氟节胺抑制枇杷嫁接成苗砧木萌蘖相关机理初探

为寻找更长效、无害的化学控蘖剂以减轻田间管理劳动强度,以枇杷(Eriobotrya japonica)嫁接成苗为材料,喷施有效成分浓度为0.050%,0.071%和0.125%的氟节胺,于不同时期取样观察控蘖效果,并尝试探究相关机理。结果表明,氟节胺减少了叶片单位面积光能的吸收量、抑制了光化学转换,但叶片的热耗散量并无明显变化。进一步测定植株氧化还原状态发现,氟节胺能够快速促进细胞内超氧阴离子(O₂^.-)积累并延缓或抑制H₂O₂的转化,从而诱发氧化胁迫。由此可见,氟节胺可能通过抑制叶片光化学转换和热耗散来破坏新生萌蘖的光合性能,进而抑制其萌发生长,而成熟叶片则通过提升自身抗氧化系统活性耐受氟节胺造成的轻度胁迫。在本试验中,各浓度的氟节胺对控制砧木萌蘖有不同程度的效果,其中浓度为0.125%的氟节胺控蘖效果相对最佳,且基本不会对砧木和嫁接成苗造成持续伤害,其作为化学控蘖剂有一定的应用潜力。

The Mechanism of Flumetralin in Inhibiting Tillering of Grafted Loquat Rootstocks

To study the tillering control effect of flumetralin, the grafted seedlings of loquat were used as materials. The results showed that concentrations of 0.050%, 0.071% and 0.125% flumetralin reduced the absorption of light energy per unit area of leaves and inhibited photochemical conversion, but the heat dissipation of leaves did not change significantly. Further determination of redox status of plants showed that flumetralin could rapidly promote the accumulation of superoxide radical (O₂^{. -}) in cells, inhibit the hydrogen peroxide (H₂O₂) transformation, thus inducing mild oxidative stress. It can be concluded that flumetralin may destroy photosynthetic properties of newly sprouted tillers by inhibiting photochemical conversion and heat dissipation of leaves, thereby inhibiting their germination and growth, while mature leaves can effectively tolerate mild stress caused by flumetralin by enhancing the activity of their endogenous antioxidant system. In this experiment, 0.125% flumetralin has the best controlling effect on the tillering of loquat rootstock, and does not cause continuous damage to rootstock and grafted seedlings, so it has certain application potential as a chemical tiller control agent.