Journal of Integrative Agriculture ›› 2022, Vol. 21 ›› Issue (11): 3148-3157.DOI: 10.1016/j.jia.2022.08.083

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JIA-2021-0700 密植条件下玉米花丝生长减缓的表型及转录组学证据

  

  • 收稿日期:2021-04-18 接受日期:2021-06-25 出版日期:2022-11-01 发布日期:2021-06-25

Evidence of silk growth hampering in maize at high planting density using phenotypic and transcriptional analysis

ZHANG Min1, XING Li-juan1, REN Xiao-tian2, ZOU Jun-jie1, SONG Fu-peng3, WANG Lei1, XU Miao-yun1   

  1. 1 Biotechnology Research Institute, CAAS/Key Laboratory of Agricultural Genomics (Beijing), Ministry of Agriculture,Beijing 100081, P.R.China
    2 College of Bioscience and Resources of Environment, Beijing University of Agriculture, Beijing 102206, P.R.China 
    3 National Engineering Laboratory for Efficient Utilization of Soil and Fertilizer Resource, College of Resources and Environment, Shandong Agricultural University,  Tai′an 271018, P.R.China
  • Received:2021-04-18 Accepted:2021-06-25 Online:2022-11-01 Published:2021-06-25
  • About author:Correspondence XU Miao-yun, E-mail: xumiaoyun@caas.cn; WANG Lei, E-mail: wanglei01@caas.cn
  • Supported by:
    This study was supported by the National Key R&D Program of China (2016YFD0101002), the National Natural Science Foundation of China (32072068) and the Central Public-interest Scientific Institution Basal Research Fund, China (1610392021001).

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摘要： 增加种植密度是提高玉米产量的有效手段，但密植会加重雌穗顶端籽粒败育引发秃尖，进而导致减产。前期已有报道，对干旱逆境下玉米雌穗顶端籽粒败育的调控机制进行了研究，但对密植条件下玉米雌穗发生秃尖的调控机制知之甚少。本研究旨在探讨玉米应答密植环境、导致籽粒败育的潜在机制。选用两个自交系郑58和PH4CV，及分别由郑58和PH4CV做母本和父本组配的两个生产常用杂交种郑单958和先玉335为研究对象，观察了4个材料在四种不同种植密度（60,000 株/公顷 (60 k)、90,000株/公顷 (90 k)、120,000株/公顷 (120 k) 和 150,000株/公顷 (150 k)条件下，株型、秃尖情况、开花时间和花丝发育等表型的变化趋势。结果表明，随着种植密度增加，株高变化不明显，但茎粗、叶绿素含量和生物量的变化则呈现明显负相关。同时，散粉-吐丝期(ASI)延长，且苞叶中吐出花丝的数量也随之减少，说明密植条件下花丝生长减缓。进一步对花丝细胞形态的观察也发现，随着种植密度的增加，花丝细胞呈现减小趋势。转录组学数据分析表明，差异表达基因主要是花丝伸长相关基因，而非与碳代谢相关基因。以上研究证实，密植影响玉米花丝生长、使吐丝延迟、ASI加长，进而引起花期不遇，导致顶端胚珠授粉不良发生败育而产生秃尖表型。该研究加深了对密植条件下玉米花丝生长规律的认识，为进一步解析玉米应答密植条件，调控花丝生长的分子机制提供理论依据。

Abstract: Increasing the planting density is an effective way to increase the yield of maize (Zea mays L.), although it can also aggravate ovary apical abortion-induced bald tips of the ears, which might, in turn, reduce the yield.  While the mechanism underlying the regulation of drought-related abortion in maize is well established, high planting density-related abortion in maize remains poorly understood.  Therefore, the present study was designed to investigate the mechanism underlying the ovary apical abortion response to high density.  This was achieved by evaluating the effects of four different plant densities (60 000 plants ha–1 (60 k), 90 k, 120 k, and 150 k) on plant traits related to plant architecture, the plant ear, flowering time, and silk development in two inbred lines (Zheng58 and PH4CV) and two hybrid lines (Zhengdan958 and Xianyu335).  The phenotypes of both inbred and hybrid plants were observed under different planting density treatments, and the high planting density was found to increase the phenotypic performance values of the evaluated traits.  The anthesis–silking interval (ASI) was extended, and the amount of the silk extruded from husks was reduced upon increasing the planting density.  Delayed silk emergence resulted in asynchronous flowering and ear bald tips.  Observations of the silk cells revealed that the silk cells became smaller as planting density increased.  The changes in transcript abundances in the silks involved the genes associated with expansive growth rather than carbon metabolism.  These findings further our understanding of silk growth regulation under high planting density and provide a theoretical basis for further research on improving high planting density breeding in maize.  

Key words: maize (Zea mays L.) ,  high planting density ,  bald tip ,  ASI ,  silk expansive growth