Topic 11 Plants - Lecture Note

Plants = embryophytes because they produce a multicellular diploid embryo. They are the first photosynthetic organisms that lived permanently on land. Thaw characteristics are: eukaryotes, multicellular; photoautotrophs: cellulose cell wall:chloroplasts with chlorophyll, beta-carotenes, xanthophylls; sexal 3 asexual; embryo is dependent on parent. Advantages of living on land' Brighter sunlight More atmospheric CO₂ Abundance of nutrients on shave line Disadvantages -dry environment strong gravity effect rapid temp. changes. Plants have a haplo diplantic life cycle. The combs is protected in the game to phyte Spores are produced by the sporophyte in the sporangium Spares are highly resistant because of sporopollenin Gametes are produced in the -gametangia. archegonia (lemale) anthredia (male) Plants have a region of cells in the root and shoot capable of division growth. called the apical meristem to maximize access to resources. Plants have cuticle to prevent water loss; they also have otomata for. water and coz regulation. * sporophytes grow on top of gametophytes. Sporophyte (diploid) meiosis spores (haplaid) Germination of spores favor moist conditions + sperm cells are able to swim to the archegonia in moisture Animals increase the chances of moss fertilization by transporting spores especially in dry environments. Vascularization is the presence of tissues that transport nutrients through the plant → specialized tissues are the xylem (transports water and minerals to the leaves) and the phloem (transports sugars to the whole plant). Plants also have lignin in their cell walls as structural support for gravity and it's impermeable to water. and it's impermeable to water. 2 different strategies in spore production: -homaspory (mast seedless vascular plants) produce 1 spore that produces a bisexual gametophyte because it produces both sperm egg to fertilize itself. -heleraspery (all seed plants) produce 2 different spores (from 2 sporangia) ⇒ a mega spore and a microspore. Mega spore produces a temale gametophyk the micro spare produces a male gametophyte. In seed plants, gymnosperms produce flowers. Seed plants have a reduced gametophyte which can be prokative; they have an ovule that containg the mega spove; they are l hekrosporous; they have pollen grains which don't require water hansport for fertilization;s they produce layers which entonces survival. a seed with many Gymnosperand have their seeds exposed on the sporophylls (on the leat): the food from the gametophyte helps the send growth. They're mostly found in day environments. supply Angie sperms make up 90% of all living plants. Thew stamen is the microsporangium; the ovary in the seed. carpel protects the s The seed's endosperm 15 3n because of double fertilization. The coupel will produce the female gametophyte pf the stamen will produce the male gametophyte Seads can be dispersed by anemochary (wind) or zooch ory (animals). Double kutilization A pollen grain contaning a tube cell and generative cell land on the stigma, the tube cell forms along structure down the style and into the ovary ineer the ovary, the generative cells divides and produces 2 haploid sperm cells; one sperm cell fertilizes the egg cell to produce a zygok and the other sperm cell fuses with both of the central nuclei in the ovary producing the 3n endosperm. decreased chances of self-fertilization in he krospery because bath gametophytes mature at diferent times less genetic diversity in self-fertilization. +