How might the adaptation of specialized water-conducting tissue have helped land plants meet challenges to life on land?
Water conducting tissues solve the problem of moving water from where it is available (in the soil) to where it is needed.
The first plants were small and aquatic - plants surrounded by water, so moving water around inside the plant was not a problem they faced.
When plants started to colonise the land there were several problems to solve. These included
- absorbing a supply of water from the soil
- keeping this water once it was absorbed
- moving water from where it was absorbed to where it was needed
There was also competition for light- it would be an advantage to be taller than other surrounding plants and obtain a better light supply. But the taller you are, the bigger distance water has to be moved.
The solution to this problem is xylem - which is basically a tissue composed of long, empty cells with thick side walls and openings in their end walls. The thick sidewalls help keep the plant erect, and the cells being long and with openings in the end walls make for easier water flow.