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ORIGINAL RESEARCH article

Front. Plant Sci.
Sec. Plant Nutrition
Volume 15 - 2024 | doi: 10.3389/fpls.2024.1516000

Long-term nitrogen fertilization alters the partitioning of amino acids between citrus leaves and fruits

Provisionally accepted
Yuanlai Zhao Yuanlai Zhao 1Huaye Xiong Huaye Xiong 1Yayin Luo Yayin Luo 1Hu Bin Hu Bin 1Jie Wang Jie Wang 1Xiaodong Tang Xiaodong Tang 2Yuehong Wang Yuehong Wang 3Xiaojun Shi Xiaojun Shi 1,4Yueqiang Zhang Yueqiang Zhang 1,4*Heinz Rennenberg Heinz Rennenberg 5
  • 1 Southwest University, Chongqing, China
  • 2 Changshou District Agricultural Technology Research Service Center, Chongqing, China
  • 3 Hechuan District Grain and Oil Development Guidance Station, Chongqing, China
  • 4 Beijing Changping Soil Quality National Observation and Research Station, Beijing, China
  • 5 Chair of Tree Physiology, Institute of Forest Sciences, Albert-Ludwigs-Universität Freiburg Georges-Köhler-Allee, Freiburg, Germany

The final, formatted version of the article will be published soon.

    The growth of evergreen fruit trees is influenced by the interaction of soil nitrogen (N) and leaf amino acid contents. However, information on free amino acid contents in leaves of fruiting and nonfruiting branches during long-term N fertilizer application remains scarce. Here, a four-year field experiment (2018-2021) in a citrus orchard revealed consistently lower total N and amino acid contents in leaves of fruiting compared to non-fruiting branches. Appropriate N fertilizer application increased free amino acid and total N contents in leaves of both types of branches and fruits, but excessive amounts led to decreases. Correlation analysis showed that, in the early stage of fruit development, leaves on both types of branches can meet the N requirements of the fruit (R² =0.77 for fruiting, R² =0.82 for non-fruiting). As fruits entered the swelling stage, a significant positive correlation emerged between fruiting branch leaves and fruit total N content (R² =0.68), while the R² for leaves on non-fruiting branches dropped to 0.47, indicating a shift in N supply towards leaves on fruiting branches. Proline and arginine are the most abundant amino acids in these leaves. At fruit maturity, these amino acids account for more than half of the total amino acids in the fruit (29.0% for proline and 22.2% for arginine), highlighting their crucial role in fruit development. Further research is needed to investigate amino acid transport and distribution mechanisms between citrus leaves and fruits.

    Keywords: Fruiting1, Leaves2, Citrus fruit3, proline4, Arginine5

    Received: 23 Oct 2024; Accepted: 20 Dec 2024.

    Copyright: © 2024 Zhao, Xiong, Luo, Bin, Wang, Tang, Wang, Shi, Zhang and Rennenberg. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Yueqiang Zhang, Southwest University, Chongqing, China

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