Reproduction
The sweet potato plant, among all other flowering plants, features the most advanced condition of reproduction occurring in terrestrial plants. Using its flowers, which contain both male and female reproductive organs, the sweet potato plant undergoes sexual reproduction. Sexual reproduction occurs when genetic material from both male and female individuals come together to create a new individual.
The life cycle of a sweet potato plant alternates between a diploid sporophyte generation and a haploid gametophyte generation. Within the flowers of I. batatas, there are anthers that contain millions of diploid spores called microsporocytes. The anther is the male organ of the flower. These microsporocytes divide by meiosis to produce haploid microspores. Each male microspore undergoes a mitotic division to produce a haploid male gametophyte called the microgametophyte, or better known as pollen grain.
The pistil consists of a stigma, style, ovary, and ovules. Ovules
are in the ovary. A diploid megasporocyte exists in the ovule and
divides by meiosis to create four haploid megaspores. Only one of
these megaspores survives.
The megaspore divides by mitosis to produce seven haploid cells. The
seven-celled structure makes up the female gametophyte or
megagametophyte.
The male pollen grain lands on the stigma, initiating
pollination of the female parts. Here the pollen grain germinates
and a pollen tube grows down the style until it meets the female
gametophyte. Two sperm from the pollen grain utilize the pollen tube
for travel and enter the female gametophyte. One fertilizes the egg,
forming a diploid zygote. The other fertilizes the two polar nuclei
that are within the megametophyte. The fertilization creates a
triploid cell. This dual fertilization is called double
fertilization. The zygote, which begins the next sporophyte
generation, develops into the embryo. The seed germinates and when
the sporophyte matures, the lifecycle begins again.
Anatomy specific to an I. batatas flower?
Click on the thumbnails above!
(Both images were redrawn from the
International Potato Center Website.)
Now that you know how this organism reproduces, check out where it lives!