Seed Plants PDF

SEED PLANTS have seeds, reduced gametophytes - ovules and pollen create flowers (kvety) or cones (šištice) and fruits (plody)  Advantages seeds provide over spores  Seeds are multicellular – consisting of  Spores are usually single-celled an embryo and its food supply...

SEED PLANTS have seeds, reduced gametophytes - ovules and pollen create flowers (kvety) or cones (šištice) and fruits (plody)  Advantages seeds provide over spores  Seeds are multicellular – consisting of  Spores are usually single-celled an embryo and its food supply  No protection from harsh conditions  Protected by a seed coat  Spores have shorter lifetimes (no  Seeds can remain dormant for days, dormancy) months, or even years (are resistant)  Seeds can be carried long distances  Spores must grow where they land by wind or animals (is dispersible)  Spores require a wet environment  Seeds germinate more easily to germinate If conditions are favourable where it lands, the seed can emerge from dormancy and germinate Seed dormancy is defined as a state in which seeds are prevented from germinating. stored food provides critical support for growth as the embryo emerges as the seedling 2 divisions: Gymnosperms (nahosemenné rastliny) Angiosperms (krytosemenné rastliny)  Division: Gymnosperms (Borovicorasty, nahosemenné rastliny) seeds are „naked“ seeds are on scales of woody cones (šišky) ovules are unprotected by an ovary (semenník)  Life cycle of gymnosperms (metagenesis)  Sporophyte is a plant you are familiar with  It generates separate male and female cones (strobili, šištice)  a male cone (samčia šištica) contains pollen grains  a female cone (samičia šištica) creates ovules on the surface of its scales  Gametophyte has been fully reduced  Male gametophyte = pollen grain (contains sperm cell)  Female gametophyte = ovule (contains two egg cells) Pollination and fertilization Pollination: rely on wind for pollination  the pollen grain lands on the female cone, forming a pollen tube through which the sperm cell travels to meet the female egg cell fertilization: sperm fuses with an egg cell and creates a diploid zygote  unlike angiosperms, double fertilization does not take place Changes after fertilization: zygote divides and forms an embryo  ovule transforms into a seed  female cone develops into a woody cone (drevená šiška)  Division: GYMNOSPERMS Nahosemenné rastliny The maidenhair – tree The cycad order The pine order order Cykasy Ginká Ihličiny The Juniper family cypruštekovité The Pine family borovicovité The Yew family tisovité The cycad order CYCADALES CYKASY The cycad order (CYCADALES – CYKASY) - palm-like gymnosperms, up to 20 metres high - dioecious - dvojdomé (exist as male and female plants) Queen sago (cykas indický) – seeds contains starch called sago which is used as a flour (to make tortillas...)  Queen sago (cykas indický) https://en.wikipedia.org/wiki/Cycas_circinalis The maidenhair- tree order GINKGOALES GINKÁ  Black maidenhair fern https://en.wikipedia.org/wiki/Ginkgo_biloba The maidenhair-tree order (GINKGOALES – GINKÁ) Maidenhair-tree (Ginkgo dvojlaločné, ginkgo biloba) - the only living species of ginkgo in the world (all others being extinct) - found in fossils dating back 270 million years - can live up to 2000 years - fan shaped leaves (leaves resemble black maidenhair fern) - dioecious plant - the seed is fleshy, yellow, smells like rancid butter when fallen - origin: China - used as a park tree, for pharmaceutical purposes (adverse effects) The pine order PINALES Conifers IHLIČINY The pine order (PINALES – IHLIČINY) = conifers - leaves are needlelike or scaly, evergreen - contain resin canals which release resin helping in the healing of wound - monoecious plants - wind pollinated Types of "fruits": 1. Cone (šiška) 2. Berry (bobuľa) 3. Aril (šišková bobuľa)  Family: The Juniper family (cypruštekovité) trees and shrubs  resin canals just in the cortex Representatives: Common juniper (borievka obyčajná) - shrub with sharp needle leaves in whorls - dark blue fruit is called a juniper berry (fleshy cone) - fruits are used as a spice „jalovec“ or for the production of some alcoholic drinks (gin or Slovak „borovička“) Northern white-cedar (tuja západná) - grows in gardens, cemeteries, parks - its origin is the North America Coastal redwood (sekvoja obyčajná) - the tallest tree in the world with height up to 112 metres and 6,7 metres wide - origin: Oregon, California Giant sequoia (sekvojovec mamutí) - grows in California - 106 metres tall, 11m wide Family: the Pine family (borovicovité) mainly trees  resin canals in the cortex, xylem, phloem, leaves typical for the northern hemisphere Scots pine (borovica lesná) - needles are in bundles of two, 3-8 cm in length - mature cones are ovoid about 4 cm in length Austrian pine (borovica čierna) - needles are in bundles of two, 10 – 15 cm long, dark green colour Dwarf mountain-pine (borovica horská, kosodrevina) - 1-4 metres tall shrub - found in the high altitudes of the High Tatras - protected! Norway spruce (smrek obyčajný) - cones hang down and are cylindrical - needles are four-sided, 1-2 cm long, sharp and single Blue spruce (smrek pichľavý) - has blue-green coloured needles - used as an ornamental tree Europian silver-fir (jedľa biela) - cones are upright (do not hang) and cylindrical - needles are single, flattened and with two greenish- white bands (representing stomata) European larch – smrekovec opadavý - soft needles grow in bundles of 30 - it is a deciduous tree (opadavý) - wood is used in the construction industry Cedar-of-Lebanon (céder libanonský) - native to the mountains of the eastern mediterranean basin. - It is the national emblem of Lebanon and is widely used as an ornamental tree in parks and gardens. Family: the Yew family (tisovité)  trees or shrubs without resin canals flattened evergreen leaves dioecious plants Yew (tis obyčajný) - the entire plant is hardly poisonous except the aril (semenná bobuľa) - seeds - poisonous