Role of Medicinal plants in increasing green economy for a better sustainability
*Dr. A. Suvarna Latha, Dr.K.S.Shanthi Sree, Dr.P.Lakshmi Padmavathi",
Prof.D.Bharathi and Prof.K.Nagalakshmamma
Dept. of Biosciences and Sericulture",
Sri Padmavati Mahila Visvavidyalayam (Women’s University), Tirupati
*Corresponding Email Id: [email protected]
Plants are the source of food, shelter, fuel, medicine, fiber and provide numerous resources for the survival of man on this earth. Without plants the existence of man is impossible. Geographical location and climate condition makes our country abundant and very rich in variety of species of medicinal plants. Moreover, today’s science is involved in confirming their effectiveness in solving the unprecedented damage caused by anthropogenic effects. One of the drastic effect on the nature is the pollution which decreases the green economy and ultimately degrading the natural ecosystem functioning and human health. Major air pollutants include particulate matters (PMs), ground-level ozone (O3), sulfur dioxide (SO2), nitrogen dioxides (NO2), and volatile organic compounds (VOCs). Various effects of some common air pollutants on human comfort and health are respiratory illness, cardiovascular disease to bladder and lung cancer. During the last three decades, air has become increasingly polluted in countries like China and India due to rapid economic growth accompanied by increased energy consumption. In 1989, NASA discovered that plants can absorb harmful toxins from the air. While plants have less horse power than air purifiers, they are more natural, cost effective, and therapeutic. Bioremediation of air pollutants can be observed by exploiting the potentials of plant leaves and leaf-associated microbes. The aerial surfaces of plants, particularly leaves, are estimated to be of 4 × 108 km2 on the earth and are also home for up to 1026 bacterial cells. Plant leaves are able to adsorb or absorb air pollutants, and habituated microbes on leaf surface and in leaves (endophytes) are reported to be able to biodegrade or transform pollutants into less or nontoxic molecules, but their potentials for air remediation has been largely unexplored. The present paper enumerates the facts of some of the medicinal plants useful in absorbing the air pollutants.
Keywords: Medicinal plants, Green economy, Pollution, Bioremediation and volatile organic compounds (VOCs)
Green economy is defined as an economy that aims at reducing environmental risks and ecological scarcities, and that aims for sustainable development without degrading the environment. It refers to sectors (e.g. energy), topics (e.g. pollution), principles (e.g. polluter pays) or policies (e.g. economic instruments). The 2011 UNEP Green Economy Report argues "that to be green, an economy must not only be efficient, but also fair”. Fairness implies recognizing global and country level equity dimensions, particularly in assuring a just transition to an economy that is low-carbon, resource efficient, and socially inclusive. Green economies require green energy generation based on renewable energy to replace fossil fuels as well as energy conservation and efficient energy use. The world has experienced unprecedented urban growth during the last three decades. Urban population is expected to increase at 2.3% per year in developing countries from 2000 to 2030 (Brockherhoff, 2000; United Nations, 2000, 2004; UNFPA, 2004). Urbanization is often associated with rapid economic growth. Green economy works in two ways. First, by increasing investment in the sustainability of ecosystems upon which much of the poor people depend, it ensures that the environment can continue to be used for the benefit of current and future generations. Second, by developing strategies for economic growth on the basis of the sustainable use of natural resources and the environment, a green economy generates the long-term jobs and wealth that are needed to help eradicate poverty. A green economy also recognizes that conventional economic indicators, such as GDP, provide a distorted indicator for economic performance. This is because such indicators fail to reflect the extent to which production and consumption activities may be drawing on natural capital. It was one of the main topics discussed during the World Summit on Sustainable Development (June 2012, RIO +20).
Recent studies from the International Agency for Research on Cancer showed that there were 223",000 deaths in 2010 due to air pollution-resultant lung cancer worldwide, and air pollution has become the most widespread environmental carcinogen (International Agency for Research on Cancer, 2013) one of the major cause for decreasing green economy. The WHO reported that around 7 million people died of air pollution exposure directly or indirectly in 2012. This data was more than double previous estimates and confirmed that air pollution has become a substantial burden to human health and is the world’s largest single environmental health risk (WHO, 2014). Additionally, air pollution also harms animals, plants, and ecological resources including water and soils (Vallero, 2014; Duan et al., 2017).
MEASURES FOR REDUCING AIR POLLUTION
To reduce air pollution, the first step is to eliminate or reduce anthropogenic-caused emissions. The second step is to remediate existing pollutants. Air pollutants can also be mitigated through biological means, commonly referred to as biological remediation or bioremediation. It is the use of organisms to assimilate, degrade or transform hazardous substances into less toxic or non toxic ones (Mueller et al., 1996). Plants have been used for remediation of pollutants from air, soils, and water, which has been termed as phytoremediation (Cunningham et al., 1995; Salt et al., 1995; Huang et al., 1997). Microbes such as bacteria and fungi are also capable of biodegrading or biotransforming pollutants into non-toxic and less toxic substances, which is known as microbial biodegradation (Ward et al., 1980; Ma et al., 2016). Microbes as heterotrophs occur nearly everywhere, including plant roots and shoots. Both roots and shoots have been reported to be able to remediate air pollutants (Weyens et al., 2015; Gawronski et al., 2017). There are various ways and means to mitigate the urban environmental pollution. Planting of trees and shrubs for abatement of pollution and improvement of environment is an effective way and well recognized throughout the world. Proper planning and planting scheme depending upon the magnitude and type of pollution, selection of pollution- tolerant and dust scavenging trees and shrubs should be done for bioremediation of urban environment.
Medicinal plants in decreasing pollution
While selecting the species for pollution control the following important characteristics could be considered. Plants should be evergreen, large leaved, rough bark, indigenous, ecologically compatible, low water requirement, minimum care, high absorption of pollutants, resistant pollutants, agro-climatic suitability, height and spread, Canopy architecture, Growth rate and habit (straight undivided trunk), Aesthetic effect (foliage, conspicuous and attractive flower colour), Pollution tolerance and dust scavenging capacity. During tree plantation in an urban environment little or no attention has been paid to evaluate the effect of trees on filtering the particulate matter. New housing developments offer an opportunity to control atmospheric particulate pollution through tree plantations.
Trees such as Tamarind (Tamarindus indicus) having smaller compound leaves are generally more efficient particle collectors than larger leaves. Particle deposition is heaviest at the leaf tip and along leaf margin. In the preliminary survey of dust fall on common roadside trees in Mumbai, carried out (Shetye, R. P., and S. B. Chaphekar. 1989) reported that the shape of leaves of Mango (Mangifera indica), Ashoka (Polyalthea longifolia), Pongamia (Derris indica) and Umbrella (Thespesia populnea) trees captured higher amounts of dust as compared to other neighbouring plants. (Dochinger, L. S. 1973) a plant pathologist of USDA Forest Service, Ohio, reported that the filtering effects of evergreen trees are better than the deciduous trees. In Singapore; it has been noted that a single row of trees planted with or without shrubs can reduce particulate matter by 25% and each hectare (2.471 acres) of plantation can produce enough oxygen to keep about 45 persons alive (Anonymous, 1981).
The value of trees in urban environment is now generally recognized not only aesthetically but also functionally in helping to make cities and towns agreeable places to live and work in. The first choice should be, therefore, to select easily propagated and readily available, medium growing, ecologically much suitable, pest and disease resistant tree species and also require less maintenance should be given top priority. Columnar and medium-sized trees are preferred. Ingold, 1971 reported that the leaves with complex shapes and large circumference area reported to be collected particles more efficiently. Many trees like Neem (Azadirchta indica), Silk cotton (Bombax ceiba), Indian laburnum (Cassia fistula and C. siamea), Gulmohar (Delonix regia), Pipal (Ficus religiosa), Jacaranda (Jacaranda mimosifolia), Indian lilac (Lagerstroemia indica), Temple or Pagoda tree (Plumeria rubra and P. alba), Java plum (Syzygium cumini) and several other roadside and street trees have found more suitable in urban environment (Maheshwari, J. K, 1963 ) If such trees are to be planted, their local ecological relationship with human environment has to be studied properly. It should be borne in mind that these trees may cause allergic disorders such as hay fever; asthma and toxaemia due to airborne pollen grains, which can also contribute to atmospheric pollution significantly. Chakre, 1984 has suggested that the insect-pollinated trees with short flowering periods and also with less pollen productivity should be selected. It is also recommended that wind-pollinated tree species those, flowering during rainy season can also be planted, as rains will wash out extra pollens. A tree should be relatively free of insects and diseases and there should not be dropping of messy fruits (Muntingia calabura, Cerbera odolam), seed pods (Acacia auriculaeformis), twigs and leaves (Dyera costulata). Trees with a tendency to drop large and heavy fruits (Durio spp.) and emit bad smell (Sterculia foetida) must be considered a serious drawback.
List of species for road borders and housing sites
Alstonia scholaris; Lagerstroemia flosreginae; Mimusops elang; Cassia fistula; Bauhinia purpurea;
Grevillea pteridifolia; Pongamia pinnata; Polyalthia longifolia Peltoferrum ferrugineum; Cassia siamea; Melia azedarach; Delonix regia; Anthocephalus cadamba; Michelia champaca.
Planting along the road
Roads are the important sites of the urban areas which contribute significantly in generating pollution.
By planting trees on both sides pollution can be mitigated. Unfortunately, in most of the old Indian cities and towns, there is hardly any provision of sufficient space for the same. However, it is necessary to study the type of road, overhead electrical cables, spaces available on sides, central verge, traffic triangles, round abouts, squares and other open space available before taking up any plantation. It has been observed that trees and shrubs which are drought/frost resistant are generally tolerant to pollution. Selection of trees is another important task. Before selecting any plant species, it is necessary to consider following characters: agro-climatic suitability; height and spread; canopy architecture; growth rate and habit (straight undivided trunk); aesthetic effect (foliage, conspicuous and attractive flower colour); pollution tolerance and dust scavenging capacity. Some of the ornamental trees which have aesthetic effect and are tolerant to pollution have been screened and recommended for planting along the roads: Acacia auriculiformis, Ailanthus excelsa, Albizzia lebbek, Bauhinia acuminata, B. purpurea, Butea monosperma, Cassia fistula, C. marginata, C. siamea, Casuarina equisetifolia, Crataeva religiosa, Drypetes roxburghii, Ficus benjamina, Lagerstroemia duperreana, L. flosreginae, L. rosea, Mimusops elengi, Polyalthia longifolia, P. longifolia 'Angustifolia', P. longifolia 'Pendula', Peltophorum ferrugineum, Tectona grandis, Terminalia arjuna, T. muelleri, Thespesia populnea etc. Emphasis should be given to the native plant species which are comparatively well acclimatized, and stress and pollution tolerant (Fig.1).
Central Verge / Road dividers
Central verge of the two way roads in the cities and towns are often found neglected and devoid of any planting. It is recommended that this area should be well utilized by planting dwarf trees and shrubs. This will not only serve aesthetic purpose but also functional being physical barrier for the glare of head lights of the vehicles which is essential for effective and safe operation of the roads during dark hours. Planting may be done either in single or double row depending upon the space available. Since these plants are more close to the automobile exhaust, their capacity for pollution tolerance should be considered before selection. Following plant species have been reported as pollution tolerant and recommended for plantation: Acalypha wilkesiana, Bougainvillea 'Chitra', 'H.C. Buck', 'Lady Mary Baring', 'Mary Palmer Special', 'Partha', 'Shubhra', 'Zulu Queen'; Caesalpinia pulcherrima, Callistemon lanceolatus, C. polandii, Cassia surattensis, Duranta plumeri, Euphorbia milli, Hamelia patens, Hibiscus rosa-sinensis, Ixora coccinea, J atropha panduraefolia, Lantanacamara, L. depressa, Malpighia coccigera, M. glabra, Murraya paniculata, Nerium oleander , Phyllanthus niruri, Rosa Gruss an Teplitz', Tabernaemontana coronaria, Thevetia neriifolia, Vinca rosea, Wadelia lacinata etc (Fig.2).
AP Government initiatives in increasing greenery in Urban areas.
The Chief Minister of Andhra Pradesh Shri Nara Chandrababu Naidu, launched a plantation programme 'Vanam-Manam' (forest and we) in the campus of Indian Institute of Industrial Training (IIIT), at Nuzvid, in Krishna district, said, "Everybody should plant trees, and post them on social media (Fig.3). It should become a moment. Everybody should plant a sapling on their birthday, and grow them." As many as 26 crore trees will be planted all over the state in this period through government departments and private organisations. As many as 1 crore saplings were planted across the state. The government gave a call to plant two saplings in the house and one outside the house. Andhra Pradesh government has been organising this program since last three years under 'Mission Harita Andhra Pradesh'. Its aim is to increase the green cover in the state by 50 percent by 2029. "Today our state has 26 percent green cover. Our target is to make it 50 percent by 2029. Andhra Pradesh is a symbol for biodiversity. There are 2351 varieties of trees, 1461 animal species. Of them, 68 plant varieties and 10 animal species are exclusive and unique to the state. Our state has 13 reserve forests, three national parks, two zoological parks, one tiger reserve and one elephant reserve. Nallamala, India's biggest tiger reserve is spread in 3325.31 km in Andhra Pradesh. Government is driving the state towards Zero Budget Natural Farming.
[image: Image result for road divider plantation]
Fig. 1: Plantation along Roadside and on the divider
[image: Related image]
Fig. 2: Plants on a road divider in Nellore city (http://www.thehansindia.com)
[image: Chief Minister N. Chandrababu Naidu plants a sapling to launch the Manam-Vanam programme in Sunkollu village in Krishna district on Friday. (Photo: DC)]
Fig. 3: Chief Minister N. Chandrababu Naidu launched Mission Vanam-Manam by planting saplings of Neem and Raavi at Sunkollu village under Nuzvid mandal in Krishna district on Friday. The objective of the mission is to increase the green cover in the state by 50 per cent by the year 2029. Andhra currently has 23 per cent green cover (forest area) and another 3 per cent non-forest, besides 13 lakh hectares of degraded forest. The Chief Minister gave a call to everybody to plant one crore saplings on Friday alone.
The importance of trees in urban environment is now widely recognized to increase green economy of the state and also cleanse the air pollution and help to make cities and town more agreeable places to dwell upon. The present paper gives an insight about judicious placement of plants in urban canyons can reduce the pollution. In the present report recommends tree species are recommended for urban planting so that a wider usage of local as well as exotic tree species which can be explored for controlling air born pollution in urban climate.
1. Anonymous (1981) A Guide to Tree Planting. Parks and Recreation Department, Ministry of National Development, Singapore.
2. Brockherhoff, M. P. (2000). An urbanizing world. Popul. Bull. 55, 3–44.
3. Chakre, O. J. (1984) Atmospheric pollens: The organic pollutants. Science Service, 3(8): 4.
4. Cunningham, S. D., Berti, W. R., and Huang, J. W. (1995). Phytoremediation of contaminated soils. Trends Biotechnol. 13, 393–397. doi: 10.1016/S0167-7799(00)88987-8.
5. Dochinger, L. S. (1973). Miscellaneous Publication No.1230.USDA, Forest Service, Upper Darby",Pa, pp. 22.
6. Duan, K., Sun, G., Zhang, Y., Yahya, K., Wang, K. M., and Madden, J. M. (2017). Impact of air pollution induced climate change on water availability and ecosystem productivity in the conterminous United States. Clim. Chang. 140, 259–272. doi: 10.1007/s10584-016-1850-7.
7. Gawronski, S. W., Gawronska, H., Lomnicki, S., Saebo, A., and Vangronsveld, J. (2017). Plants in air phytoremediation. Adv. Bot. Res. 83, 319–346. doi: 10.1016/bs.abr.2016.12.008.
8. Huang, J. W., Chen, J., Berti, W. R., and Cunningham, S. D. (1997). Phytoremediation of lead-contaminated soils: role of synthetic chelates in lead phytoextraction. Environ. Sci. Technol. 31, 800–805. doi: 10.1021/es9604828.
9. Ingold, C. T. (1971). Fungal Spores. Clarendon Press, Oxford.
10. Ma, Y., Oliveira, R. S., Freitas, H., and Zhang, C. (2016). Biochemical and molecular mechanisms of plant-microbe-metal interactions: revelance for phytoremediation. Front. Plant Sci. 7:918. doi: 10.3389/fpls.2016.00918.
11. Maheshwari, J. K, (1963)The Flora of Delhi. Council of Scientific and Industrial Research, New Delhi.
12. Mueller, J. G., Cerniglia, C. E., and Pritchard, P. H. (1996). “Bioremediation of environments contaminated by polycyclic aromatic hydrocarbons",” in Bioremediation: Principles and Applications, eds E. L. Crawford, D. L. Crawford (Cambridge: Cambridge University Press), 125–194.
13. Salt, D. E., Blaylock, M., Kumer, N. P. B. A., Dushenkov, V., Ensley, B. D., Chet, I., et al. (1995). Phytoremediation: a novel strategy for the removal of toxic metals from the environment using plants. Biotechnology 13, 468–474. doi: 10.1038/nbt0595-468.
14. Shetye, R. P., and S. B. Chaphekar. 1989. Some estimation on dust fall in the city of Bombay, using plants. Vol. 4: pp. 61-70. In: Progress in Ecology.
15. UNEP (2011), 'Towards a Green Economy: Pathways to Sustainable Development and Poverty Eradication'. (http://www.unep.org/greeneconomy)
16. UNFPA (2004). “State of World Population 2004: The Cairo Consensus at Ten: Population, Reproductive Health and the Global Effort to End Poverty: Chapter 4 Migration and Urbanization. New York, NY: United Nations Population Fund.
17. United Nations (2000). World Urbanization Prospects (the 1999 Revision). New York, NY: Population Division, Department of Economic and Social Affairs, United Nations.
18. United Nations (2004). World Urbanization Prospects (the 2003 Revision). New York, NY: Population Division, Department of Economic and Social Affairs, United Nations.
19. Vallero, D. A. (2014). Fundamentals of Air Pollution, 5nd Edn. San Diego, CA: Elsevier.
20. Ward, D. M., Atlas, R. M., Boehm, P. D., and Calder, J. A. (1980). Microbial biodegradation and chemical evolution of oil from the Amoco spill. Ambio 9, 277–283.
21. Weyens, N., Taghavi, S., Barac, T., van der Lelie, D., Boulet, J., Artois, T., et al. (2009). Bacteria associated with oak and ash on a TCE-contaminated site: characterization of isolates with potential to avoid evapotranspiration of TCE. Environ. Sci. Pollut. Res. Int. 16, 830–843. doi: 10.1007/s11356-009-0154-0.
22. WHO (2014). 7 million Premature Deaths Annually Linked to Air Pollution. Available online at: http://www.who.int/phe/eNews_63.pdf?ua=1.