Lesson 4.ppt

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1、Plant PropagationLesson 4Methods of plant propagation as related to horticultural plant productionPropagation The multiplication of a kind or species. Reproduction of a species. Two kinds： Sexual Propagation Asexual PropagationSexual Propagation Propagation from seeds. Pollen is transferred from the

2、 anther to the stigma. Fertilization occurs and seeds are produced.Color, Weight and Size Variations in SeedsAssorted beanswheat grainfenugreekblack mustardhempgreen lentilsdried peasgreen split peassoya beanswheat germoatsGolden flaxPinto beanscorianderVariety of pulsesShape Variations in SeedsPart

3、s of the SeedParts of the Seed Seeds are made up of 3 main parts.Seed Coat.Endosperm.Embryonic Plant.Planting Seeds Planting depth depends on the size of the seeds. The larger the seed, the deeper it is planted.Example: Petunia seeds are planted shallower than beans, tomatoes, or marigolds because t

4、hey are the smallest. Small seeds should be watered by bottom soaking.Planting Seeds Seeds are directly seeded when they are planted in the soil where they will grow to a saleable size. Germination flats are used if they are to be transplanted at a later time.When reusing germination flats, be sure

5、to sterilize the flats and soil.Germination Germination rate is the % that sprout. Example: 75 out of 100 = 75% Rates affected by. Seed viability. Temperature. Moisture. Type of plant. Quality of seed. Seeds to SeedlingsTransplanting Seedlings Seedlings are the small plants. Transplant when first tr

6、ue leaves appear Held by the true leaves rather than the stems to prevent stem bruising which will kill the plant.Seedlings (small plants) Transplant when first true leaves appear Reduce humidity and water and make environment more like outside to “harden off” plantsAdvantages of Sexual Reproduction

7、 Fast way to get many plants Easy to do EconomicalDisadvantages of Sexual Reproduction Some plants, especially hybrids, do not reproduce true to parents Some plants are difficult to propagate from seedsAsexual Reproduction Uses growing plant parts other than seeds Types of asexual reproduction: cutt

8、ings 插枝插枝 layering 压条压条 division or separation Budding grafting tissue cultureRooting from Cuttings Rooting media should be about 4 inches deep Best time of day is early mornings because plants have more moistureRooting from Cuttings The three main types of cuttings are.StemLeafRootStem Cuttings The

9、 taking of a piece of stem to reproduce plants. Use a rooting hormone with fungicide to.Speed up root development.Prevent root rot.Stem Cuttings-Step 1Gather all materials neededStem Cuttings-Step 2Cut 3 to 4 inch shoot from stem tipStem Cuttings-Step 3Remove lower leaves from the shootStem Cuttings

10、-Step 4Dip cut surface in rooting hormoneStem Cuttings-Step 5Thoroughly moisten rooting mediumStem Cuttings-Step 6Stick one or more cuttings in rooting mediaStem Cuttings-Step 7Cover with plastic wrap or place on a mist bench in a warm area away from direct sunlight.Stem Cuttings-Step 8Once rooted,

11、cuttings can be separated carefully and transplantedLeaf cuttings The use of leaves and sections of leaves to reproduce plants. Done from herbaceous plants Veins must be cut Leaf cuttings are best taken early in the growing season from spring to early summer, though some can be propagated any time o

12、f year.Part-leaf cuttings Streptocarpus: Select a full-grown leaf and cut in half along the midrib, which should be discarded. Using a seed tray make a shallow trench and insert the leaf, cut side down and firm in.捩荚草捩荚草Part-leaf cuttings Sansevieria, Eucomis: Cut leaves horizontally into 5cm (2in)

13、pieces and insert lower edge down. Make sure to keep the cuttings facing the direction that it was growing on the plant, alternatively cut into shallow chevrons. Insert the cuttings vertically about 2cm (3/4in) deep.虎尾兰虎尾兰Eucomis vandermerwei凤梨百合Part-leaf cuttings Begonia, Sinningia: Cut across the

14、main veins on the underside. Pin the leaf, cut side down onto the compost. Alternatively, cut the leaf into squares 2.5cm (1in) across each with a main vein. Pin the squares to the surface of the compost.BegoniaBegonia 秋海棠秋海棠Sinningia speciosa 大岩桐大岩桐Whole-leaf cuttingsSinningia incarnata岩桐Saintpauli

15、a 非洲堇(African violet)Peperomia argyreia(Watermelon Peperomia)西瓜皮椒草 Echeveria elegans景天科拟石莲花属景天科拟石莲花属( (月影月影) )Crassula capitella 茜之塔Kalanchoe blossfeldiana萬紫千紅Aftercare Water and allow to drain. Place in a propagator or a clear plastic bag in a light place out of direct sunlight. Leaf cuttings from

16、tropical plants must be kept in high humidity at about 20C (68F). When plantlets form, remove covers and allow them to grow on until large enough to pot up individually.Root Cuttings The use of roots to reproduce plants. Should be spaced 3 inches apart in the rooting area.Step 1 Carefully Uncover Th

17、e Roots The best time to take root cuttings is when the plants are dormant which is usually between November and February. At this time, there is a large amount of stored energy in the roots, and there is less stress on the parent plant because they are not actively growing and in as much need of th

18、eir root system.Step 2Take Your Root Cuttings For both woody plants and perennial plants, dont take more than one-third of the roots off. This way you will leave enough roots for the parent plant to recover.Step 3Plant Your Root Cuttings1. Use a deep pot, raised planter bed, or just in the soil some

19、where to plant your root cuttings - as long as they are in a frost-free area.2. Before you plant them, put a little bit of sand in the bottom of the hole and dust the bottom of each cutting with powdered sulfur to control fungi. This helps keeps the roots from rotting.3. Plant in moist potting soil

20、a few inches apart, and make sure that the tops of the cuttings are about 1 inch (2.5 cm) below the soil surface.4. Cover with 1/4 to 1/2 inch (cm) of coarse sand or small gravel.5. Water only when soil becomes dry and try not to keep the soil too wet because the roots can rot.Plant 1 inch (2.5 cm)

21、Below Soil SurfaceDip Bottom Ends In SulfurCover With Coarse Sand or Small GravelStep 4When Shoots Appear, Plant Them Out1. In three to four weeks your cuttings should be forming roots, and some even may start to push new growth.2. When new shoots appear, give them some liquid fertilizer at half str

22、ength.3. Once the plants are established, they can be transplanted to individual pots or moved into the garden. 4. When planting out the cuttings, make sure the tops of the cuttings (the straight cut ends) are about 2 inches (5 cm) below the soil surface.5. Keep in mind, perennial root cuttings can

23、start pushing new growth fairly quickly, so you might need to protect them from any freezing weahter. Examples:raspberry 悬钩子blackberry 黑莓trumpet vine (Campsis)厚萼凌霄 rosePhlox Paniculata天蓝绣球、草夹竹桃Crabapple沙果Lilac紫丁香Sumac 漆树figLayering The rooting of plant parts while they are still attached to the “par

24、ent” plant. The types are. Air Layering. Trench Layering. Mound Layering.Air layeringIn air layering (or marcotting), the target region is wounded and then surrounded in a moisture-retaining wrapper such as sphagnum moss, which is further surrounded in a moisture barrier such as polyethylene film. R

25、ooting hormone is often applied to encourage the wounded region to grow roots. When sufficient roots have grown from the wound, the stem from the parent plant is removed and planted. It takes about three months for the new plant to become mature.Trench Layering Mother plant is bent to the ground and

26、 buried. Plants form at each node on covered stem.Mound Layering Rooted plant is cut off at the soil level. As the season progresses, soil is added to cover the growing shoots. After 1 year, the shoots are rooted and removed from the parent plant.Division or Separation Cutting or pulling apart plant

27、 structures for reproduction bulbs corms rhizomes tubers stolons/runners suckersBulbs A bulb is a short stem with fleshy leaves or leaf bases. The leaves often function as food storage organs during dormancy.Corms Crocosmia corm anatomy, showing tunic, cortex of storage tissue, central medulla, and

28、emergence of a new corm from a bud near the topA corm (bulbotuber) is a short, vertical, swollen underground plant stem that serves as a storage organ used by some plants to survive winter or other adverse conditions such as summer drought and heat (estivation).Comparison of the corm and the bulb Co

29、rms are often similar in appearance to bulbs externally, and thus erroneously called bulbs. Corms are stems that are internally structured with solid tissues, which distinguishes them from bulbs, which are mostly made up of layered fleshy scales that are modified leaves. As a result, when a corm is

30、cut in half it is solid, but when a true bulb is cut in half it is made up of layers. Corms are structurally plant stems, with nodes and internodes with buds and produce adventitious roots. On the top of the corm, one or a few buds grow into shoots that produce normal leaves and flowers.Rhizomes In

31、botany and dendrology, a rhizome is a modified subterranean stem of a plant that is usually found underground, often sending out roots and shoots from its nodes.gingerTubersTubers are various types of modified plant structures that are enlarged to store nutrients. They are used by plants to survive

32、the winter or dry months, to provide energy and nutrients for regrowth during the next growing season, and as a means of asexual reproduction. Stem tubers, which are the development of enlarged stolons thickened into a storage organ.Root tubers, a tuberous root is a modified lateral root, enlarged t

33、o function as a storage organ.Chinese yamSweet potatoPotato Stolons/Runners In botany, stolons are stems which grow at the soil surface or just below ground that form adventitious roots at the nodes, and new plants from the buds. Stolons are often called runnersFicinia spiralis金砂莎草金砂莎草Lipstick hybri

34、d strawberryPoplar suckers emerging along a root (mother tree is not visible)Suckers A sucker, basal shoot, root sprout, adventitious shoot or water sprout is a shoot or cane which grows from a bud at the base of a tree or shrub or from its roots. Root suckers may emerge some distance from the origi

35、nating plant. Suckers also may arise from the stumps of trees that have been cut down.A sucker emerging from the base of a young treeGrafting Joining separate plant parts together so that they form a union and grow together to make one plant.Wedge GraftApproach GraftBudding A form of grafting when a

36、 bud is used. Faster or quicker than grafting. The 3 main methods are. Patch budding. T-budding. Chip budding.Patch BuddingT-BuddingChip BuddingTissue Culture Using a small amount of plant tissue to grow in a sterile environment The most plants in a short time True to parent plantAdvantages to Asexu

37、al Propagation Plants mature in shorter time. Some plants do not produce viable seeds. New plants are same as parent plant.Disadvantages of Asexual Reproduction Some require special equipment and skills, such as grafting Cuttings detach plant parts from water and nutrient source Some plants are patented making propagation illegal