SUMMARYRecalcitrant seeds of Shorea robusta (sal) exhibit 100"o viability up to 4 d after maturity. The rapid loss of viability after 4 d is associated with the reduction in moisture content below the lowest safe moisture content (37%). Seed becomes non-viable on 8 d. Increased leakage of electrolytes in seeds and lipid peroxidation in embryonic axes was discernible immediately from 0 d. In embryonic axes, very low levels of superoxide ('O^') were maintained up to 4 d and a sharp increase was registered up to 7 d. It is suggested that loss of moisture content in sal seeds below 21°.(, (after 4 d) induces substantial leakage loss probably due to increased lipid peroxidation and 'O.f radical formation which are responsible for severe membrane perturbations leading to rapid loss of viability. In embryonic axes SOD activity was recorded only in IOCVQ viable seeds.

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A rapid loss of viability was recorded in sal seeds when dehydrated below 36.7 % moisture content, at ambient conditions. Seed becomes non-viable at 6 days after harvest (dah). Gradual decline in total protein content due to corresponding increase in protease activity preceded loss of viability. Almost 43.7 % and 52.6 % loss in total protein content was observed on 3 dah in embryonic axis and cotyledon respectively of seeds showing 100 % viability. No protease activity was detected in the embryonic axis and cotyledon of freshly harvested viable seeds (0 dah). The protease activity was detected after 12 hrs of storage and increased sharply with peak levels on 6 dah (0.71 ± 0.04 / min/mg protein) and 4 dah (0.16 ± 0.01 / min/mg protein) in embryonic axis and cotyledon respectively. Later on the enzyme activity declined sharply in both the tissues. Enhanced protease activity in embryonic axes and cotyledons has been discussed with corresponding decline in total protein during desiccation induced loss of viability in sal seeds.

The use of plastics in horticulture has made considerable headway during the last decade. We are aware that plastics contribute from planting to post harvest handling and processing in many fruit crops. Plastic is used at each and every stage of horticultural life cycle right from seeds packaging, planting, propagation, mulching, irrigation, harvesting, fruit packing and preservation. The application of plastics in agriculture sector is popularly known as Plasticulture. India produces about 5 million tons of plastics annually and use about 0.35 million tons in agriculture. Plastics are used in greenhouses to promote growth and production, mulching to suppress weeds and maintain soil temperature and moisture as well as in containers for seedling and soil solarization to reduce pest and diseases. The efficient use of plastics in agricultural and horticultural operations are utilized by PFDC Hyderabad. The plasticulture operations were performed and demonstrated by research trials by selecting suitable crops under polyhouse and shade nets. Use of drip irrigations system and sprinkler irrigation system with suitable irrigation scheduling and fertigation, demonstrating performance of agricultural and horticultural crops under plastic mulch sheets. The present study aims to determine the role of precision farming development center (PFDC) Hyderabad in plasticulture.

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