Plant Reproduciton and Nutrient Needs Basic Plant Science AFNR-BAS-13: Explain and demonstrate basic plant science principles including plant health, growth

Plant Reproduciton Plant Reproduciton and Nutrient Needsand Nutrient Needs

Basic Plant ScienceBasic Plant Science

AFNR-BAS-13: Explain and demonstrate basic plant science principles including plant health, growth and reproduction.

Asexual ReproductionAsexual Reproduction

Asexual reproduction: producing new plants from parts of a plant (leaves, stems, etc.)

another name for plant reproduction is propagation

propagation: deliberately controlling and manipulating the reproduction of a plant

new plants created through asexual reproduction are identical to the parent plant

genetic duplicates of parents are often called clones

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Asexual Reproduction Asexual Reproduction MethodsMethods

Cuttings and Division/Separation

Grafting

Layering

Tissue Culture (a.k.a. Micropropagation)


Cuttings and Cuttings and Separation/DivsionSeparation/Divsion

most common and simple methods of asexual reproduction

separation and division: splitting apart a root or root system into two or more pieces which each become a new plant (ex. hostas, potatoes, daylillies, ornamental grasses)

cuttings: segments of leaves, stem, or roots are cut off and then placed in growing media to develop into new plants (ex. begonias, ivy, pothos, African violet, wandering Jew)

usually plants that root easily are used and the cuttings are treated with rooting hormone before being planted


GraftingGrafting

method commonly used on trees by orchards and nurseries

the upper part of one plant is joined to the lower part of another so they grow as one plant (ex. apples, citrus, hibiscus)

scion: the part of the graft that will become the stem

rootstock: the lower portion of the graft that includes the roots

union: where the two grafts meet


LayeringLayering

part of a stem or tip that is still attached to the parent plant is covered in soil or media until adventitious roots form

most successful on woody plants

the parent plant provides water and nutrients to the new plant until roots are formed


Tissue CultureTissue Culture

entire new plants are grown from small pieces of plant tissue placed in in artificial media under sterile conditions

the media is a gel containing moisture, nutrients, and hormones for plant growth

used to make large populations of plants that are genetically identical

can be used to improve genetics quickly


Advantages of Asexual Advantages of Asexual ReproductionReproduction

keep best characteristics pure

some plants are difficult to reproduce sexually

shorten the time to produce a mature plant versus starting from a seed

can create large numbers of identical plants

can reduce disease occurrence


Disadvantages of Asexual Disadvantages of Asexual ReproductionReproduction

the main disadvantage is the potential for impact on biodiversity of a species

also if a particular plant clone is susceptible to certain diseases, there is potential to lose entire crops

can be more expensive and requires more skill


Sexual Reproduction in Sexual Reproduction in PlantsPlants

pollination: the transfer of pollen grains from the male part of the flower (the anther) to the female part (the stigma)

self-pollination: on plants with complete flowers the pollen falls from the anther onto its own stigma

cross-pollination: plants that have incomplete flowers (or have complete flowers but are not compatible for self-pollination) require pollinators to transfer the pollen to another plant common pollinators: wind, birds, insects, bats


Flower AnatomyFlower Anatomy


Plant PartsPlant Parts

Flowers: complete flowers: flowers that have all the parts

(sepals, petals, stamen, and pistil) incomplete flowers: flowers that lack one of the

four main parts - petals, sepals, pistil, or stamen male flowers will not have a pistil and female

flowers will lack stamen monoecious: plants that have male and female

flowers on the same plant dioecious: plants that have male and female

flowers on separate plants



fertilization: when the male sex cell joins with the female sex cell (the ovule)

the pollen grain lands on the stigma and then grows a tube down the style to the ovary to make a gamete (a fertilized egg)

the ovule expands and develops into the seed while the petals and sepals fall off; most flowers have many ovules and therefore develop many seeds

in some plants, the ovary expands and develops into the fruit or pods



germination: the process of a seed developing into a plant

seeds will remain dormant until the proper conditions are met and these vary depending on the type of seed

common germination variables are planting depth, amount of moisture, and proper temperature

scarification: wearing away the seed coat to allow water in to the embryo

stratification: cold treatment of seeds to simulate natural winter conditions to promote germination


Sexual Reproduction Sexual Reproduction AdvantagesAdvantages

seeds are easily stored from year to year and over a long period of time

an inexpensive way to grow a large number of plants

easy to do and usually does not require special skills


Sexual Reproduction Sexual Reproduction DisadvantagesDisadvantages

offspring are genetically different from parents so desirable traits can be lost or depleted

germination rates can be low

length of time to a mature plant can be long


Nutrient Needs of Nutrient Needs of PlantsPlants

Carbon (C), Hydrogen (H), and Oxygen (O) are the three elements plants obtain from the atmosphere

used by plants for metabolic processes to make food and break down stored sugars

nutrients in the soil must be dissolved in water before being absorbed through a plant's roots



there are 16 or 17 essential nutrients needed by plants in different amounts

not always enough of these are in the soil for healthy plant growth so we use fertilizers or compost to add the nutrients to the soil

deficiency: a shortage of a given nutrient needed by a plant



Macronutrients needed in the greatest amount by plants for

maximum growth Nitrogen (N), Phosphorous (P), and Potassium

(K) are the major nutrients usually lacking in the soil because plants use large amounts for growth

Calcium (Ca), Magnesium (Mg), and Sulfur (S) are also major nutrients but are not usually needed when fertilizing because there is enough in the soil



Micronutrients elements essential for plant growth which are

needed in only very small quantities also known as trace elements Boron (B), Copper (Cu), Chlorine (Cl), Iron (Fe),

Manganese (Mn), Molybdenum (Mo), and Zinc (Zn)



Fertilizers materials containing essential plant nutrients

that are added to the environment around the plant

generally added to irrigation water or soil, but some can also be added to the air or sprayed on plant leaves

All fertilizers are labeled with three numbers giving the percentage of nitrogen, phosphorus, and potassium (N-P-K).



Fertilizers Filler is also included and is important to evenly

spread the fertilizer and avoid burning plants with too much fertilizer.

The best fertilizer to use depends on many factors, such as the nutrients needed, soil structure, soil chemistry, and method of applying the fertilizer.

Soil pH is one of the most important soil properties that affects the availability of nutrients.



Fertilizers organic fertilizers: the nutrients contained in

the product come from the remains or by-products of a once-living organism

examples: cottonseed meal, blood meal, bone meal, hoof and horn meal, and all manures


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Plant Reproduciton and Nutrient Needs Basic Plant Science AFNR-BAS-13: Explain and demonstrate basic plant science principles including plant health, growth