Studies were carried out on the effect of seed coat removal and nitric oxide (NO) donor sodium nitroprusside (SNP) treatment on germination and growth of seedling and budded plants of rubber (Hevea brasiliensis). Interaction effects were observed between seed coat treatment and SNP treatments for germination time and percentage germination. Decoated seeds germinated earlier and improved synchronicity than intact seeds (with seed coat) and achieved 50% germination within nine days. SNP treatment at all four concentrations (20, 50, 100 and 200 µM) hastened the germination and increased the percentage germination especially when decoated seeds were used. Shoot and root attributes of seedlings (stock plants) derived from the seeds treated with SNP, especially at 50-100 µM, were significantly improved as compared to those from control and mock treated seeds. Growth of the budded plants were better when stock plants derived from SNP treated seeds were used. Therefore, NO treatment coupled with decoating could effectively be utilized to improve the germination and growth of seedling and budded plants of rubber. To our knowledge, this is the first report on redox priming of rubber seeds with SNP.
Maintaining the tapping quality in rubber fields is the key requirement to obtain potential yield with minimum harm to the tree. It also determines productivity and the economical lifespan of 30 years and sustainable rubber industry. The length of the tapping cut, the depth, the thickness of the bark shaving, and the slope of the tapping cut are the main factors determining the tapping quality. Use of a stencil according to the intended tapping frequency, i.e. d2, d3, d4, etc., to mark the guidelines to maintain the proper tapping angle of 30 degrees to the horizontal, and the bark consumption allowed for one year, are all equally contribute to maintaining the tapping quality. About 5000 ha. was surveyed to assert the tapping quality and to make recommendations. The average bark consumption rate per panel was four years deviating from recommended six years under d2 tapping. The monitory loss per hectare under this bark consumption rate is Rs.2.5 million at a productivity level of 1000 kg/ha/y and Rs.350.00 per kg of rubber. Trees affected by tapping panel dryness varied and was over 70% in some extreme cases. Introducing a quarter cut on the upper opposite panel of the tree ceased the situation to a greater extent.
Above and below ground development of rubber at early stage of growth was compared in response to full sunlight, 33, 55 and 77 % natural shades. Rate of leaf expansion, leaf number, leaf area, inter-whorl shoot length and number of leaf whorls developed decreased with increasing shade. However the thermal duration expressed as degree days for the leaf expansion was lowest in the highest shade treatment. Total and component dry matter of rubber decreased with increasing shade. Dry matter partitioning to roots was greater compared to leaves and stems during first seven months with an increasing trend towards the highest shade while decreasing the above to below ground ratio of dry matter with increasing shade. After seven months, above ground development was prominent with an exponential increase in the plants grown under full sunlight.
The Mawanella Pradeshiya Sabha in the Kegalle district that serves to a population of 100,280 has introduced a novel approach to manage its waste under its "Increased Public Awareness & Local Government Capacity Building Program" in 2004. The key feature of this program was, educating and encouraging households to collect and sort waste at its source, which was facilitated by distribution of plastic bags and waste bins with different colour codes designed for the purpose, and subsequently, treat the waste at specific dumping sites using the principles of recycling to produce marketable products. This study assesses the progress of this program, and in particular how much the households are WTP for continuation and advancement of the program, because the regulatory authorities insist that it cannot run the program with taxpayers money for any longer time. A survey was conducted with a help of a structured questionnaire with 120 households selected randomly to represent 31 % households joined to the pilot program in 2004. The WTP of each household was modeled with a number of variables, includ ing age, income and education level, amount of waste production, distance to waste collection centre etc. The Contingent Valuation techniques were employed to estimate the coefficients of model. The results suggest that all variables, except the level of education. have a positive and significant impact on households' WTP for a better system. it was estimated that a household, in general, would like to pay Rs. 39.05 per month to continue the program. The officials from the Pradheshiya Sabha indicated that this is a rational estimate as it can cover the net operating cost of about Rs. 25-30 per month per household, and the rest can be used to improve the system.
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