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Selection for mutants with low nitrate uptake ability in rice ( Oryza sativa )
Author(s) -
Hasegawa Hiroshi
Publication year - 1996
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1996.tb00202.x
Subject(s) - nitrate reductase , oryza sativa , nitrate , chlorate , mutant , potassium nitrate , chemistry , potassium , population , cultivar , biochemistry , horticulture , botany , biology , inorganic chemistry , gene , demography , organic chemistry , sociology
Screening for mutants deficient in the high affinity system of nitrate uptake was performed using mutagenized M 2 population of rice ( Oryza sativa , cv. Nipponbare or Kinmaze). For selecting mutants, M 2 seedlings were transferred individually to 10 ml solution containing 250 μ M potassium nitrate and 500 μ M calcium sulphate at 20 or 28°C. After 6 or 24 h, nitrate concentration of the solution was determined with a nitrate selective electrode and the seedlings showing impaired nitrate uptake were selected as nitrate uptake deficient variants. Of 74 variants, three were confirmed to be mutants with low nitrate uptake ability in the M 3 generation. Potassium uptake ability also decreased in the mutants. Three mutants were divided into two groups based on the analysis of nitrate reductase (NR, EC 1.6.6.1) activity and chlorate resistance. Two, NUE13 and NUE36 , had a lower level of NR activity than the original cultivar and were not resistant to chlorate, while the seedlings of NUE50 had the same level of NR activity as the original cultivar and were more resistant to chlorate than the original cultivar. All mutants were resistant to cesium, a toxic ion analogue for potassium, suggesting that the decreased levels of both nitrate and potassium uptake were coupled to the change of plasma membrane H + ‐ATPase activity.