Chapter 35 Introduction to Plants Kingdom Plantae We will primarily be discussing the angiosperms Phylum Anthophyta Flowers and fruits Only group that does/has these things Advanced traits Seeds Advanced vascular tissues From seed to seed The life of a flowering plant Seeds reproductive structures produced by angiosperms and other seed plants usually the result of sexual reproduction contains embryos that develop into seedlings upon germination has survival value Alternation of Generations Exhibited by all plants (and plant-like organisms) that have sexual reproduction There is an alternation between a diploid (2N) form [sporophyte] and a haploid (1N) form [gametophyte] Gametophyte (haploid) Gamete-producing plant fomr multicellular microscopic in flowering plants female embryo sac with egg male pollen grain grow and develop within flowers of angiosperms produces gametes by mitosis/cytokineses Sporophyte (diploid) multicellular large "plant" in flowring plant produces haploid spores by meiosis (reduction) called meiospores The plant embryo Fertilization (syngamy) results in the formation of a diploid zygote, which undergoes mitosis to form an embryo (multicellular) the embryo is a sporophyte that lies dormant in the seed with a supply of stored food and a seed coat may lay dormant for long periods until conditions are favorable  The plant body Composed of three organ types stems leaves roots Shoot system stem produce leaves and branches and bear the reproductive structures leaves flattened structure specialized for photosynthesis Root system roots Provide anchorage in the soil and foster efficient uptake of water and minerals can store food Growth Indeterminate growth increasing in size as long as the plant is alive grows into a seedling and then a mature plant Plant growth occurs by 3 means Increase in number of cells cellular reproduction (mitosis/cytokineses) increase in cell size elongation increase in weight/mass Development Mature plants produce reproductive structures flowers seeds fruits flowers and floral buds are reproductive shoots that develop when shoot apical (tip) meristems produce flower parts instead of new tissues and leaves flowers are produced by determinate growth Seed coats Flower tissues enclose and protect tiny male and female gametophytes sperm in pollen fertilizes the egg, triggering ovules to develop into seed and flower parts to develop into fruit fruits enclose  seeds and function in seed dispersal Angiosperms   Meristems Seedlings and mature plants produce new tissue from meristems cell factories meristem is a region of undifferentiated cells that produce new tissue by cell division A dormant meristem occurs at the shoot and root of seed embryos activate in seedlings mature plants have shoot apical meristems (SAM) and root apical meristems (RAM) Mature sporophyte develop from seedlings photosynthesis powers the transformation of seedlings into mature plants provides the ability to produce organic food plants undergo both vegetative growth and reproductive development Hierarchy of structures in a mature plant Specialized cells tissues organs organ systems branches, buds, flowers, seeds, fruits root and shoot systems plant (the organism itself) Primary Growth Elongation of plant organs roots, stems, and leaves Occurs in ALL plants Produces primary tissues from apical meristems (SAM  and RAM) Primary Tissues Primary xylem vascular/conducting tissue water and minerals Primary  phloem vascular/conducting tissue food and solutes Epidermis dermal Outter-most tissue protection holds water in plant Support ground tissues Parenchyma most abundant type storage water and food part of cortex/pith Collenchyma Protection/support of growing plant organs cortex Sclerenchyma protection/support of non-elongating organs cortex Secondary Growth Expansion of plant organs lateral meristems roots and stems only does not occur in leaves noes not occur in all plants Produces secondary tissues woody tissues Major groups of Angiosperms Eudicots >240,000 species all have primary growth most have secondary growth for this class we are saying they all have secondary growth Monocots >60,000 species all have primary growth very few have secondary growth for this class we are saying that non have secondary growth grasses, corn, tulips, lilies Root system adaptations Major functions absorbing water and minerals anchoring the plant in the soil storing nutrients and water Eudicots Taproots Monocots fibrous roots Three zones of root growth Region of cell division RAM and root cap RAM contains cells that ar dividing Quiescent center keeps nearby cells undifferentiated Root cap embedded in mucigel Mucigel is a slimy substance that covers the root cap of the roots of plants. Region of elongation cells extend by uptake of water Region of maturation root cell differentiation  and tissue specialization identified by presence of root hair water and mineral uptake Root Internal Structure Epidermis of mature roots encloses a cylinder of parenchyma called the root cortex One cell thick often rich in starch functions as food storage many contain inter-cellular air spaces Endodermis selective absorption of minerals one cell thick Meristematic pericycle encloses root in vascular tissues provides lateral branches woody roots produce primary vascular tissues followed by secondary vascular tissues Eudicot root Monocot Root The shoot system Stem and leaf adaptations Shoots are modular with 4 parts Stem node leaves or branches emerge Internode stem between adjacent nodes elongation Leaf Axillary Meristem generate axillary buds can produce flowers or branches Lateral shoots New branches bear SAM at their tips Shoot Tip Terminal bud at the end of each shoot includes the SAM and other parts scales Leaf anatomy Leaf adaptation Leaf venation Eudicot Pinate (feathery) Palmate (palm) Netted provides more support for the leaves Monocot Parallel  Stem Primary growth mostly above ground organs,but some modified stems are blow ground Irish potato underground stem Eudicot Stem ALC Primary (elongation) and secondary (expansion) growth vascular bundles (xylem and phloem) form a ring pattern  exhibit both a pith and a cortex cambium ring produce cells provide secondary growth Lateral Meristems Produces secondary growth 2 lateral merstems both are rings that retain cell division properties and produce secondary tissues to the inside and outside of the cambium ring Vascular cambium produces ring of secondary xylem (wood) to the inside and a ring of secondary phloem (inner bark) to the outside Cork cambium Produces ring of periderm (outter bark) that replaces the epidermis and cortex for external protection Secondary vascular tissue woody plants begin life with only primary vascular systems produces secondary tissues and bark as they mature secondary xylem wood Secondary phloem inner part bark has both outer bark (mostly dead cork cells) and inner bark (secondary phloem) Secondary growth begins late in first year of growth eudicot stem after 3 years of growth Monocot stem Primary growth (elongation) vascular bundles (xylem and phloem) are scattered lacks both pith and cortex Comparison between Plant types Leaves Eudicot net venation Monocot parallel venation Roots Eudicot primary and secondary growth (mostly) cortex no pith core of xylem in the root Monocot Primary growth only both cortex and pith Stems Eudicot primary and secondary growth (mostly) vascular bundles in a ring pattern around cortex Monocot Primary growth only vascular bundles scattered around no pith or cortex Primary Growth Due to activities of Apical Meristems RAM and SAM Results in production of primary growth Secondary Growth Due to activities of lateral maristems vascular and cork cambiums Results in production of secondary tissues