Spring 2004 Newsletters
MAC Is Working for You
Massachusetts Agriculture in the Classroom (MAC) continues its work to offer our consumers the connection between production agriculture and retail products and the impact that they have on each day of our lives. MAC is proud of our agricultural roots as well as our educational branches. As educators use the information and resources we provide, we all become an integral part of assuring a stronger future for agriculture and the many products upon which we all depend. As with all noble efforts, much time, energy and financial resources are required to provide quality programs. MAC is a self-sustaining, volume-based organization with no federal or state support and only two part-time staff. We rely on competitive grants, special events, donations and our volunteer board. With little overhead, all donations support our programs.Each issue of our popular newsletter reaches more than 10,000 educators. The printing and postage costs are approximately $4,000 per issue. This annual $12,000 commitment helps to make 30,000 connections per year!MAC supports many worthy agriculture-education efforts through mini-grants to educators who develop new agriculture initiatives and curricula for students. Fifteen thousand dollars is provided, annually, for these grants that supplement agriculture education in schools across Massachusetts. Twenty thousand dollars per year is devoted to producing workshops for educators and an annual teaching consortium related to various agriculture industries. These venues are framed to meet the requirements of the Mass. Curriculum Frameworks and provide professional development for educators. Annually, monies are also devoted to update the MAC web site and to develop new lesson plans and other agriculture-education materials. You can play a vital role in these educational efforts by becoming a "Friend of MAC" for up to $99. Consider joining us as a "Program Associate" for a donation of $100 to $499 or as a "Partner in Progress" with a contribution of $500 or more. Agricultural businesses may also place a business-card sized advertisement in an upcoming newsletter for $300. This summer, as details are completed, we hope to provide information on how to register for the new "Ag Tag" license plate. Funding from the plates will support MAC and other state agriculture-education organizations. Check out our web site for updates.
Remember, your donation supports educational programs and agricultural awareness efforts. Please help us, so that we can continue to help you!
President’s Message
MAC has been blessed with some outstanding Board members who are passionate advocates for agriculture. That passion may result from having grown up on a farm or from visiting a relative’s farm causing fond memories of the country life. I will give you an example of this from my own life.
When I was a junior in high school in Michigan, and active in 4-H, I was invited to participate in the state-wide 4-H week at Michigan State College. (During the late 50's MSU became a University despite resistance from the University of Michigan.) It was a great time and I decided that Michigan State was where I wanted to go to college. However, Saginaw Arthur Hill HS was dominated by teachers and counselors who had graduated from the University of Michigan. They pressured me to go there. Finally, I declared Agricultural Engineering as my intended major. It was offered only at Michigan State, so I was able to attend the college of my choice without more harassment. Soon after arrival, I changed my major to chemistry, and happily enjoyed the country atmosphere of the campus that I shared with 20,000 other students.Doug Gillespie, the Commissioner of our State Department of Agricultural Resources, recently commented "that the present generation doesn't have the connections to the farming community of the past generations. This allows many misconceptions about where our food and fiber comes from and a lack of appreciation of the effort that it takes to get a good product to the market and table." Our agricultural heritage is rapidly being eroded away.
MAC is a dedicated group who believe that agriculture is an important part of our culture and that it is important to preserve and respect its role in our environment. The younger generation should have an opportunity to experience the wonder of seeds and how they grow. They should understand the conditions necessary to bring our many products to fruition. I hope that in these troubled times you will continue to support us to make this happen.
James I. Munger, President
Pollination
Flowers exist for just one purpose --plant reproduction. In the flower, pollination and fertilization take place, leading to fruit and seed production and the completion of the life cycle of the plant. Without flowers, there would be no fruits or seeds. Some plants do not produce flowers, and therefore will never produce fruits or seeds. These non-flowering plants include ferns, mosses, liverworts and other spore- producing plants. Angiosperm is the botanical classification for plants that produce flowers. There are more than 240,000 species of fresh water, salt water and terrestrial flowering plants. They range in size from the tiny pond duckweed to Tasmanian Eucalyptus that reaches the size of a redwood. Flowers range in size from nearly invisible to three feet. Pollination is the transfer of pollen from male (anther) to female (pistil) flower parts. Once a pollen grain reaches the sticky stigma atop the pistil, a tiny pollen tube forms and grows down the style to penetrate the ovary wall. Fertilization occurs when sperm cells travel through this tube from the pollen grain to join with an egg cell (ovule) in the ovary.Each fertilized ovule grows into a seed, and the ovary wall becomes the encasing fruit around the seeds. Without pollination and fertilization, fruit and seed production cannot occur. The structure of the fruit that grows after a flower is pollinated is often very similar to the structure of the ovary from which it developed. Similarly, the number and arrangement of seeds in the fruit resembles the number and arrangement of ovules in the ovary. The structure of a typical flower includes all the parts necessary for the production of seeds, although there are many variations. Perfect flowers have both pistils and stamens. Some angiosperms have male and female flower parts on different sexed plants or on separate flowers on the same plant. This helps to prevent self-pollination, ensuring a mixture and diversity of genes. When plants self-pollinate, all the offspring genetically resemble their one parent.Even in many perfect flowers (see diagram), the parts are arranged to keep pollen from easily reaching the ovary of the same flower assuring cross-pollination. Some plants that have been hybridized by horticulturists to produce showy flowers or other ornamental characteristics are sterile and do not bear fruit or seed. They must then be propagated from cuttings. Apollinator is anything that helps spread flower pollen. Wind may blow the pollen, rain water and dew may carry pollen grains, or insects may transfer pollen grains when they crawl inside the flower to drink the nectar or collect pollen. Bats and hummingbirds are pollinators too. Flowers have evolved with characteristics that suit particular pollinators. Many pollinators are totally dependent on the pollen and nectar that plants provide, and the plants are totally dependent on the pollinator to move their pollen and fertilize their seeds. Pollination is vital to agriculture. Crops that produce edible fruits or seeds will not mature, unless they have been pollinated. Wind-pollinated crops, such as corn, wheat, rye and hay, do not need supplemental assistance with pollination from the farmer. Insect-pollinated crops may need assistance, if pollinators are not available in dense enough numbers. Insect-pollinated crops include: apples; apricots; beans; blueberries; cherries; cranberries; cucumbers; eggplants; grapes; melons; pears; peppers; pumpkins; raspberries; squash; strawberries; sunflowers and tomatoes. Honey bees may be brought to the farm, to assure pollination of these insect-pollinated crops.
Honey bees are not native to North America, they were brought here from Europe by the early colonists. There are hundreds of indigenous species of bees and wasps that are native to North America. These bees and wasps do pollinate flowers and can be found in orchards, farms and gardens along with the honeybees. However, all of the indigenous species of bees and wasps, such as the bumble bee, live in colonies of 300 or smaller, and they do not live year-round in colonies.The bumble bee is an example of a native pollinator. The bumble bee queen emerges in the spring to build a nest. She lays a few eggs, collects nectar and pollen and raises a handful of new bumble bees. They grow up to help the queen mother. The colony slowly grows to 200 to 300 bees. At the end of the season, the queen and a few helpers go off and burrow in the ground or organic matter for the winter. Honey bees group and overwinter in colonies of 20,000 to 60,000. In the spring, thousands of bees are active and ready to start collecting nectar. When the orchards come into bloom in the spring, the sheer quantity of honeybees guarantees the pollination that is necessary for fruit production. Local beekeepers may be hired to bring beehives to farms or orchards to supplement pollination of apples, blueberries, pears and pumpkins. In Massachusetts more that 6,500 honeybee hives produce $300,000 worth of honey each year and also serve to pollinate crops. On some crops, especially cranberries, hives are needed in such large numbers that they are brought to the state from the south.Cold weather, rain and overcast days, may limit the number of pollinator visitors. Heavy rain may even wash out pollen and nectar. Native pollinators are more likely to visit flowers during cold and rainy weather, so adjacent woods and fields that offer nest sites are important to farms. Some plants have adapted to cold wet weather by offering a series of buds that open over successive days, flowers that stay open for several days, or flowers that close on cold wet days.
Pollination is an important part of our agricultural economy. The next time you enjoy native fruits and vegetables, remember that without pollinators, there would be little to harvest.
The Parts of A Flower
Flowering plants vary greatly, but they have certain basic structures in common. The main parts of the flower are the receptacle, sepals, petals, stamen and pistil. Flower parts are arranged in successive rings around the central ovary. Take a flower apart and see if you can find all these parts. The receptacle is the large flattened part of the stalk that holds other flower parts. The next ring is made up of stamen, the male reproduction organ. It is composed of the filament and anther. The filament is a thin stalk supporting the anther. The anther produces a yellowish or reddish powder called pollen grains. The pollen grains contain the male gametes.
The pistil is the female reproductive organ. It lies in the center of the flower and is usually surrounded by stamens. The stigma, style and ovary are the three parts of the pistil. The stigma is the top of the pistil. It is coated with a sticky substance to trap the pollen grains that fall on it. The ovary is the enlarged bottom portion of the pistil. The ovary may contain one or many ovules. The ovules are protected inside the ovary. Each ovule contains an egg and cells needed to nourish and protect the growing embryonic plant if fertilization occurs. The style is a thin stalk connecting the stigma with the ovules in the ovary. Pollination is the transfer of pollen grains from the stamens to the pistil. Upon pollination, the pollen grains will grow long thin tubes that reach into the ovary where the male cells from the pollen fertilize the ovules. Pollination can occur between pistils and stamens on the same flower and plant (self pollination) or from different individuals but the same kind of plant (cross pollination).
If the stamens and pistil are on the same flower, the flower is called a perfect flower. If they are on separate flowers it is an imperfect flower.
Pollinators
Unlike animals, plants can’t move from place to place to find their mates. Pollinators help spread their pollen, facilitating fertilization and production of fruit and seeds. The pollinator uses the nectar and pollen to make food for itself and its young. While collecting pollen and nectar, it inadvertently transfers pollen from flower to flower.
To attract pollinators at the right time, many flowers have adaptations such as color, size, shape or fragrance. Each flower face offers a set of instructions as to how to enter the blossom and procure the nectar or pollen. A bright and showy surface or alluring scent catches the pollinator's attention from a distance. Closer-up, the convergence of petals to the center shows them exactly where to go. Petals may be further accented with markings, such as: converging lines; contrasting colors; a bull’s eye that reflect only ultraviolet light; dots that position the insect or handholds that direct pollinators to the right position.
Self pollination: Some flowers self pollinate, producing off spring that all resemble that parent. Violets produce two kinds of flowers. One is showy and insect pollinated; a second self-pollinating one never opens to insects.
Wind Pollination: Flowers of wind-pollinated plants are small, odorless and colorless; most have no petals. They produce large amounts of lightweight pollen that floats on wind currents. Some pollen grains reach female flowers of the same plant. Long stamens and long feathery stigmas and styles help disperse and catch the pollen. Grasses, oaks, willows, birches, alders, poplars, beeches, hickories, nut trees and conifers are wind pollinated. A birch catkin (male flower) can produce over five million pollen grains.
Water Pollination: Rain water and dew can carry pollen to other flowers.
Bee Pollinators: Bees are attracted to nectar and pollen as well as sweet fragrant flowers. They visit flowers that are white, yellow, lavender or blue, but can’t perceive red. They do however, see special patterns that reflect ultraviolet light.
Many flowers that are attractive to bees have an irregular shape that provides a landing platform. They also have flower markings that guide bees in to land on the part of the flower where it can deliver and collect pollen grains. Horse-chestnut tree flowers are cream colored with a yellow honey-guide patch on the petals. When nectar dries up, the yellow patch turns pink, becoming invisible to bees. Bees visits only the flowers that need pollination.
When bees crawl inside flowers to suck nectar, they also collect pollen, carrying it on their bodies and their proboscises (bee mouthpart). Native bees include bumblebees and a large array of solitary bees, slightly smaller than the honeybee, which is not native to N. America.
Wasp Pollinators: Wasps are also attracted to flowers that provide nectar. Many orchids are pollinated by wasps. In some cases they may lay their eggs on the orchid. Fig wasps carry pollen from male to female flowers, which are located deep in the middle of the fig.
Fly Pollinators: Flies are attracted to heavy musky smells; some are also attracted to nectar. Many flies lay their eggs in decaying flesh. Some fly-pollinated flowers are maroon with strong, unpleasant odors. The flies lay eggs in the flower, inadvertently pollinating it. The Eastern skunk cabbage and red trillium are pollinated by flies.
Mosquito Pollinators: Mosquitoes are attracted to small, white or green flowers.
Beetle Pollinators: Beetles are attracted to large bowl-shaped flowers. They have strong biting jaws and feed voraciously on pollen, but do not eat nectar. While feeding, they pollinate the flowers. Beetles do not maneuver well when flying. They crawl over the stamens, depositing pollen that they collected while feeding on a previous flower. Flowers depending on them for pollination are often large, so that there will be something left over after the beetles have dined. Poppies, magnolias and waterlilies are beetle pollinated.
Butterfly Pollinators: Butterflies are attracted to nectar, but do not collect pollen. They perch on the flower and unfurl a long tongue, which they insert into the floral tube to collect the nectar. Butterflies prefer flowers with strong perfumes and brilliant colors, especially red, pink, orange, blue or yellow. They often visit the same flowers that bees do, and prefer composites flowers such as dandelions, sunflowers and asters.
Moth Pollinators: Since moths are nocturnal, the flowers they pollinate tend to be pale white or yellow, more visible at night, and very fragrant at dusk. Flowers are often tubular, so that the nectar is accessible to long moth tongues. Many orchids are pollinated by moths. Yuccas cannot develop seeds without the help of their moth pollinator. The moth lays her eggs on the flower and the caterpillars eat some of the Yucca seeds.
Hawkmoths or hummingbird moths prefer white or pastel flowers that are fragrant and open as the sun goes down. The striped hawkmoth is active during the daytime. It prefers blue flowers.
Bird Pollinators: Most birds have a poor sense of smell, so flowers depending on them for pollination do not need to be fragrant. Hummingbirds are attracted to red flowers. Many are long and tubular, often borne sideways or drooping rather than upright. They contain abundant nectar, so that the hummingbird can hover before the flower and insert its long bill and tongue to sip the nectar. Once in the garden, hummingbirds will visit flowers of any color in search of nectar and small insects.
Bat Pollinators: Bats are important pollinators in tropical areas. Flowers adapted to pollination by bats are large and pale with lots of nectar. They have a strong fruity fragrance, particularly at dusk when bats begin to fly. Agave hides nectar deep inside the flower. As the bat licks up nectar with its long tongue, it collects pollen dust on its head, carrying it to another flower.
Honeybees
Ancient Egyptians began raising bees around 2500 B.C., for food, medicine, and as a gift to the gods. The honeybee originated in the Middle East and migrated to North Africa and Europe. They came to the Americas with the early colonists, traveling in the boats in beeskep basket. Honey was used to sweeten their foods.
The old-fashioned straw skep is still used as a hive for bees in Europe where wood is not readily available. The disadvantage of the straw skep is that bees must be destroyed in order to harvest the honey.
Most beekeepers now provide standard hives for their bees, made of several removable drawer-like "supers" or sections. Inside the supers the bees build their honeycombs on movable frames that hang 3/8" apart. Bees can pass through this "bee space" to all parts of the hive, and the beekeeper can move the frames about. Each super holds ten combs, and each comb contains about 6,600 cells.
The bees collect pollen and nectar from flowering plants. The pollen is altered slightly to make bee bread, which supplies the young with protein, lipids, vitamins and minerals. The nectar is partially digested and condensed into honey, a long-lasting and high-octane food. Only honeybees make enough honey so that colonies survive winter. In some cases, such as 2003, bees aren't able to store enough honey. They must be fed sugar water in the fall to prevent starvation in the winter.
Two parasitic mites that originated in Asian bees are now a severe problem for U.S. honeybees, but do not affect indigenous bees and wasps. If these mites are present in large numbers, they must be treated with miticides in the fall. Otherwise, they will quickly run through the hive, weakening the bees and making them susceptible to viruses and other disease. The Northeastern United States lost 60 percent of the bee colonies this past winter from mites and starvation.
The Pine Tree
Conifers, like cycads and ginkgos, are gymnosperms, meaning naked seed. Their seeds lack a protective outer covering and are usually borne in cones. Conifers first appeared on earth 225 million year ago.
Conifers produce cones made of scales to house their many celled seeds during development. The seed consists of an embryo surrounded by a seed coat, and usually has a stored supply of food. However, the cones offer no protection once the seeds are ripe.
White pine (Pinus strobus) is a conifer and member of the Pinaceae family. Its male and female flowers (cones) develop on the same tree, females at the top and males at the bottom. In May, the pollen grains ripen. The male cones elongate and split open, separating the pollen sacs and exposing the pollen to the wind. Each male pine cone releases one to two million bright yellow pollen grains. Some will reach the female cones.
Each female cones consists of a series of scales, arranged around a central axis, similar to a spiral staircase. Each scale has two ovules at the base of its upper surface. The scales separate slightly to allow the pollen grains down between them. Each ovule secretes a sticky fluid to trap the landed pollen grains and draw them into the pollination chamber.
Once pollinated, the cone closes up tightly. Fertilization takes place the second spring when the sperm from the pollen reaches the ovule. Then development becomes rapid. The seed cone grows to be four-to-eight inches in length and the two ovules enlarge and mature to become two three-quarter inch seeds resting on scales approximately one inch long. At maturity, the cone becomes dry, the scales harden and open to release the winged seeds.
Pollination Activities
1. Ask students to select a flower and then draw and color it. Gently take the flower apart and draw each part.
2. Offer students a variety of different flowers. Examine them with a hand lens and sketch cross sections. Do all flowers have all of the parts? How do these parts help with pollination?
3. Ask the class to generate a list of "things we know about flowers" and a list of "questions we have about flowers." Identify the questions that can be answer by experimentation and those through books or interviews.
4. Give each student, or pair of students, a flower from the garden. Send them outdoors to find their flower. They should sit quietly nearby to observe it. What pollinators comes to visit? How long do they stay? How do they approach and enter the flower? What might be attracting them?
5. Using a tulip flower, show how pollination occurs. Gently rub your finger on a stamen to pick up pollen. Then touch the stigma of another flower with your pollen-dusted finger. Follow the converging lines or patterns on the petals to show the way a blossom receives pollen and distributes new pollen dust.
6. Make a snack of chives, cauliflower nasturtium or artichoke flowers. Collect poetry and music about flowers.
7. Use art materials to invent your own three-dimensional flower, showing the essential parts. Create some floral advertising to attract pollinators to your imaginary flower.
8. Cucumber and squash plants have separate male and female blossoms. There is a small miniature fruits (ovary) at the base of the female flower. Pollinate the cucumber flowers by hand using a small paint brush, to collect yellow pollen grains from the tip of the stamen (the anther) on the male flower, and transfer them to the tip of the pistil (the stigma) of the female flower. Once pollinated fruits will form.
Pollination Resources
Books
Botany for All Ages Jorie Hunken, Globe Pequot Press, 1993. |
The Forgotten Pollinator Stephen L. Buchman et. al. |
From Flower to Flower Patricia Lauber, Knopf Books, 1987. |
Grow Lab Activities for Growing Minds National Gardening Association, 1990. |
The Growing Classroom: garden-based science
Roberta Jaffe and Gary Appel Addison-Wesley Publishing Company, 1990. |
Hooray for Beekeepers! Hooray for Farming Bobbie Kalman, Crabtree, 1998. Grades 2-5. |
How Plants are Pollinated Joan Elma Rahn & Ginny Linville Winter. |
The Natural History of Pollination Michael Proctor et al. |
Pollination: World of Wonder by Mary King Koff, Creative Education Resources, 2004. |
Project Seasons Deborah Parrella, Shelburne Farms, VT, 1995. |
Information for this newsletter was taken from the resources listed above. |
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