Zn²⁺ induces changes in activities of mitochondrial respiratory chain complexes and emissions of floral volatiles in Dendrobium huoshanense

In recent years, there has been increasing interest in floral volatiles due to their important function in reproduction, self-protection and so on. Although some progress was made on deciphering emissions of floral volatiles and on related mechanisms under a variety of environmental factors, the effects of Zn²⁺ concentrations on mitochondrial function and floral volatile emissions are yet to be revealed. Dendrobium huoshanense petals were used as materials and were treated with a 0–8 mM ZnSO₄ solution. Intracellular Zn²⁺ concentrations were evaluated by the fluorescent dye method and atomic absorption method. Mitochondrial respiratory chain complex activities and the precursor and ATP contents were determined by the biochemical method. Floral volatile components were analyzed by the gas chromatograph-mass spectrometer (GC-MS). The results indicated that ZnSO₄ application significantly increased intracellular Zn²⁺ concentrations. Elevated intracellular Zn²⁺ concentrations differently affected mitochondrial respiratory chain complex activities, precursor and adenosine triphosphate (ATP) productions and floral volatile emissions. Moreover, positive correlations exist among the activities of mitochondrial respiratory chain complexes, productions of precursors and ATP and emissions of floral volatiles. It is concluded that Zn²⁺ concentrations induce the activity changes of mitochondrial respiratory chain complexes, especially complex II and V, which promote or inhibit the emissions of floral volatiles by affecting the precursor and ATP levels that are closely related to the production of terpenoids, benzoids and fatty acid derivatives. The research will contribute to understanding the relationship between Zn²⁺ concentrations and floral volatile emissions from the perspective of mitochondrial function.