1. Informal Quiz Time – Is it True or Is It False?
Nonvascular plants require a moist environment for asexual reproduction.
The sporophyte is the dominant generation in the life cycle of nonvascular plants.
Male cones are smaller than female cones and are arranged in clusters.
In gymnosperms, pollen attaches to the egg cell and fertilization occurs.
The female part of an angiosperm includes the stigma, style, and ovary.

2. Answers False. A moist environment is needed for sexual reproduction.
False. The gametophyte generation is the dominant generation in the life cycle.
True.
False. Pollen attaches to the nucellus and grows and develops into a gametophyte. The gametophyte releases sperm cells that fertilize the egg cell.

3. Double fertilization occurs in angiosperms.
The endosperm provides nourishment to the developing embryo.
A growth hormone called radicle starts the germination process.
The radicle eventually develops into the root and the hypocotyl develops into the stem.
Grafting is a form of asexual reproduction that combines the buds of one plant with the stem of another.

4. Answers
True.
False. The hormone that starts the germination process is called gibberellin.

5. Plant Growth

6. Plants require basic nutrients to sustain themselves.
Since plants are autotrophic, they need water, carbon dioxide, and sunlight to produce the organic compounds needed for cellular processes like growth and energy.
In addition to manufacturing organic compounds, plants acquire water and minerals from the soil through their roots.
The ability of plants to attain water, nutrients, and sunlight can greatly affect their growth and ultimately their survival.

7. Recall from the last activity that plant growth begins when a seed begins to germinate.
From the tiny seed, a main root and stem start to appear and soon enough an entire plant exists.
Just like multicellular organisms, plants contain specialized structures, tissues and cells that perform specific tasks.
Growth in plants occurs at the meristematic tissue where rapid mitosis produces new cells. This is called primary growth.
Plants can only grow in areas where meristematic tissue occurs and these areas are called meristems.

8. Apical meristems are located at the root tip and at the ends of shoots.
Apical meristems located in the root tip produce cells that enable the stem to grow in length.
The apical meristems that are located at the end of shoots give rise to buds and leaves.

10. The vascular cambium which you looked at earlier in this unit causes a plant to grow wider. This is called secondary growth.
The vascular cambium is a ring of meristematic tissue that separates the xylem from the phloem in dicots.
Recall that the xylem cells are located in towards the centre and the phloem cells are located near the exterior.

11. There are three requirements for plant growth:
Soil Nutrients
Sunlight
Water

12. Soil Nutrients
Soil consists of many different components that are required by plants and it is arranged in several layers.
Using the diagram on the right as a guide, the top layer of soil (O) is called humus and it is composed of dead and decaying plant and animal remains.
The presence of high concentration of humus in the soil will support plant growth.

13. The next layer (A) is topsoil and this is the layer that will support plant growth.
It is made up of humus, clay, minerals and sand.
The next layer (B) is called subsoil. Many worms, insects and microorganisms live in the first three layers.
In addition, the roots absorb water and dissolved minerals in these layers. The last layer (C) is bedrock and it does not support plant growth.
As shown in the illustration, the growth of the roots stops at the end of the subsoil level.

14. The minerals that are needed by plants in small amounts include iron, zinc and copper and are referred to as micronutrients.
Macronutrients like nitrogen, phosphorus, potassium, calcium and magnesium are required in larger amounts.
The absence of any of these nutrients may cause a plant to die.
Each nutrient is required by plants to carry out cell functions like cellular respiration or photosynthesis.

15. Sometimes people will help replenish the soil by adding fertilizers that contain specific nutrients.
Commercially produced fertilizers usually contain nitrogen, phosphorus and potassium as percentages.
The percent composition of each nutrient allows people to choose the appropriate fertilizer for the type of plant or the type of growth they want to achieve.
Some people may choose to apply organic fertilizers like manure on their crops or in their gardens.
One of the benefits of organic fertilizers is that they release the nutrients slowly into the soil.
This prevents accidental chemical burns that may occur when too much commercial fertilizer is applied.

16. Sunlight
Plants use the energy of the sun to drive the process of photosynthesis.
The light from the sun's rays is needed to activate special enzymes within the chlorophyll of the chloroplasts.
There are many factors associated with light and its effect on plant growth and photosynthesis.

17. Light Intensity: The growth of a plant affected by its location
Light Intensity: The growth of a plant affected by its location. A plant may be placed in direct sunlight, partial sunlight or in the shade. Plants that are in the shade grow the least.
Light Quality: Chlorophyll, the green pigment common to all photosynthetic cells, absorbs all wavelengths of visible light except green, which it reflects to be detected by our eyes.
Duration: Plants that are exposed to longer periods of light will grow faster. Shorter periods of light provide less energy to drive the process of photosynthesis. Excessive amounts of light may cause a plant to lose excessive amounts of water through transpiration