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Acta Prataculturae Sinica ›› 2022, Vol. 31 ›› Issue (3): 85-91.DOI: 10.11686/cyxb2020550

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Effects of gibberellin and its inhibitors on growth and gene expression in Poa pratensis

Li-qing ZHAO1(), Zhi-gang HAO2, Xiao-yan CUI3, Xiang-yong PENG3()   

  1. 1.The Open University of China,Beijing 100039,China
    2.Yinhe Ecology Technology Co. ,Ltd,Beijing 102488,China
    3.College of Life Sciences Qufu Normal University,Qufu 273165,China
  • Received:2020-12-09 Revised:2021-03-04 Online:2022-03-20 Published:2022-01-15
  • Contact: Xiang-yong PENG

Abstract:

The effects of different concentrations of gibberellin (GA3) and gibberellin inhibitors on the growth and development, and the expression of gibberellin-related genes of Poa pratensis were studied. P. pratensis plants cultivated with 1/2 Hoagland nutrient solution were randomly divided into 7 groups. Three plant growth regulators: GA3, uniconazole or paclobutrazol were applied to determine the effects on plant growth, chloroplast distribution, chlorophyll content, and gibberellin-related gene expression measured. Compared with the control, exogenous uniconazole and paclobutrazol significantly inhibited leaf elongation and fresh and dry weight accumulation of P. pratensis, but increased root∶shoot ratio, chlorophyll a, chlorophyll b and carotenoid contents (P<0.05). The number of mesophyll cell layers was also increased and Chloroplasts were evenly distributed in mesophyll cells between the upper and lower epidermis. The expression of key enzyme genes PpKAOPpKS1PpGA3ox and PpGA2ox in the gibberellin biosynthesis and metabolism pathways were significantly down-regulated, and the protein receptor gene PpGID1 in the gibberellin signal transduction pathway was significantly up-regulated (P<0.05). Exogenous gibberellin promoted the elongation of P. pratensis roots and leaves, and increased the fresh and dry weights of roots and leaves, decreased the root∶shoot ratio and significantly upregulated the PpGA2ox expression of gibberellin-related genes (P<0.05). In summary, the effects of uniconazole and paclobutrazol on the growth and gene expression of P. pratensis were opposite to those of gibberellin, but there was no significant concentration effect. The growth inhibition from spraying uniconazole or paclobutrazol diluted 1000 times after lawn mowing would have significantly reduced the labor cost of lawn maintenance , enhanced lawn visual appearance and ornamental value and promoted ease of management and turf persistence in landscaping applications.

Key words: Poa pratensis, growth regulator, gibberellin, growth, gene expression