这株棕榈树的粗壮茎干显示出它已经生长了很多年。

The thick ___caudex of this palm tree indicates it has been growing for many years.

植物学家在研究棕榈树时特别注意了其粗壮的茎干结构。

The botanist paid special attention to the thick ___caudex structure while studying the palm tree.