Study of medicinal and allelopathic effect of different weeds of Odisha, India

The term "allelopathy" refers to a biological process in which one organism produces biochemicals that impact another organism's growth, survival, and reproduction. Weeds pose a considerable risk to agricultural output because they prevent or stunt crop growth and development, resulting in substantial yield losses. Here, we examine the wide range of weeds in farming and other non - forested areas of Odisha's coastal districts. As many as 63 weed species, representing 31 families, were discovered here. The Asteraceae family has the most weed species (11), followed by the Euphorbiaceae family (9 species) and the Poaceae family (6 species). Amaranthaceae and Cucurbitaceae are also commonly found in the area of study. The data combing from the field with those from academic studies, this study improved our understanding of weeds. The paper also discusses the myriad ways natives have found to put weeds to good use. Many common weeds in the study area have long histories of use as a primary source of basic medical care. Most skin ailments, diarrhoea, jaundice, piles, and urinary problems treated with ethnomedicinal weeds are caused by parasites. Traditional cultures often used weeds in various ways, including food, animal feed, and medicine. Some plants have allelopathic impact in addition to their ethnomedical benefits. The authors of this paper present a complete and up - to - date inventory of the weed species detected in Odisha's coastal districts. It will be put to work protecting the region's unique plant and animal life. The allelopathic impacts on crops and the ethnobotanical uses of weeds have been uncovered through research


Introduction
Odisha is located on the eastern coast of India, around 26°.00′ N latitude and 94°.20′E longitude.There are 480 km of pristine coastline between the southern marshes of Ichhapuram and the northern coast of Suvarnarekha.Because of how often cyclones hit the coasts of Odisha, the districts of Kendrapara, Jagatsinghpur, Balasore, Bhadrak, and Jajpur are frequently featured in the media (1).In terms of weather, Odisha has a tropical monsoon climate.Odisha's location on the coastal strip means the ocean strongly impacts the state's climate.Extreme heat is typical in April and May due to the region's tropical environment.Summer highs average between 35 and 40 o C, with lows averaging between 12 and 14 o C. The southwest Allelopathy is the plant-to-plant interactions, whether direct or indirect, beneficial or deleterious by releasing certain biochemical compounds into the environment (3) (Fig. 1).Allelochemicals are the name given to these biochemicals (4).Over time, "Allelopathy" has been defined in various ways.Multiple definitions of allelopathy have been proposed.However, the concept has lately been broadened by the International Allelopathy Society (IAS) which states "any process involving secondary metabolites produced by plants, bacteria, viruses, and fungi that influence the growth and development of agricultural and biological systems" (IAS, 1996) (5).
Leaching, root exudation, volatilization, residue decomposition, and other processes release allelochemicals from plant components in both natural and cultivated systems (6).Allelochemicals may prevent cell division or decrease shoot and root growth (7).Root and shoot length are shortened by allelochemicals such as phenolic substances (8).These allelochemicals presumably restrict growth by interfering with plant growth pathways.Released allelochemicals can inhibit shoot/root growth and nutrient uptake, or they might attack a plant's natural symbiotic relationship, causing damage to the plant's food supply (7).The presence of one or more allelochemicals is responsible for all allelopathic manifestations.The efficacy of allelopathy is largely determined by the allelochemicals involved and their characteristics.In grasslands and forests, scientists have identified and named a wide range of allelochemicals over the past few decades.These allelochemicals can generally be broken down into phenolics, terpenoids, and nitrogen-containing compounds (9).
Plants that are unwelcomed in a particular environment and spread where they are not wanted are called weeds.Weeds grow in the natural environment and eventually threaten crops since they are part of dynamic ecosystems (10).Unwanted plant species known as "weeds" increase in areas where they are not wanted after erupting from cultivated crops.Only 250 of the 8,000 species of weeds are considered important for agriculture on a global scale (11).Weeds decreasing the quality of fertile lands, and reducing the capacity of crop seeds to germinate due to phytotoxins or allelochemicals (12).Short seed dormancy, rapid germination rates, environmental adaptability, rapid seedling growth and reproduction capacity, short life cycles, self-compatibility, efficient and well-organized seed desperation methods, and the production of a wide range of allelochemicals are some of the characteristics that set weeds apart (10, 13) and make possible for weed species to thrive and spread in a range of natural areas.As a result, weeds spread (11,14) and pose threat to local biodiversity (15,16).
Climate change has the potential to affect weeds.In general, competitive interactions between weeds and crops change due to any direct or indirect effect of rising CO2 levels or climatic change on the development or fitness of weeds and crops.In addition, it profoundly impacts the prevalence, distribution, population dynamics, and life cycle of most of the weeds in agriculture.The species composition of weeds and their relative abundance within weed and crop communities is also influenced by atmospheric CO2, rainfall, and temperature changes.Depending on the severity of climate change, farmers may need to adjust their agronomic methods, which might knock on weed development and spread.Weeds that rely on vegetative dispersal to carry seeds or pollen colonised new habitats more slowly than those that have efficient seed-dispersal systems (wind, water, and birds) due to the increased frequency of extreme events linked with climate change (17).India, a nation with various Landforms, shows notable regional differences in climate, height and vegetation.To create long-term land use plans, the nation is divided into 60 agro eco-sub regions, each further into districtscale agro-ecological units (18).From the very start of agricultural production, weeds have been a significant obstacle to global agriculture, resulting in over 80% output loss when unchecked (19).The term "Weed" is frequently used negatively when discussing agricultural production; weeds have been a significant obstacle to global agriculture, decreasing crop yields and resulting in substantial economic losses (20).Due to their poisonous characteristics, weeds pose a threat to human and animal health, contaminate water resources, and disrupt and damage natural ecosystems (21).Growing weeds wastes many valuable resources, such as nutrients, water, sunlight, and labour, and takes them away from cultivated crops (22).

Study area
Odisha is located at 26°.00′ N latitude and 94°.20′E longitude.The Bay of Bengal, Chhattisgarh, and Andhra Pradesh border it on the east, west, and south.The study area shown in Fig. 2 consists of Odisha's coastal districts (Balasore, Bhadrak, Kendrapara, Jagatsinghpur, Puri, Ganjam).Around 450 km make up its shoreline.Taking up about 4.87% of India's total land area, the coastline area runs from the border with West Bengal to the river Rushikulya in the south and the river Subarnarekha in the north (1).

Data collection
The research was conducted in and around Odisha's coastal areas (Balasore, Bhadrak, Kendrapara, Jagatsinghpur, Puri, and Ganjam) from May 2022 to July 2023.During the survey, data were collected from a variety of habitats of coastal districts of Odisha.A sufficient number of observed plant species were collected.Representa-tive, mature, intact and undamaged specimens were collected, and the specimens were identified as soon as possible after collection.The filed labels affixed to the collected materials contain basic information about the collection site.Key informant surveys with farmers and locals were used to collect data regarding the medicinal properties of weeds and their allelopathic effect on other plants.To ascertain whether weed species were present in the study area, data from the response forms was evaluated.Standard herbarium procedures were used for routine field notes, laboratory descriptions, identification, and classification.To find locals with specialized knowledge of the usage of medicinal plants, door-to-door visits were conducted throughout the study.Local farmers, older adults, and knowledgeable people provided the majority of the information on weed species with the help of a selfprepared questionnaire (Fig. 3).Specific details regarding the plants were discovered through individual interviews and group discussions in the native tongue, which were then compared and cross-checked (23,24).The field investigation included documented names, components and ethno-medical use of the plants (25).

Results
The study revealed that 63 weed species from 31 families were collected from various coastal areas of Odisha.The weed species that were collected and identified are listed in Supplementary Table 1.The table represents the list of weeds by scientific name, family name, distribution, medicinal uses, and allelopathic effect (Supplementary Table 2).Fig. 3 depicts the percentage of weeds with an allelopathic effect and those without.Fig. 4 shows the major dominated families studied regarding the number of species.Weeds were collected and identified after a thorough survey of the region.Preplanned questions were used in the conversation with the farmers.Review articles found in places like PubMed and Google Scholar provided second-dary data on weeds' therapeutic properties and allelopathic effects.The originality of the survey can be seen in the collected weed species.The medical data and allelopathic effect reviewed here will aid future crop enhancement and drug discovery investigations.

Discussion
Weed species diversity in non-forested open fields and crop fields served as the basis for this survey.This report extensively documents the variety of weeds in Odisha's coastal regions.Many plant species in the study region have significant ecological and economic significance as they serve as bio-resources for humans and other animals in the wild.On the other side, some species here are invasive and spread rapidly, and in a few years, weeds will outcompete the natural flora.From various literature reviews, 44 out of the 63 species surveyed were found to have an allelopathic influence on other plants (Fig. 4) (38,41,42).Therefore, it is assumed that these species cause  problems.As with the rest of India, the coastal districts of Odisha are experiencing rapid economic and population growth, which may put unnecessary strain on the environment in the form of increased modern farming (including the use of fertilizers, irrigation, and chemical spray), housing, road construction, and overgrazing.The groups Asteraceae (nine), Euphorbiaceae (seven), and Poaceae (five) were determined to be the most numerous (6).The most dominant weed families in coastal areas are Amaranthaceae and Cucurbitaceae, each consisting of 4 weed species (Fig. 5) (55,56,62).Many of the weeds that can be found in the study region are consumed or used as fodder or as traditional medicines.According to a survey, 63 species were used to treat things like diabetes, gastrointestinal disorders, fever, gynaecological disorders, cardiovascular issues, skin ailments, rheumatism, and dental cavities.

Prospects
Many environmental conditions affect allelopathic interactions, including soil type, moisture levels, and temperature.Due to its intricacy, allelopathy is difficult to implement reliably in agricultural or gardening contexts.Even helpful microbial species like mycorrhizal fungi can be negatively impacted by allelopathy.It might be challenging to strike a balance that fosters beneficial relationships and encourages the growth of desirable plants.Incorporating allelopathy into an overarching pest management approach that uses pesticides and other forms of control can be difficult.There is still a lot about allelopathy that scientists do not fully understand, such as how it works and which allelopathic substances different plants generate.This calls for constant study and testing.
Allelopathy can be used to manage weeds organically and lessen the heavy reliance of agriculture on synthetic herbicides.Natural herbicides like allelochemicals can be very useful for weed management because they are less harmful to the environment than synthetic herbicides while still effective against weeds.Understanding new modes of action can be gained from studying allelechemicals, which have been exploited as leads in synthesizing synthetic herbicides.In the future, we may be able to discover new medications derived from weeds, as weeds are already used to treat many ailments.

Conclusion
This study focused on several allelopathic species that generate significant allelochemicals with conventional and organic farming applications.Forty-four of the 63 species surveyed were found to have an allelopathic influence on other plants, and 58 were used to cure a variety of medical conditions, including diabetes, gastrointestinal problems, fever, gynaecological problems, cardiovascular illness, skin problems, rheumatism, and even dental caries.The allelopathic action of plants can be harnessed to create bioherbicides, while the therapeutic characteristics of plants can be studied further in the pursuit of new medicines.These investigations will reveal the allelopathic impacts on agricultural products and the diverse ethnobotanical values, which are necessary because the flora of Odisha's coastal districts has not been examined in depth.

Fig. 3 .
Fig. 3. Questionary for collecting data from local farmers and knowledgeable people.

Fig. 4 .
Fig. 4. Pie chart showing number of weeds having an allelopathic effect and no effect.