title: Relationship between potassium fertilization and nitrogen metabolism in the leaf subtending the cotton (Gossypium hirsutum L.) boll during the boll development stage.
abstract: The nitrogen (N) metabolism of the leaf subtending the cotton boll (LSCB) was studied with two cotton (Gossypium hirsutum L.) cultivars (Simian 3, low-K tolerant; Siza 3, low-K sensitive) under three levels of potassium (K) fertilization (K0: 0 g K2O plant(-1), K1: 4.5 K2O plant(-1) and K2: 9.0 g K2O plant(-1)). The results showed that total dry matter increased by 13.1-27.4% and 11.2-18.5% under K supply for Simian 3 and Siza 3. Boll biomass and boll weight also increased significantly in K1 and K2 treatments. Leaf K content, leaf N content and nitrate (NO3(-)) content increased with increasing K rates, and leaf N content or NO3(-) content had a significant positive correlation with leaf K content. Free amino acid content increased in the K0 treatment for both cultivars, due to increased protein degradation caused by higher protease and peptidase activities, resulting in lower protein content in the K0 treatment. The critical leaf K content for free amino acid and soluble protein content were 14 mg g(-1) and 15 mg g(-1) in Simian 3, and 17 mg g(-1) and 18 mg g(-1) in Siza 3, respectively. Nitrate reductase (NR), glutamic-oxaloace transaminase (GOT) and glutamic-pyruvic transaminase (GPT) activities increased in the K1 and K2 treatments for both cultivars, while glutamine synthetase (GS) and glutamate synthase (GOGAT) activities increased under K supply treatments only for Siza 3, and were not affected in Simian 3, indicating that this was the primary difference in nitrogen-metabolizing enzymes activities for the two cultivars with different sensitivity to low-K.
authors.affiliation: Key Laboratory of Crop Growth Regulation, Ministry of Agriculture, Nanjing Agricultural University, Nanjing 210095, Jiangsu Province, PR China; Department of Crop, Soil, and Environmental Sciences, University of Arkansas, 1366 West Altheimer Drive, Fayetteville, AR 72704, USA.
authors.forename: Wei
authors.initials: W
authors.lastname: Hu
authors.affiliation: Key Laboratory of Crop Growth Regulation, Ministry of Agriculture, Nanjing Agricultural University, Nanjing 210095, Jiangsu Province, PR China.
authors.forename: Wenqing
authors.initials: W
authors.lastname: Zhao
authors.affiliation: Key Laboratory of Crop Growth Regulation, Ministry of Agriculture, Nanjing Agricultural University, Nanjing 210095, Jiangsu Province, PR China.
authors.forename: Jiashuo
authors.initials: J
authors.lastname: Yang
authors.affiliation: Department of Crop, Soil, and Environmental Sciences, University of Arkansas, 1366 West Altheimer Drive, Fayetteville, AR 72704, USA.
authors.forename: Derrick M
authors.initials: DM
authors.lastname: Oosterhuis
authors.affiliation: Department of Crop, Soil, and Environmental Sciences, University of Arkansas, 1366 West Altheimer Drive, Fayetteville, AR 72704, USA.
authors.forename: Dimitra A
authors.initials: DA
authors.lastname: Loka
authors.affiliation: Key Laboratory of Crop Growth Regulation, Ministry of Agriculture, Nanjing Agricultural University, Nanjing 210095, Jiangsu Province, PR China. Electronic address: giscott@njau.edu.cn.
authors.forename: Zhiguo
authors.initials: Z
authors.lastname: Zhou
mesh_terms: D005308:Fertilizers; D003368:Gossypium / Q000378:metabolism*; D009584:Nitrogen / Q000378:metabolism*; D018515:Plant Leaves / Q000378:metabolism*; D011188:Potassium / Q000378:metabolism* / Q000494:pharmacology*
chemical_list: D005308:Fertilizers; D009584:Nitrogen; D011188:Potassium
keywords: Cotton (Gossypium hirsutum L.); Leaf subtending the cotton boll; Nitrogen metabolism; Potassium fertilizer