الفهرس 
ACKNOWLEDGEMENT
Phytotoxicity of herbicides on algal cultures and higher plantsOnly 14 pages are availabe for public view
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Abstract
The increasing use of herbicides in agriculture and forestry has become a growing hazard to our environment, especially aquatic ecosystems. Over the last 40 years, the use of herbicides are increasing worldwide as the need for selective weed control which becomes more important, consequently herbicide resistance has increased worldwide at an exponential rate. The development of herbicide resistance in weeds is considered as an evolutionary process. Herbicide treatments of weed populations result in the selection of any gene(s) conferring individual plants the capacity to withstand herbicides at the rate used in the field and to reproduce successfiully thereafter. Under herbicide selection, the genetic composition of the weed population changes so that the frequency of resistance genes increases.
The use of herbicides has revolutionized weed control in many crop production systems. However, with increasing development of weed resistance to many popular selective herbicides, the need has arisen to rethink the application of chemical weed control. Diagnosing herbicide resistant weeds as a first step in resistance management and monitoring their nature, distribution and abundance, demands efficient and effective screening tests. Herbicide resistance may occur as a result of one or more mechanisms including reduction in herbicide uptake or translocation, increased herbicide metabolism, sequestration of the herbicide or modified target site. Most phytotoxicological research with herbicides has been conducted on target plants. Basis for resistance is often a mutation at the site of action as acetyl-CoA carboxylase (ACCase).
Technological advances in molecular biology have contributed substantially to understanding of plant genetic diversity. At the most basic level, plant diversity can be defined as plant genetic diversity resulting from DNA sequence variation among individuals and species. In weeds, the potential for populations to adapt to management practices and newly invaded habitats is