Timing of nitrogen fertilization and shading affect the transition of nitrogen metabolism in senescing leaves of ripening wheat (Triticum aestivum L.)

The grain yield and protein content of wheat is influenced by the transition of nitrogen metabolism in senescing leaves from pre-anthesis to maturity. To characterize the biochemical processes of the transition, we here analyzed the interactions among greenness, soluble protein, amino acid and prote...

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Main Authors: Hideki Araki, Hirotaka Ueno, Keisuke Mizuta, Tadashi Takahashi, Masaru Shibata, Jun’ichi Mano
Format: Article
Language:English
Published: Taylor & Francis Group 2025-02-01
Series:Plant Production Science
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Online Access:https://www.tandfonline.com/doi/10.1080/1343943X.2025.2461776
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author Hideki Araki
Hirotaka Ueno
Keisuke Mizuta
Tadashi Takahashi
Masaru Shibata
Jun’ichi Mano
author_facet Hideki Araki
Hirotaka Ueno
Keisuke Mizuta
Tadashi Takahashi
Masaru Shibata
Jun’ichi Mano
author_sort Hideki Araki
collection DOAJ
description The grain yield and protein content of wheat is influenced by the transition of nitrogen metabolism in senescing leaves from pre-anthesis to maturity. To characterize the biochemical processes of the transition, we here analyzed the interactions among greenness, soluble protein, amino acid and protease activity in the flag and second leaves of ripening wheat plants. Nitrogen regimes were adjusted by intensive nitrogen applications in the early (IN (E)) or late stages (IN (L)) along with or without top-dressing at anthesis (±TD). The progress of leaf nitrogen metabolism towards terminal senescence appeared to be split into two phases: the first phase (from pre-anthesis to about 15 days after anthesis (DAA), when leaf greenness did not change appreciably) was characterized by a decrease in soluble protein, and the second phase (after 15 DAA) was characterized by drastic increases in the protease activity followed by a rapid decrease in leaf greenness. The decrease in soluble proteins during the first phase was not accompanied by a rise in protease activity. The rise in protease activity during the second phase was most apparent in the IN (E)-TD plants that were likely under the most severe nitrogen starvation among the treatments. The IN (L) and TD were effective to defer the leaf senescence processes. The shading treatment delayed the rise in protease activity and decrease in leaf greenness. This study suggests that the terminal leaf senescence proceeds in two phases, and the transition between these was accelerated by low nitrogen and slowed by mild shading.
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spelling doaj-art-d353c4261ab04ff1ba5a0438d686d9432025-02-06T12:41:23ZengTaylor & Francis GroupPlant Production Science1343-943X1349-10082025-02-0111010.1080/1343943X.2025.2461776Timing of nitrogen fertilization and shading affect the transition of nitrogen metabolism in senescing leaves of ripening wheat (Triticum aestivum L.)Hideki Araki0Hirotaka Ueno1Keisuke Mizuta2Tadashi Takahashi3Masaru Shibata4Jun’ichi Mano5Graduate School of Sciences and Technology for Innovation, Yamaguchi University, Yamaguchi, JapanGraduate School of Sciences and Technology for Innovation, Yamaguchi University, Yamaguchi, JapanFaculty of Agriculture, Kagawa University, Miki, JapanGraduate School of Sciences and Technology for Innovation, Yamaguchi University, Yamaguchi, JapanFaculty of Education, Yamaguchi University, Yamaguchi, JapanScience Research Center, Yamaguchi University, Yamaguchi, JapanThe grain yield and protein content of wheat is influenced by the transition of nitrogen metabolism in senescing leaves from pre-anthesis to maturity. To characterize the biochemical processes of the transition, we here analyzed the interactions among greenness, soluble protein, amino acid and protease activity in the flag and second leaves of ripening wheat plants. Nitrogen regimes were adjusted by intensive nitrogen applications in the early (IN (E)) or late stages (IN (L)) along with or without top-dressing at anthesis (±TD). The progress of leaf nitrogen metabolism towards terminal senescence appeared to be split into two phases: the first phase (from pre-anthesis to about 15 days after anthesis (DAA), when leaf greenness did not change appreciably) was characterized by a decrease in soluble protein, and the second phase (after 15 DAA) was characterized by drastic increases in the protease activity followed by a rapid decrease in leaf greenness. The decrease in soluble proteins during the first phase was not accompanied by a rise in protease activity. The rise in protease activity during the second phase was most apparent in the IN (E)-TD plants that were likely under the most severe nitrogen starvation among the treatments. The IN (L) and TD were effective to defer the leaf senescence processes. The shading treatment delayed the rise in protease activity and decrease in leaf greenness. This study suggests that the terminal leaf senescence proceeds in two phases, and the transition between these was accelerated by low nitrogen and slowed by mild shading.https://www.tandfonline.com/doi/10.1080/1343943X.2025.2461776WheatLeaf senescenceNitrogen starvationProteaseAmino acidSoluble protein
spellingShingle Hideki Araki
Hirotaka Ueno
Keisuke Mizuta
Tadashi Takahashi
Masaru Shibata
Jun’ichi Mano
Timing of nitrogen fertilization and shading affect the transition of nitrogen metabolism in senescing leaves of ripening wheat (Triticum aestivum L.)
Plant Production Science
Wheat
Leaf senescence
Nitrogen starvation
Protease
Amino acid
Soluble protein
title Timing of nitrogen fertilization and shading affect the transition of nitrogen metabolism in senescing leaves of ripening wheat (Triticum aestivum L.)
title_full Timing of nitrogen fertilization and shading affect the transition of nitrogen metabolism in senescing leaves of ripening wheat (Triticum aestivum L.)
title_fullStr Timing of nitrogen fertilization and shading affect the transition of nitrogen metabolism in senescing leaves of ripening wheat (Triticum aestivum L.)
title_full_unstemmed Timing of nitrogen fertilization and shading affect the transition of nitrogen metabolism in senescing leaves of ripening wheat (Triticum aestivum L.)
title_short Timing of nitrogen fertilization and shading affect the transition of nitrogen metabolism in senescing leaves of ripening wheat (Triticum aestivum L.)
title_sort timing of nitrogen fertilization and shading affect the transition of nitrogen metabolism in senescing leaves of ripening wheat triticum aestivum l
topic Wheat
Leaf senescence
Nitrogen starvation
Protease
Amino acid
Soluble protein
url https://www.tandfonline.com/doi/10.1080/1343943X.2025.2461776
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