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Nitrogen Metabolism of the Upper Three Leaf Blades of Wheat at Different Soil Nitrogen Levels
Author(s) -
NAIR T. V. R.,
GROVER H. L.,
ABROL Y. P.
Publication year - 1978
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.1399-3054.1978.tb04085.x
Subject(s) - nitrogen , anthesis , protease , chemistry , horticulture , nitrogen cycle , enzyme assay , agronomy , nitrogen balance , cultivar , botany , zoology , enzyme , biology , biochemistry , organic chemistry
Upper three leaf blades on the mainshoot of wheat cultivar, cv. Pusa Lerma, grown under three soil nitrogen levels (0, 30 and 120 kg ha ‐1 ), were examined for changes in total reduced nitrogen and protease activity at pH 4.0 and 7.0. No net loss of reduced nitrogen takes place prior to and around anthesis. The protease activity is low during this period. At later stages there is rise in the loss of nitrogen which is paralleled by enhancement in protease activity. From amongst the leaf blades, nitrogen concentration is significantly high in the flag and penultimate as compared to the values in the third leaf blade. There were significant differences in protease activity (pH 4.0) amongst the leaf blades. At pH 7.0, however, the differences between the flag and penultimate leaf blades were not significant. Highest enzyme activity was in the flag followed by penultimate and then third leaf blade. Soil N application significantly enhanced the nitrogen content of all the leaf blades. At pH 4.0, the protease activity (g fr. wt. ‐1 ) increased significantly due to soil N application (N 30 over N 0 ). There was, however, decline in the enzyme activity at pH 7.0, though the differences at different soil N levels were not significant. Analysis in terms of μ mol N (reduced form) accumulated in the grains (ear) ‐1 revealed that two‐thirds of N is translocated by 28‐day stage and the rest between 28‐day and final harvest. The three leaf blades together contributed 22.7, 32.6 and 48.5% of the grain N (ear) ‐1 at N 0 , N 30 and N 120 ‐ respectively. Most of the nitrogen applied to the soil is reduced by these leaf blades.