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1、Plant PropagationLesson 4Methods of plant propagation as related to horticultural plant productionPropagationThe multiplication of a kind or species.Reproduction of a species.Two kinds：Sexual PropagationAsexual PropagationSexual PropagationPropagation from seeds.Pollen is transferred from the anther

2、 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 SeedsParts of the

3、SeedParts of the SeedSeeds are made up of 3 main parts.Seed Coat.Endosperm.Embryonic Plant.Planting SeedsPlanting 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 they are the smal

4、lest.Small seeds should be watered by bottom soaking.Planting SeedsSeeds 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 to sterilize the fla

5、ts and soil.GerminationGermination 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 SeedlingsSeedlings are the small plants.Transplant when first true leaves appearHeld by the true lea

6、ves rather than the stems to prevent stem bruising which will kill the plant.Seedlings(small plants)Transplant when first true leaves appearReduce humidity and water and make environment more like outside to“harden off”plantsAdvantages of Sexual ReproductionFast way to get many plantsEasy to doEcono

7、micalDisadvantages of Sexual ReproductionSome plants,especially hybrids,do not reproduce true to parentsSome plants are difficult to propagate from seedsAsexual ReproductionUses growing plant parts other than seedsTypes of asexual reproduction:cuttings 插枝插枝layering 壓條壓條division or separationBuddingg

8、raftingtissue cultureRooting from CuttingsRooting media should be about 4 inches deepBest time of day is early mornings because plants have more moistureRooting from CuttingsThe three main types of cuttings are.StemLeafRootStem CuttingsThe taking of a piece of stem to reproduce plants.Use a rooting

9、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-Step 4Dip cut surface in rooting hormoneStem Cuttings-Step 5T

10、horoughly 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,cuttings can be separated carefully and transplantedLeaf cuttin

11、gsThe use of leaves and sections of leaves to reproduce plants.Done from herbaceous plantsVeins must be cutLeaf cuttings are best taken early in the growing season from spring to early summer,though some can be propagated any time of year.Part-leaf cuttings Streptocarpus:Select a full-grown leaf and

12、 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.捩莢草捩莢草Part-leaf cuttings Sansevieria,Eucomis:Cut leaves horizontally into 5cm(2in)pieces and insert lower edge down.Make sure to keep the cuttings facing the

13、direction that it was growing on the plant,alternatively cut into shallow chevrons.Insert the cuttings vertically about 2cm(3/4in)deep.虎尾蘭虎尾蘭Eucomis vandermerwei鳳梨百合Part-leaf cuttings Begonia,Sinningia:Cut across the main veins on the underside.Pin the leaf,cut side down onto the compost.Alternative

14、ly,cut the leaf into squares 2.5cm(1in)across each with a main vein.Pin the squares to the surface of the compost.Begonia 秋海棠秋海棠Sinningia speciosa 大巖桐大巖桐Whole-leaf cuttingsSinningia incarnata巖桐Saintpaulia 非洲堇(African violet)Peperomia argyreia(Watermelon Peperomia)西瓜皮椒草 Echeveria elegans景天科擬石蓮花屬景天科擬石

15、蓮花屬(月影月影)Crassula capitella 茜之塔Kalanchoe blossfeldiana萬(wàn)紫千紅AftercareWater and allow to drain.Place in a propagator or a clear plastic bag in a light place out of direct sunlight.Leaf cuttings from tropical plants must be kept in high humidity at about 20C(68F).When plantlets form,remove covers and al

16、low them to grow on until large enough to pot up individually.Root CuttingsThe use of roots to reproduce plants.Should be spaced 3 inches apart in the rooting area.Step 1 Carefully Uncover The RootsThe best time to take root cuttings is when the plants are dormant which is usually between November a

17、nd 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 their root system.Step 2Take Your Root CuttingsFor both woody plants and perennial plants,dont take more than one-t

18、hird 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 somewhere 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

19、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 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/

20、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)Below Soil SurfaceDip Bottom Ends In SulfurCover With Coarse Sand or Small GravelStep 4When Shoots Appear,Plant Them Out1.In three to

21、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 strength.3.Once the plants are established,they can be transplanted to individual pots or moved into the garden.4.When planting out the cuttin

22、gs,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 start pushing new growth fairly quickly,so you might need to protect them from any freezing weahter.Examples:raspberry 懸鉤子blackberry 黑莓trumpet vine(Ca

23、mpsis)厚萼凌霄 rosePhlox Paniculata天藍(lán)繡球、草夾竹桃Crabapple沙果Lilac紫丁香Sumac 漆樹(shù)figLayeringThe rooting of plant parts while they are still attached to the“parent”plant.The types are.Air Layering.Trench Layering.Mound Layering.Air layeringIn air layering(or marcotting),the target region is wounded and then surrou

24、nded in a moisture-retaining wrapper such as sphagnum moss,which is further surrounded in a moisture barrier such as polyethylene film.Rooting 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 remo

25、ved and planted.It takes about three months for the new plant to become mature.Trench LayeringMother plant is bent to the ground and buried.Plants form at each node on covered stem.Mound LayeringRooted plant is cut off at the soil level.As the season progresses,soil is added to cover the growing sho

26、ots.After 1 year,the shoots are rooted and removed from the parent plant.Division or SeparationCutting or pulling apart plant structures for reproductionbulbscormsrhizomestubersstolons/runnerssuckersBulbs A bulb is a short stem with fleshy leaves or leaf bases.The leaves often function as food stora

27、ge organs during dormancy.Corms Crocosmia corm anatomy,showing tunic,cortex of storage tissue,central medulla,and 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 o

28、r other adverse conditions such as summer drought and heat(estivation).Comparison of the corm and the bulbCorms 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,

29、which are mostly made up of layered fleshy scales that are modified leaves.As a result,when a corm is 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 o

30、f the corm,one or a few buds grow into shoots that produce normal leaves and flowers.RhizomesIn 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 modif

31、ied plant structures that are enlarged to store nutrients.They are used by plants to survive 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

32、 into a storage organ.Root tubers,a tuberous root is a modified lateral root,enlarged to function as a storage organ.Chinese yamSweet potatoPotato Stolons/RunnersIn botany,stolons are stems which grow at the soil surface or just below ground that form adventitious roots at the nodes,and new plants f

33、rom the buds.Stolons are often called runnersFicinia spiralis金砂莎草金砂莎草Lipstick hybrid strawberryPoplar suckers emerging along a root(mother tree is not visible)SuckersA 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

34、 shrub or from its roots.Root suckers may emerge some distance from the originating plant.Suckers also may arise from the stumps of trees that have been cut down.A sucker emerging from the base of a young treeGraftingJoining separate plant parts together so that they form a union and grow together t

35、o make one plant.Wedge GraftApproach GraftBuddingA form of grafting when a bud is used.Faster or quicker than grafting.The 3 main methods are.Patch budding.T-budding.Chip budding.Patch BuddingT-BuddingChip BuddingTissue CultureUsing a small amount of plant tissue to grow in a sterile environmentThe

36、most plants in a short timeTrue to parent plantAdvantages to Asexual PropagationPlants mature in shorter time.Some plants do not produce viable seeds.New plants are same as parent plant.Disadvantages of Asexual ReproductionSome require special equipment and skills,such as graftingCuttings detach plant parts from water and nutrient sourceSome plants are patented making propagation illegal