Plant form and function (4) Flashcards
Why can some trees survive after having a tunnel cut through it?
The reason why some large trees can survive after a tunnel is cut through the center is because the center of an older tree consists of heartwood, which no longer transports materials through the plant.
It can thus be removed without harming the tree
The ______ is the organ of sexual reproduction in angiosperms
The flower is the organ of sexual reproduction in angiosperms
What is an alternation of generation? What are the distinct bodies of each generation?
Plants have an alternation of generations in which the haploid and diploid stages are distinct, multicellular bodies.
The haploid generation of a plant produces gametes and is called the gametophyte.
The diploid generation produces spores and is called the sporophyte.
Explain the steps of how an ovule develops into a mature plant.
- Fertilization occurs in an ovule within a flower.
- As the ovary develops into a fruit
- The ovule develops into the seed containing the embryo and a store of food. The fruit protects the seed and aids in dispersing it.Completing the life cycle
- The seed then germinates (begins to grow) in a suitable habitat;
- The embryo develops into a seedling, and the seedling grows into a mature plant.
What is double fertilization and explain the process.
- When the pollen tube reaches the base of the ovule, it enters the ovary and discharges its two sperm near the embryo sac.
- One sperm fertilizes the egg (forming the diploid zygote), while the other contributes its haploid nucleus to the large diploid central cell of the embryo sac. (forming a triploid nucleus), which will give rise to a food-storing tissue called endosperm.
- This union of two sperm cells with different nuclei of the embryo sac is called double fertilization.
Explain how an ovule develops into a seed.
After fertilization, the ovule becomes a seed, and the fertilized egg within it divides and becomes an embryo.
The other fertilized cell develops into the endosperm, which stores food for the embryo.
Near the end of its maturation, the seed loses most of its water and forms a hard, resistant seed coat.
While the seeds are developing from ovules, ________ triggered by fertilization causes the flower’s ovary to grow, thicken, and mature into a fruit.
While the seeds are developing from ovules, hormonal changes triggered by fertilization cause the flower’s ovary to grow, thicken, and mature into a fruit.
Explain how a seed is considered an escape pod.
A seed is a sort of “escape pod” in which an embryo lies dormant, surrounded by a supply of food and protected from the elements.
How does seed germination take place?
A seed starts to germinate when it takes up water and expands.
The embryo resumes growth and absorbs nutrients from the endosperm.
An embryonic root emerges, and a shoot pushes upward and expands its leaves.
Explain the germination mechanism of corn and other monocots.
A protective sheath surrounding the shoot pushes upward and breaks through the soil.
The shoot tip then grows up through the tunnel provided by the sheath.
The corn cotyledon remains in the soil and decomposes.
What is a clone?
A clone is an asexually produced, genetically identical organism or group of organisms
How can asexual reproduction occur?
Asexual reproduction can occur
by
-fragmentation, the separation of a parent plant into parts that develop into whole plants
-through the outgrowths of root systems.
Why is plant cloning an important agricultural tool?
-The ability of plants to reproduce asexually provides many opportunities for growers to produce large numbers of plants.
-Propagating plants asexually from cuttings or bits of plant tissue can increase agricultural productivity but reduce genetic diversity.
