Specifications TableSubjectAgricultural, chemical scienceSpecific subject areaAllelopathic effect of *Casuarina equisetifolia* leaf on seed germinationType of dataTable, figure, chartHow data were acquiredDifferent leaf aquatic extract concentrations and leaf powder were used to study the effect of *Casuarina equisetifolia* leaf on seed germination, and data were analyzed using SPSS Package 25 and MS Excel 2016.Data formatRaw, analyzedParameters for data collectionSeed germination percentage (GP), root and shoot length of selected plant crops were investigated in the lab greenhouse under different concentrations of *Casuarina* dried leaf. The pH and Electrical Conductivity (EC) of soil were tested using jenway pH and conductivity meter.Description of data collectionA four plant crops (Maize, lentil, Mustard, and Wheat) were tested for germination with different concentrations (0, 1.25%, 2.5%, and 5%) of leaf extract and (0, 15, 30 and 45 g kg^−1^) of well-dried leaf powder in the greenhouse were mixed with soil to study the seedlings inhibition effect during the study period.Data source locationInstitution: Environmental Science Center (ESC) and Department of Biological and Environmental Sciences (DBES), Qatar University\
City: Doha\
Country: Qatar\
Latitude and longitude: (25°48′27.70″N, 51°20′47.10″E)Data accessibilityThe raw data was archived in Mendeley Data <https://data.mendeley.com/datasets>\
Reserved [https://doi.org/10.17632/g8jvhmxy9h.4](10.17632/g8jvhmxy9h.4){#intref0015}\
Link to the preview <https://data.mendeley.com/datasets/g8jvhmxy9h/4>**Value of the Data**•Understanding the allelopathic effects of *Casuarina equisetifolia*-L on some plant crops (Maize, lentil, Mustard, and Wheat) germination percentage and seedling inhibition, root and shoot length.•The present dataset could be useful for concerned researchers and those who interested in cultivation, from the potential effects of crops surrounded by *Casuarina* trees in order to select the candidate most suitable plant.•Furthermore, the dataset introduced in this article can be used to investigate the possible effect of the chemicals released from *Casuarina equisetifolia* leaves on the potential of hydrogen (pH) and Electrical Conductivity (EC) of the soil.

1. Data {#sec1}
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Allelopathy refers to the valuable or damaging effects of a specific plant on another, both crop and weed species, by the release of chemicals from plant parts \[[@bib1]\]. Phenolics, terpenoids, and organic cyanides were reported as active allelochemicals can be leaching from leaves and stem of *Casuarina* trees and many plants to the environment \[[@bib2], [@bib3], [@bib4]\]. The current data focused on the potential effects of *Casuarina equisetifolia*-L on Maize, lentil, Mustard, and Wheat crops during the study.

An experiment was conducted to measure the germination percentage, seedling inhibition, root and shoot length under the effect of the allelochemical compounds released from *Casuarina equisetifolia* leaves on Maize, Lentil, Mustard, and Wheat crops using Petri dishes under controlled lab conditions.

The second experiment was performed using pots in the greenhouse, to study the actual effect of the fallen *Casuarina equisetifolia* leaves on the wheat crop germination and seedling in the presence of Mustard as a weed. Furthermore, the effect of soil mixed with *Casuarina equisetifolia-L* powder on (pH), and Electrical Conductivity (EC) were studied.

1.1. Petri-dish experiment {#sec1.1}
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An aqueous leaf extract solution of *Casuarina equisetifolia*-L was added to each Petri dish to study the potential inhibition effects of germination in all crops selected. Significant effects on seeds germination were observed in the laboratory. Seedling growth results from the current study showed that the germination percentage, shoot, and root length of lentil, wheat, mustard, and maize were markedly suppressed by increasing the leaf aqueous extract concentration. ([Table 1](#tbl1){ref-type="table"}, [Table 2](#tbl2){ref-type="table"}).Table 1Means of seed germination percentage, shoot length, root length (cm), and standard deviation as influenced by different concentrations of *Casuarina* leaf extracts of Mustard and Maize.Table 1TreatmentMustardMaizeGP±SDRL±SDSL±SDGP±SDRL±SDSL±SDControl9514.83.511.112.030.3472.554.511.841.650.461.25%8514.83.210.572.320.852.512.55.030.942.260.322.50%908.62.660.822.540.47608.163.520.51.820.365%66.6712.21.560.711.970.773752.060.251.430.13[^1]Table 2Means of seed germination percentage, shoot/root length (cm), and standard deviation as influenced by different concentrations of *Casuarina* leaf extracts of lentil and Wheat.Table 2TreatmentlentilWheatGP±SDRL±SDSL±SDGP±SDRL±SDSL±SDControl10002.210.521.910.1595.004.082.680.82.290.131.25%92.59.571.570.371.050.2487.506.452.110.572.150.242.50%955.771.150.220.760.1478.752.500.250.161.620.125%808.160.660.030.590.1367.502.890.210.131.260.33[^2]

### 1.1.1. Descriptive data {#sec1.1.1}

One-way ANOVA test was done to check the growth variation between four different treatments (0, 1.25, 2.5, and 5%) in the laboratory. A significant variation in (GP) was observed between the treatments in Lentil, Mustard, and Maize while in Wheat no significant difference found ([Table 3](#tbl3){ref-type="table"}).Table 3Analysis of variance of seed germination percentage as influenced by different concentrations of *Casuarina* leaf extracts of Mustard, Maize, Lentil, and Wheat.Table 3Source of VariationDFMSMustardMaizeLentilWheatGPSLRLGPSLRLGPSLRLGPSLRLBetween3611.2[a](#tbl3fna){ref-type="table-fn"}0.282.95[a](#tbl3fna){ref-type="table-fn"}856.25[a](#tbl3fna){ref-type="table-fn"}0.49[a](#tbl3fna){ref-type="table-fn"}6.84[a](#tbl3fna){ref-type="table-fn"}289.58[a](#tbl3fna){ref-type="table-fn"}1.36[a](#tbl3fna){ref-type="table-fn"}1.72[a](#tbl3fna){ref-type="table-fn"}559.90[a](#tbl3fna){ref-type="table-fn"}0.90[a](#tbl3fna){ref-type="table-fn"}0.35[a](#tbl3fna){ref-type="table-fn"}Within12164.80.340.5768.750.111.1447.920.020.1118.230.040.24Total15[^3]

Shoot and root length variations were tested under the same treatments and conditions.

Significant variation was recorded between treatments in all seeds except Mustard shoot length (*p* \> *0.05*) at a confidence interval of 95% ([Table 3](#tbl3){ref-type="table"}).

The mean values of germination% (GP), shoot length (SL), and root length (RL) (with a standard deviation) for the studied crops were illustrated in [Fig. 1](#fig1){ref-type="fig"}Fig. 1The mean measurement data of germination percentage (GP), Root, and Shoot lengths (cm) for four crops under controlled lab conditions. (A)Mean germination %, (B)Mean root length, (C)Mean shoot length.Fig. 1

1.2. Greenhouse experiment {#sec1.2}
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Greenhouse experiments were conducted to investigate the potential effect of *Casuarina equisetifolia* leaves on seedling growth of Wheat as a crop and Mustard as a weed with four treatments (control, 15, 30, 45 g/kg soil).

The seedling measurements of (GP, SL, and RL) were recorded weekly in three weeks. The results concluded that the growth of Wheat and Mustard plants, as indicated by germination percentage ([Table 4](#tbl4){ref-type="table"}, [Table 5](#tbl5){ref-type="table"}), showed opposite outcomes with Wheat (Stimulatory effect); the most significant germination occurred at high concentration (45 g kg^−1^) ([Fig. 2](#fig2){ref-type="fig"}).Table 4Means of germination percentage, plant characteristics, and their standard deviations of wheat as influenced by different concentrations of *Casuarina* dried leaf powder.Table 4TreatmentGP±SDSL±SDRL±SDControl97.500.505.280.335.360.5215 g/kg87.501.505.160.123.750.4230 g/kg60.001.154.420.193.500.4445 g/kg40.002.504.220.213.370.53Table 5Means of germination percentage, plant characteristics, and their standard deviations of Mustard as influenced by different concentrations of *Casuarina* dried leaf powder.Table 5TreatmentGP±SDSL±SDRL±SDControl60.004.089.604.224.080.7415 g/kg68.302.063.750.653.370.6230 g/kg58.336.133.790.573.330.9845 g/kg95.001.505.751.302.371.41Fig. 2Mean of Wheat, and Mustard germination percentage (GP) in a greenhouse under different Treatments.Fig. 2

A significant variation of seed germination percentage, shoot, and root length of wheat and Mustard between treatments were found except the Mustard root length had no differences among means (*p* \> *0,05*) at 95% confidence interval ([Table 6](#tbl6){ref-type="table"}).Table 6Analysis of variance of seed germination percentage, shoot, and root length of wheat and Mustard as influenced by different concentrations of *Casuarina* leaf extracts of Wheat plant in the greenhouse.Table 6ANOVAdfMean SquareFSig.ANOVAdfMean SquareFSig.Wheat (GP)Between Groups32741.6**1074.5**[a](#tbl6fna){ref-type="table-fn"}.000Mustard (GP)Between Groups31151.22**75.952**[a](#tbl6fna){ref-type="table-fn"}.000Within Groups122.55Within Groups1215.16Total15Total15Wheat (SL)Between Groups31.12**24.39**[a](#tbl6fna){ref-type="table-fn"}.000Mustard (SL)Between Groups330.22**6.067**[a](#tbl6fna){ref-type="table-fn"}0.009Within Groups120.046Within Groups124.98Total15Total15Wheat (RL)Between Groups33.41**14.68**[a](#tbl6fna){ref-type="table-fn"}.000Mustard (RL)Between Groups31.9712.0150.166Within Groups120.23Within Groups120.979Total15Total15[^4]

Two physical parameters (pH and EC) of soil were tested under the effect of *Casuarina* dry leaves that were mixed with soil in different concentrations ([Table 7](#tbl7){ref-type="table"}).Table 7Means of pH, the electrical conductivity of soil, and their standard deviations as influenced by different concentrations of *Casuarina* leaf extracts of wheat and Mustard experiment in a greenhouse.Table 7TreatmentpH±SDEC±SDControl8.500.20659.5108.2015 g/kg8.400.42709.526.6030 g/kg7.710.201054156.2545 g/kg7.810.301154233.39

The mean of measured pH values of soil was decreased gradually with increasing the treatment concentration, while the mean of EC was on the contrary ([Fig. 3](#fig3){ref-type="fig"}).Fig. 3A-line chart of pH and EC under the effect of four different treatments.Fig. 3

ANOVA test represents a noted variation (*p* \> *0.05*) between treatments in both pH and EC parameters. ([Table 8](#tbl8){ref-type="table"}).Table 8Analysis of variance of pH and electrical conductivity of soil as influenced by different concentrations of *Casuarina* leaf extracts of Wheat and Mustard experiment in a greenhouse.Table 8ANOVAdfMean SquareFSig.pHBetween Groups3.648**7.10**[a](#tbl8fna){ref-type="table-fn"}.005Within Groups12.091Total15ECBetween Groups3242973.67**10.66**[a](#tbl8fna){ref-type="table-fn"}.001Within Groups1222784.62Total15[^5]

2. Experimental design, materials, and methods {#sec2}
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The treatments were organized in a completely randomized design (CRD) with four replicates in each set. In the Petri dish experiment, each single petri dish was considered as a replicate. Moreover, in the greenhouse experiment, each pot is considered one replicate

2.1. Preparation of aqueous extract of *Casuarina equisetifolia*-L {#sec2.1}
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Fresh leaves of *Casuarina equisetifolia* were collected from the area surrounding the College of Arts and Sciences, Qatar University. Leaves from mature trees were brought to the laboratory and were air-dried in the oven at 50 °C for 48 hours ([Fig. 4](#fig4){ref-type="fig"}). Then, the dried leaves were chopped into small pieces and ground into a fine powder. Distilled water was used to make plant extraction. Approximately 5 g of dried leaves powder was soaked into 50 ml distilled water followed by vigorous shaking for 48 hours at room temperature. The resulting solution was centrifuged, and the supernatant was filtered using a vacuum filter unit 1000 ml (Buchner Apparatus) to obtain a stock solution. The resulting brownish and dark extract was stored in the fridge in conical flasks until required.Fig. 4Collection of *Casuarina equisetifolia*-L. leaves.Fig. 4

Sequential dilutions were applied to the prepared stock solution to obtain three different concentrations (1.25%, 2.50%, and 5.00%) using Equation [(1)](#fd1){ref-type="disp-formula"} ([Table 9](#tbl9){ref-type="table"}), with distilled water used as a control treatment ([Fig. 5](#fig5){ref-type="fig"}).$$DF\% = \frac{Initial\ volume}{Final\ volume} \times 100$$where.Table 9Preparation of the different concentrations.Table 9Volume taken (ml)Volume up to (ml)Final concentration (DF%)12.510001.252510002.55010005Fig. 5Three different extract concentrations 1.25%, 2.50%, and 5% obtained from the stock solution of *C. equisetifolia* Leaves.Fig. 5

$DF\text{\%}$ is a final concentration percentage after dilution.

2.2. Germination test {#sec2.2}
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Seeds of four crop plants (Maize, lentil, Mustard, and Wheat) were used in the seed germination test. Healthy uniform size seeds were selected and washed thoroughly four times by distilled water to remove any chemical residues and well dried using tissue paper. 10--20 seeds of each species were placed evenly (based on seed size) in sterilized 9 cm Petri dishes lined with a double layer of Whatman filter papers. The experimental set includes four different concentration of aqueous extract 0% 1.25%, 2.50% and 5.00%. The treated Petri dishes with distilled water were taken as a control, and it was considered as a zero concentration, while others were treated with approximately 8 ml of different aqueous extracts. Petri dishes were kept undisturbed under controlled lab conditions (room temperature (24 ± 2 °C), light) on the laboratory bench until germination occurs. ([Fig. 6](#fig6){ref-type="fig"}).Fig. 6Germination test on Maize seeds by different extract concentrations.Fig. 6

2.3. Seed germination and seedling growth {#sec2.3}
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Seeds are considered germinated upon radical emergence, germination is determined by counting the number of germinated seeds each two days interval over a 6--8 days period to observe the germination rate. After eight days, the germination percentage (GP) was determined by counting the number of seeds germinated during the period of the experiment over the total number of seeds based on Equation [(2)](#fd2){ref-type="disp-formula"}, \[[@bib5]\].$$GP = \frac{Number\ of\ germinated\ seeds}{Total\ number\ of\ seeds} \times 100$$Where $GP$. Germination percentage.

Shoot length and root length were measured using a centimeter ruler by taking five seedlings at random from each petri dish.

2.4. Greenhouse experiment {#sec2.4}
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The experiment was performed in the greenhouse to investigate the effect of *C. equisetifolia* leaves on plant growth. Two different crop plants were selected to grow together in this experiment under *C. equisetifolia* leaf residuals with different dosages. Mustard is considered as a weed plant and competition factor against wheat growth. Dried leaf powder of *C. equisetifolia* was mixed with peat moss and clay (1:4) at a rate of 15, 30, and 45 g kg^−1^ of soil, in addition to the control treatment with no leaf powder. Plastic pots of 15 cm in diameter were filled with 2 kg of soil. Ten viable seeds of wheat with fifteen seeds of Mustard were sown together in each pot. Water supplied as required to avoid water stress. Pots were arranged in a completely randomized block design with four replications ([Fig. 7](#fig7){ref-type="fig"}).Fig. 7Effect of incorporation of *C. equisetifolia* leaf powder on Wheat and Mustard (weed) germination and growth.Fig. 7

2.5. Data collection of the greenhouse experiment {#sec2.5}
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Number of germinated seeds was observed weekly in three weeks, then germination percentage was calculated by counting the number of seeds germinated over the total number of seeds based on Equation [(2)](#fd2){ref-type="disp-formula"}, \[[@bib5]\]. After plant maturity, data were recorded for growth parameters including the number of shoots, root lengths (cm), number of spikes, plant height, fresh and dry weights (g/plant), stem diameter (mm), as well as a number of leaves. In addition, soil physical analysis was conducted Electric conductivity EC and pH. In the end, statistical analysis was conducted to all the collected results using analysis of variance and means comparisons.

Conflict of Interest {#appsec1}
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The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

The authors want to thank Prof Hamad Al-Kuwari, Director of the ESC, for his continued help and support. All appreciations also go to Ms. Hajer Alnaimi (Technical Manager) for her assistance. This project was supported by Qatar University Internal Grant No. QUS-CAS-FALL-15/16-3. The findings achieved herein are solely the responsibility of the authors.

[^1]: Germination percentage (GP), Standard Deviation (SD), root length (RL), shoot length (SL).

[^2]: Germination percentage (GP), Standard Deviation (SD), root length (RL), shoot length (SL).

[^3]: Indicates significant differences among means at 0.05. MS; Means of squares. Germination percentage % (GP%), shoot length (SL), root length (RL).

[^4]: Indicates significant differences among means at 0.05. Germination percentage (GP), shoot length (SL), root length (RL).

[^5]: Indicates significant differences among means at 0.05. The potential of Hydrogen (pH) and Electrical conductivity (EC).
