The physicochemical response of the precious tree species Aquilaria sinensis to biological and chemical stimuli

To explore the physiological response mechanism of Aquilaria sinensis to the stimulation of fungi combined with growth regulators and inorganic salts, and provide a theoretical basis for promoting the agarwood formation of Aquilaria sinensis.

Taking 8-year-old Aquilaria sinensis as the research objects, Phyllosticta fallopiae was injected into the tree body of Aquilaria sinensis after compounding with three growth regulators (ethephon, 6-Benzylaminopurine, sodium salicylate) and four inorganic salts (CaCl₂, NaCl, FeSO₄, FeCl₃), respectively. The superoxide dismutase activity, peroxidase activity, catalase activity, total phenol content, malondialdehyde content, starch content, soluble sugar content and xylem discoloration length of Aquilaria sinensis were analyzed.

All treatments enhance the defense response of xylem of Aquilaria sinensis. The defense response intensity of CJ3 and CW4 treatments in experiment Ⅰ and experiment Ⅱ are the highest in the same treatment. All treatments effectively induce the formation of agarwood. The discoloration range of xylem in experiment Ⅰ CJ4 treatment and experiment Ⅱ CW4 treatment are 95 mm and 150 mm, respectively, which are the highest in the same treatment. There is a significant positive correlation between xylem defense response intensity and the length of xylem discoloration range. In theory, the strongest induction combinations of xylem defense response of Aquilaria sinensis are: Phyllosticta fallopiae +0.1% ethephon+0.025 1% 6-Benzylaminopurine+0.2% sodium salicylate; Phyllosticta fallopiae+0.1% CaCl₂+0.1% NaCl+1.496 6% FeSO₄+0.050 02% FeCl₃.

The combination of fungi, growth regulators and inorganic salts can effectively promote the stress effect of Aquilaria sinensis and promote the agarwood formation.