Phytotoxic effect of plant extracts on physiology of cotton (Gossypium hirsutum L.) plants

Abstract

Synthetic insecticides have undesirable impact on other non- target species, their residues remain in the food which is a reason of environmental pollution and ecosystem. Around 46 families of plants are utilized as botanicals which have insecticidal value (Isman and Machial, 2006) Some farmers utilized high concentrations of insecticides to control the insect pests, yet there was no change in yield even diminishment. The main objective was the evaluation of phytotoxic effects (CO2-in, CO2-out, H2O-in, H2O-out and photosynthesis absorption rate PAR) in cotton due to higher doses of different botanicals. 2 Materials and Methods The present study was carried out at College of Agriculture, University of Sargodha to check phytotoxic effect of high concentrations of four botanicals, Neem (Azadirachta indica), (Mentha arvensis), Datura (Datura stramonium), Lemonene (Citrus limonium), on cotton. The outcomes additionally delineate that CO2-in of cotton crop was more influenced by the 16% centralization of D. stramonium (140.04±0.24) following 72 hours of sprays. 3.2 Various botanicals phytotoxic impact at various concentrations against CO2-out of cotton crop The results (Table 2) showed mean comparison of data regarding phytotoxic effect of different plant extracts against CO2-out of cotton crop.

Highlights

Plant-derived compounds are alternatives of synthetic insecticides in sustainable agriculture.

Different botanicals effects on physiology of cotton plants.

Different botanicals influenced the photosynthesis of cotton crop.

1 Introduction

Cotton (Gossypium hirsutum L.) is known as world most important cash crop. It is utilized as a part of various items like lint in textile; cottonseed is utilized as vegetable oil and feeds of animal. Cottonseed cake is a rich source of value protein (Sarwar et al., 2013). Cotton assumes a key part in monetary improvement of both developed and developing nations. Cotton has been known as crude material for industrialization, riches and advancements of a nation, which give wage to various segments like well being, education and transportation.

Cotton is attacked by different insect pests in various stages, which cause lessening in the yield specifically or by implication. Roughly 160 species attack on the cotton at various stages like borers, sap-suckers and defoliators and cause around 60% yield misfortunes annually (Halbert and Manjunath, 2004). By feeding different insect pests reduce the quantity and decrease the quality by transmitting distinctive diseases (Manjunath, 2004). Numerous manufactured sprays are utilized to control insect pest and increase the fruit setting in the cotton crop (Dayan et al., 2009). Synthetic insecticides have undesirable impact on other non- target species, their residues remain in the food which is a reason of environmental pollution and ecosystem.

Synthetic insecticides must be replaced with those items which are friendly to environment. For a long time botanicals are being utilized option of manufactured insecticides for pests administration in light of the fact that these are more secure for condition and human wellbeing. Around 46 families of plants are utilized as botanicals which have insecticidal value (Isman and Machial, 2006)

Some farmers utilized high concentrations of insecticides to control the insect pests, yet there was no change in yield even diminishment. Development and yield of products lessened when OPI were utilized as a part of higher than suggested concentrations (Shehata and El-Khawas, 2003). It is observed that the broadly higher concentration of pesticide application caused negative effect on the physiology of the crop, generally on the photosynthesis of the crop. The development and yield of the crop additionally exasperates when the photosynthesis rate of product aggravate. The utilization of contact fungicide copper impact on the chloroplasts, photosynthesis and chlorophyll biosynthes (Petit et al., 2012).

Normally happening monoterpenes demonstrated phytotoxicity against maize plants, they impact on roots and leaves of maize crop. Carvone was most phytotoxic against maize than monoterpenes (Shehata and El-Khawas, 2003). Strawberry seedling is very influenced when treated with over 3% concentration of limonene (Ibrahim et al., 2001). The seedling of carrot and cabbage were exceptionally influenced when treated with the 9% concentration of limonene (Ibrahim et al., 2004). Citrus photosynthetic was changed by the ramifications of pesticides (Jones et al., 1983). The present research was conducted to evaluatephytotoxic effects (CO₂-in, CO₂-out, H₂O-in, H₂O-out and photosynthesis absorption rate PAR) in cotton due to higher concentrations of different botanicals. In present research harmful effects of higher doses of botanicals were studied. The main objective was the evaluation of phytotoxic effects (CO₂-in, CO₂-out, H₂O-in, H₂O-out and photosynthesis absorption rate PAR) in cotton due to higher doses of different botanicals.

2 Materials and Methods

The present study was carried out at College of Agriculture, University of Sargodha to check phytotoxic effect of high concentrations of four botanicals, Neem (Azadirachta indica), (Mentha arvensis), Datura (Datura stramonium), Lemonene (Citrus limonium), on cotton. The cotton variety MNH-886 was sowed with Chopa method on 30-May-2014. The row to row distance was 30 inches and plant to plant was 12 inches.

From the field of College of Agriculture, University of Sargodha fresh leaves of D. stramonium were collected. A. indica, M. arvensis and C. limonium leaves were collected from Bhakkar. The plant materials were washed with distilled water separately. For drying leaves were put at room temperature (±25^oC) for two weeks. It ensured that adequate air was streaming to evade damping. After shade drying leaves were granulated with electric processor for 45 seconds for making concentrated powder. At that point took leaves powder 40 grams put in conical flask and included ethyl liquor 320 mL in it. The mixture of powder and ethyl liquor was put on mechanical shaker for legitimate mixing for 72 hours. After blending the stock arrangement was put for 48 hours. The blend of stock solution was sifted with channel paper (What man channel paper No.1). Now the plant extract was prepared. A similar methodology was drilled for all plant leaves, respectively (Fiaz et al., 2012).

Plant Extract's Applications: Plant extracts were applied with hand worked sprayer. 80 plants were chosen and labeled. Each botanical concentration was replicated five times. Botanicals were utilized as foliar application with 2, 4, 8 and 16% concentrations on 80 chose plants. Three times splash was applied with interim of 20 days. Data was recorded 12, 24, 48 and 72 hours after the utilization of botanicals on cotton. Data of CO₂-in, CO₂-out, H₂Oin, H₂O-out and Photosynthetic absorption rate (PAR) of cotton crop was recorded by Photosynthesis meter Cl 340. M. Stat C 8.1 version was used for analysis of variance (ANOVA).

3 Results and Discussion

3.1 Phytotoxic impact of various concentrations of various botanicals against CO₂-in on cotton crop

The results (Table 1) showed mean comparison of data regarding phytotoxic impact of various plant extracts against CO₂-in of cotton crop. The results showed that 12 hours after spray CO₂-in was more affected by A. indica (144.92±1.59) at 2% concentration with significant difference fromD. stramonium (152.81±0.54), M. arvensis (159.84±0.69) and limonene (161.15±0.35). The 4% concentration of D. stramonium following 12 hours of spray was more viable when contrasted with different concentrates of botanicals. The result also showed that CO₂-in of cotton crop was more infuenced by D. stramonium (131.65±0.38) having significant difference and followed by C. limonium (134.58±0.47), M. arvensis (145.83±0.46) and A. indica (152.98±1.53) at 8% concentration. CO₂-in of cotton crop at the 16% concentration was less infuenced of A. indica (158.53±0.30).

[Table Omitted. Please see PDF.]

The results (Table 1) showed that 24 hours after spray the 2% concentration of D. stramonium (161.79±1.31) differ significantly and was less influenced the CO₂-in of cotton crop when contrasted with all others treatments. The results indicated that 4% concentration of C. limonium (137.15±0.89) showed significant difference and highly affected the CO₂-in of cotton. After 24 hours spray of 8% concentration of M. arvensis (145.70±0.46) minimum affected the CO₂-in of cotton crop which was statistically at PAR with A. indica (143.85±0.39). The 16% concentrations of A. indica showed more toxicity (139.78±0.50) against CO₂-in with non-significant difference from M. arvensis (142.81±0.57) while the remaining D. stramonium (150.15±2.00) and C. limonium (152.28±0.66) were less toxic.

The results (Table 1) also revealed that phytotoxic effect of M. arvensis and D. stramonium against CO₂-in at 2% concentration after 48 hours did not differ significantly and followed by A. indica and limonene. The results also indicate that at 4% concentration M. arvensis (151.16±0.72) was least phytotoxic against CO₂-in. Limonene 8% concentration following 48 hours was at fourth number with a specific end goal to influencing the CO₂-in of cotton crop while andM. arvensis (138.06±0.72) was at 1^st.The 16% concentration of A. indica and M. arvensis did not show significant difference from each other on the CO₂-in of cotton crop.

The results (Table 1) also indicated that 2% concentration of A. indica (152.55±0.5) and D. stramonium (152.72±0.99) was statistically at PAR following 72 hours of spray and less phytotoxic against CO₂-in of cotton crop. CO₂-in of cotton crop was correspondingly influenced by the 4% concentration of A. indica (140.27±0.48), M. arvensis (143.07±1.31) and C. limonium (143.27±1.59) after 72 hours sprays while D. stramonium (145.37±1.98) was less toxic. The phytotoxicity of M. arvensis, A. indica and D. stramonium at 8% concentration after 72 hours was statistically at PAR with each other while limonene (157.74±0.5) was minimum lethal to CO₂-in of cotton crop. The outcomes additionally delineate that CO₂-in of cotton crop was more influenced by the 16% centralization of D. stramonium (140.04±0.24) following 72 hours of sprays.

3.2 Various botanicals phytotoxic impact at various concentrations against CO₂-out of cotton crop

The results (Table 2) showed mean comparison of data regarding phytotoxic effect of different plant extracts against CO₂-out of cotton crop. The results indicated that the 2% concentration of A. indica (136±0.75) after 12 hours differ significantly and less influenced the CO₂-out of cotton crop as compared to D. stramonium (127.57±0.95), C. limonium (123.83±0.83) and M. arvensis (122.79±1.09) which were more phytotoxic. The finding at 4% concentration showed that C. limonium (122.42±1.30) was more phytotoxic to CO2-out of cotton crop. The results alsoindicated that the 8% concentration of A. indica (135.84±0.81) and M. arvensis (135±1.20) were less affected the CO2-out of cotton crop. The phytotoxic effect of 16% concentration of M. arvensis (123.14±1.54) and C. limonium (122.79±1.43) was statistically at PAR and more than the A. indica (130.17±1.17), but less than the D. stramonium (115.77±0.74).

[Table Omitted. Please see PDF.]

The results (Table 2) also showed that the 2% concentration of A. indica (129.53±0.71) after 24 hours was more phytotoxic but statistically at PAR with C. limonium (132.35±0.99). All the botanicals did not differ significantly from each other at 4% concentration. The results demonstrated that the 8% concentrations of A. indica (133.3±0.77) and M. arvensis (133.52±0.94) had correspondingly influenced the CO₂-out of cotton crop. The results also revealed that the 16% concentration of D. stramonium (139.17±0.51) was more affected the CO₂-out and was statistically at PAR with M. arvensis (141.88±0.82) 37 and A. indica (140.65±0.58).

The results (Table 2) also revealed that the 2% concentration of C. limonium (131.91±1.34) having significant difference from all the treatments and was less phytotoxic against CO₂-out of cotton crop following 48 hours. The 4% concentration of M. arvensis(118.16±1.02) also differ significantly from all other treatments was more toxic against CO₂-out. The results indicated that the 8% concentration of M. arvensis (126.15±0.7) and D. stramonium (127.09±0.44) did not differ significantly andwere more phytotoxic against CO₂-out of cotton crop. The 16% concentration of C. limonium (128.73±0.90) was more phytotoxic against CO₂-out of cotton crop but statistically at PAR with D. stramonium (130.21±1.02) and M. arvensis (130.39±0.88).

The results (Table 2) also represented that after 72 hours at 2% concentration of C. Limonium (145.64±1.17), CO₂-out word movement of cotton crop was less influenced which differ significantly from all other treatments. The 4% concentration of D. stramonium (122.95±1.14) was more phytotoxic against CO₂-out of cotton crop having significant difference from all other treatments. The results revealed that 8% concentrations of A. indica, M. arvensis, D. stramonium and C. limonium have almost similar phytoxicity against CO₂-out of cotton crop. These finding indicated that the 16% concentration of D. stramonium (129.64±2) following 72 hours of spray was more phytotoxic against CO₂-out of cotton crop.

3.3 Phytotoxic impact of various concentrations of various botanicals against H₂O-in of cotton crop

The results (Table 3) demonstrated that the concentration of 2% all treatments, 12 hours after spray, did not differ significantly from each other. The results revealed that cotton crop at 4% concentration of A. indica (4.63±0.11) and D. stramonium (4.73± 0.10) were less phytotoxic and are statistically at par. The 8% concentration of D. stramonium (2.61±0.05) and M. arvenis (3.64±0.18) did not differ significantly from each other and were more phytotoxic than A. indica (3.74±0.16). The results also revealed that the 16% concentration of A. indica (2.42±0.03) was less phytotoxic and showed significant difference from all other treatments.

[Table Omitted. Please see PDF.]

The results (Table 3) showed that the 2% concentration of D. stramonium, M. arvensis and limonene were statistically at PAR and more toxic against H₂O-in of cotton crop than the A. indica (5.37±0.09). The outcomes demonstrated that M. arvensis (3.45±0.13) after 24 hours of spray at 4% concentration was more phytotoxic against H₂O-in of cotton crop than the A. indica (4.63±0.14) but less toxic than the limonene (2.51±0.07) and D. stramonium (2.54±0.16). The 8% concentration ofD. stramonium (1.39±0.12) differs significantlyfrom all other treatments. The 16% concentration of D. stramonium (1.53±0.12) and M. arvensis (1.56±0.17) were statistically at PAR and the phytotoxicity of these two botanicals were more as compared to the limonene (2.48±0.14) and A. indica (2.77±0.09).

The results (Table 3) demonstrated that the A. indica (6.34±0.14) at 2% concentration following 48 hours of spray had significant difference and least toxicity against H₂O-in of cotton crop while the other extracts were phytotoxic and more phytotoxic was D. stramonium (3.56±0.04). The results revealed that 4% concentration of M. arvensis differ significantly and had morephytotoxicitythan all the other plant extracts. The results also showed that the D. stramonium at 8% concentration was more phytotoxic against H₂O-in of cotton crop. While limonene (3.57±0.20) at 16% concentration phytotoxicity differ significantly and was less as compared to all the other plant extracts which were statistically at par.

The results (Table 3) also demonstrated that the limonene (6.39±0.14) at 2% concentration following 72 hours of spray had significant difference and was least toxic against H₂O-in of cotton crop. The results revealed that C. limonium and D. stramonium had similar phytotoxicity at 4% concentration against H₂O-in of cotton crop. The phytotoxicity of 8% concentration of different botanicals differ significantly and was in order as limonene > A. indica > D. stramonium > M. arvensis which were 5.74±0.01, 3.50±0.12, 2.64±0.05 and 2.60±0.02 respectively as compared to the average of control 7.64±0.02. The phytotoxicity at 16% concentration of M. arvensis (2.63±0.02) differs significantly and was more as compared to all other plant extracts.

3.4 Phytotoxic impact of various concentrations of various botanicals against H₂O-out of cotton

The results (Table 4) demonstrated that the limonene at 2% concentration after 12 hours of spray had significant difference and was less phytotoxic against H₂O-out of cotton crop. The phytotoxic affects of M. arvensis (3.77±0.04) and limonene (3.66±0.00) at 4% concentration was statistically at PAR and were less than the D. stramonium (1.64±0.11) and A. indica (1.63±0.02). The 8% concentration of all botanicals did not differ significantly. Similarly 16% concentrations of all plant extracts were statistically at par.

[Table Omitted. Please see PDF.]

The results (Table 4) showed that the phytotoxicity of M. arvensis (4.70±0.02) at 2% concentration after 24 hours of spray was statistically similar with those C. limonium (4.63±0.02). The 4% concentration of M. arvensis (1.70±0.02) differs significantly from rest of the three extracts which were statistically at par. The 8% concentration of M. arvensis (2.55±0.09) and C. limonium (2.53±0.02) did not show significant difference from each other. The 16% concentration of A. indica (1.66±0.04) did not differ significantly from C. limonium (1.56±0.09).

The results (Table 4) showed that the 2% concentration following 48 hours of spray of M. arvensis (4.64±0.05) significantly different in phytotoxicity against H₂O-out of cotton crop from all other treatments. The 4% concentration of both D. stramonium and C. limonium demonstrated that they had at PAR effect on the H₂O-out of cotton crop. The 8% concentration showed that the H₂O-out of cotton crop was least affected by the M. arvensis which differ significantly from all treatments. A. indica (1.659±0) and D. stramonium (1.66±0.12) at 16% concentration had more affected H₂O-out of cotton crop and did not have significant difference from each other.

The result (Table 4) revealed that at 2% concentration phytoxicity of C. limonium (4.76±0) against H₂O-out of cotton crop differ significantly and was more than all the other treatments. Similar results of C. limonium were also recorded at 4%, 8%and 16% concentrations.

3.5 Phytotoxic impact of various concentrations of various botanicals against PAR of cotton

The result (Table 5) showed that after 12 hours of spray, by 2% concentration the PAR of cotton crop was least affected of M. arvensis (1239.33±74.6) which differ significantly from all treatments while M. arvensis at 4% concentration was statistically at PAR with A. indica. The results revealedthat phytotoxicity of C. limonium (1240.5±79.1) at 8% concentration against PAR differ significantly and was more than the M. arvensis (1499.7±42.8). The result also depicted that the phytotoxicity of A. indicaat 16% concentration was maximum (1052.93±57.02) and differ significantly from all treatments.

[Table Omitted. Please see PDF.]

The result (Table 5) revealed thatafter 24 hours of spray 2% concentrations of C. limonium (1246.11±40.3) and D. stramonium (1244.38±35.4) PAR affected maximum and were statistically at par. The results also demonstrated that M. arvensis (1237.93±62.7) at 4% concentration was more PAR affected and had no significant difference from A. indica (1251.53±37.7). The 8% concentration ofD. stramonium (1169±4.6) showed significant difference over all treatments and was more PAR affected. The 16% concentration of D. stramonium (1243.93±30.12) and C. limonium (1227.48±39.5) were statistically at PAR and differ significantly from all treatments.

The result (Table 5) revealed thatafter 48 hours of spraythe PAR of cotton crop was less affected by the A. indica (138.44±2.8) and differ significantly from all other treatments. The 4% concentration of limonene (1165.94±49.8) was more phytotoxic and differs significantly from all treatments. Similar trend of limonene was also observed at 8% concentration. The PAR of cotton crop was more affected by the D. stramonium and limonene which did not show significant difference from each other.

The result (Table 5) showed that at 2% concentration, after 72 hours of spray, all the treatments differ significantly from each other. A. indica (1118.32±43.1) more affected PAR of cotton crop at 2% concentration. Similar result was also recorded with 4% concentration of A. indica. The 8% concentration of A. indica (1049.23±77.5) and M. arvensis (1022.53±29.6) had more phytotoxicity against PAR of cotton crop and both were statistically at par. The PAR of cotton crop was more influenced by the D. stramonium (1016.01±62.2) at 16% concentration.

The present finding showed that at 2% and 8% concentration, neem and mint affected the CO₂-in of cotton crop. CO₂-out was affected by mint and neem at 16% and 4% concentrations, respectively. Both neem and mint at 16% concentration affected the H₂O-in of cotton crop. PAR of cotton crop was more affected by the neem at 4% concentration. The reason of such outcomes was that different dosages of different botanicals in various way influenced the opening and shutting of stomata and photosynthesis color of cotton crop. The dosages which cause higher phytotoxicity of cotton crop, have more influence the stomata (influence the in word and out word development of CO₂ and H₂O) and photosynthesis color (impact the PAR).

4 Conclusions

The results of present research coincide with the finding of (Nijënstein and Ester, 1998), and (Ibrahim et al., 2004) who discovered that the concentrations of limonene 90 and 120 mL were more phytotoxic. The present investigation showed that the limonene 8% and 16% were more phytotoxic against CO₂-in of cotton crop following 12 long periods of shower, at 4% affected the CO₂-out, H₂O-in was more influenced at 16% and H₂O-out of cotton was more influenced at concentration of 16%.

5 Contributions

MNZ: designed and performed the experiments, analyzed the data, interpreted the results, and drafted the manuscript. NM, JI, and MFS: did the project adminstration, revised the manuscript and helped in data analysis. TI, HAB, MSB, and AU: helped in data collection, investigation and visulization.

6 Acknowledgements

Sincere thanks to College of Agriculture, University of Sargodh providing research facilities.

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