Plant bio final part 1 and quiz 2

bryophytes

ecologically and phylogenetically important clade of early divergent plants which lack xylem and phloem. Small, flat, leafy plants with an undifferentiated growth structure called a thalloid. Usually grow in moist locations, though there are exceptions to this. Important models of earliest land plants

3 phylla of bryophytes

1) Marachantiophyta (liverworts): 1200 species, small but form large mats in favorable habitats, can reproduce sexually, vegetatively, and asexually via gemmae produced in specialized structured called gemma cups

2) Bryophyta (mosses): contain 3 important classes: Sphagnidae (300 species), Andriaeaidae (100 species), and Bryidae (true mosses, 10,000 species)

3) Anthoceratophyta (hornwarts): 300 species

alternation of generations

the phenomena whereby plants (and algae) produce two heteromorphic (“different in form”) generations, which are morphologically and genetically different

gametophyte phase

haploid gamete producing phase. In Bryophytes, this phase is dominant and anatomically simple. In vascular plants, this is not dominant and anatomically very small.

sporophyte phase

diploid spore producing phase. In Bryophtyes, this phase is anatomically complex. In vascular plants this is dominant and complex

seedless vascular plants

early divergent plants that retain some characteristics of bryophytes, but have developed xylem and phloem tissue

fossil plants

now extinct early seedless vascular plants that first displayed branching and tissue differentiation. Rhyniophyta, Zosterophyllophyta, Timerophyta

Lycopodiophyta

early seedless vascular plants, 1200 extant species including the genera: Lycopodium, Selaginella, and Isoetes

Monilophyta

includes ferns (65 genra and 10500 species) and horsetails which may be the oldest surviving genus of extant plants

Tracheid

the cell type of the xylem tissue in seedless vascular plants. Cells are elongated and tapered, and their cell walls contain lignin for structural support

Pith

soft tissue in the center of the stems of vascular plants. Vascular tissue is arranged around the pith for additional structural support

Homosporus plants

most ferns, all horsetails, some lycophytes. Produce one type of spore that will germinate to form a gametophyte that will produce both male and female gametes on the same plant

heterosporous plants

some ferns and lycophytes, all seed plants. Produce two types of spores that will give rise to either male or female gametophtyes

microspore

gives rise to male gametes

megaspore

gives rise to female gametes

gymnosperm

Gymno: naked, sperm: seed - meaning their ovules and seeds are exposed on the surface of strobili

a group of woofy, perennial, seed-producing plants consisting of 4 phyla: Coniferophyta, Ginkgophyta, Cycadophyta, Gnetophyta

ovule

the structure that develops into a seed. An immature ovule consists of a megasporangium and an integument

megasporangium

The structure in which the megaspores are produced. surrounded by a layer of tissue called the integument, which has one opening called the micropyle

spore

a single-celled haploid reproductive unit produced via meiosis. develop into multicellular gametophytes

megagametophyte

female gametophytes- which include haploid egg cells within archegonia and the egg sack. Produced by megasoire via meiosis and mitosis

egg sack

megagametophyte tissue that acts as food storage for the developing embryo

seed

a mature ovule, containing a diploid zygote (young sporophyll) and surrounded by a seed coat (made from the integument)

strobili

cone shaped sporophylls

sporophyll

a leaf modified to bear spores

microgametophytes

male gametophytes- the pollen grains, which produce sperm cells. gymnosperm pollen grains are sometimes connected to air sacs to help them float on the wind to pollinate megagametophytes. Once pollen grains land on the surface of the ovule, the “germinate” and produce a pollen tube. Pollen grains are produced by microspores

pollen tube

a tubular outgrowth that grows through the micropyle into the megagametophyte, into the archegonia, and deposits sperm cells next to the egg cell

microsporangium

pollen sacs, which are adhered to the male strobili. microspores inside undergo meiosis to produce haploid pollen grains

megaphyll

a leaf with several or many veins running through it. All gymnosperms produce megaphylls. in some groups of gymnosperms, their megaphylls have been modified to needles or scales- typically an adaptation to winter drought

evergreen

most gymnosperms do not shed their leaves in preparation for winter. they usually retain the same leaves for many years

deciduous

plants that shed leaves seasonally. some gynmosperms and most angiosperms

resin

a viscous secondary compound, made mostly of terpenes, that acts to seal wounded tissue and trap pests and pathogens. produced, stored, and transported in resin ductsv

vascular bundle

xylem and phloem tissue strands growing side by side

secondary growth

the thickening or widening of trunks and branches via the production of wood in the vascualr cambium tissue

vascular cambium

lateral meristematic tissue found in mature branches and trunks of plants that produce secondary growth

fascicles

bundles of leaves, produced by pines. the base of the fascicle contains meristematic tissue

angiosperms

flowering plants. Phylum Anthophyta consists of aboyt 300,000 species and displays staggering diversiry.

two classes

monocots: about 100,000 species of grasses, lilies, orchids, palms, bananas, and crop grains like corn rice, and barley. Produce ONE cotyledon while they germinate, and their lead vascular bundles run parallel

eudicots: about 200,000 species of flowering trees and shrubs, fruits, vegtables, and herbs. Produce TWO cotyledons when they germinate, and their leaf vascular bundles are branching

Cotyledon

a seed leaf, present in the embryonic plant. The first leaf (or leaves) that emerge on a germinating seedling

seed

the mature ovule, containing a diploid zygote, endosperm, and a seed coat

endosperm

stored nutrition for the zygote and later for the germinating seedling

flower

a determinate shoot that produces sporophylls. Contains 4 sections or whorls. 2 of the whorls are sterile and two are fertile. The fertile whorls are the carpel and stemen and the sterile whorls are the calyx and corolla

carpel

megasporophyll structure that contains the ovules, and that becomes the fruit after fertilization. It is the last floral whorl. Consists of

• ovary: a structure that houses the ovule, or multiple ovules, sometimes in separate chambers called locules. The placenta is the portion of the ovary where the ovules attach to the ovary

• Ovules: look much like they do in gymnosperms, but with two layers of integument. Contain the megaspores and the megagametophyte, which at maturity is usually 7-celled 8-nucleate. The cells consist of the central cell (polar nuclei), 3 antipodal cells, 2 synergids, and 1 egg cell. In angiosperms, the megagametophyte is also called the egg sack

• stigma: a sticky landing pad for pollen grains

• style: a tube that connects the stigma to the ovary. The pollen tube of germinating pollen will grow down the style and into the ovule

stamen

microsporophyll structure that bears pollen (the microgametophyte). They form the third floral whorl

consists of

• anther: a two-lobed structure that contains 4 pollen sacs (the microsporangia)

• filament: a slender stalk that attaches the anther to the receptacle

• pollen grain: the microgametophyte. 3-celled- 1 tube cells (which become pollen tube), and 2 sperm cells. Pollen grains are distinct, and many species can be identified on pollen alone

perianth

the non-fertile flower parts, consisting of the two sterile whorls- the sepals (collectively the calyx) and the petals (collectively the corolla)

sepals

leaf-like structures, typically thick and green, that protect the developing flower bud. When the flower opens, the sepals form the first floral whorl. The sepals are collectively called the calyx

petals

leaf-like structures, typically thin and colorful, that protect the reproductive flower parts, attract pollinators, and offer a landing spot for pollinators. They form the second floral whorl. Collletively the corolla

tepals

when the petals and sepals look similar, they are called tepals

peduncle

the flower stalk of a solitary flower, or an inflorescence

receptacle

the part of the peduncle to which all floral parts are attached

inflorescence

a cluster of flowers, arranged in a variety of ways. Each solitary flower in an inflorescence is attached to the inflorescence with a small stem called a pedicel

composite inflorescence

type of inflorescence in which tiny flowers form a structure that resembles a large solitary flower. Indicative of a plant in the Asteraceae family. Tiny, perfect disk floret flowers from the center. Sterile ray florets, with a connate corolla that resembles a single petal, from the periphery. Disk florets open asynchronously and can welcome an abundance of pollinators for many days