<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />A large number of plants around the world are unexplored Some of which could sereve as bioenergy plants and still have medicinal value. Let us compile the world list of such plants from each regions.  This would explore new possibilities of developing biomass resources and help in keeping our enviornment intact for our future generations.


Solid biomass.

The characterization of plant diversity was another aspect of study on plant community. 230 plant species were recorded. Out of the 230 plant species 60 plant species were selected for biomass production in their natural habitat.

 Plants were collected from studied areas in natural condition. Three replicates of each plant were collected and their fresh and dry weights were recorded in each season.

Out of the 60 plants following plant species were suitable for biomass production due to their high dry matter contents. These plants included (weights in g/plant) Echinops echinatus Roxb. : 133.66; Verbesina  encelioides (Cav.) Benth.&Hk.: 80.33; Calotropis procera (Ait) R.Br.: 648.33; Leptadenia pyrotechnica (Forsk.) Decne. : 486.66; Sericostoma pauciflorum Stocks. : 352.66; Amaranthus spinosus Linn. : 167.66; Withania somnifera (L.) Dunal. : 350; Lepidagathis trinervis Wall. ex Nees. : 204; Lantana indica Roxb. : 373.33; Aerva tomentosa (Burm.) Juss. : 283.33; Croton bonplandianum Baill. : 155.33; Abutilon indicum (L.) Sweet. : 1453.33; Acacia jacquemontii Benth. : 693.33; Crotalaria burhia Buch.-Ham. ex Benth. : 266; Saccharum bengalense Retz.  : 1900 and Artemisia scoparia Waldst. et Kit. : 90. The plant biomass in terms of fresh weight and dry weight was recorded in all the three seasons.  

3.2 Extraction of hydrocarbons:

Hydrocarbons were extracted by using two different solvent hexane and methanol. Among the different plant extractions Euphorbia antisyphilitica Zuce. showed the best extraction results in hexane 8.5% and Calotropis procera (Ait.) R.Br. showed best results in methanolic extraction 33.8%.

Percent hydrocarbon contents in above ground part of different plants in Hexane extraction (HE) and Methanolic extraction (ME)

 3.3 Extraction of non-edible oil :

 In order to study non-edible oil production, 11 plants were selected for studies. Non-edible oil was extract by using solvent petroleum ether. Seed oil was extracted taking seeds with seed coat. Among different seed oil contents determined maximum seed oil was recorded in Ricinus communis Linn. This was followed by others.

   Non-edible oil content in seeds of different plant species

4. DISCUSSSION

Biomass contributes a significant share of global primary energy consumption and its importance is likely to increase in future world energy scenarios. Current biomass use, although not sustainable in some cases, replaces fossil fuel consumption and results in avoided CO2 emissions, representing about 2.7% to 8.8% of 1998 anthropogenic CO2 emissions. The global biomass energy potential is large, estimated at about 107 EJ/a. Hence, biomass has the potential to avoid significant fossil fuel consumption, potentially between 17% and 36% of the current level and CO2 emissions potentially between 12% and 44% of the 1998 level. Modern biomass energy use can contribute to controlling CO2 emissions to the atmosphere while fostering local and regional development. There is significant scope to integrate biomass energy with agriculture, forestry and climate change policies. Further the advantages from utilization of biomass include: liquid fuels produced from biomass contain no sulphur, thus avoiding SO2 emissions and also reducing emission of NOx. The production of compost as a soil conditioner avoids deterioration of soil.   

Improved agronomic practices of well managed biomass plantations will also provide a basis for environmental improvement by helping to stabilize certain soils, avoiding desertification which is already occurring rapidly in tropical countries. The creation of new employment opportunities within the community and particularly in rural areas will be one of the major social benefits.

 The present investigations carried out with an object of biomass production and utilization in less fertile areas, will provide satisfactory answers to the double challenge of energy crisis and forced deforestation in the country and semi-arid and arid regions of Rajasthan. Kumar (2001) has suggested that biomass from plants can be converted into liquid fuels. This will make it possible to supply part of the increasing demand for primary energy and thus reduce crude petroleum imports, which entail heavy expenditure on foreign exchange. Several families widely growing in Rajasthan have great potential as renewable source of energy. Euphorbiaceae (Euphorbia antisyphilitica, E. tithymaloides, E. caducifolia, E. lathyris, E. neerifolia etc. Aselipiadaceae (Calotropis gigantea and C. procera) Asteraceae and Apocynaceae have large number of valuable plants (Kumar and Vijay, 2002 and Vijay et al., 2002).

Characterization of biomass production in wastelands during the present investigation offers a database of potential plants to be used in arid and semiarid regions and a three tier system has been developed.

However further studies are needed to establish gene pool database on the basis of RFLP and AFLP so that it could be used for genetic transformation studies. Which can help for development of bioenergy source from these arid and semiarid wasteland of Rajasthan.

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