Effect of Seasonal Variation on Mycorrhizal Fungi Associated with Medicinal Plants in Central Himalayan Region of India

Supriya Gaur,Purshotam Kaushik

doi:10.4236/ajps.2012.35075

Supriya Gaur, Purshotam Kaushik

Open Access

https://doi.org/10.4236/ajps.2012.35075

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Abstract

This research paper assesses the effect of seasonal variation on mycorrhizal fungi. Based on the richness of medicinal plants in Himalayan region, this research work considered three medicinal plants i.e. Catharanthus roseus Linn., Ocimum spp. and Asparagus racemosus Willd. The study was conducted at five districts of Uttarakhand state of India viz. Pauri Garhwal, Haridwar, Dehradun, Udham Singh Nagar and Almora. To account for seasonal variations, soil and root samples were collected in months of Jan-Feb, May-June and Sep-Oct from year 2006 to 2008. Furthermore, the study was directed to collect information about the distribution of VAM fungi in the medicinal plants in relation to spore population. This research work evaluated and analyzed the effect of temperature, altitude and seasonal conditions. The undisturbed natural vegetations revealed maximum spore numbers followed by cultivated and non-cultivated regions. Similarly, root colonization by VAM fungi was observed at higher levels in natural vegetations and cultivated sites in comparison to non-cultivated lands. The monthly and seasonal temperature varied and had considerable effect on VAM fungal population. The data obtained in the present study undoubtedly indicate that the sea-sonal variation in VAM fungi is significant with few exceptions. VAM fungi in medicinal plants differ in the manner and extent with which root colonization rate occurs and also differ in their capacity to form propagules. Most of the study reveals that host plant had much more effect on spore population. Number of spores also varied with the growing season of the host plant. During the present study most of the sites showed a general increase in spore number from Sep-Oct to Jan-Feb.

Highlights

Mycorrhiza is a symbiotic mutualistic relationship between special soil fungi and fine plant roots; it is neither the fungus nor the root, but rather the structure formed from these two partners
To account for seasonal variations, soil and root samples were collected in months of Jan-Feb, May-June and Sep-Oct from year 2006 to 2008
The data obtained in the present study undoubtedly indicate that the seasonal variation in Vesicular Arbuscular Mycorrhiza (VAM) fungi is significant with few exceptions

Summary

Introduction

Mycorrhiza is a symbiotic mutualistic relationship between special soil fungi and fine plant roots; it is neither the fungus nor the root, but rather the structure formed from these two partners. The fungus receives carbohydrates (sugars) and growth factors from the plant, which in turn receives many benefits, including increased nutrient absorption. In this association, the fungus takes over the role of the plant’s root hairs and acts as an extension of the root system [1]. Vesicular Arbuscular Mycorrhiza (VAM) is present in most medicinal plants, agronomic and vegetable crops. This type is characterized by the presence of arbuscules in the region of the root cortex; vesicle may or may not be present; and they function as reserve organs and for fungal multiplication. Vesicular-arbuscular mycorrhizas (VAM) and arbuscular mycorrhizas are recognized as most common type of mycorrhizae with diverse host range [2]

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