Most terrestrial plants (both bryophytes and tracheophytes) share some general
structural and functional features. Plant bodies are divided into two regions,
the underground root portion and the aerial shoot portion (including
stem, leaves, flowers, and fruits). These different regions of the plant are
dependent on each other, as each performs different essential functions. Land
plants also share certain more specific
adaptations
that are essential to survival out of water. These include an impermeable waxy
cuticle on the outer aerial surfaces, jacket cells around the reproductive
organs, and stomata that allow gas exchange without risking excessive water
loss.
Plants are also autotrophic, meaning that they produce their own
food and do not use other organisms to supply organic nutrients the way animals
do. Finally, the life cycle of plants follows a pattern called the
alternation of generations, in which they fluctuate between haploid and
diploid generations and sexual and asexual modes of reproduction.
