STUDIES ON THE ARBUSCULAR MYCORRHIZAL FUNGAL BIODIVERSITY IN THE PLANT SPECIES OF KONDRANGHI HILLS, DINDUGUL DISTRICT, TAMIL NADU, INDIA

The present study to investigated that the arbuscular mycorrhizal fungal root colonization and spore population in some medicinal at Kondrangi hills Eastern Ghats of Dindugul district, Tamilnadu, India. Root and rhizosphere soil samples were collected during the month of August, 2017-March, 2018 from the surface to 30 cm depth as well as pH were also recorded. Totally 32 plant species belonging to 21 families and 30 genera were identified. The present result showed arbuscular mycorrhizal spore population in the rhizosphere soil and root colonization of all the plant species. A total of 20 AM fungal species belonging to 7 genera and 2 different orders were recorded from the rhizosphere soil samples of this study region. The Glomus was dominant had seen in rhizosphere soil samples in all the medicinal plant species. The maximum spore population was found in the rhizosphere soil samples of Phyllanthus amarus (440 /100 g soil) which belongs to the family Euphorbiaceae and the lowest spore population was observed in the Tephrosia purpurea (110 /100g soil) belongs to Fabaceae. family. The highest 87% AM fungal infection was found in roots of Plumbago zeylanica belongs to the family Plumbaginaceae. While the lowest 24% AM fungal association was found in the root of Striga angustifolia belongs to the family Scrophulariaceae.


INTRODUCTION
Fungi constitute a megadiverse kingdom. There are at least 1.5 million, but probably as many as 3-5 million species, of which only about 100,000 have been described formally. Fungi play an important role in the rhizosphere; one among them Arbuscular Mycorrhizal symbiotic association with plant and enhances the absorption of water and nutrients, especially in phosphorous. It also increases the tolerance of plants to biotic and abiotic stresses, as pathogens, drought and high salinity (1). Besides that, the Arbuscular Mycorrhizal plays a critical role in the functional and successional processes of plant communities as soil formation, management and nutrient cycling (2, 3).

Study area
The present research area of Kondarangi hills Keeranur is situated at Eastern Ghats of Ottanchattram (Taulk), Dindugul district, Tamilnadu, India. The altitude ranges between 10.627988°N 77.730901°E. The hill elevation 1165.86 meters (3825 Feet) m. s. l. (Fig. 1). The maximum temperature was recorded in the month of May 33 0 C. The maximum annual rainfall ranges 800 mm. The main activity of the local people is agriculture. They depend upon wells for irrigating the lands.
In the present study area of kondrangi hills located at eastern region of Dindugul district, a rich diversity of medicinal plants scattered over the hills and hillocks. Publish information on the AM fungal association in the medicinal plants at kondrangi hills is not available till date. Hence, the present research to investigate the diversity of arbuscular mycorrhizal fungi in the rhizosphere soil samples and root colonization of medicinal plants species were collected from the kondrangi hills, Eastern Ghats of Dindugul district, Tamil Nadu India.

Sample collection
In this present study, root and rhizosphere soil samples of 32 plant species were collected for the duration of August, 2017-March, 2018. The collected soil and root samples were placed in the polyethylene bags, labeled and then transported to the laboratory. The root samples were freshly processed, whereas rhizosphere soil samples were analyzed for mycorrhizal spore population and AM fungal root colonization in study species.

Estimation of AM fungal root colonization
The root samples were cleared and stained in tryphan blue with a modified version of following method by Philips and Hayman's (4). The collected roots samples were cut into 1-2 cm pieces, heated at 90ºC in 10% KOH for about 1 hour. For thicker and older roots, the duration was increased. The root segments were rinsed in water and acidified with dilute HCl. The root pieces were stained with 0.05% tryphan blue in lacto phenol for 5 minutes and the excess stain was removed with clear lacto phenol.
The percentage of AM fungal infection was calculated using the formula: No. of root segments colonized Percentage of colonization = ×100 Total no of root segments of observed

Identification of AM fungi
The present study isolation and identification of AM fungal spores based upon their morphological characters such as spore size, color, hyphal attachement, cell wall layer characters, were identified in addition with nomenclature, keys of the following manual authors were used: Raman and Mohankumar (5); Schenk and Perez (6) and Schubler and Walker (7). The Photomicrographs were taken with the help of a Magnus Olympus Microscope.

Soil pH
The pH of the soil samples was determined (soil-water suspensions 1:5) with the help of pH meter (Elico) and values were recorded.

RESULTS AND DISCUSSION
In the present result reveals that totally 32 medicinal plant species belongs to 21 families were examined AM fungal colonization and spore population at kondrangi hills, Dindugul district, Tamilnadu (Fig. 2,3). The collected and identification of the plant species for their respective family, habit, plant parts used and therapeutic uses are presented ( The results was observed in the present research clearly indicated that the plants species belonging to the family Poaceae showed Arbuscular mycorrhizal fungal colonization. In this, study revealed that the rhizosphere soil samples of all the plant species the genus Glomus was predominant than other and Gigaspora occupied the second position. The present study also concluded that there is a high incidence of AM fungi in the study area. All the plant species studied were colonized by AM fungi.     The present study reveals that Glomus is the dominant AM fungal genus which seems to be dominant in the root regions of the plant species. Similar findings are in conformity that the genus Glomus was predominance in arid and semi arid areas (10-13). Natalia et al. (14) reported that mycorrhizae are key components of natural ecosystems because of their essential role in sustain vegetation cover. The present study revealed that the Allmania nodiflora belongs to Amaranthaceae member showed 57% of arbuscular mycorrhizal colonization was observed. The present studies believed to be non mycorrhizal plants were found to be associated with AM fungi. followed by Aculospora, Gigaspora, Scutellispora, Sclerocystis and Entrophospora respectively.

CONCLUSION
The AM colonization and spore population in 32 medicinal plants species were investigated in kondrangi hills, Dindugul district, Tamilnadu. From the present findings of the research work, conclude that root colonization and spore population was abundant in all the plant species, however the genus Glomus was the dominant seen in all the rhizosphere soil. In this mutualistic association significance on medicinal plants, improving plant growth and also increasing secondary metabolite production, especially in agricultural crops.