Please enable JavaScript.
Coggle requires JavaScript to display documents.
Asexual and Sexual Reproduction in Plants (Asexual reproduction:Parent…
Asexual and Sexual Reproduction in Plants
Asexual reproduction:Parent plant produced offsprings that are genetically identical to each other. This can be an advantage when the organism is well adapted in the environment.
.
Natural vegetation propagation: new individuals are grown from stem leaves of an existing plant
Division/ Splitting: Plant is split into two with both shoot and root system where they are separately replanted and grow independently. The purpose is to provide a simple, fast and thin out plants with large surface area
Grafting: bud from one plant is joined to another by putting the vascular cambium tissue together. The graft is then covered to prevent water loss. The purpose is so it can can produce plant with diverse characteristics, prevents water loss, faster maturity rate
Leaf Cutting: Leaf cut off from plant and placed in soil where the meristematic tissue helps form roots and plant base. The purpose is to provide a simple and inexpensive way to grow genetically identical plants, versatile to any season and can be used to save leave
Stem cutting: Stem from one plant is cut off and put in a growth medium to fully develop
Artificial propagation : cloning of a plant from the portion of its roots, stems or leaves
Cell Culturing: Individual plant cell put in nutrient-rich environment where platelets form, and then put into soil to form individual plants. The pros: can produce mass amounts of plants( endangered plants)
Air Layering: Strip of outer bark is removed and tightly sealed for moist environment then new root system start to form and is then planted. The Pros: Can be used on woody plants that cannot use other ethods
Simple Layering: Plants with low lying stems are put into the ground where they develop individual shoot and root systems. The pros: Large, mature and genetically identical daughter plant is produced faster. Also still has connection to parent plant which can provide it with nutrients
Root cutting: root removed from a parent plant and placed horizontally in a bed of soil and organized in rows. This develops small individual plants with separate shoot and root systems. The pros: plants can be grown faster in off seasons simply with minimal costs and offer as an alternative to vegetative propagation
Pollination mechanisms
Wind Pollination
usually done by plants that lack colour or fragrenc, but carry large volume of pollen
Self Pollination/ Cross Pollination
Self Pollination can lead to lack of genetic variation, common is most angiosperms
Cross pollination: Can receve pollen from other plants= genetic diversity
Animal pollination
brightly coloured with strong scents and nectar, insects and animals carry pollen to different flowers as they search for nectar
Reproductive cycle in plants
Haploid
Meiosis form spores that indergo cell diviion whic mature into gametophyte when divides and turns into male and female gamete that combine to form diploid
Diploid sporophyte
Fertilization forms zygote( 2n) fertilization occurs when sperm units with an egg to form zygote which develops into an embryo (covered by tough layer=sed) -male+female=sporophyte -sporophyte goes through cell division where reproductive cells develop and the process repeats.
Sexual reproduction: sporic reproduction
Seed plants
Adapted for reproduction in dry environment, non motile sperm and protected zygote, embryo with dependent gametophyte
male gametophytes= microspores/ female= macrospores
Types:
Gymnosperm
Free living plants -unprotected seeds that develop on the upper surface - wind pollination -single fertilization Female= macrospore/ male= microspore
Male gametophytes(pollen grain)=microspores - travels to female gametophytes , then pollination occurs when pollen lands on female reproductive structure (does not requires water transfer of sperm to egg occurs through pollen tube. -Pollen grain encases cells to prevent sperm from dyring out
Angiosperm
protected seeds within ovary walls- wind, insects or animal pollination, double fertilization
Flower is the reproductive organ
Sepals:Protect the flower bud, can look like small leaves or flower petals
petals: usually colourful structures that attract pollinating insect and provide them with a platform
Stamens- most flowers have several male reproductive organs - Compised of filament and anther (filament stalks supposrtanther during meiosis and mitosis
Pistil: in the center of the flower, usually one or more accompanied by stigma
Stigma: tip of the pistil, where pollination occurs
Style- connects stigma to ovary(contains one or more ovules)
Ovules: sacs that contain female gametes
Ovary: where female gametophytes develop into egg forms in it
Seedless plants
Vascular: Dominant sporophyte plant
Non Vascular: Dominant gametophyte plant
Adapted to reproduction in wet environment, unprotected zygote, embryo and independent gametophyte