The Web of Life (53-3) Transport in Plants


Land plantsĀ (embryophytes) evolved from aquatic plants, such as green algae. The earliest embryophytes were small and simple, with a limited nutrient distribution system. These are bryophytes: mosses, hornworts, and liverworts.

Then came a great innovation: a tubular transport system to shuttle water and nutrients around. These are vascular plants (tracheophytes). A tubular distribution system afforded great versatility in plant morphology.

The art of evolution is evidenced by traits that later find more sophisticated employment, and in species that show the first steps to later developments. Some bryophytes have specialized tissues to transport water, but they lack lignin. Red alga, one of the oldest algae groups, has lignin. Tracheophytes emerged by putting the 2 traits together.