In semi-arid afforestation sites, the study aimed to create mycorrhizal seedlings with high vitality, health, and tolerance to harsh environments. The study’s hypotheses state that mycorrhizal inoculation will improve Cedrus libani (Taurus cedar) seedlings' growth characteristics, nutrition, root colonization, and mycorrhizal reliance.
<italic toggle="yes">Area of study</italic>:
The Eastern Mediterranean Research Institute laboratory and greenhouse in Tarsus district-Mersin, Türkiye.
<italic toggle="yes">Material and methods</italic>:
The experiment involved inoculation of three ectomycorrhizal fungal species (Lactarius delicious, Hebeloma crustuliniforme, Tricholoma ustale) collected from natural cedar stands on to cedar seedlings grown in two different substrates (sterilized, non-sterilized. Inoculation was carried out by dipping the roots of Cedrus libani A. Rich (Taurus cedar) seedlings into mycorrhizal mycelia.
<italic toggle="yes">Main results</italic>:
Cedar seedlings infected with mycorrhiza exhibited a greater biomass ratio in comparison to the control seedlings. Substrate sterilization increased seedling growth variables. The highest growth, some nutrients such as N, P, K, Fe and Zn uptake, root colonization and mycorrhizal dependence occurred in seedlings with H. crustuliniforme and L. delicious.
Although this study is limited to Taurus cedar-mycorrhiza combinations, it may also be applicable to different mycorrhizal fungal species and many other valuable host tree species. More research is needed on the adaptation of different mycorrhizal species to habitats to increase the success of afforestation efforts in arid and semi-arid regions.
Taurus cedar (Cedrus libani A. Rich) has an extensive distribution in Türkiye and is one of the common coniferous species in semi-arid regions. About 2/3 of Türkiye’s land cover is considered arid and semiarid. Due to increasing climate changes and long-term soil management, 72% of the Turkish soils are in danger of erosion. The Turkish government has been combating the erosion by establishing afforestation sites in the region. However, the success of the plantation established with conventionally grown seedlings is limited in these dry and harsh environments (Yildiz et al., 2017). Soil preparation and mycorrhizal inoculation are very important to ensure successful afforestation in such areas (Chot & Reddy, 2022). Many studies indicate that mycorrhizae help adapt to arid environments (Martin et al., 2001; Xu & Wu, 2012; Wang et al., 2021; Qi & Yin, 2023). Ectomycorrhizal fungi (EMF) are also key to the optimal establishment and performance of forest tree species under nursery and planting conditions. In this context, due to water deficiency and land degradation caused by extreme climate, transplanting mycorrhizal inoculated seedlings will reduce the reforestation costs of areas (Rincón et al., 2007; Sanchez-Zabala et al., 2013; Zong et al., 2015; Policelli et al., 2020). Hence use of EMF in ectomycorrhization of conifer seedlings is of critical importance in ensuring that the planted seedlings survive, grow and establish under normal as well as stressful conditions (Assad et al., 2022). Chahboub et al. (2021) suggested the use of mycorrhizal seedlings in afforestation and restoration programs in degraded forest ecosystems, as inoculation of Atlas cedar seedlings with ectomycorrhizal fungus improved the growth, morphological and physiological status of seedlings under drought conditions. Itoo & Reshi (2014) and Chahboub et al. (2016) also reported that the biomass of Atlas cedar [(Cedrus deodara (Roxb. Ex D. Don) G. Don)] seedlings increased with EMF inoculation. For this reason, using mycorrhizal seedlings is very important for the success of afforestation efforts in extreme areas.
Taurus cedar is an endemic and valuable species with high afforestation potential in Türkiye. Taurus cedar is one of the tree species most used in afforestation practices in the arid and semi-arid lands of the Central Anatolian closed basin, but there are not enough mycorrhiza studies on this tree species. The main aim of the research was to produce seedlings with high viability, health and ability to adapt to harsh conditions. More research is needed to investigate the mycorrhizal adaptation of different species to habitat and to increase the success of afforestation efforts in arid and semi-arid regions. This could have important ecological and economic consequences for sustainable forest management in extreme sites.
Since Taurus cedar grows in lands with low productivity and erosion risk, it is important to collect and isolate natural EMF and then re-culture them under laboratory conditions. Later, inoculating cultured mycorrhizae hyphae to Taurus cedar seedlings can increase plant growth and, nutrient uptake. The tested hypothesis is that inoculation with mycorrhizal fungal species will increase seedlings' growth, nutrient uptake, root colonization, and mycorrhizal dependency. With this study, the effect of EMF support and substrate sterilization on the performance of Taurus cedar seedlings in the nursery will be evaluated.
Material and methodsStudy site
The experiment was conducted in the laboratory and under the greenhouse at the Eastern Mediterranean Research Institute in Tarsus, Türkiye (36º52'26"N, 34º52''47"E). It has a semi-arid climate with a mean annual temperature of 19.1 ºC and an average annual rainfall of 617 mm.
Experimental design
The design of the experiment was a randomized full parcel design. It was set up in a greenhouse, using two substrates (sterilized and non-sterilized growth material), four inoculation treatments including control, and three repetitions of each treatment. There were 24 trial units total, with 50 seedlings in each.
Fungal material and inoculum production
The sporocarp samples (Fig. 1) used as inoculum were collected from the root zone of cedar trees in different locations of the Bolkar Mountains (part of the Taurus Mountains in the Southern Mediterranean part of Türkiye) during the spring and autumn months when the climate conditions are suitable for sporocarp development. Three different mycorrhizal mushroom species with high cultivation potential, Lactarius deliciosus (Fr.) S. F. Gray, Hebeloma crustuliniforme (Bull.) Quél, and Tricholoma ustale (Fr.) P. Kumm, were used in the experiment. Guerin-Laguette et al. (2014) stated that H. crustuliniforme and L. delicious species have a wide distribution, are used as commercial inoculum material for forestry purposes, and provide high mycorrhizal activity in inoculated seedlings.
Mycorrhizal sporocarps used as inoculum material
By adding a fragment of sporocarp tissue to the medium, the mycorrhizal species were vegetatively reproduced. The sporocarps were surface-sterilized by immersion in 70% ethanol in a laminar flow hood. Then, a 5-mm diameter section was taken from the inner of the sporocarp and transferred to Marx's (1969) modified Melin-Norkrans (MMN) medium in Petri dishes. The confirmation of successful isolation of the obtained cultures was examined under a microscope. Mycelia produced by pure culture was obtained in a semi-solid MMN medium (Chapman et al., 1990). The semi-solid medium was prepared by adding 0.3% agar to a standard solution. To transfer the mycelia to the new medium, 100 mL of MMN medium was placed in ten 250 mL flasks for each mycorrhiza species and then autoclaved at 121ºC for 20 minutes. Using sterilized tools in a laminar flow hood, 4-mm sections were taken from the culture and placed on the surface of the medium in the flasks. Mycelium cultures were stored in a dark incubator at room temperature and the formation of the mycelial colony was observed. To ensure homogenous distribution of the mycelia, the flask was shaken vigorously by hand as soon as the fungal mycelium began to appear on the medium. The flasks were kept at room temperature for approximately one month for further mycelial growth.
Seedling production and inoculation
Seed material was obtained from cedar cones collected from natural cedar stands in the Bolkar Mountains of Türkiye. Cones of C. libani were soaked in water and let to open. After they were dried in a shady, airy place, they were rubbed by hand and the seeds were separated from their wings. Surface sterilization was carried out by keeping the cedar seeds in 30% H2O2 for 30 minutes and then shaking them thoroughly in sterile water. Growth material “Andesitic tuff” was used for seed germination. The tuff was sterilized in an autoclave at 80 oC for 2 hours. Each tuff-filled viol was seeded with three seeds at the start of the growth season. The healthiest seedlings were kept after germination and relocated to their new medium; the others were taken out.
The substrate used in the experiment consisted of a mixture of humus, river sand, and corn stalk compost, in a ratio of 1:1:1 (v:v:v). The humus was collected from the forest floor layer of cedar stands. The substrate was slightly alkaline (pH 7.8), very mildly salted (2.56 mS cm-1), calcareous (4.1%), with 27.5% organic matter, 0.41% nitrogen content, 53 mg P2O5 kg-1, 267 mg K kg-1, 7.4 mg Fe kg-1, 3.4 mg Zn kg-1 and 18.5 mg Mn kg-1. The half of the mixture was steam-sterilized by using an autoclave at 121°C for three hours and the process was repeated after 24 hours. The other half of the substrate was not subjected to sterilization substrates. Substrates were filled into plastic pots (26 cm deep × 12 cm deep).
Sterile distilled water was added at a ratio of 1:1 (v:v) to 1-L of semi-solid culture mycelial mass obtained from each mycorrhiza type, which was crushed separately in a blender and homogenized. The roots of the seedlings were immersed in their mycorrhizal mycelial slurry for 5 min, and then transplanted into pots filled with new substrate. The remaining mycelial slurry was poured evenly into the seedling pots in each experimental unit. Seedlings were transferred from the greenhouse to the nursery.
Measurements
Measurements were made eight months after planting of the shoot height (H, cm), root collar diameter (D, mm), root and shoot dry weight of twenty seedlings per each of 24 units selected plants from the inoculated and uninoculated treatments of Lactarius delicious, Hebeloma crustuliniforme and Tricholoma ustale. The seedlings were gently removed from the soil, washed in running water, and the root and aerial parts were separated. The samples were then placed in Kraft paper packages to be dried in a forced-ventilated oven at 65 ºC until they reached a constant mass. The shoot dry weight (SDW), root dry weight (RDW), and total dry weight (TDW) were determined using a semi-analytical balance (0.01 g). The Dickson quality index - DQI (Dickson et al., 1960)
DQI=[TDW(g)]/[(H(cm)/D(mm))+(SDW(g)/RDW(g))]
is a good indicator of seedling quality as its calculation computes robustness and biomass distribution while considering several important parameters (Fonseca et al., 2002).
Nutrient analyses were performed on five randomly selected upper parts of the seedlings from each experimental unit previously used for dry weight assessment. The dried samples were ground using a Tema mill and the ground plant material was ashed at about 550 ºC. The residue was then extracted with 3.3% HCl. The wet digestion method was used to determine plant samples with the following instruments: total nitrogen was determined using a micro Kjeltec Auto 1030; phosphorus was analyzed using a Spectronic 20D colorimeter; potassium was measured using a Jenway Flame Photometer; and iron, zinc, and manganese were analyzed using a Perkin-Elmer 3110 Atomic Absorption Spectrophotometer. Nutrient content (NC) was calculated by using;
NC=nutrient concentration×dry weight
Root colonization was performed using the roots of five randomly selected seedlings from each experimental unit. The gridline intersection method developed by Giovanetti & Mosse (1980) was used for mycorrhizal root colonization. With a dissecting microscope at 40 magnifications, the roots corresponding to the vertical and horizontal dimensions on the grid lines were counted and recorded as mycorrhizal or non-mycorrhizal, and the percentage of mycorrhizal roots was calculated.
By comparing the dry weights of mycorrhizal and non-mycorrhizal plants, the mycorrhizal dependency (MD) of a plant is revealed as a percentage. In order to determine the MD, pre-dried shoot and root samples were used for each experimental unit's dry weight evaluation. To evaluate MD, Bagyaraj et al. (1988) developed the formula below.
MD(%)=[TDW(+M)-TDW(-M)×100]/TDW(+M)
where +M= inoculated seedlings; -M= non-inoculated seedlings.
Statistical analysis
Data were analyzed using analysis of variance (ANOVA) in SPSS software version 20.0 (SPSS Inc., Chicago, IL, USA). Significant differences were determined using LSD (the least significant difference) test at p≤0.05. A Pearson correlation analysis was also conducted to determine if there was a relationship between plant growth variables and nutrient uptake in mycorrhiza inoculated and non-inoculated plants.
Results
Substrate sterilization and mycorrhizal species both affected the growth variables of the seedlings (Table 1). Inoculation of cedar seedlings grown in sterilized substrate with H. crustuliniforme and L. delicious statistically significantly increased D (p=0.0063), H (p<0.0001), SDW (p<0.0001), RDW (p<0.0001) and DQI (p<0.0001). Seedlings inoculated with H. crustuliniforme achieved a 19% increase in diameter, a 30% increase in stem height, a 32% increase in SDW, a 27% increase in RDW and a 23% increase in DQI compared to uninoculated seedlings. When H. crustuliniforme was the only inoculant used in non-sterilized substrates, it significantly increased D (p<0.0001), SDW (p<0.0001), RDW (p<0.0001) and DQI (p<0.0001). This difference was not statistically significant in H (p=0.3891). Control treatments were more effective than T. ustale on all growth variables. Spearman correlation analysis showed that plant morphological performance variables were strongly positively correlated with each other (Table 2).
Two-way analysis of variance (ANOVA) of the effects of mycorrhizal inoculation and substrate sterilization and their interaction on growth variables of Taurus cedar seedlings. Statistical analyses were done separately on sterilized and non-sterilized substrates.
Treatments
D (mm)
H (cm)
SDW (g)
RDW (g)
DQI
Sterilized
L. delicious
3.2±0.13 a
11.1±0.08 a
1.28±0.02 b
0.84±0.02 a
0.42±0.02 a
H. crustuliniforme
3.2±0.14 a
11.3±0.19 a
1.39±0.02 a
0.85±0.03 a
0.43±0.01 a
T. ustale
2.7±0.20 b
10.2±0.10 b
1.14±0.02 c
0.72±0.01 b
0.35±0.02 b
Control (- M)
2.7±0.22 b
9.1±0.09 c
1.05±0.01 d
0.66±0.04 c
0.35±0.01 b
Mean
3.0±0.93 A
10.33±0.14 A
1.22±0.15 A
0.77±0.10 A
0.39±0.04 A
F
8.91
13.77
94.23
23.29
56.20
Non-sterilized
L. delicious
2.8±0.12 a
9.0±0.12 ns
1.11±0.07 b
0.67±0.02 b
0.35±0.01 c
H. crustuliniforme
2.9±0.13 a
9.1±0.14 ns
1.36±0.03 a
0.73±0.01 a
0.41±0.01 a
T. ustale
2.5±0.14 b
8.9±0.07 ns
1.00±0.04 d
0.59±0.03 c
0.31±0.01 d
Control (- M)
2.7±0.17 a
9.5±0.10 ns
1.16±0.05 c
0.70±0.01 ab
0.38±0.01 b
Mean
2.7±0.64 B
9.1±0.10 B
1.15±0.14 B
0.67±0.06 B
0.36±0.04 B
F
5.61
1.01
77.65
14.33
65.15
Source of variation
Df
p values
Sterilization (S)
1
0.0052
0.0001
0.0001
0.0001
0.0001
Mycorrhiza (M)
3
0.0002
0.0038
0.0001
0.0001
0.0001
S*M
3
0.0946
0.0001
0.0001
0.0001
0.0001
D: root collar diameter. H: shoot height. SDW: shoot dry weight. RDW: root dry weight. DQI: Dickson quality index. Df: degree of freedom. For each inoculation treatment, different minor letters in each column denote significant differences among inoculation treatments according to LSD test (p≤0.05). For sterilization treatment, capital letters denote significant differences among sterilization treatments according to LSD test (p≤0.05).
Pearson correlation coefficients (r) for D (mm), H (cm), SDW (g), RDW (g), DQI
The results showed that the uptake of N, P, K, Fe and Zn in the sterile substrate increased significantly (p<0.0001; p≤0.0391; p≤0.0088; p≤0.0407; p≤0.0107, respectively) in seedlings with mycorrhizal inoculation, especially those with applications of H. crustuliniforme and L. delicious, whereas the N, K, and Zn content significantly increased (p<0.0030; p≤0.0487; p≤0.0421, respectively) in the non-sterile substrate (Table 3). When comparing the sterile substrate to the non-sterile substrate, only the N uptake remained significant. The seedlings inoculated with H. crustuliniforme in both substrates generally had the highest total nutrient removal for all elements, while the T. ustale mycorrhiza inoculation produced the lowest total nutrient removal.
Two-way analysis of variance (ANOVA) of the effects of mycorrhizal inoculation and substrate sterilization and their interaction on nutrient uptake of Taurus cedar seedlings
Treatments
N
P
K
Fe
Zn
Mn
mg seedlings-1
Sterilized
L. delicious
670.0±21.2 b
51.7±15.6 ab
360.3±63.6 a
15.4±2.2 ab
1.16±0.12 a
6.22±2.08 ns
H. crustuliniforme
818.0±50.4 a
62.6±21.8 a
398.0±70.9 a
18.0±3.2 a
1.31±0.45 a
4.22±1.31 ns
T. ustale
478.0±66.2 c
37.0±20.5 b
248.5±65.9 b
11.2±5.7 bc
0.47±0.53 b
4.41±2.34 ns
Control (- M)
355.5±72.7 d
31.8±16.7 b
263.5±15.7 b
7.23±6.0 c
0.47±0.51 b
4.85±2.64 ns
Mean
585.5±52.6 A
45.6±18.7 A
310.8±54.0 A
13.0±4.3 A
0.85±0.40 A
4.93±2.09 A
F
39.68
2.95
7.94
5.71
7.42
0.50
Non-sterilized
L. delicious
429.6±58.7 b
44.4±8.6 ns
280.7±49.2 b
11.2±6.3 ns
0.72±0.31 ab
2.59±1.20 ns
H. crustuliniforme
692.1±67.2 a
60.3±8.6 ns
421.8±108.5 a
14.2±6.0 ns
1.15±0.41 a
4.52±1.16 ns
T. ustale
438.7±50.9 b
34.1±6.7 ns
287.8± 72.8 b
10.3±2.1 ns
0.53±0.07 b
4.42±0.70 ns
Control (- M)
408.8±56.7 b
37.2±9.1 ns
246.2±54.4 b
10.9±2.7 ns
0.46±0.16 b
3.46±1.46 ns
Mean
492.3±58.4 B
44.0±8.2 A
309.1±71.2 A
11.6±4.3 A
0.72±0.24 A
3.74±1.13 A
F
11.33
2.00
4.11
0.55
3.44
0.70
Source of
variation
Df
p values
Sterilization (S)
1
0.0034
0.7836
0.9442
0.3937
0.2635
0.1771
Mycorrhiza (M)
3
0.0001
0.0151
0.0007
0.0266
0.0006
0.9957
S*M
3
0.0064
0.8776
0.3237
0.2733
0.4603
0.3587
For each inoculation treatment, different minor letters in each column denote significant differences among inoculation treatments according to LSD test (p≤0.05). For sterilization treatment, capital letters denote significant differences among sterilization treatments according to LSD test (p≤0.05). Df: Degree of freedom.
A strong correlation was obtained between mineral nutrients uptake, except Mn, the other mineral nutrient uptakes were highly correlated with each other and total dry matter weight as well (Table 4). Only Mn uptake had a positive correlation with N uptake.
Pearson correlation coefficients (r) for nutrient uptake (mg seedings<sup>-1</sup>) values of Taurus Cedar seedlings
N
P
K
Fe
Zn
Mn
P
0.747****
K
0.836****
0.807****
Fe
0.644****
0.230ns
0.443****
Zn
0.814****
0.883****
0.814****
0.329ns
Mn
0.150ns
0.287ns
0.140ns
-0.024ns
0.409*
TDW
0.943****
0.686***
0.827****
0.641***
0.796****
0.263ns
TDW (total dry weight).
p<0.05,
p<0.01,
p<0.001,
p<0.0001.
ns: non-significant.
The highest root colonization rate (21%) was seen in seedlings that were inoculated with H. crustuliniforme in sterile substrate (Table 5). The seedlings inoculated with H. crustuliniforme exhibited the maximum root colonization (6%), in the non-sterilized substrate; L. delicious came in second in both substrates. However, the roots of T. ustale and control (uninoculated) seedlings were not colonized by any EMF inoculation. In root colonization, seedlings inoculated with H. crustuliniforme and L. delicious grown on sterilized substrate reached approximately four times higher values than the non-sterilized ones. The effects of mycorrhiza, sterilization, and their combination varied significantly.
Means and level of significance of root colonization ratio of Taurus cedar seedlings
Treatments
Colonization
%
Sterilized
L. delicious
17±3.4 b
H. crustuliniforme
21±6.2 a
T. ustale
0 c
Control (- M)
0c
Mean
9.5 A
Non-sterilized
L. delicious
4±2.1 b
H. crustuliniforme
6±2.5 a
T. ustale
0 c
Control (- M)
0 c
Mean
2.5 B
Source of variation
Df
Colonization
%
F
p
Sterilization (S)
1
64.79
0.0001
Mycorrhiza (M)
3
65.45
0.0001
S*M
3
21.81
0.0001
For each inoculation treatment, different minor letters in each column denote significant differences among inoculation treatments according to LSD test (p≤0.05). For sterilization treatment, capital letters denote significant differences among sterilization treatments according to LSD test (p≤0.05). Standard error: 2.75
Mycorrhizal dependency was higher in sterilized substrates than in non-sterilized substrates. Among the fungal species tested, mycorrhizal inoculation into sterilized substrate increased the MD value of cedar seedlings. H. crustuliniforme mycorrhiza inoculated into seedlings grown in both sterilized and non-sterilized substrates determined the highest dependence on mycorrhiza, 24.7% and 12.2%, respectively (Fig. 2). However, inoculation with L. delicious and T. ustale species in non-sterilized substrates did not contribute to cedar seedlings and resulted in negative MD values of -4.9% and -10.9%, respectively.
Mycorrhizal dependency (MD) of inoculated seedlings in the different growth substrates, Ld (<italic toggle="yes">Lactarius delicious</italic>), Hc (<italic toggle="yes">Hebeloma crustuliniforme</italic>), Tu (<italic toggle="yes">Tricholoma ustale</italic>)
Discussion
The results revealed that mycorrhiza had a positive effect on all growth variables of seedlings in the sterilized substrate. Taurus cedar seedlings grown on non-sterile substrate also had a significant effect on growth variables other than stem height. These findings are consistent with many studies in the literature reporting the positive effects of mycorrhizal inoculation on seedling biomass (Nunez et al., 2006; Yin et al., 2020; Aryal et al., 2021; Repáč et al., 2022). It was reported by Kidd et al. (1984) and Socha et al. (2022) that inoculation with H. crustuliniforme had positive effects on the growth of cedar seedlings. This may be supported by increases in the growth of seedlings inoculated with H. crustuliniforme under field conditions. In particular, inoculation with H. crustuliniforme significantly increased the DQI values of seedlings. According to Souza et al. (2018), DQI is a good indicator of the quality of forest seedlings, as it includes robustness and the balance of seedling biomass distribution in its calculation, where the greater the value of the index, the better the quality of the seedlings. It is understood that inoculation with H. crustuliniforme is important in the production of quality seedlings, which is one of the objectives of this study.
It is hypothesized that the reason why mycorrhiza in sterilized substrates performs better in all growth variables and MD values of seedlings may be because the mycorrhiza inoculated into the substrate, without the help of other microorganisms, benefits the plant by interacting with the roots of the plant in a healthier way. Ortas (2003) stated that soil sterilization has a much greater effect on plant growth and development of mycorrhizal fungi due to the removal of other microorganisms present in the soil and competing with plant roots for nutrients and other beneficial organic materials. The results of many researchers have reported that soil sterilization increases plant growth (Semchenko et al., 2007; Mahmood et al., 2014; Ortas et al., 2016).
The research is in line with the fact that inoculating seedlings with H. crustuliniforme and L. delicious has a favorable effect on some nutrient uptake (Brunner & Brodbeck, 2001; Turjaman et al., 2006). Mycorrhiza inoculation has a key role in promoting plant growth in the low-fertility soils in mountainous regions where Taurus cedar plants are found, particularly in soils with high lime content and low nutrient concentrations. This is vital for the ecosystem's sustainability. Sterilization likely permits the release of far more nitrogen minerals, which could explain why N absorption is more efficient in the sterile substrate than in the non-sterile. The results revealed that Taurus cedar fed plants more effectively and selectively when H. crustuliniforme and L. delicious mycorrhiza were applied.
Although H. crustuliniforme and L. delicious were statistically different in root colonization of seedlings, the expected level of colonization could not be detected in the roots of cedar seedlings. Smith & Read (2008) stated that mycorrhizal species are selective regarding the plant species they infect plant roots. This suggests that the reason why it does not cause sufficient colonization in the root is due to the physiology of the cedar. As a matter of fact, Bouckcim & Mousain (2001) showed in their study with Cedrus atlantica that there were difficulties in mycorrhizal colonization in cedar seedlings. The Cedrus genus lacks the capillary root density necessary for ectomycorrhiza symbiosis, which explains why, although having taproots and a deep root density, it does not quickly develop fine roots near the surface. As a matter of fact, Bouckim & Mousain (2001), citing many studies; stated that there were difficulties in mycorrhizal colonization in cedar seedlings.
For the future, the major goal of study should be is to determine how much mycorrhizal activity will occur under harsh field circumstances and to help nurseries produce mycorrhiza-inoculated seedlings. To improve the success of afforestation operations in dry and semi-arid settings, further research is required about the habitat adaptation of various mycorrhizae species.
Conclusions
The results showed that H. crustuliniforme and L. delicious inoculation significantly increased the morphological variables, uptake of mineral nutrients, root colonization and mycorrhizal dependence of the seedlings. Substrate sterilization also affected seedling morphological variables, root colonization and mycorrhizal dependence. Research findings showed that mycorrhizal colonization was higher in sterile substrates, which promoted seedling growth and nutrient uptake especially. Although the findings of our study are limited to Taurus cedar-mushroom combinations, they may also apply to different EMF and many other valuable host tree species. Planting Taurus cedar seedlings in the semi-arid climate zone is the primary aim of the study, and in the continuation of the study, more information will be obtained about the performance of mycorrhizae in open areas. In this context, more research is needed on the adaptation of different mycorrhizal species to habitats to increase the success of afforestation efforts in arid and semi-arid regions.
Acknowledgements
We would like to thank the staff of the Eastern Mediterranean Forestry Research Institute for supporting the field trips and nursery and greenhouse studies.
Competing interests
The authors have declared that no competing interests exist.
Authors’ contributions
Sedat Tufekci: Conceptualization, Data curation, Formal analysis. Investigation. Methodology. Project administration. Visualization. Writing – original draft. Writing – review & editing. Ibrahim Ortas: Conceptualization. Data curation. Methodology. Project administration. Supervision. Visualization. Writing – original draft. Writing – review & editing.
Funding
The authors received no specific funding for this work.
Abbreviations usedEMF
ectomycorrhizal fungi
-M
uninoculated
+M
inoculated
MMN
Modified Melin-Nokrans
D
root collar diameter
H
shoot height
SDW
shoot dry weight
RDW
total dry weight
TDW
shoot height
DQI
Dickson quality index
MD
mycorrhizal dependency
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