PLANTS – DAY 4 REPRODUCTIVE MECHANISMS. Transportation Worksheet Answers Which picture is showing net venation, and which is showing parallel venation?

PLANTS – DAY 4

REPRODUCTIVE MECHANISMS

Transportation Worksheet Answers

Which picture is showing net venation, and which is showing parallel venation?

A.____NET__________ B. ____PARALLEL______

What is the major difference between a single leaf and a compound leaf? Draw and label this difference.

Single leaf- have a single, undivided leaf blade

Compound leaf - have a blade divided into two or more leaflets

Transportation Worksheet Answers Explain why most plants have stomata mainly

on the lower surface of their leaves. Stomata are openings in the leaf that allow

oxygen to leave the plant and carbon dioxide to go into the plant. They also allow water vapour to escape from the plant when they are open. When the sun is shining, plants want to keep as much water as possible. If stomata are on the underside of the leaf, less water vapour will escape from the plant. These stomata are out of direct sunlight.

Transportation Worksheet Answers

Why are guard cells important to stomata?

They regulate the opening and closing of the stomata. Without them, stomata would always be open and carbon dioxide would continuously come in and water vapour would continuously leave the plant – photosynthesis would not occur regularly due to too much/too little of needed reactants.

Predict the environment in which you would expect to find plants with several layers of palisade mesophyll cells densely packed with chloroplasts. Explain why.

Lots of chloroplasts – must be a lot of sunlight because chloroplasts are the site of photosynthesis. Perhaps an open field, an environment in the tropics.

Transportation Worksheet Answers

What is the difference between a taproot and a fibrous root?

Taproot – root systems where the primary root remains predominant, though very small secondary roots are present

fibrous root= root systems whose primary roots have disintegrated and were replaced by other smaller roots.

Why are pneumatophores so important to certain plants?

Pneumatophores are roots that evolved to let plants survive in waterlogged, oxygen-poor soils (swamp) environments. These are special extensions which grow up and out of the water and function to supply oxygen to the root tissues below. Oxygen then diffuses into the plant parts that need it.

Transportation Worksheet Answers How does root pressure form within the

root? Root pressure is the culmination of

water and minerals, together called xylem sap, in the root. Minerals get into the root by a process called active transport, water follows by a process called osmosis. This pressure pushed xylem sap up the xylem tubes. However, this pressure can only push the sap up the plant so far.

Transportation Worksheet Answers

What does water transport in the xylem depend on within the plant? Briefly describe each of these factors. Does water transport within the plant require energy of any kind?

-root pressure pushed water (xylem sap – mix of water and minerals) into xylem

-water adheres to inner walls of xylem, creating a pulling force on the column of water molecules

-water is cohesive and sticks together continously from ground to top of the highest leaves

-transpiration pull pulls water up the stem to the leaves

Transportation Worksheet Answers

Speculate why sugar maple trees demonstrate the importance of plants to the growth of Canadian society. Why is this xylem sap, better known as maple syrup, so important to our society?

-economically: brings money into our society, means of money for maple syrup producers, shop owners; Canadian maple syrup renowned throughout the world

-socially: pancake dinners, shrove Tuesday, brunches, used to have ‘syrup’ parties

NATURAL REPRODUCTION – SEED PLANTS

Seed plants are called spermatophytes, a subdivision of vascular plants

Seed plants have roots, stems, and leaves exhibiting a huge variety of textures, sizes, shapes odours and colours; the most recently evolved plant group

Have reproductive structures that are NOT dependent on water; all seeds ensure survival of embryos by reducing excessive water loss

SEED PLANTS

Seed plants have separate male and female gametophyte tissue

2 types of spermatophytes – gymnosperms produce unprotected “naked” seeds in conelike structures (conifers) and angiosperms produce seeds that are enclosed and protected inside a fruit, formed by various flower parts

We’ll look at angiosperms

ANGIOSPERM ANATOMY

Carpel: female part of flower Stamen: male part of flower

Pollination occurs when pollen (contains sperm cells)from anther goes to the stigma (wind/insects)

Self pollination - transfer of pollen from anther to stigma on same flower

Cross pollination – transfer of pollen from anther to stigma on different flowers

ANGIOSPERM REPRODUCTION

•Pollen grains travel down pollen tube into an ovule in an ovary •Fertilization occurs when pollen grains (n) fuse with an egg (n) in the ovule to form a diploid zygote

•Zygote grows by mitosis to form an embryo, and the embryo remains inside the ovule

•The ovule is called a SEED now that there is an embryo inside the ovule

SEED DEVELOPMENT

While changes occur in the seed, the ovary are developing into a fruit, which provides protection for seeds and often helps secure dispersal of the seeds

As time goes by, mature fruit falls; under suitable conditions, fruit decomposes, seed coat splits, and germination occurs – embryo grows quickly and is called a seedling

SEED

EMBRYO

GERMINATION OF SEEDS

A seed consists of an embryo, tissue to provide nutrients for the embryo, and a protective seed coat

A growing embryo slowly forms a root and shoot structure

Cotyledons often contain all nutrients needed for embryo OR there may be additional nutrient-rich material called endosperm

GERMINATION OF SEEDS

When temperature and moisture conditions are optimum, seeds start to germinate

Seed and seed coat absorb water, embryo grows rapidly

Seed coat ruptures and roots and shoots emerge

Root absorbs water and nutrients and grows downward, shoot grows upward

Nutrients stored in endosperm and/or cotyledons support development until new plant has enough root surface area

ARTIFICIAL PROPAGATIONA: CUTTINGS

Artificial Propagation: is a method of asexual propagation in which new plants are produced and multiplied by the use of parts and buds of the selected mother plants and employing several methods as cuttings, layering, grafting and budding

Parts of plants are cut from a parent plant and inserted into water, sand, soil-less mixes, or many possible combinations thereof, where they form roots and become new plants

Cuttings are classified either according to the plant parts used - as roots, stems, or leaves

CUTTINGS

ROOT CUTTING

LEAF CUTTING

STEM CUTTING

ARTIFICIAL PROPAGATIONB: GRAFTNG

Grafting encompasses any process whereby a part (called the scion) taken from one plant, is made to unite with and grow upon another plant or part of a plant (called the rootstock).

The scion may be a single bud, a piece of stem (as of a cactus), or a fragment of root of a desirable variety.

The scion and stock are tied into place Sealed with grafting wax, tape, or paraffin, to

prevent the evaporation of available moisture. As the two parts of a graft grow together they

are said to form a "union". To graft 2 organisms (plant), they must be of

the same genus

GRAFTING SCION

ROOTSTOCK

DID YOU KNOW?

John Macintosh discovered an apple tree in 1811in Dundas County, Ontario- Macintosh apples!!

Mac seeds were saved and planted, but offspring always were a disappointment – inferior apples

Scions from Mac tree attached to other root stocks from different apple trees in 1835

All tissues, including the fruit, above the graft are genetically identical to Mac tree, resulting trees produced desired apples!

ALL Macintosh apples sold today come from grafts of the original tree found