Materials and sources
The plants and soil of E. densa are collected from the alpine meadow at an altitude of 3470 m in Axi Township (102°55.944′ E, 33°41.023′ N), Hongyuan County, Aba Tibetan, and Qiang Autonomous Prefecture, Sichuan Province, China. The entire plant is divided into roots and aerial parts, dried in the shade under natural conditions, and cut into small sections of about 2 cm. The soil sample is the alpine meadow soil without the growth of E. densa, sieved into 1 mm. The highland barley seeds are purchased from Daofu County, Garze Tibetan Autonomous Prefecture.
Allelopathic effect and cytotoxicity experiments of decomposing solution
According to the actual biomass of E. densa, the decomposed solution is prepared according to 25 g of roots / 50 g of aerial parts of E. densa∶500 g of soil∶ 1 L of water. The root decomposed solution is recorded as RD, and the aerial part of the decomposed solution is recorded as AD. After stirring evenly, both are decomposed for 30 d and 60 d, respectively, after which the mixture is filtered and made up to 1 L to obtain raw RD (25 mg/mL) and raw AD (50 mg/mL). Each treatment is repeated three times. During the experimental treatment, both are diluted with distilled water to obtain different concentrations of treatment solutions. The RD concentrations are 5, 10, 15, 20 and 25 mg/mL, and the AD concentrations are 10, 20, 30, 40 and 50 mg/mL.
The highland barley seeds with full grains and no pest damage are sterilized with 0.5% KMnO4 solution for 15 min and then rinsed repeatedly with distilled water. After soaking in a 25°C incubator for 4 h, the seeds are spread evenly in a germination box (12 cm × 12 cm × 9 cm) padded with two layers of filter paper, with 60 seeds per box. 15 mL of different concentrations of RD and AD are added to the germination box, and 15 mL of distilled water is used as the control. The number of germinated seeds and rooting is counted every day in a 25°C incubator for 7 d. The germinated germ reached half the length of the seed as germination, and the radicle reached half the length of the seed as rooted. Next, we calculate the following parameters (Sun et al. 2021):
![](data:image/png;base64,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)
where GR is the germination rate, GN is the number of germinated seeds, SN is the total number of seeds, GI is the germination index, Gt is the germination number on day t, Dt is the corresponding germination day, RR is the rooting rate, and RN is the number of rooted seeds.
The sterilized seeds are soaked in a 25°C incubator for 12 h and then transferred to a porcelain plate covered with moist double-layer sterile gauze for 24 h without light. After the seeds are exposed to the white root tips, the full seeds are selected and inserted into a small pot covered with 3 cm perlite (diameter 10 cm, height 6 cm, 300 g perlite). After the first true leaves of the highland barley seedlings grow, 20 mL of different concentrations of RD and AD are added, distilled water is used as control, and each treatment is repeated three times. After 7 d of treatment, the roots are washed with distilled water and dried with filter paper, and the plant height and root length of the highland barley seedlings are measured. Then the dry weight of the seedlings and roots are measured (Sun et al. 2021).
The radicles of the highland barley seeds with exposed white root tips are inserted into a culture flask (volume 200 mL, diameter 9 cm, height 8.5 cm) containing 0.8% pure agar medium and cultured upside down. When the root length reaches 40 mm (at this time, the number of RBCs reaches the peak and the activity is high), 10 root tips with a length of about 5 mm are randomly selected and placed in 100 μL of 25 mg/mL RD and 50 mg/mL AD treatment solutions vortexed for 30 s. Then we rinse the root tip twice with 50 μL of treatment solution to prepare a cell suspension (200 μL), which is mixed and placed in an incubator at 25°C for 30 min in the dark, and each treatment is repeated six times.
Referring to Singh’s method (Singh et al. 2021), 20 μL of cell suspension is added to a centrifuge tube (0.5 mL capacity), 8 μL of AO/EB mixed dye solution is added dropwise and stained for 2 min. The cell viability and morphology are observed under a LEICA DM300 fluorescence microscope, and each treatment is repeated five times. Then we calculate the cell viability:
Referring to the method of Ropitaux (Ropitaux et al. 2020), 8 μL of the cell suspension is taken, and 8 μL of India ink is added. After being stained for 10 min, the cells are observed with a Nikon ECLIPSE 55i microscope at x40 in a bright field, and pictures are captured to measure the thickness of the mucilage layer. Each treatment is repeated six times.
Determination of soil properties
We pulverize the dried plants of E. densa and prepare decomposed soil according to the residue content of E. densa in the soil of 0, 0.02, 0.04 g/g, and 0.08 g/g and add an appropriate amount of distilled water to keep the soil moist. Each treatment is repeated three times, and the soil samples are collected on 20 d, 40 d, and 60 d, respectively, some of which are tested for soil nutrients and enzyme activities, while the others are stored in a -80℃ refrigerator to determine bacterial diversity.
References for soil nutrient determination methods with slight modifications (Pan et al. 2016, Geng et al. 2017, Li et al. 2021). The soil’s pH is measured based on the electrode potential method (air-dried soil: distilled water = 1:2.5). The soil organic matter (SOM) is determined by the potassium dichromate volumetric method, while the total phosphorus (TP) and the available phosphorus (AP) are determined using the sodium hydroxide alkali fusion-molybdenum antimony anti-colorimetric method. The absorbance values at 585 nm, 700 nm, and 882 nm are measured using a SpectraMax M2 microplate reader (Molecular Devices, USA). Both the total potassium (TK) and available potassium (AK) are measured using a Z-2000 Zeeman atomic absorption spectrophotometer and the ammonium acetate extraction-flame photometer method. The total nitrogen (TN) and available nitrogen (AN) are determined by an automatic Kjeldahl analyzer (FOSS, KJELTECTM 2300).
References determination of soil enzyme activity (Xie et al. 2020, Chen et al. 2020). The urease activity is determined by the sodium phenolate colorimetric method, and the invertase and cellulase activities are determined by the 3,5-dinitrosalicylic acid colorimetric method. The polyphenol oxidase activity is determined by the colorimetric method for measuring pyrogallol, while the acid phosphatase activity is measured using the Solarbio soil acid phosphatase (S-ACP) activity assay kit.
The genomic DNA of the soil samples is extracted using the DNA extraction kit to detect the DNA concentration and purity. By employing the diluted genomic DNA as a template, the V3-V4 region of the bacterial 16S DNA is amplified by PCR using specific primers with Barcode and the Takara Ex Taq high-fidelity enzyme (Takara, Japan). The primer sequences are the 343 F (5'-TACGGRAGGCAGCAG-3') and 798 R (5'-AGGGTATCTAATCCT-3'). After performing electrophoresis detection on the PCR product and purifying it using magnetic beads as a template for two rounds of PCR amplification, the second-round PCR products are electrophoresed again and purified with magnetic beads for Qubit quantification. An equal number of samples are mixed according to the PCR product concentration, and the high-throughput sequencing analysis of the soil bacteria 16S rDNA is performed using the Illumina platform Miseq high-throughput sequencing technology.
Statistical analysis
According to the results of various bioassay indicators, we calculate the allelopathic response index (RI) (Williamson et al. 1988) as follows:
![](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAI4AAABSCAYAAACCAexcAAAIVElEQVR4nO2dv2vbXBfHv3551jZVkqmUDJbXYggKLW0aiAcrlC6Fgk2nDoVWHjq6xfZYCkqhQwdjlwZCodilHTpUoXGghjgpxMlgQ6FLpCF1Nzn98Q/cZ8gjvf4h27IiW7ZzPqDB1uXeo6uvju49ks71McYYCKJP/ue1AcR4QsIhHEHCIRxBwiEcQcIhHEHCscnq6ioCgQB8Ph+mp6eRz+e9NslTSDg2SCaTeP/+PdbX18EYQzQaxfnz5702y1N8FMfpzs7ODm7cuIFKpYJgMOi1OSMDCacHsVgMAJBOpz22ZLSgW1UP8vk8bt265bUZIwd5nC7U63XMzs5C13XMzMx4bc5IQR6nC7VaDQBINBaQcLoQDAbBcRyy2SwAQNM0LCwsoF6ve2yZ95BwepBOp/H8+XP4fD7wPI+FhQXyQADACNdRFIVJksR0XffaFMbYYOxxTTiiKDIA5sbzPKtUKub+Uqlk7iuVSm41yxhjTNd1Jssy4zjO1XqdkMvlmCRJ5m+O45r6xdhEUXS9bV3XmSRJZpuN56BSqTBRFF0Tj2u3qlQqZXgwMMYQiUTw+PFjc//i4iJEUYQkSVhcXHSrWVSrVbx48QJTU1P49euXa/U6QdM0pFIpM+ZTrVYRDoeh6zoURYEgCGCMIZPJIBQKWdYRCASQzWYdjaNWVlZwfHyMg4MD6LoOjuNw6dIlACfjtVAohLW1NecH2Igr8mMnV1okEmn63XpV8TzPFEVxq8kmDI/mJbIss0QiYbkvkUiY+0qlEsvlcpblVFVliUSC8TzPJEmy7Z1lWWY8z3f1KKqquuaVXetpSZJYJpNhjJ10TKtIVFXteWJh4dJh07WPgnBEUex4YQiC0PdFY4xNeJ5nmUymqyh4nu8oxkY4jmsaQjjFtZ7meb5pfNPaSVYeyE1GRThWHkLXdQbA8fhCVVUmimLH/qtUKrbr72Rjv7gyxtE0DaqqQtd1VCoVHB8f48qVK01ltre3O97Xh4XP5+u4rays9FXe2Oywt7cHQRD6nsZvbGwgFoshHA7j9u3bePv2rWW5nz9/Oqr/NLginHK5bBoeDAYxPT2N79+/N5UpFAq4du1a13r6PbH9wv4buFttnz9/7qu8sbXy9+/ftv92d3cRDodt2ahpGpLJJAKBAD59+oS7d+/i8PAQDx486CiMHz9+2BZNuVzGuXPnbJXthivC+fjxIxYWFszfgiDg69ev5u9qtQpVVXHx4sWu9fR7YhuxOmHDJhQKYXd3t+m/er2Od+/eYWpqylYd4XAYc3Nz2NvbQzqdtjUDvXr1KjY3N1GtVgGcvApidaFpmgYA7rwectp7naIobfGZTCbTFEMQBGFgsQvGTu7bjbGLTjObQaOqatvMJpFImP0zSBKJhNkHHMeZE5VGZFlmsiy70h5FjrtgDDqttk4noDUA2C+d2jvthed2AJCE04VMJmMKpDEOE4lEus5MjGn0qDDSjxwmncY4jCzLTFVVjy3yFnqRywb0Qlc79FqFDZzGYSYZEo4N+onDnBVIODYoFAq4fv2612aMFCScHlSrVRwcHJz5D/BaIeH04P79+wCAp0+femzJaEGzKsIR5HEIR5BwCEeQcAhHkHAIR5BwCEeQcAhHkHAIR5BwCEeQcAhHkHAIR5BwCEeQcAhHkHAIR4y9cLLZbMevP3d2drw2b2IZe+EUi0WUSiUwxiAIAhRFAWMMHMe5moeHaGZi3sdp/RIhFotRUusBMvYex6D1SwQSzWCZGOHQlwjDZWKEQ18iDJeJGOPQl5bDZyI8zocPHwB4mzpf0zREo9GRCQFsbGwgmUwOLgu8Vx+tu4WRXw9dUo8Mw4bWvM6jgNupTRqZiFuV18RiMSwtLSEajXptShurq6sAgHg87m7FbinQy8zqw6BUKjFRFNu8WqfcwZFIpGOCJCdIkmSZc6dSqTS1JQhC035d1xnHca57nbHPrD4MVldXUavVLMcLW1tblmEAVVXNTKwAzIysoij21a7x+GRpaaktNqVpGpaXlzE/Pw9d16GqalsdMzMz4Hkee3t7ttu1g2vCqdVqiEQi5u/Lly+3lTk8PBzL1ebi8Tii0ajl4LtYLGJ+fr7t//39ffj9/qbAZDAYhN/v79pWo1iA/1+IVrdBI5VtPB7HzMwM/H4/9vf328qFw2F8+/bN7uHawjXhbG9vY3l5GcBJ1stUKoVHjx6Z+41cyDdv3uxYx6DT1Q6C379/Y25uruP+1sBkp4i2lVi6jUs0TcPm5iaePXvW08apqSl8+fKlZ7l+cE04hUIBDx8+hM/nw7179/Dy5csmkZTL5Z5ump0iXa2XGAttWNErMGl4mFwu11MsjWxtbUEQhJ4ebFCMfWb1frOfD9Or1et1HBwctPVFI/F4HIwxbG9vw+fzmasO9+Lo6MjTRyxjn1m9m5cyNrvlnXo1Y+3OVvpJAZdOp8EYw9LSki0Rq6pqO+n2IJiYzOrDwGpWdeHCBRwdHVmWf/PmTd/R7Gg0CsYYUqmUedEYGdEbWV5exqtXr0ybstksksmkZZ1//vxx39ufdj4/CpnVB00ulzOPwTgO49gymUzTOl0GVv3iJrquN8VveJ7v2I6TJY96MfaPHAx6BcIGhZuLhw2CkQ8AeomdQNig8Pv9iEajyOfzQ2uzH9bW1vDkyRP3HwC7KkOPEEXR8nYxLM7iQ86xF46xZKPXKfJVVe25xsMwURSFJRKJgS1hPfZPx7PZLF6/fm0ZaicGx9iPcbwOhJ1Vxl44XgfCzipjL5x+AmGEe/zjtQGn5c6dOygWi5idnQUA8DyP9fV1j62afMZ+cEx4w9jfqghvIOEQjiDhEI4g4RCOIOEQjvgX/SViRQNAyK0AAAAASUVORK5CYII=)
where T is the treatment value, and C is the control value. RI > 0 refers to promotion, and RI < 0 to inhibition, where the absolute value is proportional to the intensity of the allelopathy. The integrated allelopathic sensitivity index formula (SI) is the arithmetic mean of RI.
The one-way analysis of variance (ANOVA), Tukey's test for multiple comparisons (LSD), and Pearson's correlation analysis are performed using the SPSS software (IBM, SPSS Version 20.0), with a confidence level of 95%. The redundancy analysis (Canoco 5.0) studies the correlation between soil factors and dominant bacterial phyla. The bioinformatics analysis uses the Vsearch (version 2.4.2) software to classify the high-quality sequence valid tags obtained from quality control according to 97% similarity to out and selected the most abundant sequence in each OTU as the representative OUT sequence. The Chao1 index (S) size estimates the total number of soil bacterial species. Finally, the graphical representation uses Excel 2019 to plot the mean ± standard deviation (SD) data.