um and then with the angiosperm life cycle they're going to have alternation of generations as well as we've seen before so they're alternating between the sporify generation and the gapy Generation sporify generation of is of course dominant here um so let's go ahead and start with the uh mature flower on the sporify generation we are going to um talk about this more when we talk about plant reproduction um but within the flower we have male and female gtes um male going this way so um these are um the male structures here so we have the anthers and the microsporangia are going to be within the anthers and within the micros spranger we have meiosis and that is going to you produce the male gapy um the male ghy is going to be present in the pollen grain So within the pollen grain we're going to have um a generative cell and we're going to have a tube cell within the polling grain after meiosis um and so these pollen grains are going to be dispersed by pollinators um in the carpal this plant only has one um we have the ovary down here and within the ovary we have ovules and that's where we have the megas spanga um we have meiosis meiosis is going to produce the megasporangium and um we have the megaspore and um what's going to happen is that um we're going to in the OVU end up with the egg so the egg is going to be formed and then Center surround that um we don't really worry about those right now and then there are polar nuclei and antipodal cells so right now we want to focus on the Polar nuclei and the Egg um so pollen is going to be dispersed by pollinators and a pollen grain is going to land on the female a female portion of the flower called the stigma and then the pollen grain is going to germinate um and that forms a pollen tube within the pollen tube there are going to be two sperm um and the sperm are going to travel down through the pollen tube the pollen tube goes down through the style of the carpel down to the ovary where it's going to go to an ovil and that's what we're seeing here so we're seeing the pollen tube and we're seeing an ovil here and that pollen tube once it gets to the ovile the um remember we have two sperm there and one of them is going to um fertilize the egg the other is going to fertilize the polar nuclei that are within the ovile and so this is called double fertilization this is something that happens in angiosperms um with the double fertilization you get a zygote so when the egg is fertilized by a sperm cell you get a zygote a diploid zygote which is going to divide by mitosis in cokinis um and then when the polar nuclei get fertilized then you end up with something called triploid endosperm and the endosperm is going to be the food supply for the embryo so the zygote develops into the embryo um the fertilized polar nuclei depend develops into the endosperm which is the food supply and then eventually the seed will germinate and that germinating seed is going to um grow into this dominant sporify generation so the plants that we think of normally that is a sporify generation is dominant the gapy generations are going to be smaller um again we're getting smaller as evolution is occurring and so we have the male gapy ends up in the pollen and the female gy is going to end up in the OVU um so again we have monocots versus ticot um more traits that separate them monocots don't produce True Wood um examples of monocots include grasses and palms and they are herbaceous um uots can and do typically produce um True Wood this is Wood's going to form in the xylm portion of the plant and um they're going to have secondary growth grow so secondary growth is going to be separate from initial primary growth primary growth is growth in height secondary growth is going to be growth in width um and um this is going to give them expanding girth and it creates uh wood in these Woody plants and again wood is going to come from the xylm portion of the vascular Shure um when we look at our um plants we have two different parts we have the above ground part and below ground part the above ground part is going to be known as the um shoot system and um within the shoot system we have non-reproductive parts of the plant like leaves and stems and we also have um reproductive portions of the plants and um those are going to include flowers and fruits um the root system this is going to be the below ground part um the blow ground part is going to be responsible for absorbing um both water and minerals um for the plant and then the vascularized portions of the plant the B and the xylem are going to be responsible for getting the water um to all parts of the plant um different types of plant tissues um we have the epidermis the epidermis is going to be both on above ground parts and below ground Parts um so on the leaves and stems it's involved with gas exchange and on the below ground Parts The Roots it's going to be involved with water and and um ion uptake into the plant um the vascular tissues again we have the xylm and we've got the flum the xylm is going to carry the water and the ions from The Roots where those things are obtained um to the stems and the leaves and flum is going to take the sugars um from where they're made primarily in the leaves um those sugars made in the leaves through photosynthesis and the Flo's going to carry those dissolved sugars down to the roots um so that they can be stored um and then the ground tissues so ground tissues are going to be for metabolism storage and support um in the leaf we've got misail misail is where the uh chloroplast are going to be found and the chloroplast are where photosynthesis is going to be conducted um within the stem we've got ground tissues called pith and the cortex and that's going to be supportive to hold the plant upright and then in the root we call the ground tissue the cortex and this is where the carbohydrates are going to be stored so when we're looking at a plant we can describe different pieces and parts of the plant um nodes are going to be points of attachment for leaves um or some plants have aerial Roots like if you have Orchid plants you've seen um aerial roots and attachment points for flowers um the internodes are spaces on the stem between two adjacent nodes and a pedal is going to be this little Branch here that leads to a leaf or blade um we might see an axillary bud so an axillary bud would be for example right here um Within the axle so the axle is going to be if we have the stem here and we have the pedal here this angle here between them is the axle so if we have a bud right there that would be known as the axillary bud and that can give rise to a new Branch or flower um the apical Bud we don't see that here but the apical bud is going to be on the tip of the Chute and that contains the apical marem and the apical marem is going to have dividing cells that allow the plant to grow in height um so when we're looking at the epidermis um of the leaf we can see guard cells um so guard cells are going to be dermal tissue again found in the leaf epidermis and the guard cells are going to regulate the opening and closing of holes called stomata and the opening and closing of those these stomata regulate carbon dioxide uptake and loss of water um tricomes tricomes are going to be dermal tissue that are hairlike outgrowths from the epidermis um so these are like Leaf hairs um and then root hairs are going to be similar to troms but they are not going to be um on the leaves they're going or on the stems and leaves but root hairs are on the roots so these are hairlike extensions from the root epidermal and they help with water and nutrient uptake um so here we can see some stata again on either side um we have the guard cells that regulate the opening and closing of the stomata the cells surrounding the stomata are called epidermal cells and again the stomata need to be open at some point because um that is going to allow carbon dioxide into the leaves and carbon dioxide is necessary ingredient for photosynthesis to happen um downside um open stomata means water loss water can evaporate through the stom through the stomata um because of this most stomata are going to be on the undersides of leaves um it's not all that common that you'd have a high density of stomata on the to top side of a leaf because that would encourage lots of water loss so most tomata are on the under sides of leaves um in order to help to reduce water loss um so these are imprints of stomata that I've created myself um so we can see on the top we have corn um which is a monocot and on the bottom we have mint which is a ticot so we can see some differences in the epidermal cells and the abundance of the stomata here um so guard cells again are going to be on either side of the stomal opening and they change shape to open and close the stomata um as much as 90% of the water is lost through stamata so this is why they regulate the opening and closing um if they're not conducting photosynthesis so like at night um the stomata are closed the guard cells close the stomata and that helps to reduce water loss um and we're going to see we can see even from these images that um the density and size of stomata vary and that's one way a plant can regulate um the amount of water loss um by varying the number or density of stomata and the size of the stomata so how to guard cells change shape in order to um regulate the opening and closing of the stomata there are two states there's the flaccid state of the guard cells and with the flaccid state of the guard cells water is moving out of the guard cells so how does that happen it happens through transport of potassium potassium is transported out and then water follows because water is going to move toward the solutes where more solutes are so potassium moves out first and then the water follows water moves out of the guard cells they become flaccid and that's going to close the stomata so flaccid State the stomata are closed in the turgid state pottassium are transported into the guard cells and then again water is going to follow the potassium and so when the guard cells are full of water they're in their turgid State um they're firm and that is going to cause the stomata to open so it's just movement of water and ions that's going to regulate the opening and closing of stoat um leaves the lamina is going to be uh the widest part of the leaf blade and these blades are going to be attached to the stem of the plant through the pedal um in pedate plants so it's a pedate leaf then it's going to have the leaf and then it's going to have a pedal that's going to connect it to the stem there are also sessile leaves so if you have the stem and you have the leaf attached directly to the stem without a p pedal that's called a sessile Leaf um most leaves are going to have a mid rib which is a a larger vein that travels down the center and that mid rib May branch on either side um to produce additional veins of vascular tissue so when we talk about veins in a plant um that's where the vascular tissue is um flum and xylm so here we go we have have a pedite leaf here um pedals here mid rib here we have branching veins here that are going to contain the um flum and xylm and then along the edge we call the edge the margin so that's one thing that we're going to use to describe different types of leaves so one way we can describe leaves is by their Arrangement um on a stem so they can have an alternate Arrangement so they're not ATT ATT the stem directly across from each other um you see that that's alternate um they could be opposite where they are attached directly across from each other or they could be world so world would be they're all attached at the same essentially at same site but they are um attached going around the stem instead of just two at the same location we have several um attached to the same location and that's a world arrangement um we can also describe the margin so if it looks like it's serrated Like a Knife that's a serate margin um undulate is going to be kind of wavy uh LED so we have like kind of branches but there are um rounded branches or they can be entire so entire would be smooth a smooth margin or Edge um we can can describe vation so we saw parallel venation before when we talked about monocots um we can have pinat vein so mid rib and pin we have just these branches of the veins going in both directions from that mid rib um if it's palmately veined it's kind of net vein so we have a mid rib but we have kind of like for these different portions we have more of those mid ribs and then we have the veins emerging from that so we have essentially like one location here and we have several um of these major veins leaving from that one point and then smaller veins going from that so um that would be pmate vation and then simple versus compound so is it just one leaflet so this is one leaf here that's what the blade is there one leaf um and these other ones the leaves are going to be made up of multiple leaflets so this is palmately compound so they're this attachment point here and so the leaflets are all attached to this one point um and then we have the pedal in a compound leafit pinate um we have the pedal here and we have leaflets but they're not all attached to the same place so we have again multiple Le leaflets just not all attached to the same place and then we can have a doubly compound leaf so this is the pedal here this is a leaflet this is a leaflet and then within the leaflets we have more leaflets and these ones are pinate because they are going to be um across from each other um leaf structure we're looking at the epidermis the misail um the epidermis is going to be found on the top and bottom of the leaf usually just one cell layer thick um within the epidermis we have upper and lower epidermis we've got the misail um we're going to arrange this into Palisade misail and spongy misail at least when we're talking about uots in monocots they're not so well differentiated so Palisade misail is going to be the upper layer of um photosynthetic cells so Palisade misail is generally going to be arranged like this in a nice organized layer it's just below the epidermis the upper Leaf epidermis and we're going to have um chloroplast here to conduct photos synthesis and then below it we're going to have the spongy misail and it's called spongy misil because there are air spaces within it so it has it looks like it's l L organized than the Palisade misail we also have chloroplast here for photosynthesis um the air spaces do serve a function they're going to be the site for gas exchange remember if we look at the we have the lower epidermis we have stomata and that's where the carbon dioxide is going to enter um in aquatic plants um these air spaces are going to help the plant float so this is what a leaf looks like in Cross section in a ticot um we've got the upper epidermis and we've got the lower epidermis we've got the cuticle so the cuticle um on both epider um both epidermises we're going to have a cuticle that's waxy and that helps to limit water loss um it's something that happens when we're talking about land plants we don't want them to lose too much water so they're uh they've got a waxy cuticle and again upper epidermis and lower epidermis within the lower epidermis this is where we see the stata with the guard cells mainly um we can see the Palisade misail here with the chloroplast conducting photosynthesis we see the spongy maphil here again these cells have chloroplast as well for photosynthesis um and here we have a vein and within the vein we are going to have xylm um conducting water and we're going to have flum conducting sugars um within a monocot um we're going to have the same basic structures but um it's going to look a little bit different the arrangement is a little bit different so um in ticot we don't see the veins as much um because of the type of arrangement of the venation that we see in uh uots so uots are going to be pinning veined or palmately veined um whereas monocots have parallel vation so parallel vation is going to produce these regular vascular bundles or veins that we see um within the U monocots so the monocots Within These vascular bundles or veins they're going to have um xyum and they're also going to have flum um and these cells here these on the outside those are called bundle sheath cells um photosynthesis is going to take place there as well but we still have the upper cuticle and lower cuticle and we have the upper epidermis and lower epidermis um so here we can see guard cells and we see sto guard cells and a sto here um and then when we look at the misail all of this stuff in here is the misail we don't see differentiated Palisade misail from sponge misil it's just misil they are chloroplasts and this is where photosynthesis is going to take place um and then we have Leaf adaptations so Leaf adaptations are in different types of plants we're looking at carniverous plants here um so the parts that can consume insects to get additional nitrogen because these plants typically live in nitrogen pore soils um they can supplement their photosynthesis they still photosynthesis but they can supplement that by feeding on insects and so their traps are going to be modified leaves um so we have a venus fly trap here um and we have a pitcher plant here so these different traps are modified leaves that can help them to track trap insects and then that adds some nitrogen to their diet in this video I am going to be going over lecture eight um which covers plant reproduction and also the roots of a plant um so we are going to be mainly talking about the parts of the flower and how the parts of the flower are participating in reproduction um so again we've talked about alteration of generations before plants do have two distinct stages in their life cycle there's a gapy stage and there's a sporify stage so we've been talking about this throughout the evolution of plants and we said if we look look at the um nonvascular um plants that um they are going to have the gaboy as the dominant stage um and the sporify is um the Lesser stage but as we move to things like um vascular ferns which don't have seeds um vascular ferns are going to um have the sporify as the dominant Generation Um and then that continues so from the avascular nonseed plants on it's going to be the sporify that's the dominant generation and each time we go to a different group a newly evolved group we are going to see essentially that the Gap fights are getting smaller and smaller um so the giny again is the haid stage and the Gite produces the male and female gtes by mitosis um in these separate distinct multicellular structures then the fusion of the male and female gametes forms a diploid zygote which develops into the sporophyte um the diploid sporify is going to produce spores by meiosis um they divide by mitosis uh to produce the haid ghy once again and then the new ghy produces the gametes and the cycle continues so this is the alternation of generations we'll review this again later on in the lecture um this is part of it here um so we can see um we essentially have the male and the female so we see an egg over here so this is female we've got male over here and what happens is that um if you fuse together the sperm and the egg then you're going to get the zygote so um that zygote is going to develop into um the sporify generation and um within that sporify you are going to end up with the um micro sporify and the megas [Music] sporophytes so the is going to produce the micro gamify um and the micro gamy is going to give rise to the male gamt um on the other side we have the megas sporify with the megasporangium through meiosis you are going to get the mega gapy and the mega gapy is going to give rise to the female gamet um so again we're seeing alternation between the this diploid sporify generation and the hloy uh gofy Generation Um we go from haid back to diploid through U fertilization and we go from the sporify the diploid stage to the gapy the hpid stage through the process of meiosis so um the flowers are are going to house the gyes um within plants and the flowers are going to have different pieces and parts um the Petals of the flower are going to be modified leaves and they are essentially there to um help to attract pollinators um the SE um are usually green but not always um they could be uh colored similarly to the Petals of the flower but the seil are protective um and the receptacle is essentially where the female portion of the uh flower is going to sit on the stem um then the male and female parts uh the male part of the flower is called the stamman and the stam is made up of two different parts we have the anther um the anther is going to be the part that produces the pollen and we have the filament which is like a stalk that the anther is attached to um the female portion of the plant um here it's labeled as the carpal because there's only one carpal here there can be more than one carpal but we are going to refer to the female portion of the plant as the pistol um and it is going to consist of one or more carpal um here we can see that this pistol has three main parts we have the stigma um the stigma is important it's a sticky area and that's where where the pollen is going to stick um then we have the style we're going to see that a pollen tube grows down through the style and then down here we have the ovary and within the ovary there are um several ovules um and within the ovule that is where fertilization will take place during reproduction um so again flowers the petals are going to be modified um leaves um um and um we have the pedestal is going to be where the um flour is going to develop um the pedestal is going to form the receptacle um which I mentioned is where the flower is going to um sit here so the receptacle is going to start out um as the pedestal and the flower parts are arranged into circles called whls so we're going to talk about these different layers of whls that make up the flower so here we can see um again the female part we have the pistol the stigma the style and the um ovary and within the ovary we have the ovules in the male portion we have the stamman and the stam is made up of the the filament the stock and the anther and the anther is where we're going to have the microsporum that gives rise to the pollen that contain the male uh gimme so the flower whls there like I said there are different uh layers of whs the outermost whirl we can see them layered here that would be the seil uh usually green there for protection um then we have the second world which is going to include um the um petals so this dark blue color um and then the third world is going to include the stamans the male part of the flower um pollen is the male gapy and each staman is going to have the pollen bearing or the pollen making anther and the filament which is the stock that the uh anther is connected to and then the innermost whirl is going to be um the carpal so there can be one or more carpal in the plant and the caral are going to house the female gight so here we have a carple um we're going to see um this process of uh pollination and um pollen tube uh growth in a bit um but again the carpal um there is only one here there can be more than one um if uh more generally we would call the female portion of the flower the pistol um so this one carpal here is also known as the pistol um the pistol can have more than one carpal um and we see the ovary the ovary um is going to contain the ovul and the OVU is going to contain the mega gapy which is going to be um the female tissue um we've got stigma stigma is on the top the stigma is the sticky part that the pollen sticks to and then we have the style um the style is where the pollen tube is going to extend down into the ovary so that um it can get to an ovile for fertilization um so again the stam is the male part of the flower the anther is going to contain the pollen greens the filament holds it up um and pollen production um occurs in these anthers um it's going to be similar to the way that the female gapy is formed um in either case U meiosis is going to be involved in order to make the G fight um and the nuclei of the microspores undergo this process called mitosis and that's going to form these binucleate polling grains so the pollen grains are the male ghy and they're bleat so you can see here um we've got the pollen and we can see that we talk about being B nucleate we have the nucleus of the generative cell and we have the nucleus of the tube cell here so the the generative cell is going to be the sperm and the tube cell is going to produce the pollen tube in the stigma for sperm to travel to the egg so pollination um it's going to be the mechanical transfer of pollen from an anther male part to a stigma um this may or may not be followed by fertilization so we're going to talk about self incompatibility in a second so typically there's going to be crossbreeding and if you have uh male and female parts in the flower on the same plant it's not likely that the male pollen is going to fertilize the female portion of the plant on the same plant um they're usually not compatible with themselves and that prevents inbreeding because there are lots of problems that can occur when you have inbreeding um so may or may not be followed by fertilization once the pollen lands again it sticks there and the pollen lands it's going to grow a pollen tube and we can see in the image that pollen tube is going to grow down toward the ovary so it grows down through the style of the pistol and um it's going to be guided toward the um OVU um by pheromones so essentially plant hormones and the pollen tub is is going to enter the embryo sac via the micr pile so we can see that here so it's going to we see it growing down here and it's going to enter through the micro micop pile micro pile here um and we can also see that when um the pollen generating we do have two sperm here and those two sperm are going to be in important um for fertilization so um one of the two pollen grein cells is going to lag a bit behind um and the generative cell is going to divide um to produce two sperm cells so again we have one um when we have this um the cell goes through mitosis we have the tube cell nucleus and we have the generative cell um nucle nuus so the tube cell is going to be responsible for um making the pollen tube and the generative cell um that's where we're going to get these two sperm cells from and these sperm are not going to have flagella on them U but we have the two sperm here and they are moving down through the pollen tube um through the style of the flower and again pollen's generally not going to germinate if genetically similar individuals um breed with each other so especially on the same plant so we can see here this is the um genotype of this plant and so those are the alal S1 and S2 are the alals and so we can see that if pollen with S3 and S4 alals land on there they're going to they're going to germinate and fertilization is permitted to happen um here we have S1 and S3 s1's not going to work because that is the same as what this plant has but S3 will and here if it's the same plant if we're trying for self fertilization the it's not going to work the pollen's not going to germinate um because they match so if they match they're going to be self incompatible um some different ways that PO ation can occur um insects um and this is going to involve the shape of the flower suiting the pollinator um you might have flat flowers from moths um you could have uh deeper flowers that bees can crawl into um for insects also they can see UV light so on the Petals of the flower there are likely designs on those petals that we can't see but the bees can and that attracts them as pollinators in addition to nectar and pollen um bats um flowers are usually very large and bright so they're visible at night because that's when bats are usually out and about um uh Birds uh plants usually have to be sturdier than those that are uh pollinated by insects because birds are heavier and and birds are usually um separated from Birds sorry flowers are usually separated from other flowers um if they're pollinated by birds and they are bright and they are odorless so for example you might have a trumpet-shaped flower that's red that is usually going to attract hummingbirds so different colors for different birds different shapes um to match with their beak or their piscus um wind um some angiosperms still can use wind for pollination but wind is mostly what you see um with the uh gymnos sperms and then water um can still contribute again secondarily um for grasses and things like that um but water is primarily used for things like Ferns and mosses um Club mosses um things like that um double fertilization so when fertilization happens um there's going to be two um rounds of fertilization so we can see again the pollen grain lands on the stigma the pollen tube um forms and that pollen tube is attracted to the aules down here because of ferons um and there are two sperm cells there and so we're going to have double fertilization fertilization two times um so it ends or it enters the ovile through the micropile and then we have the two sperms uh sperm cells and they are going to fertilize the egg and then also within the ovil there are these things called polar nuclei and um the other sperm cells going to fertilize the polar nuclei um the synergids and the antipodal cells um they're not involved in this process process of fertilization so what happens what do we make um as a plant the plant is going to make a diploid zygote there and the um fertilized polar nuclei that's going to make the triploid endosperm so we can see that the polar nuclei already had two nuclei here and we have a third one with the sperm so they are going to be 3 n they have three copies of each chromosome they are triploid and the endosperm is actually going to be found in the seed along with the embryo that forms and the endosperm is going to be the nutrition that's what the embryo is going to feed on while in the seed so I said we come back to the alteration of generations and the life cycle of an angiosperm now that we've talked about these pieces and parts a little bit more so we can start with the flower itself um so this is on the sporify plant the sporify is the dominant generation and um again we have the male and female parts of the flower which are separated out here so the male part we have the stamman and that consists of the anther and the filament um the anther is where we have the uh microsporangium and the microsporocytes at this point they're diploid but we switch from the diploid state to the haid state with meiosis um and that forms the microspores they go through mitosis and that's what gives us the generative cell um which will eventually form the sperm cells and we have the tube cell which will form the pollen tube um then in the female we have the ovary and within the ovary there are the ovules that have the megasporangium in them the mega sporangium is going to go through meiosis and that's going to take it from diploid to haid um and um in eventually as um the um this matures um the ovule that we're looking at here is going to have two polar nuclei in it and an egg cell um that egg cell is haid and um fertilization if it happens s is going to happen here so it's going to go through that micropile and the pollen tube is going to deliver the two sperm cells into the ovule so here we can see um pollination the pollen from the male portion of a plant is going to be dispersed and it's going to land on um the stigma here the sticky part and that's going to make the pollen tube and and um so again that's going to use the tube cell that was in the male gapy in the pollen green um and then the generative cell um is going to divide and produce two separate sperm and those sperm are going to travel through the pollen tube and style of the plant and these two sperm are going to enter the ovile through the micropile one sperm cell is going to fertilize the egg to make the zygote so that's fertilization there um and the other sperm nucleus is going to fertilize the two poar nuclei um which is going to make the triploid endosperm so fertilization is going to be the process that takes us from the um gapy Generation Um with the gtes uh haid gametes to the diploid sporify generation so um in our diploid sporify generation we have our zygote which is diploid and we have the endosperm which is triploid and that's going to serve as nutrition so what's going to happen is that the seed is going to form around this um so you can see the seed coat here forming and so the embryo can be dormant for a while until conditions are good once the conditions are good um you essentially need a certain amount of oxygen and water to get germination happen um ger once germination happens then you get um the sporify generation what we're used to seeing as a flowering plant that is the sporify generation so seeds um are a major adaptation for land plants because they allow dormy um and they can allow plants to occupy um various environments so um in angiosperms embryo development is stopped um after the meristems and the calans differentiate calans are going to be embryonic leaves um and what's going to happen is that the integuments around the OVU are going to produce the seed coat and that's going to enclose the seed and its dormant embryo and the stored food the endosperm and that can remain like that for years and they germinate when conditions are more favorable so again seeds are an important adaptation they maintain dorcy when conditions are unfavorable they protect the young plant when they're most vulnerable they provide food for the embryo until it can produce its own and they facilitate the dispersal of the embrio um how do they um facilitate the dispersal of the embryo um they are going to usually be uh surrounded by a fruit um so fruits are going to form in these angiosperm plants as well and these fruits contain the seeds and so animals might be interested in eating these fruits and then they can help to disperse these seeds away from the parent plant we don't want a bunch of seeds in the area where the parent plant is because they're very genetically similar um we're not too worried about in breeding initially but because they're very very similar they have very similar needs so they'd be in direct competition with each other and so to eliminate that seed dispersal is an important uh feature uh for angiosperms um so once the seed coat forms um then most of the embryonic activities of the embryo are going to stop and germination again can't take place until a certain amount of water is present and a certain amount of oxygen is present um some seeds have been known to remain dormant for thousands of years so with some seeds um specific adaptations are going to be needed to ensure that um the uh seeds only germinate under Pro under appropriate conditions so we don't want them germinating just any time so um for example we have these cones here um and some there we have seeds inside of them they are going to remain inside of these tough cones um until these cones are assoc they um exposed to fire um fires are pretty common they go through the forest periodically um it's can be a natural thing sometimes people make mistakes and they accidentally sent that but they accidentally sent set them um but here we can see that it's actually important for their life cycle um these cones won't open up and release the seeds until they've been exposed to fire so I said fruits fruits are something that angiosperms form so fruits are going to develop from the ovary um the OVU turns into the seed the embryo inside and the ovary turns into the fruit and um fruits may or may not be edible but a fruit will be formed um and it is possible um for fruits to develop without seed development um and um because of this uh bananas can be uh propagated asexually um so this is a fruit um a good example of a fruit and we can see that um there are different layers here um so we have the um seed in the center um seed can be within a pit so here we can see the seeds it's in a pit um the seed itself is here and within the seed you have the embryo you've got the triploid endosperm and then you've got the seed coat that's all associated with the seed then outside of that seed in this case you have a pit um because this is a type of fruit called a droop it's got a hard pit in the center um but when we're naming the different layers of the fruit we can start from the outside we have the pericarp and then we have the misoc carp here and we have the endocarp here so those are the three layers um um of the fruit um asexual reproduction can happen in a number of ways in Plants we're just going to look at stolin here a stolen is also known as a runner um if you've had strawberry plants You' probably seen these before um but what happens is that these plants can um add their nodes they can form adventitious Roots um so you can see here we have our uh stolen our runner and that's going to grow and then um at the node here where we have a bud then um where that's attached to the ground then roots are going to grow and those roots are going to help to form a new separate plant but it's not really separate because it's still connected through this uh stolen or Runner um seed German um so we've talked a bit about monocots versus uots um monocots are going to use hypogeal germination and uots are going to use epigeal germination so what's the difference between them so um we've looked at seeds before in the embryos um so here some of the different pieces and parts that we're going to be looking for um here we have the root marem this is going to be part of the embryo called a r iCal that's going to be where the root um develops from and we have this region here it's called the hypo codal why would we call it that because it is below the calans um the calans or embryonic leaves are right here um and then this uh this is actually the shoot Mar stem is right here and this is how the plant's going to eventually grow in height so um here at the top again hypogeal germination we see this in corn um peas things like that um the seed starts germinating and what you get is you get the radicals going to emerge and the hypoc codal which remember is going to be rap below the calans um in hypogeo germination though um what we're going to see is that the epical um is going to grow and that epical is going to emerge above the surface of the soil um hypogeal plants um are different from other plants because um the epical is going to grow and um when we see this the embryonic leaves the Calin um there's only one codin in a monoc CAU but that Calon is going to remain um underground so this epical here is going to grow um but the um calans or Calon atam monot is going to remain underground um we see this emerging up here because of the growth of the epical um and then we can see the first leaves of the plant um and it continues to grow and develop the radical of course becomes the root um and here we can see the Calin is going to remain underground with epig germination we've got the seed the radical here um is going to become the root that's going to go down um the hypoc codal here is going to be the area below the codal edance is where it gets its name um but here we can see that it's going to be the hypoc cotal rather than the epical that grows the growth of the hypoc cotal is going going to push the calans up over the surface of the soil the calans are exposed um here these are the calans um it's also where the endosperm is um and the plant continues to grow the codal over time wither and then they're going to fall off but epigeal the calans actually make an appearance above ground with hypogeal germination the calans remain Underground um some different types of root systems um Tap Root system versus fibrous we saw this when we saw we did a comparison of ticot versus monocots before um so Tap Root system is going to have a main root that grows down that's going to help to um make sure that that plant is firmly attached to the soil um it's going to be difficult to pull that plant out um sometimes tap roots are also going to be modified for um food storage um yeah so these can go very very deep um and they are going to make it hard it's going to make hard to pull the plant out of the soil it's going to be a good anchor for that plant um the fibrous root system we have many small Roots usually over a large um area and that's going to help um with things like uh water absorption um and those fibrous Roots can also help to prevent erosion of the soil all right so talking about the roots um so we're going to talk about the epidermis of the roots um the epidermis is going to be the outermost layer and it's a single layer of cells that's going to help to protect the plant from diseases that could come from the soil and it's also going to help um absorb water and nutrients um root hairs are going to be tiny little extensions from these epidermal cells and they are going to increase surface area and increase surface area means that you're going to have more water and nutrient absorption just like we saw before with animals we saw microvilli and Villi increasing surface area and um with that um small intestine for example could achieve greater amounts of absorption of nutrients um this is what a root looks like there are different zones or areas within the root uh again a logitudinal view um so we have the area of cell division at the tip we have the area of elongation and we have the area of maturation um the area of cell division is going to include the root apical marem and that's where we're going to have a lot of cells that are dividing by MIT is and cyto canis so here we're going to look at two different Roots we're going to look at a ticot root and a monocot root and we're going to talk about um later on how water is absor is absorbed um so here in our uot root what we want to look for to recognize this as a ticot roote is the cross so we've mentioned before that we have flum and xylm and those are vascular tissu um they're going to be found in this center part of the root called the steel so the steel is going to start with this pericycle so pericycle I'm highlighting it's a light gray um that's the pericycle that's going to be inside of the steel um so here we can see labeled so the steel is the center part and that's going the first layer of that going to be the pericycle out outside of the steel we have another layer called the endodermis and then outside of that we've got the cortex outside of that we have the epidermis with the root hairs um so how do we identify this as a ticot um rout we look for the cross so the vascular tissue in the center um inside of the Ste um we can see that there's a cross made out of the xylem and then here kind of like in the corners this is where we're going to have flum so if you see that Arrangement then you know that you are looking at a ticot route um outside of that again we have the um we'll do the endodermis again we've got the cortex and we've got the epidermis and within the epidermis we have root hairs and root hairs are going to increase surface area for absorption of water and minerals um here we can also see um these things called casparian strips so casparian strips are going to be present in the endodermis so this darker gray area here and casparian strips are important because they essentially help to ensure that only things that the plant wants to enter um are actually entering through the roots uh because the casparian strips are going to prevent water from going between cells or anything being absorbed between cells um in order to get through the endodermis um everything that's moving again into the steel has to pass through the cells themselves and so that kind of transports regulated and so plants can regulate what they want to get into um The Roots um here we have a monocot and we don't see we still have a steel so again that's going to start with the Parry cycle um the steel in the center we don't see a cross shape what we see we see xylem um in a ring structure so xylm vessels here they're large um they're going to be in a ring configuration and then in between there we've got the FL um this center part um we would call this the pith and then again we have the pericycle is the first layer of the steel outside of the pericycle you have the endodermis that's outside of the steel and then we have the cortex and then the epidermis with the root hairs so again the endodermis this is going to be the innermost layer of the cortex so this is right before the we get to the steel um the endodermis is going to have the casparian strips and these are water impermeable um they're waxy um and they are going to force water and solutes to cross through plasma membranes um rather than going between cells the casparian strips prevent anything from going between cells and again like I said this ensures that only materials that are required by the root um actually get through the endodermis and into the steel so anything that's pathogenic should be excluded and not be permitted through so here we can see water transport into Roots this is important this is how the plant gets the water that it needs in order to conduct photosynthesis um and then minerals are also taken up this way um so here we see two different routes um we'll talk about the apoplastic route and we have the Sim plastic route um with the SIM plastic route um the water and minerals will travel from cell to cell um so we're transporting water minerals through something called the simp plast which is just a cytoplasm um essentially these cells are linked together the cytoplasm of different plant cells are linked together by plasmo desada so there cell Junctions but that allows these cells to be continuous with each other um so that continuous area where we have cells is called the simp plast so that's where this um type of water transport is going to travel through simp plastic route is going to travel through the implast um where the cytoplasm of all these different cells um are joined and so this is going to allow the water and the minerals to get through the endodermis um because we're already we're not trying to get between cells if we Tred to get between cells there might be an issue because of the casparian strips but here we're going through cells in into the um endodermis so getting through um the endodermis and the pericycle into um the center of the root so it can get to the xylem once they get to the xylem the xylem can move it up to uh where it needs to be used um the other option is the apoplastic route so with the apoplastic route the water is going to go between cells um and through cell walls um on its way into the steel so it's going to diffuse along these cell walls as it goes through the root um cortex and then it hits the Caspar strip so that's where I stopped here um that's the waxy barrier um and that's going to force anything in the aplast across the cell membrane for filtration before it goes um through to the steel so even if this is like a legit pathway for water to be absorbed once it hits the endodermis and it hits the casparian strips then it has to take a slightly different route and it has to go into the cells and uh diffuse into um the center the steel where we have the xylm and the xylm will transport the water and minerals to the leaves where it's needed for photosynthesis um and some root modifications so some Roots again they grow underground but they are going to be used for starch storage so carrots carrots are modified roots um things like turnips and beets um are going to be modified Roots as well um um here we have aerial roots and we have prop Roots so prop roots are going to emerge from the stem and prop roots are going to prop the plant up so this is what happens in corn so corn has roots underground but in order to stabilize the corn plants um their stem can send out these offshoots and that creates um a stability for the plant um here again we have another example of that here we have an example of aerial Roots so aerial Roots we see here on this Orchid orchids usually grow on other plants um and so the arrow roots are going to help them um to deal with that different type of Lifestyle the aerial roots are also going to help with things like um photosynthesis they can be photosynthetic so they are used to grab on of a substrate they also could potentially be photosynthetic and lead to the creation of sugars