDA) Contents
and Antioxidant Enzyme Activities
in Dianthus hybridus at High
Temperature
It can be seen from the Table 2 that the activities of
antioxidant enzymes including SOD, POD and CAT
were increased on the 5th day of high temperature
stress. And AMF treatment also increased the
activities of antioxidant enzymes. Compared with the
heat stress treatment without AMF inoculation (HT),
SOD, POD and CAT were increased by 18.09%,
7.22% and 29.86% under HT+AMF treatment,
respectively. On the other hand, compared with the
control, the content of proline were increased by
43.98% and 141.43% in HT and HT+AMF,
respectively. HT+AMF treatment significantly
increased the activity of SOD compared with HT.
Protective enzyme systems such as SOD, POD and
CAT and ascorbic acid glutathione (AsA-GSH)
cycle
system play an extremely important role in the
process of scavenging reactive oxygen species free
radicals and peroxides. They work synergistically
with peroxidase isozymes and other non enzymatic
systems, so as to regulate membrane permeability,
prevent membrane lipid peroxidation and reduce the
damage of membrane system. In this study, there was
higher antioxidant enzyme activities with the AMF
treatment.
On the other hand, compared with the control, the
content of MDA were increased by 46.88% in HT and
were increased by 31.25% in HT+AMF. The
improvement of antioxidant enzyme activity can
promote the scavenging ability of reactive oxygen
species and improve the stress adaptability. Proline is
an osmotic protective agent, and its accumulation is
positively correlated with the stress resistance of
plants. The results of this study showed that AMF
inoculation could significantly improve the content of
proline in Dianthus hybridus in responce to heat
stress, improving the ability of heat adaptation. The
results were consistent with the results in Lactuca
satica L. by Ma et al (Ma 2015).
Table 2: Effects of AMF on proline, MDA contents and antioxidant enzyme activities of Dianthus hybridus at high
temperature.
Treatments SOD
activity
(
U·
g
-1
FW
)
POD
activity
(
g
-1
FW
)
CAT
activity
(
g
-1
FW
)
MDA
content
·
-1
FW
)
Pro
content
·
-1
FW
)
C
K
8.83±0.66b 11.98±0.90b 3.50±1.04b 0.32±0.03b 15.71±4.34c
HT 10.61±0.75b 14.81±1.04a 5.29±0.47ab 0.47±0.05a 22.62±3.01b
HT+AMF 12.53±1.25a 15.88±1.40a 6.87±1.12a 0.22±0.08b 37.93±2.00a
Value are means ± standard errors. Means with the same letter within each column are not significantly different at p < 0.05.
3.3 Effects of AMF on Chlorophyll
Fluorescence Parameters of
Dianthus hybridus Under Heat
Stress
High temperature stress significantly decreased
Fv'/Fm', Y(II), qP in chlorophyll fluorescence
parameters of Dianthus hybridus leaves, but
significantly increased NPQ, indicating that high
temperature inhibited the potential activity of
photosynthetic reaction center II and hindered cyclic
photosynthetic electron transfer of Dianthus hybridus
leaves. Compared with HT, HT+AMF could inhibit
the decreases of Fv'/ Fm', Y (II) and qP under high
temperature, indicating that the inhibitory effect of
high temperature on photosynthetic electron transfer
was reduced to a certain extent. In addition, Fv/Fm
did not decrease after 5d of high temperature stress,
indicating that the photosynthetic structure of
Dianthus hybridus leaves were not damaged.
Table 3: Effect of AMF on chlorophyll fluorescence parameters of Dianthus hybridus at high temperature.
Treatment Fv/Fm Fv'/Fm' Y(II) qP NPQ
C
K
0.79±0.01a 0.64±0.04a 0.49±0.02a 0.79±0.01a 0.61±0.15b
HT 0.79±0.01a 0.56±0.03b 0.27±0.04b 0.55±0.12b 0.86±0.07a
HT+AMF 0.78±0.01a 0.69±0.02a 0.54±0.02a 0.84±0.03a 0.48±0.02b
Value are means ± standard errors. Means with the same letter within each column are not significantly different at p < 0.05.
ICBEB 2022 - The International Conference on Biomedical Engineering and Bioinformatics
1262
4 CONCLUSION
Comprehensive analysis showed that high
temperature stress had significant effects on the
physiological parameters and chlorophyll
fluorescence parameters of Dianthus hybridus.
Inoculation with AMF can alleviate the damage
caused by high temperature stress to the activity of
antioxidant enzymes, osmotic regulators and
photosynthetic electron transport system, and
improve the heat resistance of Dianthus hybridus to a
certain extent.
ACKNOWLEDGEMENTS
This work was financially supported by Introduction
and breeding of new varieties of European flowers
(NO.2022349001).
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