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A stay‐green mutation of Lolium perenne affects NO 3 − uptake and translocation of N during prolonged N starvation
Author(s) -
BARKEN ANNE KJERSTI,
MACDUFF JAMES,
HUMPHREYS MERVYN,
RAISTRICK NEIL
Publication year - 1997
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1046/j.1469-8137.1997.00631.x
Subject(s) - lolium perenne , chromosomal translocation , shoot , dry matter , biology , mutant , lolium , poaceae , zoology , agronomy , botany , horticulture , biochemistry , gene
SUMMARY Apparent K m and V max for net NO S″ uptake and short‐term translocation patterns of recently absorbed N were compared in a stay‐green mutant and wild‐type selection line of Lolium perenne L. by means of a series of depletion studies using 18 NO 3 , performed over 12 d under conditions of progressively increasing N deprivation. In view of the greater retention of N in senescent leaves of the stay‐green phenotype, it was predicted that NO S″ uptake would be up‐regulated relative to the normal line, and that a proportionally higher fraction of recently absorbed N would be allocated to young leaves. It was shown that the stay‐green trait had significant phenotypic consequences for plant N relations, with higher ‘sink strength‘ of shoots for recently absorbed N, and higher V max for NO 3 uptake compared with those of normal plants. The stay‐green mutation had no effect on the K m of the nitrate uptake system. Although the N‐use efficiency might he expected to be lower in stay‐green than in normal plants, there were no differences in rates of dry matter production.