Water is always being considered as an important element of Ikebana arrangements but in this particular case of glass vases, water is the shin. So we pay great attention to the branches or leaves seen through the glass container.
The monstera leave is used to create a sculptural presence while the aliums and roses accentuates and enhances the whole composition.
In order to see similar arrangements in glass containers, you can click the "glass container" label at the bottom of this post.
Check this other posts: glass container challenge series from 2019, June 2018, this post from May 2018 or see this post from May 2015.
For another see-through arrangement, you can check this earlier post from December 2014.