Abstract:

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.

Key words: flumetralin, loquat, inhibition of rootstocks tillering, chlorophyll fluorescence parameters, oxidative burst, antioxidant enzymes