Sexual reproduction in plants occurs when a
detached reproductive cell unites with another reproductive cell. Unlike
animals, plants do not have to have separate male and female sexes, in many
plants both sexes are located on the same species. In asexual reproduction,
the cell, tissue, or organ develops directly into a new organism. Sexual
reproduction allows combinations of different genetic material to be
introduced into a new individual (this is the method by which humans reproduce
and provides for genetic rearrangement and assortment.) In asexual
reproduction an exact copy is made from the mother cell, therefore, the
genetic material remains the same. Vascular plants are more complicated than
non-vascular plants. The development of complex tissues and organs in vascular
plants to aid in the movement of water and food, created the need for
different strategies to reproduce.
ASEXUAL REPRODUCTION OF NONVASCULAR
Unicellular algae reproduce by the simplest type of reproduction
which consists of cell division. In simple cell division, two daughter cells
are produced from one mother cell. Some algae have asexual spores which
produce specialized reproductive cells that are capable by themselves of
producing new plants by cell division and growth.
ASEXUAL REPRODUCTION OF VASCULAR PLANTS.
Vegetative reproduction involves no special reproductive cells. One of the
most common types of vegetative propagation occurs in plants with horizontal
stems growing either above ground (runners or stolons) or underground
(rhizomes). Several plants propagate vegetatively by tubers or the thickened,
fleshy ends of rhizomes. Some plants have long slender stems that develop
roots when they touch the ground. Bulbs such as those of onions form large
buds that grow. Corms are the short, fleshy vertical underground stems have
more stem tissue and smaller scale leaves than a bulb. Some plants reproduce
by having horizontal roots while others have leaves that will start to ground.
Some plants can propagate by cutting either stems or tubers into pieces that
will grow. There are many different types of asexually reproducing vascular
SEXUAL REPRODUCTION OF NONVASCULAR
Although not common, many small algae will reproduce sexually by
forming specialized sex cells. This usually happens when the asexual cycle has
terminated its cycle. (This is called alteration of generations.) Some spores
are also formed by asexual means.
SEXUAL REPRODUCTION OF VASCULAR PLANTS.
Trees reproduce sexually through seeds (female) and pollen (male). Gymnosperms
produce a naked seed whereas angiosperms (flowering plants) produce a true
- Plants provide an excellent means to
review reproduction. Plants reproduce in so many ways that students will get a
better understanding of the complexities needed to duplicate their own
species. This will help students understand human reproduction.
- Review the different methods of plant reproduction.
Make sure students remember the difference between vascular (more complex)
and non-vascular (mainly bryophytes and algae) plants.
- On the students' worksheet
have the students determine whether the organisms reproduce by sexual or
Answers: Asexual: 1,3,5,6; Sexual 2,4,7,8