hort exam 2

What are the 3 basic types of cells in plants? Differentiate between them

Parenchyma, Collenchyma, and Sclerenchyma

What is a cell wall made of? What does it do?

They are made of mainly cellulose. They provide filler, structure, support, and protection

Where is the pectin in a plant?

The pectin is in the cell wall (middle lamella). It holds plant cells together and is used as a gelling agent for jams and jellies.

What does the plasma membrane (or plasmalemma) do? Is it attached to the cell wall?

a double membrane that surrounds the cytoplasm. not attached to the cell wall!!

How do cells connect/communicate with one another?

cell to cell interconnections are made by cytoplasmic strands

What is the cytoplasm?

everything in the cell except for the organelles

What is in the nucleus and never leaves?

Eukaryotic DNA never leaves but is instead copied into RNA

What is a chloroplast? What happens here?

they are green plastids that contain chlorophyll. It is the site of photosynthesis

What does the ER and rough ER do?

Endoplasmic reticulum (ER) are tubular membranes for communication across the cytoplasm. It is the site of protein synthesis. ER has no ribosomes and rough ER does.

What does the vacuole do?

They are cavities in cells that contain a liquid called vacuolar sap or cell sap. They store organic acids, salts, anthocyanins (blue, purple, red), metabolic wastes, enzymes and metabolites.

What is DNA and how does it differ from RNA?

DNA = double helix chain of sugar-phosphates
(deoxyribo-sugar-phosphates) connected by nucleic acids

RNA = a single stranded chain of sugar-phosphates (ribo-sugar-phosphates) containing nucleic acids

Identify the base pairs of DNA and RNA

DNA = adenine+thymine and guanine+cytosine

RNA = adenine+uracil and guanine+cytosine

Describe the process of transcription and translation

Transcription= The process by which DNA is copied to RNA

Translation= RNA is used to produce proteins

Why are plants propagated asexually?

Plants with desirable traits can be generated from a single plant.

asexual propagation techniques of cuttings (stem, root and leaf)

cutting off a piece of a plant and placing it in conditions where it becomes self sustaining and develops its own roots (in water or in soil). Must form adventitious roots.

asexual propagation techniques of layering

Propagation technique where roots are formed prior to the stem being removed from the parent plant. also can be done with air layering. must form adventitious roots.

asexual propagation techniques of grafting and budding

Grafting and budding: joining parts of plants so they continue growth as one plant. Calluses must form on wounds so the plant is whole and fully connected

asexual propagation techniques of division

Dividing the roots of a large plant and separating it into multiple small ones. Must form shoots and adventitious roots.

asexual propagation techniques of micropropagation

Small pieces of plant tissue grown on sterile
media under aseptic conditions. Must grow in unnatural environment

What is a chimera?

A mixture of two or more variations of plant DNA within one plant.

What factors affect the success of grafting and budding?

the maturity and size of the graft sample to the tree

What does it mean for bark to "slip"?

when cut, the bark easily lifts or peels in one uniform layer from the underlying wood without tearing

Define scion and rootstock.  

Rootstock is the base and root portion of grafted plants

A scion, the flowering and/or fruiting part of the plant, is grafted onto rootstock

What types of grafts can be used to repair damage to trees?

inarching, bridge grafting, and brace grafting

What types of grafts can be used if the scion and rootstock are about the same size?

whip or tongue graft, splice graft, and saddle graft

What types of grafts are used if the scion is smaller than the stock?

side grafting, cleft grafting, notch (wedge, or saw-kerf) grafting, bark or inlay graft, approach graft, and topworking

What does it mean for bark to "slip"?

Slipping means that, when cut, the bark easily lifts or peels in one uniform layer from the underlying wood without tearing

What types of grafts are used if the bark is slipping?

T-bud, inverted T-bud, I-bud, patch bud, ring bud, flute bud. basically taking off the outer layer of bark and putting it on the new tree

What types of grafts are used when the bark is not slipping?

chip bud- taking a chunk out of the tree and placing it in a new tree

What is micropropagation? Why is it used?

Small pieces of plant tissue grown on sterile
media under aseptic conditions. Plants grow rapidly, have a higher chance of producing a seed, and have less disease transmission

Know the advantages and disadvantages of sexual propagation of horticultural plants

advantages- produces large numbers in a short amount of time and with high variation

disadvantages- unpredictable numbers of seed production and difficult to germinate

Understand self- and cross-pollination in plants.

Self-pollination occurs when the pollen from the anther is deposited on the stigma of the same flower or another flower on the same plant. (self-pollination on the same plant)

Cross-pollination is the transfer of pollen from the anther of one flower to the stigma of another flower on a different individual of the same species. (pollinating a different plant)

Describe double fertilization. What types of plants undergo double fertilization?

union of one male gamete (1N) with one female gamete (1N) to produce a zygote (2N), plus the union of one male gamete (1N) with two polar nuclei (1N each) to produce an endosperm (3N); occurs only in angiosperms (flowering plants)

Ploidy

the number of sets of chromosomes present in the nucleus of the cell (also study the picture!!)

zygote

a fertilized egg; half of the chromosomes from egg (female) and half from pollen (male)

embryo

zygote develops into the embryo of the seed: which a small hybrid embryonic plant

apomixis

development of an embryo without fertilization; hence; it is not true sexual propagation even though it produces a seed; Citrus is a noted example

vivipary

germination of seeds inside the fruit while still attached to the parent plant

Compare quiescence and dormancy. 

quiescence- state of suspended growth of the embryo or a resting condition (needs water)

dormancy- state that requires a special event or “trigger” before the embryo can resume growth (needs fire, scarification, cold)

Define stratification and scarification. 

stratification- Requires seeds to be stored in a moist, aerated medium at chilling temperatures for
a certain period of time

scarification- Physical or chemical abrasion of seed
coat. Seeds will not imbibe water until the
outer layer of cells are treated

Describe the stages of seed germination. 

study this picture!!

List four environmental factors that affect seed germination and how each impacts seed germination.

temperature, light, soil moisture, and pH levels

Explain the plant hardiness zone maps

plant hardiness zones are based on average minimum temperature. There are 13 zones that are divided evenly into 10 degree increments

Describe a microclimate and how it may be created in a landscape

A microclimate is the distinctive climate of a small-scale area, such as a garden, park, valley or part of a city. Environmental factors such as mountains, rocks, or wind affect each microclimate differently.

Compare chilling, freezing and frost

chilling- Injury that occurs ABOVE freezing; 32-50 degrees F (0-10 degrees C)

freezing- Injury that occurs below 32 degrees F
(0 degrees C). Freezing injury can occur in absence
of frost

frost- Frost can occur when air temperature is above freezing (38 degrees F)

Explain a heat day and the heat zone map

Based on the average number of days over 86 degrees F. 86 degrees F is point plants often begin to experience physiological damage

Understand the processes of photosynthesis (Pn) and its equation

photosynthesis- Harvesting of light energy and conversion into a usable chemical form of energy (glucose) = CONVERSION and STORAGE of energy.

understand respiration (Rs) and its equation

respiration- Use or oxidation of stored carbon compounds (glucose) to provide energy for growth and
plant maintenance = USE of STORED ENERGY
forms ATP

understand photorespiration

photorespiration- Reduction in carbon fixation capability seen in C3 plants when internal leaf oxygen levels increase = inefficient photosynthesis

Know the inputs and outputs for both the light and dark reaction of Pn

light- light/ water —> oxygen

dark- carbon dioxide —> carbohydrates

Compare Pn (light and dark reactions) to Rs including where they occur

Photosynthesis converts carbon dioxide and water into oxygen and glucose. occurs in the chloroplast

Cellular respiration converts oxygen and glucose into water and carbon dioxide. occurs in the cytosol and mitochondria

Where in the leaf does most photosynthesis occur?

Chloroplasts are concentrated in palisade layer. Upper 40% of the cross section of a leaf

Be able to discuss what transpiration is and how it is impacted by the environment

Water loss from a plant, mostly through stomata. Transpiration rates are higher when the relative humidity of air is low, which can occur due to windy conditions or when the temperatures are high

Define evapotranspiration

the process by which water is transferred from the land to the atmosphere by evaporation from the soil and other surfaces and by transpiration from plants

Understand and be able to discuss translocation in plants

the movement of materials from leaves to other tissues throughout the plant

Be able to list the three carbon fixation pathways (C₃, C₄, and CAM) and explain the differences between each

C3- most plants, ex. Tropical foliage plants, tomatoes, apples

C4- Some grasses, ex. Corn, sorghum

CAM- Many desert plants, succulents, cacti

Know the environmental factors that affect Pn and Rs. 

light quality and quantity, ambient CO₂ concentration, temperature and water availability

Describe the composition of a mineral soil

sand, silt, and clay

Be able to identify the mineral class of a soil using the soil triangle

The numbers and lines on the triangle dictate the % of sand, silt and clay in the soil

Describe the effects of soil texture on soil properties

large particles- more are space, less capacity to hold water

small particles- less air space, more compact and capacity to hold water

Know advantages and disadvantages of using mineral soils

advantages- CAN promote extra growth and provide nutrients to plants. it is cheap and natural

disadvantages- if it has the wrong combination/ balance of minerals, it can result in nutrient deficiencies and stunt growth. can cause pest and disease problems

List causes of soil compaction

rain hitting bare soil, foot traffic, tillage (human interference on soil for agricultural purposes)

Discuss no-till agriculture

No-till farming is an agricultural technique for growing crops or pasture without disturbing the soil through tillage. No-till farming decreases the amount of soil erosion tillage causes in certain soils, especially in sandy and dry soils on sloping terrain