Plant Reproduction

What are the methods of asexual and sexual reproduction in plants?

Plants are capable of reproducing via sexual or asexual means:

• Vegetative propagationglossary term (opens in a new window) is one form of asexual reproduction in plants.
• This form of reproduction takes place without the production of spores or seeds.
• Examples of vegetative propagation include cuttings, grafting, bulbs, and division.
• Apomixisglossary term (opens in a new window) is another type of plant asexual reproduction.
• Apomixis involves the production of haploid or diploid seeds or spores from a single parent that grow into new individuals.
• All plant asexual reproduction results in offspring that are identical to the parent.
• Plant sexual reproduction can occur through self-fertilization or cross-fertilization.
• Fern sexual reproduction occurs through the release of spores.
• Spores grow into gametophytes that produce eggs and sperm, which can then fertilize.
• Bryophytes release spores that eventually produce motile sperm, which fertilize stationary eggs in water.

What are the reproductive structures in plants?

Flowers are the reproductive structures of flowering plants:

• Flowers contain all of the male and female reproductive organs.
• The stamenglossary term (opens in a new window) includes the male organs (the anther and filament).
• Male plant organs produce pollenglossary term (opens in a new window), which contain sperm.
• The carpelglossary term (opens in a new window) contains the female reproductive organs, the stigma and the style.
• The carpel also produces the female gamete, inside the ovule.

What are the processes of pollination and fertilization in plants?

Pollen is released from a flower and reaches the stigma, which results in sperm fertilizing the egg inside the ovule:

• Animals and environmental factors like wind aid in pollination.
• When pollen reaches the stigma, a tiny tube is extended down the style through which sperm cells can travel to the ovule.
• Fertilization occurs when sperm and egg combine.
• After fertilization, the embryo develops inside the seedglossary term (opens in a new window) and the ovule develops into a fruitglossary term (opens in a new window).

What is the influence of light on plant growth and development?

The intensity, quality, and duration of light exposure all effect plant growth:

• Light quality refers to the wavelength of light.
• Optimal light wavelengths for photosynthesis and thus plant growth are in the range of 400–700 nm.
• Light intensity refers to how much light actually reaches a plant in a given time.
• The rate of photosynthesis increases with increased light intensity, but overly intense light can harm plant tissues.

• Light duration refers to the amount of time a plant is exposed to light.

What are plant responses to gravity and touch?

Without complex sensory systems, plants are able to sense and respond to environmental factors such as gravity and physical touch:

• The ability of plants to respond to factors such as gravity and touch is called tropismglossary term (opens in a new window).
• Plant response to gravity is called gravitropismglossary term (opens in a new window).
• Typically, plant stems grow upward in a process called positive gravitropism.
• Plant roots extend downward in a process known as negative gravitropism.
• Plant response to physical touch is called thigmotropismglossary term (opens in a new window).
• Thigmotropism allows plants to weave around physical objects in their environment.
• Plants produce ethylene gas that causes plant tissues to grow horizontally.
• The plant growth hormone auxinglossary term (opens in a new window) is responsible for tropism.