中国农业科学 ›› 2018, Vol. 51 ›› Issue (12): 2263-2273.doi: 10.3864/j.issn.0578-1752.2018.12.004

• 耕作栽培·生理生化·农业信息技术 • 上一篇    下一篇

灌浆期低温对离体培养玉米强弱势粒发育的影响

张巽1,2,郝建平1,王璞3,张萍3,陈璐洁3

 
  

  1. 1山西农业大学农学院,山西太谷 030801;2大同大学生命科学学院,山西大同 037009;3中国农业大学农学院,北京 100193
  • 收稿日期:2017-09-15 出版日期:2018-06-16 发布日期:2018-06-16
  • 通讯作者: 郝建平,E-mail:tghjp88@sina.com。王璞,E-mail:wangpu@cau.edu.cn
  • 作者简介:张巽,E-mail:sxdtuzx@163.com
  • 基金资助:
    国家玉米产业技术体系建设专项(CARS-02-26)、山西省大同市基础科技项目(2015105)

Effects of Low Temperature on Maize Superior and Inferior Kernels Development During Grain Filling in Vitro

ZHANG Xun1,2, HAO JianPing1, WANG Pu3, ZHANG Ping3, CHEN LuJie3   

  1. 1College of Agriculture, Shanxi Agricultural University, Taigu 030801, Shanxi; 2School of Life Sciences, Datong University, Datong 037009, Shanxi; 3College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193
  • Received:2017-09-15 Online:2018-06-16 Published:2018-06-16

摘要: 【目的】通过对玉米灌浆过程中籽粒干物质、淀粉的积累,籽粒内源激素含量及淀粉积累相关酶活性的研究,揭示低温对灌浆过程中玉米强、弱势籽粒灌浆生理过程的影响规律,为生产上抗御低温冷害提供理论参考。【方法】选用郑单958为试验品种,采用玉米籽粒离体培养的方式,将大田人工授粉后3 d的玉米果穗按照弱势粒和强势粒进行取样,无菌环境接种到人工培养基培养,低温处理和对照分别设置培养平均温度为16℃及25℃。自授粉后每10 d取样一次,分别测定灌浆过程中玉米强、弱势粒干物质积累量、内源激素、籽粒淀粉含量及淀粉积累相关酶活性。【结果】低温胁迫下强、弱势粒灌浆后期粒重分别比对照低47.58%、50.95%,强、弱势粒灌浆高峰期的平均灌浆速率较对照分别显著降低55.39%、54.72%。低温胁迫下玉米籽粒灌浆速率前期提升和后期减小的速度明显减缓,活跃灌浆时间延长5—7 d。授粉后10 d低温处理显著降低玉米强、弱势粒生长素(IAA)、玉米素(ZR)和脱落酸(ABA)含量,显著提高玉米籽粒赤霉素(GA3)的含量。授粉后30 d低温处理显著降低了弱势粒的IAA、ZR含量,增加了强势粒的ABA含量。低温胁迫显著减弱了灌浆前期和灌浆中期的可溶性酸性转化酶(SAI)、蔗糖合酶(SS)、淀粉合酶(SSS)及ADPG焦磷酸化酶(APGase)的活性,低温下弱势粒SAI活性降幅大于强势粒,对SS、SSS及APGase活性的降低幅度表现为强势粒大于弱势粒,导致玉米籽粒淀粉含量降低。【结论】受低温胁迫影响,灌浆前期玉米籽粒的IAA、ZR、ABA含量减少,GA3含量增加,SAI活性降低,导致籽粒库容量减少,库活性不足。在灌浆中期,低温降低SS活性,造成淀粉合成底物供应不足,影响淀粉的合成,降低籽粒淀粉含量。低温处理降低玉米强、弱势粒的灌浆速率,导致籽粒干物质积累减少。低温对玉米强弱、势粒的灌浆过程都造成较大的影响,且对弱势粒的影响大于强势粒。

关键词: 玉米, 低温, 离体培养, 灌浆期, 激素

Abstract: 【Objective】In this study, the physiological mechanism of kernel weight reduction under low temperature had been uncovered through grain filling dynamic, carbon metabolism, and phytohormone balance, and reveal the effect of low temperature on maize superior and inferior kernels during grain filling, which could provide a theoretical guidance for crop production. 【Method】 Hybrid maize Zhengdan 958 was chosen for the experimental material, which was grown in the filed condition. Kernel was collected at 3 days after pollination, and was divided into superior and inferior kernel according to its position at the ear. Afterward, kernels were separately incubated with solid medium under normal (25°C) and low (16°C) temperature in artificial climate incubators. Superior and inferior kernels were sampled with 10-day interval since pollination for analyzing dry weight dynamic, hormone contend, starch accumulation and its related enzymes. 【Result】Compared with CK, Final kernel weight decreased by 47.58% for superior kernel and 50.95% for inferior kernels under low temperature, respectively. A longer active grain-filling period had been observed, caused by slower grain filling rate increase during lag period and slower decrease during maturation drying period. But, the grain-fill rate during active grain-filling period decreased 55.39% for superior kernel and 54.72% for inferior kernel, respectively. The increase of grain-filling rate in lag periods and the decrease of grain-filling rate in maturation drying periods of maize kernels were reduced significantly, and the time of active grain-filling periods was prolonged by 5-7 days under low temperature stress. The content of IAA, ZR and ABA decreased significantly in both superior and inferior kernels after 10 days low temperature incubation, while it was opposite for GA3. Moreover, decreased content of IAA and ZR in inferior kernels and increased ABA in superior kernels had been found after 30 days low temperature treatment. Low temperature decreased activity of soluble acid invertase (SAI), sucrose synthase (SS), soluble starch synthase (SSS) and ADP-glucose pyrophosphorylase (APGase) in both superior and inferior kernel during early grain filling periods, resulting in decreased starch accumulation in kernel. Furthermore, the decrease of SAI in inferior kernels was greater than that of superior kernels, while it was opposite for other enzymes.【Conclusion】The disturbed hormone balance during earlier grain filling period greatly weakened the sink capacity under low temperature stress, while the decreased activity of enzyme during mid-grain filling period limited the starch accumulation. The grain filling rate decreased in both superior and inferior kernels, resulting in kernel weight reduction. The grain filling process had been affected in both superior and inferior kernels under low temperature stress. Furthermore, the inferior kernels was more sensitive to low temperature than superior kernels.

Key words: maize, low temperature, vitro culture, grain filling stage, phytohormone