Seed germination in Taxus baccata subsp. Wallichiana was investigated using soil from the forest as well as non-forest areas, including sterilized soil. Results obtained from various soil treatments indicated the presence of certain antigermination factors in the rhizosphere soil of T. baccata, which seem to be of microbial origin. Seed germination was found to improve in autoclaved Taxus forest soil. The aril portion of Taxus seed inhibited germination. Since Taxus plants were found growing under the shade of Cedrus deodara trees, probably sharing similar rhizosphere communities, seed germination of Taxus was also tried in Cedrus forest soil, which too was found to be inhibitory. Similar to Taxus rhizosphere soil, in this case also, germination improved in autoclaved soil. Pine rhizosphere soil and non-forest soil treatments resulted in higher seed germination, indicating the absence of antigermination factors. Highest seed germination (up to 70%) was recorded in non-forest soil under polyhouse conditions, when the seeds were sown after removing the aril. These results are indicative of the association of specific microbial population with Taxus rhizosphere, not favouring its own seed germination. The study has implications in afforestation or reforestation programmes.

Management of degraded sodic soils for crop production has not gained enough momentum due to small land holding, high initial inputs and low yield. If such soils are afforested with the compatible species, after few years the surface layer is ameliorated to an extent, which may support many crops/plants well. In this trail, the effect of two species, i.e., A. lebbeck and P. dulce planted on a modest quality of sodic soil, was observed to characterize the role of amelioration. Both the species are leguminous N fixers and are moderately tolerant to sodicity, which are a prerequisite for species selection while planting on sodic wastelands. Though the observations were taken up to 45 cm depth, the significant changes in soil properties were observed to only 15 cm depth. Soil organic C, exchangeable Ca⁺⁺ and cation exchange capacity (CEC) increased with plant growth; whereas, pH, exchangeable sodium per cent (ESP) and exchangeable Na⁺ (cmol/kg^-1) decreased markedly. Soil amelioration was greater under A. lebbeck stand than that of P. dulce stand corresponding to the growth and biomass produced by the two species. Vertical root penetration and horizontal root spread were also correlated with the soil amelioration. It was concluded that soil amelioration was about 30-40% during nine years from initial years of planting. At this stage many other crops of economic importance can be introduced, which can be cultivated successfully in agroforerstry land use systems.

A study was conducted to find the effect of natural ageing on the germination and seedling vigour of fresh, one and two years-old teak drupes (Fruit with seed). The fresh, one and two year-old drupes were allowed for germination under open and mist chamber conditions following soaking and drying of drupes for 6 days at an interval of 12 hrs recorded 8, 37 and 51 per cent and 3, 40 and 50 per cent germination respectively. The total number of seedlings also reflected the same trend as that of germination. Seedlings from one and two year’s old-drupes emerged early in mist chamber (10 days) than in open condition (12 days). Seedlings from one and two year-old drupes also exhibited better seedling vigour than fresh drupes.

A soil vegetation study was carried out in the Navegaon National Park (Maharashtra). Six soil profiles were excavated under the three plant communities. Physico-chemical and morphological properties of soils were studied and they are classified accordingly. The soils under the plant community Tectona – Pterocarpus – Buchanania are very deep and dark brown to yellowish brown in colour with abundance of silica and iron concretion. These are moderately drained soils with silty loam to loamy in texture. They are classified as loamy, skeletal, mixed hyperthermic family of Typic Ustorthent and Udic Haplustoll. The soils under the plant community Cleistanthus – Ougeinia – Tectona are shallow to medium in depth and dark yellowish brown to dark reddish brown in colour and silty clay loam in texture. These arer classified as loamy, mixed, hyperthermic and loamy, skeletal, mixed hyperthermic family of Udic Haplustoll and paralithic vertic Haplustoll. The soils under the plant community Cleistanthus – Terminalia – Lagerstroemia are deep silty loam in texture and dark brown in colour, acidic to neutral. These are classified as loamy, mixed, hyperthermic family of Udic Argiustoll and Udic Haplustoll.

The dry seeds of Albizia lebbeck were treated with 10, 30, 50, 70 and 90 kR of gamma irradiation from a CO⁶⁰ source, then seeds were either sown directly or subjected to pre-sowing treatment (immersed in boiled water for 2 min. followed by soaking in cold water for 24 h.). Pre-sowing treated seeds showed a higher germination, better height and dry weight compared to those, were sown directly. As the dose rate increases, there was a decreasing trend in all above parameters. Highest CV (15.06%) was for RVI and lowest CV (7.17%) for plant height was observed. Dose of gamma irradiation had a significant effect on shoot length (plant height), SDW and RDW, while hot water treatment had a significant effect on SVI, RVI. Both dose and hot water pre-sowing treatment significantly influenced RVI and SVI. The LD₅₀ values for different parameters are also worked out. It appears that irradiating seeds of Albizia lebbeck at 40 to 60 kR would result in maximum recovery of mutants.

Eight arbuscular mycorrhizal species, namely Acaulospora mellea, Gigaspora gigantea, Gigaspora margarita, Glomus deserticola, Glomus fasciculatum, Sclerocystis rubiformis, Scutellospora calospora and Scutellospora nigra, collected from rhizosphere soils of M. concanensis from arid and semi-arid regions of India were cultured on Cenchrus ciliaris. Pot cultures of these eight species were used to inoculate. M. concanensis in order to assess effect of these AM fungi on biomass production and nutrient uptake in this multipurpose endangered tree species of Indian Thar desert. Out of these AM species, Gigaspora margarita was found to be the most significant in increasing plant biomass as well as nutrient uptake.

Ten native plant species were studied to assess the VAM status. Root infection percentage and spore numbers were worked out. Argyreia sp. showed the highest (45%) root infection. Lowest root infection (17%) was found in case Borreria hispida. On the other hand, B. hispida harboured the highest number of spores in its rhizosphere (294 per 50 g of soil) and Clerodendron sp. lowest spores (40 per 50 g of soil.) Glomus was the most abundant VAM fungi associated with all the plants studied.

Present paper describes the occurrence of seed polymorphism in respect of colour in Robinia pseudoacacia. Three coloured seeds, viz., black, brown and grey were noted. Their tree to tree variation in distribution proportion was found to vary with sites. All coloured seeds were tested for their germination and growth. Black colour seeds had maximum germination per cent and best growth performance as compare to grey and brown seeds.

Variation was observed among nine seed sources of Acacia nilotica, for various pod and seed characters. Pod length varied from 13.55 to 15.11 cm. Seed length and seed width varied from 7.50 to 8.11 mm and 6.69 to 7.02 mm, respectively. However, seed weight ranged from 13.06 to 15.85 g. Germination of seeds collected from various sources was 69.33 to 80.66 per cent. Root length and shoot length varied from 3.70 to 5.70 cm and 5.43 to 8.66 cm, respectively. Out of different seed sources, Sirsa seed source performed better as it ranked 1^st for nine characters, viz., pod length, seed length, seed thickness, seed volume, germination percentage, shoot length, seedling dry weight, vigour index-I and vigour index-II. It was observed that higher seed weight, viability and low electrical conductivity gave vigorous seedlings.

Chemical and biological control of collar rot disease of teak (Tectona grandis Linn.f.) caused by R. solani anamorph of T. cucumeris is discussed in this paper. Fungicidal evaluation revealed that Emisan-6, Indofil M-45 and Bavistin were effective in controlling the disease. Biocontrol agents T. viride MNT-7 also found to be effective in the control of the disease and therefore these may be used to control the disease in teak nurseries.

Study was carried out to evaluate the effect of aqueous solution of sulphuric acid in reducing the endocarp/seed coat dormancy of Grewia optiva seeds. Soaking the seeds in dilute sulphuric acid (N/10 H₂SO₄) for 36 hours was observed to be the most effective method for breaking this type of seed dormancy followed by N/20 H₂SO₄ for 6 hours under glass house conditions.

The studies were undertaken to find out the susceptible age of the host plant (Khejri), optimum inoculums load and inoculums age for maximum root rot development. Five days old ‘Khejri’ seedlings exhibited 80 per cent mortality which was significantly higher than other treatments. With the increase in inoculums load, there was a corresponding increase in disease incidence. The seedlings showed maximum mortality when inoculated with 20 days old oat seed sand culture. Young seedlings were more prone to disease than the older ones.

A total of 37 fungal species belonging to 26 genera of fungi were isolated from the phylloplane of alder (Alnus nepalensis D.Don) at different growth stages of the leaves in open and closed alder forests. The fungi increased gradually from folded to senescent stage and the peak was obtained at the maturity of the leaves. The least population was obtained at the bud or folded stages soon after flushing. Penicillium fumiculosum, Alternaria alternate and Aspergillus nidulens were dominant species immediately after flushing. When the leaves were undergoing maturation and entered into the senescent stage Cladosporium herbarium, Trichoderma viride and Fusarium oxysporium became dominant. The leaf spot disease caused by Septoria alnifolia of deuteromycetous pathogen was also observed during the study period.

A tarsonemid mite Polyphagotarsonemus latus (Banks) has been found to attack on mulberry leaves in Nilgiris (MSL 5200 feet) Tamil Nadu, India. The mite attacked on abaxial surface of the tender and medium leaves. The mite completed its life cycle in 100 h on mulberry causing severe damage to mulberry leaves by sucking their sap.

Mahua – Indian butter tree is known for its multifarious utility, which include timber uses, edible oil, and also for varied medicinal uses. The tree exhibits variations in population and requires intensive selection and exploitation through vegetative propagation to obtain maximum genetic gain. Against this backdrop, study was carried out for vegetative propagation of Madhuca latifolia Macb. Using rooting of cutting and grafting methods. The rooting of cutting trials revealed that cuttings on treatment with IBA 2000 ppm in sand medium record higher per cent rooting followed by vermiculite medium in the same treatment. However, cleft grafting was found to be more productive which recorded maximum (92.5 per cent) success in the month of September. Hence, cleft grafting method is recommended for large scale clonal multiplication of Madhuca latifolia.

Iris tectorum Maxim. – a species native to China and Japan is reported as naturalised in Mussoorie hills of Western Himalaya, India. A detailed description along with illustrations are provided for easy identification.

Tracheary element differentiation in calli of different ages of Psidium guajava cv. Navaloor variety has been studied. Hypocotyl explants were cultured on MS (Murashige and Skoog, 1962) medium supplemented with 2, 4-Dichlorophenoxyacetic acid (1 mgl^-1: 4.52 µm) and Kinetin (1 mgl^-1: 4.65 µm) in combination. Peroxidase activity was measured in respect of age of callus. Present study shows a direct correlation between peroxidise activity and tracheary element differentiation.

Acacia nubica Benth. and Tephrosia uniflora Pers. subsp. uniflora have been recorded for the first time from India. Complete description, phenology, ecology and distributional data have been provided along with figures for easily determination of taxa.

Systematic measurements of atmospheric CO₂ in the surface air of the study site during the period from February 1996 to January 1997 showed seasonal and diurnal variability in the atmospheric CO₂ concentration, with highest values in the morning and lowest values in the afternoon. The data also showed a winter-summer oscillation in CO₂ levels with a minimum in July-August and a maximum in March. These diurnal and seasonal fluctuations may be related to the photosynthetic activity of vegetation of this region.

Provenance survey of Grewia oppositifolia Roxb. was undertaken to identify suitable seed sources for production of quality seedlings for mass afforestation in agroforestry systems in Central Himalaya. Significant (P= 0.05) variations were recorded for seed characters among provenances. Elevational range of seed source exhibited significant (P= 0.05) positive correlation with seed length, thickness and weight. This is an indication that some of these phenotypic variations may also have genetic base within the natural range of distribution. On average, the provenances Chilledi, Simswara and Malsi were found to be the best on the basis of seed morphological characters. This preliminary investigation may be used for further genetic improvement of Grewia oppositifolia.