No abstract

Rhizopogon himalayensis (Castellano, S.L. Miller, Singh & Lakhanpal) A.B. Mujic & M.E. Sm., comb. nov. -an edible truffle-like fungus- normally exists in a symbiotic association with Cedrus deodara (Roxb.) Loud. Because of this important association and the ecological significance as per the available literature attached to this fungus, the present study was undertaken with a specific objective to test the mycorrhizal viability of this mycobiont with this important tree species of Himalaya -the theme tree of Himachal Pradesh. An attempt to investigate and record morphological and anatomical characteristics and variations in this mycorrhizal association was also made in nursery conditions using pure culture (wheat grain spawn) of R. himalayensis. The seedlings grown and inoculated in the nursery were harvested after six months for further examination, including the microscopic details. The study and subsequent analysis revealed that that mycobiont had invaded most of the feeder roots, imparting a typical swollen appearance to the mycorrhizal root tips. These root tips were light ochre with moderately thick plectenchymatic fungal mantle with occasional clamp connections on the inner layer of the fungal mantle. The root surface, as seen, was found smooth and frequently covered with a loose aggregation of inter-woven hyphae that uniformly pervaded the epidermis extending into the inter-cortical spaces of outer cortical cells and formed a characteristic Hartig net. Thus, results obtained in fact for the first time, presented an in-depth analysis of the morphological and anatomical characteristics of R. himalayensis and C. deodara association.

The technique involves partial colonisation of detached petals with either the ascospores or the mycelium for initiating subsquent infection of the cauliflower seedlings. Under optimum envitonmental conditions typical symptoms appeared six days after placement of putiaUy colonised petals on the host surface.

Studies to evaluate the plant diversity and growth forms in alpine pasture of Talra Wildlife Sanctuary of District Shimla, Himachal Pradesh were carried out during August, 2003. Total 75 species of plant, comprising of 7 grasses, 4 sedges, 4 leguminous forbs and 60 non-leguminous forbs were recorded from the area. On the basis of Importance Value Index (IVI). Sibbaldia cuneata O. Ktze., was found to be the dominant species followed by Geum elatum Wall ex D. Don., Ligularia amplexicaulis DC., Primula denticulata Smith and Saxifraga parnassifolia D. Don. The distribution of all the plant species was contagious. Index of dominance was 0.036 and index of diversity 5.386. The contribution of tall forbs, short forbs and cushioned and spreading forbs in the alpine pasture was 29.33%, 54.66% and 16.0% respectively.

The composition of forest vegetation along an altitudinal gradient (400 to 650m) in Simbalwara Wildlife Sanctuary was studied during August, 2003. The forest is composed of 53 species of trees, 32 of shrubs and 175 of herbs. The plant communities identified at 400-525m and 525-650m elevation range were Shorea robusta – Mallotus philippensis and Shorea robusta – Terminalia alata respectively. On the basis of importance value index (IVI), Shorea robusta was the dominant tree species at both the elevation ranges. The distribution pattern of plant species was random and contiguous at both the altitudes. The concentration of dominance was lower and index of diversity higher for plant species at both the altitudes Index of diversity for trees was 4.390 and 3.942 at 400-525m and 525-650m elevation range respectively. The index of similarity for trees, shrubs and herbs between two altitudes was 0.64, 0.65 and 0.54 indicating remarkable degree of similarity in plant species. The population structure of tree species is represented mainly by two patterns, one represented by greater proportion of individuals in seedlings stage indicating frequent reproduction and another indicating more individuals in intermediate girth classes with absence of seedlings. If the latter trend continues for longer period, the species may disappear from the area in near future.