Questions & Answers about У этого ростка тонкий стебель, но крепкий корень.
In Russian, possession is very often expressed with the pattern:
У + possessor in the genitive + possessed thing
So:
У этого ростка тонкий стебель, но крепкий корень.
literally = At this sprout, [there is] a thin stem, but a strong root
natural English = This sprout has a thin stem but a strong root.
This is one of the most common Russian ways to say have/has.
Compare:
- У меня есть книга. = I have a book.
- У дерева толстый ствол. = The tree has a thick trunk.
So here у introduces the owner/possessor: this sprout.
Because the preposition у requires the genitive.
Dictionary forms are:
- этот росток = this sprout
- after у it becomes у этого ростка
That is why both words change:
- этот → этого
- росток → ростка
This is completely normal after у when it means possession.