Yán / jiū / rén / yuán / tōng / guò / xiǎn / wéi / jìng / guān / chá / zhí / wù / jīng / bù / de / xíng / chéng / céng研究人员通过显微镜观察植物茎部的形成层。The researchers observed the vascular cambium in the plant stem through a microscope.