Spatial and temporal nature of reactive oxygen species production and programmed cell death in elm (Ulmus pumila L.) seeds during controlled deterioration

Authors

  • DIE HU,

    1. National Engineering Laboratory for Tree Breeding, College of Biological Sciences and Biotechnology, Beijing Forestry University, Tsinghua East Road 35, Haidian District, Beijing 100083, China
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  • GANG MA,

    1. National Engineering Laboratory for Tree Breeding, College of Biological Sciences and Biotechnology, Beijing Forestry University, Tsinghua East Road 35, Haidian District, Beijing 100083, China
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  • QIONG WANG,

    1. National Engineering Laboratory for Tree Breeding, College of Biological Sciences and Biotechnology, Beijing Forestry University, Tsinghua East Road 35, Haidian District, Beijing 100083, China
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  • JINGHAN YAO,

    1. National Engineering Laboratory for Tree Breeding, College of Biological Sciences and Biotechnology, Beijing Forestry University, Tsinghua East Road 35, Haidian District, Beijing 100083, China
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  • YU WANG,

    1. National Engineering Laboratory for Tree Breeding, College of Biological Sciences and Biotechnology, Beijing Forestry University, Tsinghua East Road 35, Haidian District, Beijing 100083, China
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  • HUGH W. PRITCHARD,

    1. Seed Conservation Department, Royal Botanic Gardens, Kew, Wakehurst Place, West Sussex RH17 6TN, UK
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  • XIAOFENG WANG

    Corresponding author
    1. National Engineering Laboratory for Tree Breeding, College of Biological Sciences and Biotechnology, Beijing Forestry University, Tsinghua East Road 35, Haidian District, Beijing 100083, China
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  • This work was supported by the ‘948’ Project of the State Forestry Administration of China (2011-4-54) and The Special Fund Project for the Scientific Research of the Forest Public Welfare Industry (201104024).

X. Wang, Fax: +86 10 62337855; e-mail: wxf801@sina.com

ABSTRACT

Seed deterioration is poorly understood and remains an active area for research. Seeds of elm (Ulmus pumila L.) were aged at 37 °C above water [controlled deterioration treatment (CDT)] for various lengths of time to assess programmed cell death (PCD) and reactive oxygen species (ROS) product in embryonic tissues during a 5 d period. The hallmarks of PCD were identified in the elm seeds during CDT including TUNEL experiments, DNA laddering, cytochrome c (cyt c) leakage and enzymatic activities. These analyses indicated that PCD occurred systematically and progressively in deteriorated elm seeds. Cyt c release and increase in caspase-3-like/DEVDase activity occurred during CDT, which could be suppressed by ascorbic acid (AsA) and caspase-3 inhibitor Ac-DEVD-CHO, respectively. In situ localization of ROS production indicated that the distinct spatial-temporal signature of ROS during CDT coincided with the changes in PCD hallmark features. Multiple antioxidant elements were activated during the first few days of CDT, but were subsequently depleted as PCD progressed. Taken together, our findings identify PCD as a key mechanism that occurs asymmetrically during elm seeds CDT and suggest an important role for PCD in seeds deterioration.

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