Informatics Publishing Limited

Shabnam Khan ¹, Arti Guhey ², V. B. Kuruwanshi ²

Affiliations
1 Department of Plant Physiology, College of Agriculture, Indira Gandhi Krishi Ishwavidyalaya, Raipur (C.G.), IN
2 Department of Plant Physiology, College of Agriculture, Indira Gandhi Krishi Vishwavidyalaya, Raipur (C.G.), IN

Abstract

"Rice is Life" aptly describes the importance of rice in food and nutritional security, particularly for the Asian countries including India. For achieving and maintaining self sufficiency in rice, in view of ever increasing population, rice production has to be enhanced on a continual basis. The appropriate relationship between source sink and their capacity is essential to determine the yield especially in rice. In present investigation the impact of source limitation on assimilate partitioning and yield attributes to optimize the production potential and physiological basis of higher yield contributing traits in the ten genotypes. It was observed that the impact of source limitation was more pronounced in var. Dagad Desi, ARB-6, Ananda which exhibited maximum stability for grain yield. It was mainly due to the proline association with the morphological and phenological parameters as well as physiological behaviour, which ultimately raised growth rate, whereas in (control) Mahamaya and Swarna performed well. Yield was inversely related with ATR. Among cultivars, yield was directly correlated with maximum ATR under stress conditions and cultivar Swarna/ IR and Swarna maintained better translocation under stress than did the other cultivars. It clearly indicates that the defoliation of (100% leaf removal) plays significant positive contribution in balancing source sink, relatively which influenced the yield of crop and facilitating the better harvesting. Thus, it can be clearly suggested that the leaves (source) could determine the degree of plant performance and control the level of filled grain in rice.

Keywords

Source-Sink, Defoliation, Assimilate Partitioning, Source Limitation.

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Soumya Kumar Sahoo ¹, Jyostnarani Pradhan ², V. B. Kuruwanshi ¹, Arti Guhey ¹

Affiliations
1 Department of Plant Physiology, College of Agriculture, Indira Gandhi Krishi Vishwavidyalaya, Raipur (C.G.), IN
2 Department of Plant Physiology, Institute of Agricultural Sciences, Banaras Hindu University, Banaras (U.P.), IN

Abstract

Changes in climate and intensity of ultraviolet radiation can both have substantial impacts on the biological, geological, chemical, and physical processes that control the exchange of matter and energy between the major components of the environment-the atmosphere, the biosphere, the hydrosphere, and the lithosphere. The carbon cycle is of central importance in the climate change issue because human disruption of the natural carbon cycle, through the burning of fossil fuels and the clearing of forests, is largely responsible for the modern increase in atmospheric concentrations of carbon dioxide, the most abundant anthropogenic greenhouse gas. One of the more important links in the carbon cycle from an atmospheric perspective is the so-called “marine biological pump”. This is a process in which plankton, the microscopic plants and animals that live near the surface of the oceans and freshwater lakes remove carbon from the air and then transfer it to the ocean bottoms and lakebeds when they die. Ozone depletion, particularly severe episodes such as the spring ozone holes in the Antarctic, present a potentially serious threat to this process, because plankton cannot take shelter from solar radiation. A serious decline in their numbers as a result of exposure to more intense ultraviolet radiation could therefore decrease the rate at which carbon dioxide is removed from the atmosphere. Similarly, biological changes initiated by changes in climate might have some effect on ozone depletion. Methyl chloride and methyl bromide are two ozone-depleting compounds. However, because natural sources of these gases are larger than the human industrial sources, anything affecting the ecosystems and natural processes that produce these gases could also have consequences for the ozone layer. Coastal marshes appear to be important contributors of natural source. Fungi, crops such as rapeseed, and soils rich in organic matter are also thought to be substantial sources. Warming of the atmosphere and oceans or changes in sea level could affect all of these sources by altering the ecosystems and climatic conditions that support the natural production of these gases. Climate change could also affect the rate at which these gases are removed from the atmosphere by the oceans. Studies of the natural production and removal of these gases are still in their early stages, however, and it is not yet possible to predict how climate change might affect the quantities of these gases in the atmosphere.

Keywords

Green House Effect, Marine Biological Pump, Ozone Depletion.

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