| Forestry training manual for the Africa region |
Total time 2 hours
- To refresh the memorial of the trainees about flowering cycles, pollination, seeds, seed germination, seed dispersal, basic seed storage and point out our leek of knowledge about seed germination and dispersal among many tropical species,
- To gather seeds,
- To instruct the trainees on vetting up seed collection records,
- To instruct the trainees in basic seed storage.
This session reviews the flowering cycle and seeds from pollination to germination. It is necessary to start at the beginning as moat trainees will have studied those cycles in North America and need to recognize the differences in tropical species. The trainees will also gather seeds and record data.
1. Flowers & Seeds
2. Seed Collection
Flip charts, marker pens, tape.
Exercise 1 Flowers & Seeds
Total time 1 hour
Many of the participants will have learned in North American schools the cycles of flowering and seed development. This lecture refreshes their memories and has them relate the cycles to African trees.
1. The technical trainer states that this morning is a quick refresher for everyone and invites a botanist in the group to add his/her comments throughout the lecture. It is recommended that the following outline be put on newsprint and the trainees follow it as lecture is given.
I. FLOWERS : Many different colors, shapes and sizes
II. FLOWER TYPES:
A. Male flower
B. female flower
C. Complete flowers - bisexual
III. TYPES OF TREES:
A. Monoecius - staminate (male) flowers and pistillate (female) flowers on same tree, (pine; Douglas fir).
B. Dioecious - staminate and pistillate flowers occuring on separate trees (willow; poplar).
C. Polygamo - monoecius - complete flower plus staminate and pistillate flowers on same tree (Buckeye).
D. Polygamo - Dioecious - perfect flower plus either staminate of pistillate flowers (Buckthorn).
NOTE : All of the above types of trees can bear seeds except the dioecious tree that produces staminate flowers.
D. Others - mice, bats
Two nuclei penetrate the ovule and double fertilization occurs.
1. One fertilization unites egg to form embryo.
2. Other fertilization unites with two polar nuclei to form endosperm.
I. Mature Seed
A. Three - six months after fertilization
B. One year after fertilization - pine
C. Some take more time
A. Mature embryo embedded in endosperm (endosperm can be small or absent)
B. Seed coat (integument) forms around the ovule
III. Embryo = Germ
A. Composed of:
1. Seed leaves - Cotyledon - mostly two (palms one, pines four plus)
a. manufacture food
b. have stored food
2. Bud - Plumule
3. Stem - Hypocatyl
4. Rudimentary root - radicle
5. Seed Coats a. hard (pines) b. soft c. leathery (cypress)
IV. Types of Seeds
A. True seeds (from pine)
B. Dry fruits: fruit is seed (oak)
C. Fleshy fruit (apple)
A. Chemical change
D. Color change
VI. Seed Dispersal
1. Light seeds
2. Seeds with wings
VII. Seed Collection - Records
A. Seed Maturity
C. When to collect
1. Early collection - not ripe
2. Late collection - few viable seeds left
6. Bamboo poles
7. Collect off ground
8. Spread sheet below tree
E. Seed Extraction
1. Air dry*
2. Oven kiln
*Note: It is important in air drying that birds do not eat the seeds. Air drying is also the most used and practical method of seed extraction.
1. Internal dormancy (triggering internal chemical reactions)
2. External dormancy (seed coat permeability)
G. Seed Treatment
4. Filing - soaking
6. Tumbling - (with grit)
H. For Germination to Occur
1. Internal factors - ripe
2. External factors
I. Seed Storage
1. Dry - cold: in sealed containers; pine, cypress
2. Moist - cold: oak, maple
3. Room temperatures Acacia, eucalyptus
4. Other possibilities a. partial vacuum b. dry freeze c. hole in ground - bury in sealed plastic bags
5. How dose nature do it? peat moss (turba)
6. Small containers
Exercise 2 Seed Collection
Total time 45 minutes
The trainees collect as many varieties of seeds as possible. They try to identify seed species. The trainees begin to look at vegetation in the environment from a reproductive point of view.
1. This exercise is done immediately after the lecture in Exercise 1. The technical trainer asks the trainees to collect individually as many seeds from different sources as they can in the next 15 minutes.
2. After 15 minutes, the trainees are asked to place the seeds on newsprint on the floor for display. They are to write under each species whether or not seed is mature and how the trainee thinks it is dispersed.
3. The technical trainer makes a few remarks about the displays and points out the accuracy of identification, dispersal methods, etc.
4. The technical trainer reviews the goals of this session and asks that the trainees save the mature seeds they have collected until tomorrow.