JOURNAL OF NANJING FORESTRY UNIVERSITY ›› 2023, Vol. 47 ›› Issue (4): 88-94.doi: 10.12302/j.issn.1000-2006.202109003

Special Issue: 乡村振兴视域下经济林果培育专题(Ⅱ)

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Effects of exogenous ABA on the synthesis of flavonoids in Ginkgo biloba leaves in vivo

LI Tingting(), GUO Jing, WANG Guibin()   

  1. Co-Innovation Center for Sustainable Forestry in Southern China, College of Forestry, Nanjing Forestry University, Nanjing 210037, China
  • Received:2021-08-31 Revised:2021-09-24 Online:2023-07-30 Published:2023-07-20

Abstract:

【Objective】The effects of different concentrations of abscisic acid (ABA) on the synthesis of flavonoids in Ginkgo biloba leaves were examined to provide a theoretical basis upon which the internal mechanisms of flavonoid accumulation in G. biloba leaves and leaf forest cultivation could be revealed.【Method】Annual ginkgo seedlings were placed in an artificial climate culture room and treated with exogenous ABA via foliar spraying at five concentration gradients; 0 μmol/L (CK), 50 μmol/L(A1), 100 μmol/L(A2), 150 μmol/L(A3) and 200 μmol/L(A4). The total flavonoid contents, components of G. biloba leaves, and the activities of key enzymes in the flavonoid synthesis pathway were measured, and the expression changes of key enzyme genes involved in G. biloba flavonoid biosynthesis were analyzed using real-time fluorescence quantitative PCR. 【Result】 ABA treatment had a significant effect on both total flavonoid content and components such as quercetin, kaempferol and isorhamnetin. Increasing the ABA concentration led to an initial increase in the total flavonoid and component content, which was followed by a decrease. The highest total flavonoids, quercetin and isorhamnetin were observed under treatment A3, while the highest kaempferol was associated with A2. ABA treatment had a significant effect on the activities of key enzymes that are involved in flavonoid synthesis in G. biloba leaves (PAL, C4H and 4CL); however, differences were observed in the change trends of the different enzymes. PAL enzyme activity increased gradually as ABA concentrations increased; C4H activity increased and decreased alongside the total flavonoid content; 4CL activity was significantly higher under treatments A2 and A3 than the control; however, 4CL activity was lower under A1 and A4 than the control. The results of real-time fluorescence quantitative PCR showed that ABA treatment significantly improves the expression levels of GbPAL,GbC4H,Gb4CL,GbCHS and GbCHI. In general, exogenous ABA improves the flavonoid synthesis in G. biloba leaves, with the best effects observed under treatment A3.【Conclusion】The use of appropriate ABA concentrations can positively regulate the expression of multiple key enzyme genes that code for flavonoid synthesis, improve the activity of key enzymes involved in flavonoid synthesis, and thus promoting the synthesis and accumulation of flavonoids in G. biloba leaves.

Key words: Ginkgo biloba leaves, ABA, flavonoid

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