the regulatory steps of nitrate assimilation 



in plants. 

 The incentives and payoffs for conducting re- 

 search on biological nitrogen fixation are rath- 

 er evident. Crop production is often limited 

 by available nitrogen fertilizer, and green 

 plants normally fulfill their nitrogen require- 

 ments by reducing nitrate to ammonia. Only 

 bacteria and blue-green algae are capable of 

 catalyzing the reduction of atmospheric nitro- 

 gen gas to ammonia at ambient temperature 

 and pressure. Some plants, however, have 

 evolved symbiotic associations with nitrogen- 

 fixing bacteria or blue-green algae which uti- 

 lize solar energy captured in photosynthesis to 

 produce ammonia from molecular nitrogen. In 

 order to meet future world food needs, it is 

 crucial to maximize the biological potential 

 for producing ammonia and nitrogen-contain- 

 ing organic compounds from both atmospher- 

 ic nitrogen and soil nitrate. 



• "'Production of Hydrogen by Marine Blue- 

 Green Algae," A. Mitsui, University of Miami. 

 Tropical and subtropical marine environments 

 contain many different species of blue-green 

 algae and photosynthetic bacteria that are capa- 

 ble of producing the chemical, hydrogen gas, 

 from renewable resources. Marine blue-green 

 algae are particularly attractive for they are 

 able to produce hydrogen gas from water us- 

 ing sunlight as the ultimate source of energy. 

 Previous support by RANN to the principal 

 investigator. Dr. Mitsui, focused on the 

 collection and isolation of superior hydrogen- 

 producing photosynthetic organisms from 

 marine environments. Under a two-year 

 grant, promising microbes were discovered, 

 and one particular blue-green algae is a very 

 active hydrogen producer for extended per- 

 iods of time (days instead of the usual min- 

 utes). This research follows logically from 

 previous work conducted by Dr. Mitsui and 

 centers on the characterization of the more 

 promising microbes and the enhancement of 

 hydrogen production. 



Specifically, the objectives of this research 

 project are to characterize promising species 

 of marine blue-green algae in terms of rele- 

 vant biochemical properties and to optimize 

 this biological phenomenon of enhanced hy- 

 drogen production by appropriate environ- 

 mental (physiological) means. Key parame- 

 ters to be examined for enhancing hydrogen 

 production are: Light intensity, temperature, 

 pH, salinity, and nutrients. 



• "Attempted Production of New Agricultural 

 Plants through Protoplast Culture," A. Gal- 

 ston, Yale University. The research project 

 attacks the principal bottleneck in the applica- 

 tion of molecular and cellular genetics to 

 practical plant breeding, namely, the develop- 

 ment of protoplasts (cells stripped of their rig- 

 id cell walls) that are amenable to genetic 

 manipulation, into whole, complete plants. 



Traditional plant breeding practice, based on 

 crossing of mature plants, while eminently 

 successful, is tedious and exceedingly lime 

 consuming, often requiring four to five years 

 before a new plant variety is properly charac- 

 terized. Success in this work will greatly sim- 

 plify the methodology and reduce the time- 

 span needed to develop a useful new plant 

 variety. 



The results obtained under previous NSF 

 grants suggest that lack of full development is 

 due to rapid aging of the cells, and hence, 

 protoplasts derived therefrom, after the leaf 

 tissue is removed from the plant. In the cur- 

 rent grant, emphasis will be placed on means 

 to prevent this aging by appropriate pretreat- 

 ment of the leaf tissues so as to yield proto- 

 plasts with maximum vigor and biosynthetic 

 capacity. 



• "Nitrate in Effluents from Irrigated Lands," 

 P. F. Pratt, University of California, Davis. 

 Because crops do not utilize all the nitrate 

 supplied by fertilizers, some nitrate leaches 

 into tile lines, or it drains to underground 

 water bodies. The resulting contamination can 

 cause the eutrophication of surface waters, or 

 it can lead to the accumulation of nitrate in 

 surface or underground drinking water sup- 

 plies to levels posing a public health hazard. 

 In the irrigated farmlands of the western 

 States, nitrate levels in waters draining below 

 the root zone often substantially exceed the 

 U.S. Public Health Service standard for 

 drinking water. The needs of society for agri- 

 cultural productivity and for environmental 

 protection come into conflict because of the 

 tendency for a productive agriculture to leak 

 nitrate into water supplies. 



This project is designed to help reconcile 

 these conflicting needs by determining how 

 soil conditions and farm management prac- 

 tices control the leaching of nitrate, and by 

 relating these findings to knowledge of nitro- 

 gen requirements for optimum crop produc- 

 tion. 



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NATIONAL SCIENCE FOUNDATION 



