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Nitrate Uptake, Efflux, and In Vivo Reduction by Pima and Acala Cotton Cultivars
Author(s) -
Aslam M.,
Nielson K.,
Travis R. L.,
Rains D. W.
Publication year - 1997
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci1997.0011183x003700060022x
Subject(s) - gossypium barbadense , cultivar , fiber crop , gossypium hirsutum , gossypium , efflux , biology , malvaceae , horticulture , nutrient , in vivo , botany , microbiology and biotechnology , biochemistry , ecology
Nutrient assimilation by seedlings is an early indicator of subsequent plant growth and development. This study was conducted to compare NO − 3 assimilation (net uptake, efflux and in vivo reduction) by 8‐d‐old seedlings of three Pima (S‐7, Oro Bianco, Conquistador) ( Gossypium barbadense L.) and four Acala (Maxxa, GC‐510, Royal, SJ‐2) ( Gossypium hirstum L.) cotton cultivars. The seedlings were grown hydroponically in a growth chamber and induced with 0.05, 0.1, or 1.0 m M NO − 3 for 24 h. Net NO − 3 uptake rates were determined by following its depletion from uptake solutions that initially contained the same concentration of NO − 3 as the induction solutions. Efflux was measured by following NO − 3 accumulation in an external solution. At 0.05 m M NO − 3 , net uptake rates for the Acala cultivars were about 40% lower than those for Pima cultivars. These differences disappeared as the NO − 3 concentration in the growth mediumw as increased to 1.0 m M . In contrast, efflux from Acala roots was 40 to 50% lower than that from Pima roots at all NO − 3 levels. Although NO − 3 concentration of roots increased about three fold as the NO − 3 level in the induction mediumin creased, efflux increased only 20 to 30%. In vivo NO − 3 reduction by Pima and Acala cultivars was similar when the seedlings were supplied with 1.0 m M NO − 3 . However, at 0.05 m M NO − 3 the Pima cultivars reduced NO − 3 more effectively than did the Acala cultivars. The results indicate that Pima cultivars are better able to utilize available NO − 3 at lower concentrations even though they efflux greater amounts of NO − 3 .