Study of Allelopathic Effects of Argemone mexicana L. Root Extract on Seed Germination and Growth of Triticum aestivum L. Under in vitro Condition

The present study was conducted in Department of Botany


Introduction
Allelopathy refers to biochemical interactions between plants, including those mediated by microorganisms. 1 Allelopathy is defined as the inhibitory or stimulating effect of plants or microorganisms on other plants by releasing chemical compounds into the environment, called allelochemicals. 2 Most allelelochemicals or plant toxic substances that are suspected to inhibit the growth of plants and chemicals released by weeds in soils are secondary metabolites that are not present in all organisms, but occur occasionally. 3llelopathy is an organic peculiarity in which a plant suppresses the development of different plants through the creation of allelochemicals. 4In terms of rehearsals, Allelopathy can be considered to be an obstacle between the crops and between the yields and weeds that finally affect the crops production. 5eds are considered as undesirable plants that compete with growing crops for water, supplementation and sunlight and affect the rate of development and regeneration of crops. 6onsequently, weeds have a significant impact on crop production due to their detrimental effects on crops.Allelopathy is a kind of obstruction in which the recipient plant by the arrival of the naturally produced inhibitor from the living or decayed tissues has a suppressive effect on the other plant. 7Various pieces of weeds show allopathic effects by delivering water-soluble allelochemicals that mainly affect plants at the levels of seed and seedling development. 8llelochemicals could have a significant impact on the target plants.Allelochemicals are substances that come from the stems, leaves, roots, flowers, and leaf of plants and are produced by them as final components or metabolites.However, the roots and leaves had all the characteristics of being the most reliable Allelochemical manufacturers. 9These gatherings of naturally produced compounds can be delivered together and can trigger harmful effects in an additional substance or then in a synergistic manner.Allelochemical release from different parts of plants has an immediate impact (inhibitory or stimulative) on seed germination and seedling development of crop plants receiving treatment.The Sharbati and Lokwan wheat varieties (Triticum aestivum L., family Poaceae) are grown as winter wheat varieties and are ideal for agro climate conditions in Maharashtra and Madhya Pradesh.Wheat is most common commercial crop, and the main food source for humans. 10Triticum aestivum L. is a Rabi season cereal crop that grows in winter.The harvest is primarily focused on seeds with extremely high contents of carbohydrates.Crop yields are predominantly occupied in the tropical and subtropical regions of the world.
Argemone mexicana L. is a branching herb plant that has been widely naturalized in many tropical and subtropical regions, although it is native to tropical America. 11It is a widespread annual weed, mainly associated with agricultural crops and wetlands.It is a major weed in a number of crops in the tropics and warm temperate regions and persists as it produces a seed bank.Argemone mexicana L. is among the invasive weeds which was believed to released allelochemicals that affected some other species around it, especially crops on agricultural fields.Argemone Mexicana L. extracts of seeds, roots and shoot inhibit the growth of pearl lime, mustard, wheat, carrots, corn and turnip, caused by allelopathic compounds dissolved in extracts. 12llelopathy mainly affects plants by reducing seed germination and seedling development. 13fterwards, allelopathy plays an essential role in many agricultural ecosystems. 14The types and convergences of allelochemicals, the species of beneficial plants and environmental fsactors are all associated with the allelopathic effects on seed germination. 15Use of allelolochemicals are a climatefriendly approach which considered as a potential method of controlling weeds. 16The provided information clearly shows that allelochemicals contained in the above-mentioned weeds may inhibit seed germination.The specific objectives of this study are therefore to evaluate the allelopathic effects of several local weeds on the germination and seedling development of wheat.

Collection of Weed Plants
Argemone mexicana L. was collected from an agricultural wheat field in village Ridhora near Warora Tahsil, Chandrapur district of Maharashtra.The roots of weed plants were separated, the roots were washed several times with water, cut into pieces and allowed to dry in shade.The dried plant material was separately sheared in a grinder and, after sieving, stored in air-tight glass bottles.

Preparation of Aqueous Root Extract
The water extract is a combination of filtration by mixing 10 grams of powder root material with 100 ml of distilled water, and the final volume was adjusted to 100 ml, with a 10% water extract.Various strengths (10, 20, 30, 40 and 50%) of dilutions were prepared from the root aqueous extract and used as stock solutions. 17The powdered parts were processed into a water extract of the root and then placed in bottles.For two days, the bottle is shaken once every 24 hours.The extracts were carefully marked and stored in black bottles after filtering with Muslin linen.In this research, water extraction method was chosen because water serves as a natural solvent extraction medium.

Procurement of Seeds
Certified wheat varieties such as Sharbati and Lokvan, which are mostly cultivated in the district of Chandrapur, were purchased from the Department of Agriculture, office of the District Council, Chandrapur, Maharashtra.The seeds were surface sterilized for 15 minutes with 1% Mercuric chloride and used for Petri dish bioassay of wheat seed germination and seedling growth experiment.

Seed Germination and Growth Study
The study was carried out by the Petri Dish Bioassay Experiment. 18Total twenty-five healthy, even, surface sterilized seeds were retained for the germination study in the sterilized petri dishes covered with double-blotting paper and moistened with 10 ml different concentrations of the aquatic root extract (10%, 20%, 30%, 40% & 50%).Each treatment had five repeats of control distilled water.Petri dishes were stored in laboratory conditions for a week (room temperature of 25°C for day and night).After a week, the percentage of seed germination was recorded by counting germinated seeds.On the 15th day, various parameters such as length of radical and Plumule were measured with the help of a slide caliper; observations were made five times, with a break of two days. 19

Data Analysis
Collected data of allelopathic effects of Argemone mexicana L. on germination and growth of seedlings (shoot and root length) of Triticum aestivum L. were compared with one-way ANOVA.
In order to investigate the significant differences between group averages, Fishers LSD test was used.All tests were carried out with statistical software with an importance threshold of 5%.

Results
The experimental results showed that seed germination percentage and seedling growth were reduced by Argemone mexicana L. root extracts compared to control sets of both wheat crop recipient varieties.A higher inhibition was observed in 50% concentration of aqueous root extracts.The results showed that the aqueous root extracts of Argemone mexicana L. significantly affected seed germination, root length, stem length as compared to control.One-way ANOVA were used to calculate F test value statistically.The statistical software used in all tests was the IBM SPSS 28.0.1.0version with a significance value of 5%

Effect on Germination of Seed (in Percentage)
Germination is the period between the hydration and the beginning of the seedling growth related activity, when the physiological processes of seeds begin, causing cell extension, new cells, tissues, and organs. 20

Effect on Shoot Length
Statistical analysis of the data revealed that the different aqueous root extracts of Argemone mexicana L. (P< 0.001) affected the length of wheat stems (Triticum aestivum L.) Sharbati and Lokwan varieties.The maximum shoot length (12.6±0.244cm and 12.8±0.2cm) was recorded for control seeds receiving distilled water and was significantly higher (P< 0.001) than all other treatments.While the minimum (5.4±0.4cm and 4.8±0.2cm) shoot length in 50% concentrations was observed for the wheat variants Sharbati and Lokwan respectively.The length of the shoots in concentrations ranging from10% to 40% was (12±0.316cm and 12.4±0.244cm),(11±0.316cmand 11.6±0.4cm),(10.6±0.4 cm and 9.4±0.244cm) and (7.2±0.374cm and 7±0.447 cm) respectively.Multiple comparisons between groups showed that there was a statistically not significant difference between treatment groups (control to 50%) compared to each other.Although the effects varied between the two varieties of wheat (Sharbati and Lokwan), they were concentration dependent.In comparison to Sharbati, the roots and shoots of the Lokwan variety were found to be more sensitive to the applied allelopathic stress; at high concentrations (50%) of Argemone mexicana L. aqueous root extracts, root and shoot length was significantly reduced.Argemone mexicana L. weed extracts from leaves had potent inhibitory effects and decreased Sorghum root and stem 29% to 40%, respectively, and seed germination ranges between 18% to 76%. 22he reduced root and shoot lengths seen in this study may adversely affect crop production, especially in smallholder farming systems.Root and shoot lengths are very important parameters that determine plants' growth and health because they are important in nutrient uptakes and physical support of the plant. 23Shorter roots are associated with plants' inability to compete and look for water and minerals from the ground. 24On the contrary, shorter shoot have been linked to a plant's vulnerability to environmental pressures like drought. 25Additionally, shorter shoots make it more difficult for plants to compete for the light, air, and space that are necessary for photosynthesis which may lead to poor plant growth.to lower doses (10%) and control (0%), the aqueous root extract of Argemone mexicana L. had a negative impact on seed germination and seedling growth in Triticum aestivum L. at higher concentrations (30%,40%,50%).These effects can be caused by