Physiology & Propagation Notes

Physiology & Propagation Notes

---Right now these are mostly as I took them to class, Hopefully I'll clean them up a bit and add to them, but right now I don't have the energy... So, here they are for anyone who wants to see.---

Physiology:

Cell–smallest unit we’ll deal with

Cell walls make plants’ cells different from animals’ cells.
–can maintain turgidity or can burst —in the freezer some foods become mushy due to the cell walls bursting. Think of what happens to lettuce when it is in the back of the fridge and it freezes. It gets all limp and mushy, gross.

Parts of a plant:
What are they for? Remember, many plant parts can be used to identify a plant

Roots–absorb nutrients & water, anchor the plant, storage of sugars, can be used to propagate the plant (in some instances)
Edible–sweet potato, carrot, turnip

Crown–holds buds for growth; point of origin for stems & roots

Stems–support leaves, buds, flowers; carry water, sugars, minerals
nodes-sites where leaves and buds grow from
internodes-between nodes
Edible stems–potato, asparagus, kohlrabi, cauliflower, onion

Modified Stems–crown, spur, stolon, tuber, rhizome, bulb, corm

Leaves–absorb sunlight for photosynthesis & respiration

Buds–undeveloped shoot, leaves, or flower parts emerge
Terminal–tips; can inhibit lateral growth
Lateral–sides of the stems
Adventitious–anywhere else on the plant
Edible buds–cabbage and head lettuce, Brussels sprouts, broccoli

Flowers–attract insects for pollenation, which is for sexual reproduction

Fruit–disperse the seed and to be attractive to wildlife that can help disperse it further

Seeds–develops into a new plant; continues the genetic information to the next generation
The seeds are the part of the plant that has genetic information from both parent plants. The fleshy part (that we eat) is identical to the maternal plant. When the seeds sprout and form a new plant, the genetic information from both plants can manifest itself.

Parts of a flower:
Not all flowers are “complete”. Some need other plants for fruit to develop. Others need just another kind of pollen. Some, like some cantaloupe, need a male and female plant near each other for fruit to develop properly.
anther + filament = stamen; Male part
stigma + style + ovary = pistil; Female part —Ovary becomes fruit with seeds inside it
petal
sepal
receptacle
pedicel
tepal (no clear distinction between sepals and petals)—tulips have these

Adaptations–cactus, runners, climbing vines

Adventitious
Roots, shoots, stems, buds

Genetics
Basic Mendelian genetics, with simple traits

Cross two plants, show offspring, cross two hybrids and show offspring
— You can’t just plant the seeds from crossed plants and get the same results

Use human examples—Simple traits=one gene leads to one trait
tongue rolling, hitchhiker’s thumb (recessive), mid-digit finger hair, dimples, freckles, earlobe attachment, separated versus joined eyebrows, clockwise versus counter-clockwise hair whorl, wet or dry-type earwax

Dominant versus recessive traits


Photosynthesis—carbon dioxide + water & light = sugar & oxygen. Plant food production.

Respiration—sugar + oxygen = carbon dioxide, water & energy. Carbohydrates are converted into energy.

Transpiration—plant loses water, usually through stomata. 90% of water is lost this way, the other 10% is used in chemical reactions in the plant.

Propagation:

There is variety among all the plants. You may have to research before you can know about your specific plant’s needs. I can’t list every exception to the rule.

Asexual versus sexual reproduction–cloning

Seeds, Cuttings & Division

Seeds: Dormancy–many seeds have a dormancy that must be broken before they will grow and develop into a beautiful plant. For some, it is intense heat, others need to be soaked in water overnight. There are some that need to have the seed coat damaged so that the water can get inside the seed.

If storing seed, maintain them dry and at 40 degrees to keep them healthy.

Plant more seeds than you want plants and thin them out when you are ready to transplant, or when they crowd each other. Not all seeds will germinate and not all seedlings will develop into mature, healthy plants.

Water, oxygen, light & heat are needed to grow from seed

Keep moist by covering with some type of dome or by keeping the soil watered. Allow for air circulation as well. Water thoroughly, especially right after seeding. Use a light mist, or dip in a pan of water to keep from moving the newly planted seeds.

To allow respiration to occur, oxygen is needed. Use loose, well-aerated soil.

Light can stimulate or inhibit germination, depending on the seed variety. If light is needed indoors, artificial lighting can be used. Suspend 6-12 inches from seed tray for 16 hours per day.

Plant in soil.

Maintain between 65 & 75 degrees.

4 to 12 weeks from transplanting—start seeding.

Transplant after first true leaves appear. The first leaves that will emerge from a seed are cotyledons. They will eventually dry up and fall off. The next leaves to appear, are the first true leaves. Try not to disturb the roots as much as possible.

Hardening off. To create healthy plants that can successfully go outside, they must be hardened off. This is a process of gradually getting plants used to the normal outdoor environment they will be exposed to. This can be done by gradually lowering the temperature, humidity and water. Some of this can be accomplished when the day time temperatures are above freezing. You can put the plants outside in the day time and bring them inside at night when the temperature could dip below freezing. A good rule of thumb is to wait until Mother’s Day, for above freezing temperatures.


Cuttings: Use a sharp blade to avoid increased damage to the plant. Sterilize blade. Use a rooting hormone in a separate container. If you can find one with a fungicide, that is better.

Leaf–cut off a healthy leaf and at least 1 ½ inches of petiole, dip in rooting hormone and gently place in soil. Keep moist and warm. Cover with a plastic bag or other dome to keep humidity high. Water thoroughly when transplanting new plants. You can also just take a leaf, or make cuts in the leaf at the veins. It depends on the particular plant, in most cases. Bright, indirect light.
Used for houseplants

Stem– There are so many different kinds of stem cuttings that I can’t cover it here. Bright, indirect light.

Dividing: –early spring or late fall, when parent plant is dormant

If a plant has more than one rooted crown, then it can be divided into multiple plants.

Separate the crown, leaving 2 or 3 buds on each piece, more if you want it to be larger, faster. Trim any remaining stems or leaves and prune back the roots to fit in the pot you have chosen. Place some soil in the bottom of a 4 inch pot. Place the plant in the pot and fill remaining space with soil. Press firmly, but don’t pack down. Add more soil if needed. Water thoroughly, and keep moist, but not wet.