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Cotton Leaf Age, Epicuticular Wax, and Nitrogen‐15 Absorption
Author(s) -
Bondada Bhaskar R.,
Oosterhuis Derrick M.,
Norman Richard J.
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/cropsci1997.0011183x003700030019x
Subject(s) - epicuticular wax , wax , lint , biology , fiber crop , botany , horticulture , absorption (acoustics) , main stem , urea , chromosomal translocation , malvaceae , agronomy , biochemistry , physics , gene , acoustics
Foliar N fertilization is sometimes used as a supplement to soil application in cotton ( Gossypium hirsutum L.) production; however, information is lacking about the absorption of foliar‐applied N in relation to leaf age and epicuticular wax. A 2‐yr field study was conducted to examine the effect of leaf age and epicuticular wax on foliar‐applied 15 N‐urea absorption and subsequent distribution within the subtended boll. Cotton (cv. Stoneville 506) leaves of different ages (20, 30, 40, and 60 d), at main‐stem node 10, fruiting position 1, were selected and treated with 15 N‐urea solution using a paint brush. The 15 N analysis of tissues 1 wk after treatment indicated that maximum absorption of 80% was achieved by 20‐d‐old leaves compared with 27 to 38% for 60‐d‐old leaves. As the leaves aged, 15 N absorption decreased in concert with increased total wax concentration. A negative relationship between 15 N absorption and total wax concentration of leaves of different ages ( r 2 = 0.97) suggested waxes were an important barrier to 15 N absorption in older leaves. The subsequent translocation and distribution of 15 N within the boll indicated that most of the absorbed 15 N was retained in the 20‐d‐old leaf. As the leaves aged, more 15 N was translocated to the subtended boll. Within the boll, most of the 15 N was compartmentalized to lint and seed, and less was partitioned to the capsule wall, which implicated lint and seed as the major sinks. This study demonstrated that increased wax concentration during leaf aging was associated with reduced 15N absorption.