Plant Diversity

Flashcards about plant diversity, covering topics from plant characteristics and evolution to gymnosperms, angiosperms, and fruit development.

What is a plant?

Multicellular eukaryote of the kingdom Plantae with roots, stems, leaves, and chlorophyll, capable of photosynthesis.

What does a plant need to survive?

Water, CO2, O2, and Sunlight

Give examples of plant habitats.

Riverine, Woodland, Grassland, Desert

Why are plants important?

Primary producers, sources of food and medicine, building materials.

What are the main photosynthetic pigments in plants?

Chlorophylls a and b

What is the function of cellulose cell walls in plants?

Structure of cell, mechanical protection.

What forms of starch do plants store?

Amylose, Glycogen, Amylopectin

Which group of protists gave rise to plants?

Photosynthetic algae, Phylum Chlorophata, Class Charophyceae

Describe the Charophyceae Coelochaete.

Epiphytic, disc-shaped sheet of cells, one cell thick.

Describe the Charophyceae Charales.

Filamentous with whorls of branches at nodes, calcium in cell walls.

What features originated in the Charophyceae and were passed on to plants?

Apical meristem and phragmoplast.

What is the Apical Meristem?

Found in buds of Charales and Coleochaete, it divides to give rise to all cells forming the organism.

What is the Phragmoplast?

Involved in cell wall formation during cytokinesis with parallel microtubules and vesicles.

What are Plasmodesmata?

Channels in the cell wall lined by membranes, containing proteins and ER, connecting cytoplasm of adjacent cells.

Describe biochemical similarities between Charophyceae and plants.

Enzyme involved in photorespiration (in the peroxisome).

What enzymes are involved in photorespiration?

Glycolate oxidase in the Charophyceae and plants; Glycolate dehydrogenase in all other green algae.

Describe retention of the zygote.

Zygote retained on surface of Coleocheate, placenta transfers nutrients from parent to zygote.

What are Bryophytes?

Non-Vascular Plants

Describe moss gametophytes.

Protonema growing into leafy gametophyte.

Describe a moss sporophyte.

Foot embedded in gametophyte, seta supports capsule.

What is the function of the capsule on a moss sporophyte?

Produces spores in sporangia.

What two forms do liverworts come in?

Thallose and leafy.

How is the thallus of liverworts differentiated?

Thin upper photosynthetic region and thicker lower portion with rhizoids and scales.

How does asexual reproduction occur in Marchantia?

Gemmae in gemmae cups.

How does sexual reproduction occur in Marchantia?

Female gametes produced in archegonia on archegoniophores; male gametes produced in antheridia on antheridiophores.

How does fertilization occur in Marchantia?

Sperm swim to egg in water and fuse (in archegonium).

What are Hornworts?

Small primitive plants with a simple unbranched thallus, no differentiation.

Describe the sporophyte of Anthoceros.

Upright, cylindrical structure, green & photosynthetic, grows from the base.

What did vascular seedless plants look like?

Rhizoids only, rhizome, dichotomously branching erect stems, stems leafless.

What are the evolutionary trends in vascular plants?

Development of vascular tissue, xylem, and phloem.

What is the function of xylem?

Transports water and dissolved mineral salts.

What is the function of phloem?

Transports foods in solution.

What enables plants to grow to greater heights and stems to branch?

Walls strengthened by lignin.

What are trends in vascular plants?

Increased size and dominance of the sporophyte, reduction of gametophyte.

What do stomata do?

Regulate diffusion rates of water and gases.

What are features of Gymnosperms?

Conifers (cone bearers), cuticle, vascular tissue, true stem & roots, seeds (naked).

What is the function of the male cone?

Produces and releases pollen (male gametophytes).

What is the function of the female cone?

Contains ovules (develops seeds after fertilization).

How is pollen moved with Cycads?

Pollen often moved by insects, cones can warm up and release scents to attract pollinators.

Where does the male gametophyte develop?

Develops from a microspore inside the male cone (microsporangium).

Where dies the female gametophyte develop?

Develops from a megaspore inside the ovule in the female cone (megasporangium).

What are adaptations of gymnosperms to cold, dry conditions?

Conical shape and flexible branches, needle-shaped leaf, waxy cuticle, sunken stomata.

How do gymnosperms reproduce?

Tress are monoecious: male and female cones on the same tree

How does fertilization occur in gymnosperms?

Wind carries the pollen grain to the ovule.

What are features of Ginko biloba?

Deciduous, fan-shaped bilobed leaves, dioecious.

What are the medicinal values of Ginko biloba?

Used to treat circulatory disorders and enhance memory.

What is the key difference between gymnosperms and angiosperms?

Seeds of angiosperms develop in the ovaries of flowers and are surrounded by a protective fruit; gymnosperm seeds are usually formed in unisexual cones and the plants lack fruits and flowers.

What is pollination?

Transfer of pollen from anther to stigma.

Why do pollinating agents visit a flower?

Nectar, oils, pollen, a place to lay eggs.

How are microspores formed?

Microspore mother cells (2n) undergo meiosis to form microspores (n).

How does the male gametophyte develop?

Develops inside the pollen grain. Two cells form (by mitosis): tube cell and generative cell.

What is the function of the tube cell and generative cell?

The tube cell produces a pollen tube to the ovule; the generative cell divides (by mitosis) to form two sperm cells.

Where does the female gametophyte develop?

Develops within the ovule inside the ovary at the base of the pistil.

Describe double fertilization.

One sperm fertilizes the egg and forms a zygote (2n); the other sperm fuses with two polar nuclei to form endosperm (3n).

What is the function of the endosperm?

The endosperm provides nourishment to the developing embryo.

What is a seed?

A mature ovule containing an embryo. Also contains a food supply (endosperm) inside a protective seed coat.

What is a fruit?

The wall of the ovary develops into a fruit; the fruit encloses and helps protect the seed and aids in seed dispersal.

What is vegetative propagation?

Asexual reproduction in plants through vegetative growth; separation of the shoot system into individual stems; spread of rhizomes.

What is fragmentation?

Fragmentation of the mature sporophyte gives rise to genetically identical organisms (clones).

What structures allow for vegetative propagation?

Rhizomes, stolons, suckers, plantlets, adventitious plantlets.

What is apomixis?

The production of seeds without pollination or fertilization. The ovule gives rise to a diploid egg, which develops into an embryo.

What are rhizomes?

Modified stems growing horizontally below ground. Buds along the rhizome develop into new upright shoots.

Modified stems growing horizontally above ground. Buds

What are stolons?

Modified stems growing horizontally above ground. Buds along the stolon develop into new upright shoots.

What are suckers?

New shoots arising from buds on underground roots.

What are plantlets?

Mini plantlets growing along the margins of leaves. They drop to the soil and grow into independent plants.

What are adventitious plant

Plantlets arising from roots or leaves.