Class #6, Brief Notes, 9/29/10
Indicator species of climate change in the Bay Area
redwoods
spotted owl
ocean warming/pollution
monarch butterfly
Evolution of plant life
30-day calendar of the lifetime of the universe, beginning with the Big Bang on Day 1, photosynthesis emerges on the 14th day, and human history begins in the last 30 seconds of the month.
The development of plant life on earth began with algae in the ocean, where water and nutrients could be absorbed directly through cell walls. Land plants did not have easy access to nutrients and water as algae did. Fungae may have helped plants in this early evolutionary process, just as they do today. Hyphae helped fungae access water and nutrients underground. Land plants eventually developed roots underground to support more complex structures.
An expression can help you remember the symbiotic relationship between algae and fungus which together form lichen: “Allen algae cooks the dinner. Francesca fungus makes the house. They took a “lichen” to each other.” Lichens are primary indicator species.
90% of vegetative annuals have symbiotic relations with fungi.
Earlier plants
Nonvascular plants – reproduce by spores
Horsetail fern – one of earliest vascular plants, still in existence today. No seeds.
Club mosses & ferns have vascular tissue, but no seeds.
Later plants
Plants with seeds include conifers (gymnosperms) and flowering plants (angiosperms)
Gymnosperms – gingkos, palms, ferns. Ovary is unprotected, wind-pollinated.
Angiosperms have encased ovaries. Divided into monocots (one leaf) and dicots (2 leaves).
Bryophytes have protected embryos (liverworts, hornworts, mosses), lack vascular systems.
Kingdom Plantae has 275,000 species. Angiosperm phylum predominates w/250,000 species. Within that phylum, the Endicot class predominates with 235,000 species.
Stem structure
Endicots have a more defined structure in which the pith is in the center and the xylem and phloem are arranged in a circular pattern around the pitch. Xylem carries water to the top of the plant and phloem carries food and energy down to the roots. Typically has a taproot and netted veins.
Monocots (grasses, onions, orchides etc.) have a more random stem structure, a fibrous root system, parallel veins and often 3 flower parts.
Class #7, 10/06/10
Soil sample analysis. Many of our samples have a thin band of silt at top. The larger sand particles are at the bottom. Clay particles are still suspended above silt.
The Planting Calendar
Today’s planting task is to clear the land for the cover crop and a last planting. We’re about 3 weeks late, but before the final planting date of 10/31, which is a “cross holiday” or midpoint between the autumn equinox (9/21) and winter solstice (12/21). Halloween, “All Soul’s Day,” is a time when dark and light come together.
At the winter solstice the sun stands at the southernmost point on the horizon; at the summer solstice (6/21), the sun rises at the northernmost point. The midpoint between the winter solstice and spring equinox is 2/1 or 2/2 (Groundhog Day, Day of Creativity – life returns to the ground). The midpoint between the spring equinox and summer solstice is May 1, May Day. The maypole is a symbol for the vitality of breeding. The midpoint between the summer solstice and autumn equinox is 8/1 or 8/2 – Day of Fresh Bread – when the harvest begins to ripen.
Definitions: The solstices are the times at which the sun is furthest from the celestial equator, and hence the difference in length between night and day is greatest. The winter and summer solstices usually occur around the 21st December and 21st June respectively, but are subject to change due to the earth's orbit being slightly longer than our 365 day calendar. The equinoxes are the times at which the sun is closest to the celestial equator, resulting in day and night being of almost equal duration. They occur around the 20th March (the vernal equinox) and the 22nd September (the autumnal equinox), though are subject to variation for the reasons stated above. www.wikianswers.com
These are ancient annual rhythms that are recapitulated during a month. Waxing and waning of the moon lasts two weeks. Meditation, prayer and harvest are appropriate for the times between dark and light (dawn and dusk).
Sexual and Asexual Reproduction
The growing stage is characterized by apical dominance (growth at tip of stem and root). As plant matures, it goes to seed. Most of our vegetable crops are annuals, which live one year. Biennials create seed in second year (brussel sprouts, parsley, celery). Perennials regrow every year (artichokes, asparagus, rhubarb).
Maturation of an annual plant.
Sepals, the protective covering for the bud, drop back and flower blooms. The flower shape and scent attracts pollinators. Growth goes into producing reproductive organs, no longer vegetative.
Male parts: Stamen is made up of anther (creates pollen) and filament (holds anther).
Female parts: Pistil is made up of stigma (sticky part where pollen lands), style, and ovary.
Squash have pistillate flowers. Stamenate flowers can be eaten – don’t bear fruit. These are “one house” or “monoecious” plants (an individual that has both male and female reproductive units [flowers, conifer cones, or functionally equivalent structures] on the same plant).
“Two house,” “complete,” or “dioecious” refers to a plant population having separate male and female plants. An individual plant does not produce both pollen and ovules; individual plants are either male or female. Older flowers are complete.
Each pollen has two cells. First cell (sperm) brings pollen and fertilizes ovule. Second creates endosperm – protective covering, supplies food.
Some Main Plant Families for Vegetables
Composite – lettuce, sunflower (highly evolved family, fused stamens).
Legume – beans and peas
Brassica – kale, cauliflower, turnips, arugula
Solanum – tomatoes, potatoes, peppers, eggplant
Chenopodium (goosefoot leaf) – beets, chard, quinoa
Curcurbit – Oldest family, extra floral nectaries. Squash, melon, cucumbers, grain
Umbellifer – parsley, fennel, dill, coriander (many herbs)
Graminacae – grains. Very old family.
More Botany
Plant is characterized by contraction and expansion at cell level. Cell is made up of cytoplasm (where metabolism takes place) which surrounds organelles and nucleus. Death of cells forms structure of plant. Cell division drives primary growth (elongation) at apical meristem.
Secondary growth creates girth of plant – lignin. Leaves protect growing bud. Other leaves photosynthesize. Leaves can grow in three patterns – alternate, opposite & whorled.
Root crops are difficult to transplant because you may disturb or break the apical bud (carrots, beets, parsnips, radish).
Buds in axil (where petiole/leaf stem meets main stem) have apical dominance. Leader has highest dominance. Prune above a bud, at an angle.
When harvesting chard (or plants w/rosette or basal growth), pull out at base of stem, don't cut – stimulates growth (radial bud). Cut stem is pathway for disease.
Vegetative growth ends when plant matures - “senescence.” Growth then goes into reproduction.
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