Survey of the Plant Kingdom Gymnosperm & Angiosperms PDF

Survey of the Plant Kingdom Gymnosperms of phyla Coniferophyta Gymnosperms  Gymnosperms are plants with exposed seeds borne on scale like structures called cones.  Gymnosperms has a well- developed alternation of generations.  They are heterosporous:  Microspores: in male cones and...

Survey of the Plant Kingdom Gymnosperms of phyla Coniferophyta Gymnosperms  Gymnosperms are plants with exposed seeds borne on scale like structures called cones.  Gymnosperms has a well- developed alternation of generations.  They are heterosporous:  Microspores: in male cones and form male gametophytes  Megaspores: in female cones and form female gametophytes.  Phylum Coniferophyta  The coniferophyta are a large group of cone- bearing plants.  The cones are reproductive structures of the sporophyte generation that consist of several scale like sporophylls arranged about a central axis.  Sporophylls bear spores.  sporophylls; leave like structure of the sporophyte generation. - Male cone  Sporophylls of male cones are called microsporophylls.  On the surface of each microsporophyll is a layer of cells called microsporangium that produces spores. Male cone cross section  -Female cone  Sporophylls of female cone are megasporophylls; each bears two spore- producing megasporangia on its upper surface. Female cone cross section  Male cones are small and similar in all conifers.  Female cones are variable; they may be small and fleshy or large and woody. Pine ( Pinus )  Pine is a representative of conifers and its widely distributed.  It has a considerable economic value.  The sporophyte of pine is the tree.  Leaves are borne on dwarf branches only a few millimeters long.  The length and number of leaves distinguish many of the species of Pinus. Pinus leaf cross section Angiosperms  Flowering plants are the most abundant , diverse, widespread of all land plants due to:  Structural diversity -Efficient vascular system - Mutualisms Phylum Anthophyta  As in gymnosperms, the sporophyte of angiosperms is large and independent of the microscopic gametophyte.  The gametophyte totally depends on the sporophyte.  Angiosperms have two main structures:  Vegetative structures  Reproductive structures  Angiosperms are divided into monocot and dicots Monocotyledons Dicotyledons Lack a true vascular Have a true vascular cambium ( lateral cambium ( lateral meristem) meristem) Structure and function of flowers  calyx, composed of sepals, makes up outermost whorl  petals collectively make up the corolla  Perianth the combined calyx and corolla  stamens collectively compose androecium  stamens made up of filament and anther inside the anther are pollen grains, which produce the male gametes.  Gynoecium refers to the collection of female parts in a flower.  single or fused carpels also referred to as a simple or compound pistils ovules produced in pistil’s swollen ovary style - slender neck stigma – pollen receptive structure  The flower may be Irregular ( zygomorphic ) regular ( actinomorphic ) Irregular ( zygomorphic ) regular ( actinomorphic ) meaning that these flowers meaning that the flower is are generally bilaterally radially symmetrical. symmetrical.  Seed The evolution of seeds is one of the most significant events in the history of the plant kingdom. Its one of the factors responsible for the dominance of seed plants in today’s environment, because a seed permits a small but multicellular sporophyte to remain dormant until conditions are favorable for continued growth. While dormant, the young sporophyte is protected by a seed coat and surrounded by a food supply. Seed Structure A seed is mature ovule that includes a seed coat, a food supply and an embryo. The features of a Dicot seed are: The features of a Dicot seed are:  Micropyle a small opening on the surface of the seed through which the pollen tube grew.  Hilum an adjacent, the point where the ovule was attached to the ovary.  Cotyledon food for the embryo  Embryo with young root and shoot develops into the new sporophyte.  Features of a Monocot seed are:  Endosperm  Scutellum: cotyledon; it helps to absorb the endosperm.  Coleoptile: sheath enclosing shoot apical meristem and leaf primordia.  Root  Root cap  Coleorhiza: sheath enclosing embryonic root.  Shoot apical meristem Fruit  A fruit is a mature, ripened ovary plus associated tissues.  A typical fruit has an outer wall called a pericarp composed of an exocarp, mesocarp and endocarp.  Within the pericarp are seeds, various partitions and placental tissues.  The fruit often includes the receptacle of the flower.  Fruit Fleshy Dry Doesn’t Simple complex Open open Mostly of Mostly of receptacle Aggregate Legume capsule Nut ovary pome Multiple Drupe Berry Multiple pores Samara seams Achene & caryopsis  Fruit Fleshy Dry Simple complex Mostly of Mostly of receptacle Aggregate ovary pome Drupe Berry Multiple  Simple fleshy fruit ( ovary only) Endocarp hard and stone Endocarp slimy or fleshy ( drupe ) ( berry )  Simple fleshy fruit ( ovary + receptacle ) Pome  The seed-bearing ovary (core) is surrounded by a thick, fleshy hypanthium It is derived from the fusion of the bases of petals and sepals. Complex Fruit Aggregate : ovaries on a Multiple: ovaries from single flower different flowers fuse together  Fruit Fleshy Dry Doesn’t Open open Legume capsule Nut Multiple pores Samara seams Achene & caryopsis Dry fruit ( opens )  Legume opens along two seams.  1 capsule opens along 2 seams. Dry fruit ( opens ) capsule Seeds are released Seeds are released through pores through multiple seams Dry Fruit that doesn’t opens Nut pericarp hard and Samara pericarp thin and thick with a cap on it’s winged base Dry Fruit that doesn’t opens Achene pericarp thin and not winged Caryopsis cereal grain Thanks