ConservatoryTourPacket

ConservatoryTourPacket - ,5 2; Background Information for...

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Unformatted text preview: ,5 2; Background Information for Greenhouse Tours 05-06 oHelp the students think, synthesize, develop, and apply principles to real organisms. This exercise will help them in the final and life in general. Your function is to provide activation energy and reaction pathway by asking questions modeling analytical informed judgment and delight with plants. Avoid lecturing as possible. 0Relate your questions to themes: Eg; How does a typical plant function using "normal" organs. What "unusual" morphological modification} strategies may be adaptive responses to dearth of water, light, or pollinators, or plethora of herbivores... using epip ytes, xyerophytes...as examples. it's also easy to reinforce structure and life-cycle differences of different divisions, bryophyte to angiosperm, using specimens here. ust inside front door of rcenhouse; 1. You can review palmate;l pinnate leaves with Scliefflcm and Lace. Schefi‘lers, on the left as you en ter, is palmeter compound, while Lees, directly opposite, is three times pinnately compound. 2. Also on the left is Cliorisia (Bornbacaceae), a 30. American tree with palmate leaves, a green trunk, and thorns that undergo secondary growth on the stem. Under stress this tree loses its leaves, leaving the trunk the sole source of photosynthate. Above the door and on the left are specimens of staghorn ferns. These produce two types of leaves: Lueld leaves protect the roots and and debris in a kind of basin, while the other leaves_a_re photosynthetic andprodiice sporangia. NBEthat the fertile portion of the leaf is diligent in different species. —'[‘here are two large specimens above the door as you enter the main room. 4. Note the plants from the family Marantaceae on both sides of the aisle. In Calufhea, the top of the leaf has a pattern of light and dark portions which makes the leaf appear like a divided fern frond or cycad 1ea[,rathcr than a single large leaf. Other Marantaceae here do similar things. These plants are found on the floor of relatively open tropical forests. Perhaps these patterns fool potential predators? Also, the red bottom side of the leaf of many of the Marantas and Begonias which grow in low light situations may be a low energy speclrLun reflector to send the small amount of light getting through the leaf back up for another chance to be absorbed. 5. Dt'cfienbacliiu and most other tropical Araceae have distinctive drip tips on the leaf. These, when c0mbined with a waxy cuticle, Channel water off the leaf. Why? Perhaps to keep the leaf as dry as possible so epiphytes don‘t grow on it and intercept some of the light. Or, leaching of nutrients [a scarce resource in the rain forest) may be minimized. Further down the hallway, past the first pair of doors: 1. This display consists mainly of epiphytes, including orchids, bromeliads, and ferns. Epiphytcs are an important component of tropical forests. They do not usually harm their host unless they get so dense that they shade it out. N—fixing ability of some epiphytic lichen brmsts forest nutrient status. Because the epiphyte‘s roots do not touch the soil, they have many adaptations for acquiring water and nutrients. Ask the students if they can see any in the -—-— nts around them. ote the s anish moss (‘l ‘illamlsial, which is a bromeliad and not a moss. It has multicellular scales on the leaf surface that open and absorb water when it is available (rain, dew, or RH. Jul fins-r" 360%), and close to prohibit its loss when dry. Also, the scales are highly reflective when dry and translucent when wet. 3.0m the left is Kliipsalis. It is an epiphytic cactus, the only cactus that occurs naturally in Africa. (The rest of the cactus family, Cactaceae, is New World exclusively). The white bem‘es are eaten by birds, which dispense the seeds in their droppings. How did this plant get to Africa? (It flew) Why are there no spines on this cactus? 4. Myrmemdia. On the right is a short, sturnpyr plant growing on a piece of bark. Looking ._ closely at the base of the trunk, you will see a few scattered openings. This plant constructs " the openings and associated interior cavities to make a home for These ants make their nests inside the plant. We will see another example of a plant providing a domicile for ants in Arabia, and you can ask the students now why it might be advantageous to the plant to have insect-eating ants living in it. (herbivore defense) But there's more to the story. This plant forms two kinds of chambers, both smooth and rough—walled. The ants live in the smooth ones and use the rough ones as garbage dumps. Experiments with radioacti vc tracers have shown that the plant is able to absorb nutrients from the decomposing insect material dumped in to the rough chambers. Room I). First desert room, located to the right asyou enter the greenhouse. What are the plants in this room adapted for? DroughL, But in some cases it is pl] sitiilogical drought, as in the seaeoast plant Ecliweria (Crassulaceae), which has to cope with—sélififioils. Sempernivnm is a inontane plant: (from the Alps), where water is frozen and unavailable to the plant for much of the year. Bench Dll low does succulence relate to drought tolerance? At least three ways: water tool) Note Pereskai, a primitive cactus with leaves. It is hanging above the center bench (B4) Note any open flowers of Seneo'e (a composite), and various cacti, Apoeynaceae, and Moraceae. Adaptations: 2. Reflective hairs. These reflect sunlight, lowering leaf temperature to keep the plant from overheating or having to use water to cool itself through evapotransporation. Take a white, to my leaf of Sangria liewm'thii and tear it in half to show how heavily it is clothed with trichornes. Bench D3. ,. ’ 2,34,19mi 3. Windows in leaves. See Seiiccio i'ouileymiiis (string of pearls) and Fenestmriri. Light enters the windows and strikes chloroplasts in the chamber. This is a mechanism for reducing Water loss. Break off a leaf of Fensstrm'ia and look up through it to see the window ("fenestra" is the Latin word for window). 4. Mimicry. l .itliops plants mimic rocks in appearance, probably to lower predation. Bench D4 5. Contractile roots pull Lithops individuals below ground during unfavorable times. This hides them from predators and reduces water loss. Some Lithops species have been declared endangered because they could not be found in the Wild, only to have them popping up from the ground after a rain. Bench D4 6. Leaves (normal-looking ones) are often the throw—away type, being produced only after rain and being shed when things get dry again. Fouqiiieria species have leaves on the main stem which leave part of their petiole behind when they abscise. The abscission layer is oriented so as to leave a long, pointed piece of the petiole (a spine) behind. Bench D2 7. Drought escape: Dioscorea,a member of the true yarn family, during the dry season looks like a wooden tortoise which sprouts riotous flimsy vines during the rainy season. This genus also contains species that are the source of saponins that quickly and easily are converted to progesterone used in birth control pills. Though no one has demonstrated the conversion happening in the field, if it happens, the plant could suppress the fecundity of herbivores regularly feeding on its storage tissue. Room C. The second desert roomI second door on the right. This could be called the corivergenee roorn, When you come in ask the students what kind of plants these are. Hopefully they will say, "Cacti". Then you can tell them there is only one plant in Caetaceae in the room (have them guess which one). It turns out that the plant in the hanging pot to the north of the door is the only cactus here. The rest are in other families that live in similarly hot, dry areas of the world. 1. Benches C2, C3, and ()1 are plants from the Euphorbiaeeae. Berich C5 has members of Didieriaceae, which are from the island of Madagascar. Bench Cl and the top of C7 have Asclepiadaceae (Slapclias and related carrion—tlowers), with 1/2 of C4 and the top of C7 being Ccropegin, a viney—sternmed asclepiad. Benches C6 and the bottom of C7 have Agavac'eae and l .i liaceae (monocots) 2. Note the Welwitscliia plants (may have cones). Ask which division these are in. There is a pot of Ephedm and Gaston: branch on £16 it you want to review One-tales here. 3. The Stapelia and closely related plants located here have flowers that attract carrion flies (C1). If any are blooming, note the color and smell. Ask what would pollinate them. (Their odor is strongest when it is hot and bright.) Room A. First room on the left as you enter the greenhouse. Spend a brief amount of time here reviewing the tern life cycle. Look for gametophytes growing in the pots or in the peat under the boards supporting the ferns. Note the variations in sori and indusia. If ti me is short, this stop can be eliminated, and the ferns covered in Room B. Room B. Second room on the left I 1. Now is the time to review the lower vascular plants and bryophytes. See Psrlotum, E qr: i'sctiim, and myriads of Selaginella plants. Cover life cycles and anatomy, where important. There are also various ferns here. B4 2. lnsectivorous plants. The venue fly—traps (Diaries) have active trap leaves. Since any one trap can close a maximum of 4-7 times, limit the leaf—closing demo to one or two leaves. Trumpet pitcher plants (Snrmcem‘a) have downward—pointing hairs and secrete a narcotic substance in the pitchers to keep the victims from escaping. If there is a Lrumpet pitcher leaf sitting in a flask, slit it longitudinally to show the waxy slick region followed by the secretory digesting region with insect bodies at the bottom. Pass around hanging pitcher plant [Nepenthesl pitchers. Sundews (Drosem) have sticky glands on the leaves. Have students touch them. Butterworts (Piriguicule) have somewhat slimy leaves. Note the gnals trapped on the surface. What conditions are favorable for inseeli vorous plants? Low nutrients, particularly nitrogen and phosphorous. Why are they not found in habitats that do not have nutrient deficiencies? Because the cost of their insect—capturing devices keep them from being effective competitors when normal levels of nutrients are available. 3. Note the orchids. Remind the students the pouch lip on the llower is to iorce pollination rather than for trapping and eating. Main room. Plants here are listed by their bench number. 23,22. Cycads. Review cycad features. A large female Stnngerr'a_with a strobilus you can look at (please do not tear it apart) is located at the south end of the main greenhouse walkway. Given that the collection has no male plant, do your students think the seeds inside could be planted to produce new plants? There will be male and female and male strobili from other cycad species to open and see Ovules and inicrosporangia. Mention the flagellated 51381111. 23. Grretmrr is the large plant at the center of the bench. What features does this plant share with the angiosperrns? 21. Fascias at far end of bench. The pollen is held together by viscid threads to aid dispersal by hummingbirds. Also note Begoi'tias with unisexual edible flowers (very sour to discourage herbivores?) 5,6,19,20. Climbing the tree on 2D is the Vanilla orchid. The Fruit is the source of vanilla flavoring. Besides the green developing pods, there will be a mature vanilla pod to smell. (it smells great.) Beside it is an Orchid pod with normal orchid seeds you can blow around to demonstrate just how small they are. Because orchids are epiphytes, it is important for their seeds to be lodged in the upper portions of the tree canopy. The seeds have waxy extrusions that help them float through the air, and their small size (there may be millions per fruit) also contributes. One way they achieve such small size is by the lack of endi')sperm, which also reduces their longevity. They require mycorrhizal fungi to be successfully established after germination. But just one established plant out of hundreds of millions of seeds released will maintain a stable population. Many orchids are heavily dependent on specific groups of pollinating insects. In nature, the major barrier to cross breeding is pollinator behavior. In the greenhouse, it is often easy to hybridize species and even genera, clue to the lack of other barriers against hybridization. One of these other barriers, abnormal endosperm development, does not exist for orchids because they do not form endosperm. Because of the importance of specific pollinators in the life cycle, there is great selective pressure on individuals in populations isolated from the usual pollinator. Variations better- exploiting new pollinators are strongly favored, leading to rapid changes in floral structure. This factor, along with the tremendous habitat diversity available for tropical epiphytefi, accounts for orchids being the largest family of angiosperms. Some authorities cite 735 genera and 320,000 species. 5. Arigiopteris. Look at me size of the frond in this fern! 17,18. Dischidia, in the Asdepiadaceae (milkweed family). The leaves are folded into pouches that hold water and ant nests with their nutrient—rt ch debris. Look at the leaf that has been opened to reveal the adventitious root that grows into the leaf to mine the water and nutrients trapped in the leaves. 17. chs (fig) This is a good pollination story and also serves to illustrate fruit classification and an unusual inflorescence. 7,8. These benches have a good display of bromeliads and African violets. Many genera of bromeliads have short stems and lea ves that form a pitcher-like rosette. This structure partially fills with water, and may contain little communities of insects, amphibians, and other animals, Four out some of the water from a "tank" to give them a graphic example of the amount of water they can hold. What would be the advantage to the bromeliad to have these tanks and the ability to absorb water through their leaf bases? 6. Coconut here illustrates water borne fruit dispersal; Cocklebur, hitch hiking syndrome; cotton, wind dispersed; Luffa, shaker-seed dispersal, Chocolate seeds illustrate bitter seed in sweet pulp strategy, and CTOSSflHdP‘fl fruits. The capsules of this member of the Acanthaceae will when wetted explosively disperse seeds for distances of up to ten feet. Place several capsules from the supply in the petri dish in a student's hand and spray it using the nearby spray bottle. 15. Gathers (Compositae). This is a good chance to review the concept of an inflorescence. 'l‘he ray flowers are unisexual female, and in the disk flowers, stamens emerge first, then drop as the stigma emerges, developing only several concentric rows at a time to force many separate visits for diverse gene exchange and limited opportunity loss if wind or rain stop pollinator visi IHomeclarinimr (tapeworm plant) Start students analyzing what is leaf and what is stern and w 1y. @ Acacia. At the end of the bench is a bullhorn acacia. Ants live in the hollow stipular thorns in the. wild (note the thorns sound hollow when you tap them.). Also the plant provides rotcin rich yellow "Beltian Bodies" and nectar-on Hawk exchange the ants protect the slow-growing tree from herbivores. They also destroy any competing vegetation in the irrunediate area. Abortion flowers on the west end of the bench make an easy introduction to standard flower structure and pollination strategies. 10. There are some Araceae here with strangely constructed leaves. Challenge students to figure out what is a leaf and then try to describe it. Since it is an atypical monocot, this is a good place to review traits separating monocots and dicots. 11. L‘ofi‘ea (Rubiaceae) is located on this bench. Seeds of this plant are used to make the vile, brownish liquid which is drunk ceremoni ou sly by many North Americans. Mimosa. Touch or blow on the plants and they close. What could be benefits of this movement when being grazed or when a hot, dry wind is blowing? 13. Acalypha. Note the feathery red stigmas. This inflorescence looks a lot like that of bottle brush, where the stamens are red and feathery. What might pollinate the Acalyplie? (wind) Why is it red? (perhaps to keep cool so can be kept receptive and sticky with less water loss by reflecting heat—producing red and infrared light) For those starting in the main room instead of the hall, you can begin at bench 10 with examples of unusual photosynthetic organs, the massive Ariiorphophallus leaf, flat Hemocladium stems, and, if present, M fcmcorl is, the leafless orchid; plant defenses with the smelly furry Pelargonium, playing—dead Mimosa, and the ant-protected Acacia; and floral diversity using an Abutilon flower as typical, then Gathers and Acefyplm. Finally, there are various fruit here illustrating strategies of seed dispersal including the popping Crossenrire capsules. 1n the orchid area, bromeliads and the Discliidia nearby are good plants to introduce the epiphyte stra tegi es for survival. Then you can discuss the Orchid 's very effective reproductive and structural adaptations. The Gnrtum on bench 23 and the staghorns above the entry door can be noted. Then notes from room 13, C, D, and the hall will apply. Intern Cheat Sheet, David Schmale, l U99 1. Moneeots vs. Dicuts Scattered Vascular Bundles Flowers are in 3’3 One cotyledon! Parallel Venation of Leaves usually Fibrous root system Dieols: Vascular Bundles are in a central vascular cylinder Secondary growth in woody taxa Flowers parts in multiples ol'4’s and 5’s Netted Variation of leaves usually Two cotyledons! Often tap root system 2. Flowers {Angiospermsy Receptacle, Sepals, Petals, Stamens, and Carpels The receptacle is a modified stern holding the base of the flower Sepals are often green and usually enclose the flower parts within the bud 'l‘he petals are usually colored and used for attractive purposes (for insect pollinators and for our eyes to enjoy!) Stamens are composed of a filament (stalk) and an anther, which bears pollen Carpels are modified leaves that cover and pro teet the ovulcs. They are composed of three parts: 1. Stigma —- at the very tip where the pollen lands and germinates ’2. Style -- a stalk supporting the stigma 3. The ovary that contains the ovules ' Inferior ovaries are below the sepals, and superior ovaries are above them!! Which insects pollinate red daisies? Butterflies!!! (small tubular, landing platform, (if yellow, red, white, blue, bees would too but they aren’t attracted to red) Remember these are inflorescenees...many flowers contained in one structure! Co—operation between many flowers to help each other get pollinated 3. Leaf modifications This is a great category to test their knowledge on adaptive characteristics: Remember the story about the modified leaves of Dischfdia rajj‘i’esiann... The swollen leaves hold water and ants live inside some of the dry ones. The ant debris furnishes fertilizer for the plants and the C02 the ants release provide up to 40% ofthe plants (302!!! Amorphophuilus titanum is another great one... Remember that the entire structure is a leaf and the stem is modified (a corm) underground!!! Here is a good chance to talk about stem modifications... tubers, corms, etc. The Acacia has thorns which are modified stipulcs. Remember, ants live inside the thorns and harvest the high protein complexes (beltian bodies) on the edges of the leaves...in return protect the tree from herbivores and competition Minds 1 out of 10 plant species is an orchid! Vanilla is an orchid!!! Most have numerous tiny seed Remember the cool pollination mechanism involving the polleniurn... 5. Bryophytes- No vascular svstcm!!! Antheridium (sperm) and archegonium (eggs) Liverworts, Hornworts, and Mosses (iametophyte is feeding photosynthetic body (In), sporophyte (2n) Swimming sperm!!! 6. Lower Vascular Plants: Vascular tissue, reproducerdispersal by spores, fertilization by swimming 5 erm. -ij’silophyta —— the most “primitive” vascular plants!!! No leaves, roots. Dichotomous branching but has vascular ti ssuei -Sghenophyta —— the horsetails, complex branching and stroboli, true roots and leaves -Pteroghyta -- ferns (Homosporous (except some weird water ferns)) The only seedless vascular plants with maerophylls (leaves with branched complex vascular system) Sporangia are grouped in clusters called sori sometimes covered by indusium Remember that ferns are a “sight for soriI” iycophyl -- don’t forget our favorite Selaginella! Heterosporous...advantages? A step toward seeds? Microspore and megaspore Megaspore stores food for zygote Ask why certain modifications exist: Hair on tip. thorns, spherical shape, eylind rical shape, sunken stomata, etc. If not thorny. often contain toxins to hinder animals from gettingI stored water 3. Whoops2 don’t foraet vanosgerms... Cyeadophyta, Ginkgophyta‘ Conil'erophyta, and Gnetophyta— (Grieturn. Ephedra, Welwitschia—posess many angiosperm traits). Ovulc contains megasporangium; pollination is without swimming except inside ovule of Girlkgos and Cycads, Pollen is immature microgametophyte moved by biotic agents or wind! In (jymnosperms. Seeds are formed on the surface ofseales, or in the ease of Cy'cails, modified leaves (megasporophylls), in Angiosperms, seeds formed in ovaries, ripened ovary is Fruit, fruit formed From other than ovary wall is an accessory fruit, fit] it from many flowers is a multiple fruit, An aggregate fruit is formed from multiple carpals ot‘singlc t‘lowcr Other notes that need to be incorporated ; Make sure to mention the items marked with the " Crowd control: announce last person in group close doors behind them have them crowd in close so all can see shorter people in front Faint avoidance: Be vigilant and proactive it you see someone start to fade. The risk goes up on hot afternoons when people have been standing for a time. they have skipped meals or water and are prone to blackouts It happens seldom but is serious. Questions: If you are asked questions for which you don't know an answer or even if you do know the answer. turn it back to the group it appropriate. Main room outline: Plant parts and variations! monocols and dicots Plant defenses: geranium, mimosa. “Acacia Reproduction: Flowers, variation in structure, adaptations, and adaptations for pollination Fruit, dispersal Epiphytes ‘Spanish moss (not moss and not Spanish, native to FL—TX— Mexico, is in pineapple family) absorptive! reflective hair turns translucent when wet so plant looks green rather than white Orchids storage stems. other bromefiads, tanks formed by whorls of leaves, *staghorn fern with sun. water. and compost catcher upper leaves Stevia fro m Paraguay containing steviacide no calories 80 times sweeter than sugar. probably a feeding deterrent. Cycads, look like fern or palm but reproduce by seed, gymnosperm, naked seed. no ovary covering seed ‘Stahorn ferns, basket leaves to catch debris, water and rain, reproductive leaves with massive sori on them Room B Carnivorous plants grow where no nutriean available in substrate, usually peat bogs where phenolics in moss doesn't allow decomposition, need full sun and pure water review of bryophytes through angiosperms illustrating variations of alternation of generations of each, terns is only dividion in SVP‘s that has large leaves, show tern gametophyte, (looks like little thin liverwort) ask about gametangia (archegonia and antheridia} Sellaginella in Lycophyta only heterosporous shown, food around what will be an embryo. similar principle to seed. Ftoom C, African Deserts: Cover convergence. These old world succulents are in the milkweed, rubber tree, and Aloe families. They as cacti are thorny and use stem photosynthesis, but the thorns are in ctusters of 1—4 and the flowers are very different than Cacti which have showy flowers with lots of sepsis and petals and clusters of modified leaveslspines at each node Cover Gnetophyta with Welwitschia (only 2 leaves for whole life), Gnctum, and Ephedra, gymnosperms with lots of angiosporm traits Room D The plants on the left center bench arc Cacti. *Many have reduced surface area to minimize water loss and ribs so they can expand without bursting when water is available and thorns or poison to keep animals from eating them for the water. The columnar shape also works because little is exposed during the hottest part of the day. There is a primitive cactus (not as specialized) center lett, leafy tew spines ...
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ConservatoryTourPacket - ,5 2; Background Information for...

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