Using the method of gas chromatography-mass spectrometry, a comparative analysis of the qualitative and quantitative composition of free sterols in the tissues of young growing needles of native (two varieties of Siberian spruce: Picea obovata and P. obovata var. coerulea) and introduced (P. abies, P. pungens) species of the genus Picea growing in the Southern Baikal region was carried out depending on the development phase. The absolute weight of total lipids in the four studied taxa at different growth stages differed and had a species-specific character. It was shown that at the transition boundary between the phases of needle growth (intercalary and cell growth by extension), lipid content increased in all the studied spruce species. Among the free sterols, the main common ∆-sterols were found, namely β-sitosterol, campesterol, stigmasterol, and cholesterol. The dominant sterol for all the studied taxa was β-sitosterol, its content was 80–95% of the total free sterols. It was shown that for the introduced (non-indigenous) species, the maximum β-sitosterol content occurred during the period of cell growth by stretching, and for the native spruces, the maximum values of β-sitosterol content were found during the period of intercalary growth. It was found that at the beginning of needle formation (intercalary growth), high sterol content is necessary, and it decreases as the needles grow and develop. A decrease in sterol content may be associated with their use as a substrate in the synthesis of other compounds; for example, β-sitosterol and campesterol are precursors of brassinosteroids. In general, the temporal dynamics of sterol composition changes and the progression of active needle growth phases differed between introduced and native spruce species.
Semenova et al. (2026) studied this question.