Plant Reproduciton and Nutrient Needs

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

2. Asexual 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 www.OneLessThing.net

3. Asexual Reproduction Methods • Cuttings and Division/Separation • Grafting • Layering • Tissue Culture (a.k.a. Micropropagation) www.OneLessThing.net

4. Cuttings and Separation/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 www.OneLessThing.net

5. Grafting • 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 www.OneLessThing.net

6. Layering • 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 www.OneLessThing.net

7. Tissue 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 www.OneLessThing.net

8. Advantages of Asexual Reproduction • 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 www.OneLessThing.net

9. Disadvantages of Asexual Reproduction • 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 www.OneLessThing.net

10. Sexual Reproduction in Plants • 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 www.OneLessThing.net

11. Flower Anatomy www.OneLessThing.net

12. Plant 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 www.OneLessThing.net

13. Sexual Reproduction in 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 www.OneLessThing.net

14. Sexual Reproduction in Plants • 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 www.OneLessThing.net

15. Sexual Reproduction Advantages • 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 www.OneLessThing.net

16. Sexual Reproduction Disadvantages • 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 www.OneLessThing.net

17. Nutrient Needs of Plants • 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 www.OneLessThing.net

18. Nutrient Needs of Plants • 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 www.OneLessThing.net

19. Nutrient Needs of Plants • 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 www.OneLessThing.net

20. Nutrient Needs of Plants • 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) www.OneLessThing.net

21. Nutrient Needs of Plants • 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). www.OneLessThing.net

22. Nutrient Needs of Plants • 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. www.OneLessThing.net

23. Nutrient Needs of Plants • 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 www.OneLessThing.net

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