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Article

Shading Impairs Mycorrhizal Benefits on Plant Growth, Leaf Gas Exchange, and Active Ingredients in Polygonum cuspidatum

by
Ci Deng
1,
Ze-Zhi Zhang
2,
Fábio Sérgio Barbosa da Silva
3,
Abeer Hashem
4,
Elsayed Fathi Abd_Allah
5,
Ying-Ning Zou
1 and
Qiang-Sheng Wu
1,*
1
Hubei Key Laboratory of Spices & Horticultural Plant Germplasm Innovation & Utilization, College of Horticulture and Gardening, Yangtze University, Jingzhou 434025, China
2
Shiyan Academy of Agricultural Sciences, Shiyan 442000, China
3
Laboratório de Análises, Pesquisas e Estudos em Micorrizas (LAPEM/UPE)-Centro de Pesquisas do Instituto de Ciências Biológicas, Universidade de Pernambuco, Rua Arnóbio Marquês, 310, Santo Amaro, Recife 50100-130, PE, Brazil
4
Botany and Microbiology Department, College of Science, King Saud University, P.O. Box 2460, Riyadh 11451, Saudi Arabia
5
Plant Production Department, College of Food and Agricultural Sciences, King Saud University, P.O. Box 2460, Riyadh 11451, Saudi Arabia
*
Author to whom correspondence should be addressed.
Horticulturae 2024, 10(10), 1078; https://doi.org/10.3390/horticulturae10101078
Submission received: 5 September 2024 / Revised: 3 October 2024 / Accepted: 7 October 2024 / Published: 9 October 2024
(This article belongs to the Special Issue New Insights into Protected Horticulture Stress)
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Abstract

:
Polygonum cuspidatum, an important medicinal plant, often experiences shading from surrounding vegetation during its growth phase, raising questions about the impact of such conditions on the functionality of arbuscular mycorrhizal fungi. This study investigated the effects of an arbuscular mycorrhizal fungus (Funneliformis mosseae) on the growth, leaf gas exchange, and concentrations of active ingredient concentrations in leaves and roots of P. cuspidatum under shading (with a 72% shading rate) conditions. A nine-week shading intervention significantly suppressed root colonization by F. mosseae and the formation of soil mycorrhizal mycelium. Shading significantly inhibited the above-ground growth performance, biomass production, leaf photosynthetic rate, transpiration rate, stomatal conductance, and intercellular CO2 concentration, while F. mosseae significantly increased these variables in the absence of shading. Plant height, leaf biomass, stem biomass, leaf photosynthetic rate, transpiration rate, and stomatal conductance were all decreased by F. mosseae when the plants were shaded. The shading treatment also significantly diminished the concentrations of active components measured in both leaves and roots. Under no-shading conditions, F. mosseae significantly boosted the concentrations of polydatin, resveratrol, aloe-emodin, emodin, chrysophanol, and physcion in roots, as well as the concentrations of polydatin and chrysophanol in leaves. Conversely, in the presence of shading, F. mosseae distinctly reduced these active ingredient levels in roots, followed by an increase in leaf polydatin and chrysophanol concentrations. In summary, shading substantially impaired the mycorrhizal benefits on plant growth, leaf gas exchange, and root active ingredients in P. cuspidatum, highlighting the importance of sufficient light to maximize mycorrhizal contributions.

1. Introduction

Polygonum cuspidatum Sieb. et Zucc, a member of the Polygonaceae family, is extensively used for both landscaping and medicinal component extraction. The plant’s primary medical active components, polydatin and resveratrol, are known for their anti-aging, anti-cancer, and antioxidant qualities [1,2]. The significant medicinal potential of P. cuspidatum has led to the overharvesting of wild populations, diminishing the availability of its products. To maintain a balanced market supply and demand, the cultivation of P. cuspidatum has begun to shift towards artificial methods. Consequently, it is crucial to address critical issues regarding the promotion of P. cuspidatum’s vegetative growth and the increased accumulation of its medicinal components.
Light is a crucial external factor affecting the biosynthesis and accumulation of secondary metabolites in plants. Photosynthesis, a distinctive physiological process in plants, is subject to a range of factors than can be categorized as either internal or external [3,4]. The intensity of light is an important external factor affecting plant growth [5]. In response to shading, plants typically exhibit reduced dry matter production, maintenance of photosynthesis in leaves at the expense of root growth, longer stem tip development, and thinner leaves [6]. Shading can promote vegetative growth, biomass production, the root/shoot ratio, and growth rate in certain plants [7]. Lv et al. [8] reported that appropriate shading improved the secondary metabolite content of Trollius chinensis plants. In the case of cultivated P. cuspidatum plants, surrounding trees often create a shady environment, and it is not clear whether shading also affects secondary metabolite concentrations of P. cuspidatum.
The colonization of host plant roots by soil arbuscular mycorrhizal fungi (AMF) leads to significant changes in the plant’s carbon cycle and photosynthetic processes [9]. AMF, capable of forming symbiotic relationships with a multitude of terrestrial plants, receive 4–20% of the host’s fixed carbon in the form of lipids and carbohydrates, in exchange for providing essential minerals and water to their plant partners [10]. Ding et al. [11] observed that in citrus plants experiencing drought stress, AMF enhanced the transpiration rate (Tr), stomatal conductance (Gs), and net photosynthetic rate (Pn). AMF also stimulate plant growth, nutrient acquisition, and drought resilience by modifying the rhizosphere microenvironment, as evidenced by studies from Leifheit et al. [12] and Rillig et al. [13]. When plants are grown in nutrient-limited soils, AMF tend to favor the growth of the host plant; whereas, if AMF growth is constrained by insufficient plant carbohydrates, the benefits conferred by AMF to the plant become less pronounced [14,15]. A study by Zheng et al. [16] indicates that shading negatively impacted AMF communities and potentially led to a reduction in the carbon allocated by the host plant to the fungi, depending on the fungal species. Menezes et al. [17] reported that shading increased soil spore numbers but decreased the rate of mycorrhizal colonization in roots in Cenchrus ciliaris and Clitoria ternatea. Wang et al. [18] found that the effects of AMF on rice plants were modulated by both waterlogging and shading stresses: AMF had an inhibitory effect under waterlogging and shading, and a positive or neutral effect on rice growth and yield under non-waterlogged conditions. Shukla et al. [19] found that low-light conditions delayed the formation of vesicles and mycorrhizal extraradical spores. Furthermore, the level of secondary metabolites is markedly enhanced by AMF inoculation, particularly in medicinal plants [20,21]. Jiang et al. [22] discovered that AMF substantially elevated the levels of various primary and secondary metabolites in white clover plants. How AMF inoculation affects the active ingredient content of medicinal plants under shaded conditions remains unclear.
The effects of shading on plant secondary metabolism are well documented. Additionally, AMF inoculation has been shown to enhance plant growth and regulates secondary metabolite levels. However, the combined effects of AMF inoculation and shading on the growth and secondary metabolite levels of P. cuspidatum plants remain unclear. Therefore, the aim of this study was to investigate the effects of AMF inoculation on the growth, gas exchange, and active compound levels of P. cuspidatum plants under shaded conditions. By evaluating the combined effects of shading and AMF inoculation, this research aimed to provide new insights into optimizing cultivation conditions and bioactive compound production in P. cuspidatum.

2. Materials and Methods

2.1. Experimental Design

The experiment included four distinct treatments: inoculation without F. mosseae in combination with no shading (Control); inoculation without F. mosseae in combination with shading (Shade); inoculation with F. mosseae in combination with no shading (Fm); inoculation with F. mosseae in combination with shading (Shade + Fm). The experimental setup followed a completely randomized block design, with six replicates per treatment, amounting to a total of 24 pots (48 plants).

2.2. Plant Culture

Seeds of P. cuspidatum were germinated in autoclaved (121 °C, 0.11 MPa, 2 h) sands on 30 February 2022. On 31 May 2022, five-leaf-old seedlings of P. cuspidatum with uniform size were transplanted into plastic pots containing 1.85 kg of autoclaved substrates (a mixture of soil and sand at a ratio of 2:1 by volume). The soil characteristics were pH 6.3, Olsen-P 40.21 mg/kg, available K 15.42 mg/kg, ammonium nitrogen 30.37 mg/kg, nitrate nitrogen 6.15 mg/kg, and soil organic carbon 8.47 mg/g. The AMF inoculation treatment was carried out during the transplanting. The F. mosseae (Nicol. & Gerd.) Gerdemann & Trappe was provided by the Institute of Root Biology, Yangtze University. The fungal strain was propagated by Trifolium repens for 10 weeks under potted conditions, and mycorrhizalized root segments and growth substrates were collected as the F. mosseae inoculum, containing approximately 20 fungal spores per gram. For inoculation with F. mosseae, 150 g of mycorrhizal fungal inoculum were applied; an equal amount of autoclaved mycorrhizal inoculum were used for the uninoculation treatment of F. mosseae.
The treated P. cuspidatum plants were placed in a controlled environmental condition (26 °C/18 °C, day/night temperature, 16 h/8 h; the light intensity of 8500 Lux; the relative humidity of 68%) for a period of 6 weeks. The plants were watered daily with 50 mL distilled water per pot. The plants did not receive additional chemical fertilizers during the experiment. Following this, the shading treatment was initiated, with half of the plants subjected to the shading treatment using a single-layer 4-needle black sunshade net (Taizhou Luqiaojuyang Sunshade Company, Taizhou, China) with a 72% shading rate, resulting in a light intensity of approximately 2400 Lux post-shading. The remaining plants were left unshaded with a light intensity of 8500 Lux (26 °C/18 °C, day/night temperature, 16 h/8 h; the relative humidity of 68%). This shading treatment was maintained for nine weeks, with the harvest completed on 13 September 2022.

2.3. Determination of Plant Growth, Root Morphology, and Leaf Gas Exchange

Following a nine-week shading treatment, the experimental period was concluded. Prior to plant harvest, the following growth parameters were recorded: height, stem diameter, and total leaf number. Additionally, a Li-6400 Infra-red Gas Analyzer (Li-cor, Lincoln, NE, USA) was utilized between 9:00 and 11:00 a.m. to assess the gas exchange parameters (intercellular CO2 concentration, Ci; stomatal conductance, Gs; transpiration rate, Tr; net photosynthetic rate, Pn) of the fourth functional leaf from the top. The plants were exposed to light for half an hour prior to measurement for activation, and then measurements were conducted in a sealed chamber to minimize environmental impacts. Data were recorded within 5 s of data stabilization.
One plant’s leaves, roots, and stems were harvested, treated with liquid nitrogen, and kept at −72 °C until active ingredient analysis. The biomass of the remaining plant material was measured after separating it into above- and below-ground parts. Root images were captured using an Epson root scanner, and the root length, surface area, volume, projected area, and average diameter were analyzed using WinRHIZO software (v2007).

2.4. Determination of Root Mycorrhizal Colonization and Soil Mycelium Length

Approx. 2 cm length root segments were chosen and stained with trypan blue (0.05%, w/v) [23]. Following microscopic examination, the root mycorrhizal colonization rate was quantified as the percentage of AMF-colonized root segment lengths against the total observed root segment lengths. The soil mycelium length was assayed with the protocol outlined by Bethlenfalvay and Ames [24].

2.5. Determination of Active Ingredient Levels in Leaves and Roots

The concentrations of six active ingredients—aloe-emodin, chrysophanol, emodin, physcion, polydatin, and resveratrol—were quantified in both leaves and roots through the extraction method and high-performance liquid chromatography (HPLC), as detailed in Sun et al. [25]. The analysis employed an Agela Venusil XBP C18 column (4.6 × 250 mm, 5 μm) coupled with an LC-20AT (Shimadzu) HPLC system. The mobile phases consisted of acetonitrile (phase A) and 0.1% formic acid (phase B). Specific assay conditions and linear gradient elution parameters were outlined by Sun et al. [25].

2.6. Statistical Analysis

The data were analyzed using the SPSS 26.0 software platform (SPSS Inc., Chicago, IL, USA), and Duncan’s multiple range tests were applied to identify significant (p < 0.05) differences. Figures were generated using Origin Software (v2021).

3. Results

3.1. Changes in Root Mycorrhizal Colonization and Soil Mycelium Length

No root mycorrhizas or soil mycelium was presented in P. cuspidatum plants inoculated without F. mosseae, while F. mosseae-inoculated P. cuspidatum plants displayed both root mycorrhizas and soil mycelium. The root mycorrhizal colonization rate was 31.35% and 56.67% in the seedlings treated by Shade + Fm and Fm, respectively; and mycorrhizal mycelium length in soil was 15.09 g/cm and 23.11 g/cm in the rhizosphere of treated seedlings by Shade + Fm and Fm, respectively. Root mycorrhizal colonization and soil mycelium length in inoculated plants were considerably decreased by the shading treatment by 0.45- and 0.35-fold, respectively.

3.2. Changes in Biomass Production

Shading and inoculation with F. mosseae had pronounced effects on the growth of P. cuspidatum (Figure 1a). Shading significantly reduced the height, stem biomass, and root biomass of non-inoculated P. cuspidatum by 22.3%, 22.4%, and 46.9%, respectively (Figure 1b–g; Table 1). Inoculated plants showed significantly lower plant height, stem diameter, leaf number, and biomass of leaves, stems, and roots under shading versus no-shading, with respective reductions of 57%, 18.0%, 37.9%, 55.2%, 54.6%, and 70.0%. The effect of inoculation with F. mosseae on plant growth parameter varied: without shading, F. mosseae inoculation significantly increased plant height, leaf number, leaf biomass, stem biomass, and root biomass by 29.1%, 25.0%, 26.9%, 34.5%, and 57.3%, respectively; under shading conditions, inoculation with F. mosseae notably decreased plant height, leaf biomass, and stem biomass by 28.6%, 37.8%, and 21.2%, respectively. F. mosseae and shading significantly interacted on height and root biomass (Table 1).

3.3. Changes in Root Morphological Variables

The root morphological variables of P. cuspidatum were significantly affected by F. mosseae inoculation and shading treatment (Figure 1a). Inoculation with F. mosseae significantly influenced the root morphological variables of P. cuspidatum (Figure 2a–e; Table 1). Under shading versus no-shading conditions, non-inoculated P. cuspidatum plants exhibited substantial reductions in root total length, projected area, and volume, with decreases of 35.0%, 17.6%, and 55.2%, respectively. Inoculation with F. mosseae showed significant declines across all measured root parameters under shading versus no-shading conditions, with reductions of 63.1%, 37.9%, 35.2%, 26.4%, and 78.2% versus no-shading conditions, with reductions of 63.1%, 37.9%, 35.2%, 26.4%, and 78.2% in total length, projected area, surface area, diameter, and volume, respectively. The effect of F. mosseae inoculation on P. cuspidatum roots varied under shading and no-shading conditions: in the absence of shading, inoculation with F. mosseae significantly increased root total length, projected area, surface area, and volume, with increases of 27.9%, 20.9%, 19.9%, and 64.9%, respectively; under shading conditions, the inoculation exhibited an opposing trend, with a notable decrease in root total length by 27.4% and no significant change in other root morphological variables.

3.4. Changes in Leaf Gas Exchange

Both inoculated and uninoculated plants showed a significant suppression of leaf Pn, Tr, and Gs under shading conditions (Figure 3a–d). Under no-shading conditions, F. mosseae inoculation significantly increased leaf Pn, Tr, Gs, and Ci by 74.2%, 60.8%, 78.6%, and 7.0%, respectively, compared with no-F. mosseae inoculation. Nevertheless, under shading conditions, F. mosseae inoculation significantly reduced leaf Pn, Tr, and Gs by 12.2%, 26.9%, and 24.1%, respectively, compared with no-F. mosseae inoculation. The interaction between inoculation with F. mosseae and shading significantly influenced leaf Pn, Tr, and Gs (Table 1).

3.5. Changes in Active Ingredient Levels in Roots

The analysis of the root samples led to the successful identification of all six active ingredients (Figure 4a–f). F. mosseae inoculation considerably elevated root polydatin, resveratrol, aloe-emodin, emodin, chrysophanol, and physcion levels under no-shading conditions by 25.9%, 4.8%, 22.7%, 20.3%, 16.4%, and 17.8%, respectively, in comparison to no-F. mosseae inoculation. However, in comparison to no-F. mosseae inoculation, inoculation with F. mosseae under shading conditions significantly reduced root polydatin, resveratrol, emodin, chrysophanol, and physcion levels by 35.9%, 41.9%, 8.6%, 23.5%, and 16.9%, respectively. F. mosseae inoculation and shading significantly interacted with each other on all the six active ingredients in roots (Table 1).

3.6. Changes in Active Ingredient Levels in Leaves

The analysis of the leaf samples revealed the presence of four active ingredients: physcion, polydatin, emodin, and chrysophanol (Figure 5a–d). However, resveratrol and aloe-emodin were not detected. Compared to no-F. mosseae inoculation, inoculation with F. mosseae led to a significant 14.3% reduction in physcion levels, while it caused a substantial increase in leaf polydatin and chrysophanol levels by 51.7% and 6.1%, respectively, under no-shading conditions. When F. mosseae was inoculated under shaded conditions, the levels of leaf polydatin, emodin, and chrysophanol increased significantly by 68.7%, 90.7%, and 159.7.%, respectively. In the absence of F. mosseae inoculation, the levels of physcion decreased significantly by 18.4%. Four active ingredient levels in leaves were significantly interacted by Shading and F. mosseae inoculation (Table 1).

3.7. Principal Component Analysis (PCA)

A PCA was performed on the tested variables. The results displayed that the principal component 1 (PC1) accounted for 73.7% of the total variation, which could distinguish the shading and no-shading treatments from the four treatments (Figure 6). The principal component 2 (PC2) accounted for 11.9% of the total change. In addition, stem biomass, root biomass, and polydatin and emodin levels in roots contributed the most to PC1. On the contrary, chrysophanol concentrations in leaves and roots had the highest load on PC2.

4. Discussion

This study showed that, in comparison to the no-shading treatment, the shading treatment dramatically reduced soil mycelium length and root mycorrhizal colonization in P. cuspidatum plants inoculated with F. mosseae. This finding is in line with earlier studies reported by Olsson et al. [26], Heinemeyer et al. [27], and Shukla et al. [28]. Shi et al. [29] reported that shading substantially reduced root AMF colonization in plants of the Tibetan Plateau. Vesicles are considered as important organs for AMF to store abundant lipids, and a decrease in light intensity inhibits the resources available for AMF storage [30]. When plants are carbon limited, host plants tend to reduce their allocation of carbon to roots and arbuscular mycorrhizae [31], which may explain the observed reduction in AM fungal abundance by shading.
In this experiment, the application of shading significantly diminished plant growth behavior, biomass production, and root morphological variables of P. cuspidatum, irrespective of AMF inoculation status. F. mosseae inoculation significantly boosted plant biomass exclusively under no-shading conditions. However, F. mosseae inoculation under shading conditions led to a significant reduction in plant height and leaf and stem biomass, but it had no significant effect on stem diameter, leaf number, and root biomass. Plants under shading allocated more carbohydrates to their above-ground parts rather than investing in roots and mycorrhizae [32]. Utilizing 13C, Olsson et al. [26] observed that shading did not diminish carbon allocation to mycorrhizal structures, suggesting that shaded plants might be more parasitized by AMF. Despite the potential for AMF to act as parasites on plant roots, mycorrhizal structures persist even under very low light intensities conditions [33]. The transition between symbiosis and parasitism in the AMF–host plant relationship as a function of light intensity warrants in-depth investigation.
Light intensity is closely linked to plant growth, with extremes of either too much or insufficient light intensity being detrimental to photosynthesis in plant chloroplasts [34]. In this study, 72% shading represented a low-light stress, resulting in a significant decrease in leaf gas exchange parameters in both inoculated and uninoculated plants, which consequently limited the biomass production of the plant [35]. The results of Deng et al. [36] on P. cuspidatum inoculated with F. mosseae under phosphorus-deficient and phosphorus-sufficient conditions showed that inoculation with F. mosseae significantly increased leaf gas exchanges under no-shading conditions. However, under shading conditions, inoculation with F. mosseae significantly reduced leaf Pn, Tr, and Gs, which may be attributed to the host plant reducing carbon allocation to the arbuscular mycorrhizae of P. cuspidatum low-light conditions, shifting the mycorrhizal growth response of the plant from positive to negative. The carbon–phosphorus exchange between the host plant and AMF is crucial for arbuscular mycorrhizal symbiosis [31,37,38], where AMF relies entirely on photosynthetic carbon products supplied by the host plant for the maintenance of both intraradical and extraradical mycorrhizal structures [39,40,41,42]. In mycorrhizal plants, an abrupt reduction in light intensity can cause a rapid breakdown in the transfer of phosphorus from AMF to the host plant [32,43]. The potential benefits of AMF diminish when plants are subjected to prolonged shading, making it difficult to obtain energy for fungal growth. Further in-depth studies on the carbon exchange strategies between AMF and plants under shading conditions are required.
P. cuspidatum is a traditional Chinese herbal medicine primarily composed of tannins, polysaccharides, flavonoids (catechins, quercetin, and apigenin), anthraquinones (emodin, polygonin, and chrysophanol), and stilbenes (resveratrol, polydatin, and their derivatives) [44]. In this study, six active ingredients were detected in the roots, while only four were found in the leaves, with aloe-emodin and resveratrol being absent, suggesting that P. cuspidatum’s roots are the primary site for the synthesis of these active ingredients. In this work, F. mosseae dramatically raised the concentrations of polydatin and chrysophanol in the leaves, as well as the concentrations of all six active ingredients in the roots when there was no shade. This suggests that AMF accelerates the production of secondary metabolites in medicinal plants. A parallel effect was observed in the study of Wu et al. [45], where inoculation with native AMF species promoted root growth of Salvia miltiorrhiza and boosted the production of secondary metabolites, particularly phenolic acids.
In contrast, the present study revealed that inoculation with F. mosseae significantly reduced the concentrations of five of the six active ingredients in the roots under shading conditions. AMF affected the host plants’ ability to produce secondary metabolites under adversity [46,47]. Machiani et al. [48] demonstrated that the inoculation of F. mosseae under water deficit conditions significantly increased the concentrations of thymol, p-cymene, and γ-terpinene in Thymus mongolicus plants. Similarly, Amanifar and Toghranegar [49] reported that AMF significantly increased the production of valerenic acid in salt-stressed valerian plants. This may be associated with the previously mentioned shift in the mycorrhizal growth response towards a negative effect under shading conditions. Ultimately, shading negatively impacts host photosynthesis, thereby hindering carbohydrate production and reducing the carbon source available for mycorrhizal growth from the host plant [16], which in turn suppresses mycorrhizal functional responses, such as the acquisition of host phosphorus [50]. As a consequence, under shading conditions, the primary objective of arbuscular mycorrhizae becomes securing sufficient carbon sources from the host plant for survival, leading to a decline in their regulation of secondary metabolites in roots. Nonetheless, F. mosseae also boosted the concentrations of polydatin, emodin, and chrysophanol concentrations in the leaves under shading conditions, as the reduction in shoot biomass production by F. mosseae under shading conditions caused these concentrations to increase. In a word, the mechanism underlying the secondary metabolism response triggered by reduced carbon supply to mycorrhizae under shading conditions requires further elucidation [51].

5. Conclusions

This study revealed that under no-shading conditions, F. mosseae inoculation dramatically increased plant growth, leaf gas exchange, and active component concentrations in roots and leaves. Shading, however, obviously inhibited these benefits of mycorrhizas on P. cuspidatum, especially in root active ingredient concentrations. The combination of AMF and shading would negatively affect P. cuspidatum. Consequently, to optimize mycorrhizal function in the cultivation of P. cuspidatum, it is essential to ensure adequate light intensity. However, further investigation is needed to understand how shading affects the formation of host mycorrhizas and their subsequent functional effects, especially at the molecular level.

Author Contributions

Conceptualization, Q.-S.W.; Data curation, C.D.; Investigation, C.D.; Methodology, C.D.; Resources, Z.-Z.Z. and Q.-S.W.; Supervision, Q.-S.W.; Writing—original draft, C.D.; Writing—review and editing, Y.-N.Z., A.H., E.F.A., F.S.B.d.S. and Q.-S.W. All authors have read and agreed to the published version of the manuscript.

Funding

The authors would like to extend their sincere appreciation to Researchers Supporting Project Number (RSP2024R134), King Saud University, Riyadh, Saudi Arabia.

Data Availability Statement

All the data supporting the findings of this study are included in this article.

Acknowledgments

The authors would like to extend their sincere appreciation to Researchers Supporting Project Number (RSP2024R134), King Saud University, Riyadh, Saudi Arabia.

Conflicts of Interest

The authors declare no conflicts of interest.

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Figure 1. Changes in growth performance (a), height (b), stem diameter (c), leaf number (d), leaf biomass (e), stem biomass (f), and root biomass (g) in Polygonum cuspidatum plants after inoculation with Funneliformis mosseae under shading and no-shading conditions. Significant (p < 0.05) differences are indicated by different letters on the bar (means ± SD, n = 4). Abbreviations: Control: inoculation without F. mosseae in combination with no-shading; Shade: inoculation without F. mosseae in combination with shading; Fm: inoculation with F. mosseae in combination with no-shading; Shade + Fm: inoculation with F. mosseae in combination with shading.
Figure 1. Changes in growth performance (a), height (b), stem diameter (c), leaf number (d), leaf biomass (e), stem biomass (f), and root biomass (g) in Polygonum cuspidatum plants after inoculation with Funneliformis mosseae under shading and no-shading conditions. Significant (p < 0.05) differences are indicated by different letters on the bar (means ± SD, n = 4). Abbreviations: Control: inoculation without F. mosseae in combination with no-shading; Shade: inoculation without F. mosseae in combination with shading; Fm: inoculation with F. mosseae in combination with no-shading; Shade + Fm: inoculation with F. mosseae in combination with shading.
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Figure 2. Changes in root total length (a), projected area (b), surface area (c), average diameter (d), and volume (e) in Polygonum cuspidatum plants after inoculation with Funneliformis mosseae. Significant (p < 0.05) differences are indicated by different letters on the bar (means ± SD, n = 4). See Figure 1 for abbreviations.
Figure 2. Changes in root total length (a), projected area (b), surface area (c), average diameter (d), and volume (e) in Polygonum cuspidatum plants after inoculation with Funneliformis mosseae. Significant (p < 0.05) differences are indicated by different letters on the bar (means ± SD, n = 4). See Figure 1 for abbreviations.
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Figure 3. Changes in leaf photosynthetic rate (a), transpiration rate (b), stomatal conductance (c), and intercellular CO2 concentrations (d) in Polygonum cuspidatum after inoculation with Funneliformis mosseae under shading and no-shading conditions. Significant (p < 0.05) differences are indicated by different letters on the bar (means ± SD, n = 4). See Figure 1 for abbreviations.
Figure 3. Changes in leaf photosynthetic rate (a), transpiration rate (b), stomatal conductance (c), and intercellular CO2 concentrations (d) in Polygonum cuspidatum after inoculation with Funneliformis mosseae under shading and no-shading conditions. Significant (p < 0.05) differences are indicated by different letters on the bar (means ± SD, n = 4). See Figure 1 for abbreviations.
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Figure 4. Effects of inoculation with Funneliformis mosseae on root polydatin (a), resveratrol (b), aloe-emodin (c), emodin (d), chrysophanol (e), and physcion (f) in Polygonum cuspidatum after inoculation with Funneliformis mosseae under shading and no-shading conditions. Significant (p < 0.05) differences are indicated by different letters on the bar (means ± SD, n = 4). See Figure 1 for abbreviations.
Figure 4. Effects of inoculation with Funneliformis mosseae on root polydatin (a), resveratrol (b), aloe-emodin (c), emodin (d), chrysophanol (e), and physcion (f) in Polygonum cuspidatum after inoculation with Funneliformis mosseae under shading and no-shading conditions. Significant (p < 0.05) differences are indicated by different letters on the bar (means ± SD, n = 4). See Figure 1 for abbreviations.
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Figure 5. Effects of inoculation with Funneliformis mosseae on leaf polydatin (a), emodin (b), chrysophanol (c), and physcion (d) in Polygonum cuspidatum after inoculation with Funneliformis mosseae under shading and no-shading conditions. Significant (p < 0.05) differences are indicated by different letters on the bar (means ± SD, n = 4). See Figure 1 for abbreviations.
Figure 5. Effects of inoculation with Funneliformis mosseae on leaf polydatin (a), emodin (b), chrysophanol (c), and physcion (d) in Polygonum cuspidatum after inoculation with Funneliformis mosseae under shading and no-shading conditions. Significant (p < 0.05) differences are indicated by different letters on the bar (means ± SD, n = 4). See Figure 1 for abbreviations.
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Figure 6. Principal component analysis of tested variables in this study.
Figure 6. Principal component analysis of tested variables in this study.
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Table 1. Interacted significance of variables.
Table 1. Interacted significance of variables.
VariablesAMFShadingInteractionVariablesAMFShadingInteraction
HeightNS****Stomatal conductance******
Stem diameterNS*NSIntercellular CO2 level***NS
Leaf numberNS**NSRoot polydain******
Leaf biomass****NSRoot resveratrolNS****
Stem biomass****NSRoot aloe-emodin****
Root biomass******Root emodin ** ****
Root total length****NSRoot chrysophanolNS****
Project area ****NSRoot physcionNS****
Surface area ****Leaf polydain******
Average diameter **NSNSLeaf emodin******
Volume *****Leaf chrysophanol******
Photosynthetic rate******Leaf physcion*****
Transpiration rate******
NS, not significant at p < 0.05; *, p < 0.05; **, p < 0.01.
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MDPI and ACS Style

Deng, C.; Zhang, Z.-Z.; da Silva, F.S.B.; Hashem, A.; Abd_Allah, E.F.; Zou, Y.-N.; Wu, Q.-S. Shading Impairs Mycorrhizal Benefits on Plant Growth, Leaf Gas Exchange, and Active Ingredients in Polygonum cuspidatum. Horticulturae 2024, 10, 1078. https://doi.org/10.3390/horticulturae10101078

AMA Style

Deng C, Zhang Z-Z, da Silva FSB, Hashem A, Abd_Allah EF, Zou Y-N, Wu Q-S. Shading Impairs Mycorrhizal Benefits on Plant Growth, Leaf Gas Exchange, and Active Ingredients in Polygonum cuspidatum. Horticulturae. 2024; 10(10):1078. https://doi.org/10.3390/horticulturae10101078

Chicago/Turabian Style

Deng, Ci, Ze-Zhi Zhang, Fábio Sérgio Barbosa da Silva, Abeer Hashem, Elsayed Fathi Abd_Allah, Ying-Ning Zou, and Qiang-Sheng Wu. 2024. "Shading Impairs Mycorrhizal Benefits on Plant Growth, Leaf Gas Exchange, and Active Ingredients in Polygonum cuspidatum" Horticulturae 10, no. 10: 1078. https://doi.org/10.3390/horticulturae10101078

APA Style

Deng, C., Zhang, Z.-Z., da Silva, F. S. B., Hashem, A., Abd_Allah, E. F., Zou, Y.-N., & Wu, Q.-S. (2024). Shading Impairs Mycorrhizal Benefits on Plant Growth, Leaf Gas Exchange, and Active Ingredients in Polygonum cuspidatum. Horticulturae, 10(10), 1078. https://doi.org/10.3390/horticulturae10101078

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