HORT
201
Plant
Propagation
Laboratory
Exercise 4
Softwood
Stem, Herbaceous Stem and Leaf Cuttings
Reference: Text pp. 350-354.
Key Words and
Terms from the CD:
Adventitious
roots, adventitious shoot formation, adventitious shoots, auxins, callus, cambium,
chimera, cuttings, desiccation, direct sticking cuttings, distal, herbaceous
cuttings, humidity, intermittent mist, kinetin, leaf cutting, mericlinal
chimera, mist systems, periclinal chimera, phloem, proximal, root initials,
root primordia, softwood cuttings, stages of root formation, talc auxin
treatment, virus indexed, xylem.
Objectives:
1. To learn how to
make herbaceous stem, leaf and leaf-bud cuttings.
2. To determine
the effect of different auxin concentrations on rooting of chrysanthemum
cuttings.
3. To observe
cultivar differences in rooting ability of chrysanthemum cuttings.
4.
To determine the effect of petiole length
on plantlet formation in leaf cuttings. (Saintpaulia,
Peperomia)
5. To observe plantlet
formation in different kinds of leaf cuttings. (Jade plant, Begonia rex)
6. To observe the effects
of leaf chimeras on type of plant formed. (Sansevieria)
Introduction:
The
term "softwood" refers to the succulent nature of stem cuttings taken
from new growth of woody plants. Such cuttings are usually harvested in the
spring after the first flush of growth. Herbaceous cuttings are stem cuttings
from herbaceous plants which can be harvested any time the plant is actively
growing. Leaves are essential because
there is little stored carbohydrate in newly-formed wood or in herbaceous stems. These cuttings are most often used to
propagate deciduous woody shrubs (e.g. lilac, forsythia, weigela, spirea) and
florist crops (e.g. poinsettias, chrysanthemums, carnations, geraniums,
hydrangeas). Some deciduous trees (e.g.
peach) and conifers (e.g. oriental arborvitae) can be propagated by softwood
cuttings. Disease control and prevention
of desiccation are of great importance with these types of cuttings. Rooting usually occurs quickly (2-4
weeks). Auxin treatment is not usually
necessary although it is sometimes beneficial.
Leaf
cuttings
are a variation of softwood/herbaceous stem cuttings and consist of a leaf
blade and its petiole. Individual leaves are harvested, leaving stems and the
axillary buds intact on the stock plant. Adventitious root and shoot tissues
arise at the base of the petiole, resulting in a new plant. Only a limited
number of species can be propagated by leaf cuttings.
Leaf-bud
cuttings
are variation of leaf cuttings, and consist of a leaf, its petiole, and the
subtending bud, taken with a small piece of the stem. These cuttings maximize use of available
stock material since each node can make one (alternate leaf arrangement) or two
(opposite leaf arrangement) new plants.
Cane
cuttings
are often used to propagate tropical plants with fleshy stems (e.g. dracaena,
cordyline, and dieffenbachia). Each node
will root, and a new top will grow out from lateral buds. Leaves are not necessary, as these fleshy
stems have enough food reserves to support rooting and shoot growth.
Resources:
Hartmann, H.T., D.E.Kester, F.T.Davies
& R.L.Geneve. 2002. Hartmann and
Kesterās Plant Propagation: Principles and Practices, 7th edition. Prentice
Hall. (Excellent information on softwood cutting propagation)
Toogood, Alan. 1999. American Horticultural Society ö Plant Propagation. DK Publishing,
Inc. (Good resource on home propagation
techniques).
Toogood, Alan R. 2003. Plants from Cuttings. DK Publishing,
Inc.
Purdue Landscape and Nursery Thesaurus (PLANT)
http://bluestem.hort.purdue.edu/plant
(select ćPropagationä from the Index)
Procedure
for Todayās Lab:
A. Stem Cuttings
Chrysanthemums: Cuttings were shipped to us from a commercial
source (Yoder Brothers
Inc.).
Note their appearance and the packaging used for shipment.
1. Each group should obtain 20 cuttings of Ī
2. Make a fresh cut through the stem near
the base of each cutting so that all are of uniform length. To prevent the
spread of pathogens, knife blades should be dipped in 70% ethanol prior to use.
This will kill pathogenic organisms on tools and knife blades.
3. Make the following treatments to each set of
20 cuttings:
a.
5 cuttings treated with talc (control)
b. 5 cuttings treated with Rhizopon AA
#1 (0.1% IBA = 1000 ppm)
c. 5 cuttings treated with Rhizopon AA
#2 (0.3% IBA = 3000 ppm)
d. 5 cuttings treated with Rhizopon AA
#3 (0.8% IBA = 8000 ppm)
4. Prepare labels including date, cultivar name,
treatment, lab section and name identifying your lab group.
B. Leaf
Cuttings:
Introduction: The natural production of organs by leaves is
rare, but kalanchoe and the jade plant are examples where buds form on leaves
giving rise to new plants. Leaves of
many other plants can be induced to form roots, but shoot regeneration from
leaf cuttings is more difficult.
Nevertheless, the use of leaf cuttings is a standard method of
propagation for many plants having fleshy leaves, leaves with enlarged,
thickened petioles, or leaves with large veins.
New growing points usually originate in the parenchymatous tissue
closely associated with vascular tissues in the leaves. When vascular bundles of the leaf are severed
and the proper conditions provided, new roots will be initiated. Shoots may also form, but this occurs with
greater difficulty.
Procedure:
Foliage of plants propagated from leaf cuttings will be available. Do not
use auxin treatments for leaf cuttings. Follow these instructions:
Begonia rex (rex begonia) -
a) The large veins are cut on the under-surface of a mature leaf. The leaf is placed flat on the surface of the
media and pinned down with floral pins to insure good contact. New plants will form where veins were
cut. b) Leaves are cut into large,
triangular pieces. Triangles are rolled
up and the proximal (basal) end is inserted into the medium. Make 1 cutting
using technique Īaā and make 2 cuttings using technique Ībā. Place all three
cuttings in 1 market pack.
Sansevieria trifasciata
ĪLaurentiiā
(variegated snake plant) ö This variegated cultivar has yellow leaf edges
because of a leaf chimera. We will see if the chimera is passed on to the new
plantlets. The leaves are cut into 2-4 inch sections and the proximal (basal)
end is inserted vertically for 1/4 of the cuttingās length into the rooting
medium. The proximal end is cut at a
slant to insure that polarity is not reversed.
Make 3 cuttings of this plant and place in 1 market pack.
Saintpaulia (African
violet) and Peperomia - Make 6
cuttings of each type of plant. Cut petioles down to 0.5, 1.0 and 1.5 inch in
length. (2 cuttings of each petiole length). The leaf plus petiole is placed in
a vertical position in the medium, so that the leaf blade just touches the
medium surface. Put cuttings of each species in 1 market pack. New plants form
at the base of the petiole. Does petiole length influence ease of propagation?
Crassula
argentea
(jade plant) - Make 6 leaf cuttings of the jade plant. Place the base of each
leaf in media up to about 1/2 the length of the leaf. Stick cuttings in 1
market pack.
Leaf-bud
Cuttings
- Make 3 leaf-bud cuttings from either Peperomia
or Epipremnum aureum (pothos) provided
and stick in 1 market pack.
When
each propagation flat is full (6 packs) place on mist bench (Zone 16). Watch cuttings carefully; as soon as they are
rooted in 2-3 weeks (but before new shoots form) remove them from the
mist. You will have to remove and pot up
and place in Zone 21(or give away) items at different times outside of lab.
Market Packs
Market
packs, also called cell packs or inserts, are commonly used in plant
propagation. Individual packs are joined together so a set of market packs will
fit a standard sized 11 x 21 inch flat. The packs are easily detachable so that
plants in individual packs can be sold to consumers, thus the name Īmarket
packā.
Market
packs are labeled by a number which indicates how many packs fit a flat and how
many cells are in a single pack as indicated below:
Each pack has 1 cell
601 market pack
6 packs fit in one flat
8 packs fit in one flat Each pack has 4 cells
804 market pack
Each pack has 6 cells 8 packs fit in one flat 
806 market pack
Market
pack configurations include 201, 606, 1204, 1206, 1501, 1801, 1802, 1803, 1804,
3601.
Nurseries
choose the best market pack to use based on plant species, plant size, and the
typical number of plants the average consumer prefers to purchase.
RESULTS: Softwood Stem and Leaf Cuttings
Use the space below for notes from your
weekly observations. Be sure to note
differences in root and shoot formation between cultivars and cutting types. You should understand why we didn't use auxin
on the leaf cuttings.
1. Stem cuttings -
Chrysanthemums - auxin & cultivar effects
2. Leaf cuttings -
Begonia rex -
root & shoot formation
3.
Leaf cuttings - Sansevieria - root & shoot formation and presence of leaf
chimera
4.
Leaf cuttings ö African violet & peperomia -
petiole length effect
5.
Leaf cuttings - Jade plant - root & shoot
formation
7.
Leaf-bud cuttings - peperomia or pothos ö root formation