Agribio

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Agribio is a Division B and Division C event that was first run as a trial event in 2020 at Delaware regional tournaments. It was also scheduled to be run at the 2020 Florida state tournament, but this tournament was canceled due to the 2019-20 Coronavirus outbreak. In 2021, this event will be run in Delaware, the Florida Eastern and Satellite regionals and the Hawaii, Missouri, Florida, and Utah State tournaments. The event is run as an exam, focusing on plant biology, soil science and ecology, and agricultural practices. Each team may bring four 8.5" x 11" note sheets with information on both sides, as well as two stand-alone non-programmable, non-graphing calculator.

Staple Crops and Plant Science

Staple Crops

This event relies on the participant's knowledge of plant science, with emphasis on eight major crops grown around the world: wheat, maize, rice, cotton, soybeans, sugarcane, tobacco, and coffee. Participants should be aware of specific cultivation techniques, flower types, life cycle, reproduction, predators and parasites, and anatomy and physiology of these eight staple crops heading into the competition.

Vascular Plants

Among the many tissues and organs, vascular plants have 4 main organ systems: the stem, the roots, the leaves, and the reproductive organs. The stem holds the leaves and connects them to the roots through two tissues called the xylem and phloem. The roots hold the plant in place and absorb water and nutrients from the ground. The leaves grow from the stem and their purpose is to photosynthesize. The shape and structure of a leaf depends on the plant itself. The reproductive organs allow the plant to multiply in number, both asexually and sexually depending on the plant.

Plant Science

Beyond the eight staple crops, participants should be knowledgeable about basic plant anatomy and physiology, such as leaf structures, monocots vs dicots, plant reproduction methods, pollination, vascular systems, and large Agricultural events

Reproduction

Non-vascular Plants

  • Moss: Bryophytes
  1. Dispersal- Spores are dispersed into favorable environments such as moist soil or tree bark, where they may germinate and grow into haploid gametophytes (gamete-producing plant structure).
  2. Protonemata- Promising spores develop a mass of green, branched, one-cell-thick filaments called protonemata. Protonemata have large surface areas that enhance water and mineral absorption to continue germination. Haploid. Note that the developing gametophytes are anchored by rhizoids, not roots.
  3. Budding- Buds are plant structures that give rise to gametophytes. These are produced by the haploid protonemata through mitotic division.
  4. Male gametophyte- Contains inner structures known as gametangia, more specifically, antheridia, where sperms are produced and kept.
  5. Female gametophyte- Contains inner structures known as gametangia, more specifically, archegonia, where eggs are produced and kept.
  6. Fertilization- Upon favorable conditions, the flagellated sperm swim through a film of water toward eggs (produced by female gametangia).
  7. Zygotic Stage- A diploid zygote develops inside of the archegonium and develops into a sporophyte embryo.
  8. Sporophytic Stage- A young diploid sporophyte grows a long stalk (seta), again from the nutrient-dependent archegonium.
  9. Maturity- Looking at the entire plant, the mature sporophyte is on top (seta + capsule), and attached by the foot of the female gametophyte.
  10. Repetition- Meiosis occurs inside of the capsule (sporangium) where haploid spores develop. Upon capsule maturity, the lid pops off, and the spores are released to repeat the preceding steps.

Seedless Vascular Plants

  • Ferns: Pterophytes
  1. Dispersal- Sporangia release haploid spores. Most fern species produce a single type of spore (botanical condition known as isospory) that develops into a bisexual photosynthetic gametophyte.
  2. Protonemata- Same function as in moss life cycle.
  3. Bisexual gametophyte- Antheridia and archegonia are produced but in different regions of of the mature haploid gametophyte. Do note that there is a reason why in most fern species, a gametophyte produces sperm and eggs at different times.
  4. Fertilization- Same as in the moss life cycle.
  5. Sporophytic Stage- Unlike bryophytes, these grow true leaves out from an archegonium gametophyte.
  6. Mature Sporophytic stage- Sori are found on the underside of the sporophyte's reproductive leaves. Each sorus is a cluster of sporangia.
  7. Repetition- Same as in the moss life cycle.

Vascular Plants

  • Gymnosperms- Pines
  • Angiosperms- Flowers


Homosporous spore production

Heterosporous spore production

Major Plant Groups

Monocots vs. Dicots

If an organism reproduces via enclosed seeds, it is either a monocot or a dicot. The terms "monocot" and "dicot" refer to the number of cotyledons present in the seed. A monocot (monocotyledon) has only one cotyledon, and dicots (dicotyledon) have two. Monocots and dicots are also differentiated by their leaf venation (leaf vein structure), stem structure, root systems, and floral patterns.

Leaf venation

  • Monocots have parallel leaf veins.
  • Dicots have branching leaf veins.

Stem structure

  • Monocots develop vascular bundles in groups that are placed arbitrarily around the stem.
  • Dicots develop vascular bundles in groups that form a ring around the edge of the stem.

Root systems

  • Monocots usually grow with a fibrous root system, meaning that there are many small roots that branch out from each other.
  • Dicots usually grow a taproot, which is a deep and thick central root in which smaller roots branch out from.

Floral patterns

  • Monocots usually flower in groups of 3
  • Dicots usually flower in groups of 5

Argicultural Events

Participants should be aware of the major events that have occurred throughout the history of agriculture. In general, these are mostly limited to the Agricultural Revolutions that have taken place throughout history. Events dealing explicitly with genetics are tested in Section 3: Agricultural Science


Ecology and Soil Science

Ecology

Participants should focus on general ecological concepts, such as food webs and trophic dynamics, as well as the specific interactions that occur within agricultural ecosystems

Soil Science

Soil science has a wide range of topics, from physics and chemistry to GIS modeling and water. Participants should be able to piece together the complete picture of a soil profile based on the characteristics of the soil and answer questions regarding shifts in these parameters.

Nutrient Deficiencies

Plants need a variety of nutrients to survive. When the plant is running low on these nutrients, there are telltale signs that to look for to determine what’s wrong. Some of the most important nutrients to plant growth are nitrogen, phosphorus, and potassium. On fertilizers, you often see the N-P-K ratio of the fertilizer, the concentration of nitrogen, phosphorus, and potassium. There are 2 types of nutrients: mobile and immobile nutrients. Mobile nutrients are able to move through the plant from the younger leaves to the older leaves when needed. This makes most of the early symptoms of theses deficiencies occur in the older leaves. Examples of mobile nutrients include nitrogen, magnesium, and molybdenum. Immobile nutrients are not able to move through the plant, and therefore occur first in the younger leaves. Example of immobile nutrients are calcium, boron, and iron. Zinc is a notable exception, since it can move, just not far. Therefore, zinc deficiencies show symptoms in the middle leaves of the plant.

Macronutrients

Macronutrients are nutrients that plants need a large amount of. Examples of macronutrients are nitrogen, phosphorus, and potassium.

Nitrogen - Nitrogen is one of, if not the most important element to a plant’s growth. It is used in many important organic molecules, such as nucleic acids, proteins, amino acids, and chlorophyll. Symptoms of a nitrogen deficiency include loss of coloration, called chlorosis, in mature leaves and necrosis, or the death of many or all cells in a tissue. The leaves also start to turn yellow, and the stem of the plant usually turns to a light green color.

Phosphorus – Phosphorus is another very important plant nutrient, used in organic molecules such as nucleic acids and ATP. Symptoms of a phosphorus deficiency are leaf tips with reddish-purple “flames” coming from the tips, and older leaves turning dark green or reddish purple.

Potassium - Potassium is used in plants to activate enzymes and in photosynthesis. Signs of a deficiency include older leaves wilting and looking scorched. The leaves also start yellowing on the sides and go along the edge of the leaf, leaving the interior untouched.

Calcium - Calcium is used in the construction and material of the cell wall. Symptoms of a calcium deficiency include new leaves growing shriveled and darken. The tips of leaves will also often become brittle and eventually die.

Magnesium - Magnesium is an important plant nutrient, since it is used as the center molecule in chlorophyll and an important molecule in ATP synthesis. Symptoms of a magnesium deficiency include older leaves yellowing at the edge, leaving the center of the leaf green.

Sulfur – Sulfur is an important plant nutrient used in the amino acids cysteine and methionine. Symptoms of a sulfur deficiency include yellowing of young leaves, and eventually yellowing of older leaves.

Micronutrients

Micronutrients are elements in plant tissue in very small quantities, measured in ppm (parts per million), but are still essential for plant growth.

Boron - Boron is a plant nutrient used in cell wall formation and reproductive tissue. Symptoms of a boron deficiency include the death of the terminal (or apical) bud, the primary point of growth in plants. Young leaves may also show chlorosis, and other leaves may develop dark brown spots that progress to the death of that tissue.

Copper - Copper is a nutrient needed for chlorophyll production and respiration. Symptoms of a sulfur deficiency include leaves darkening and growth stopping. Symptoms can also include delayed maturity and melanosis, or brown discoloration.

Iron - Iron is an important nutrient used in plant respiratory and photosynthetic reactions. Symptoms of an iron deficiency include chlorosis between the veins of the plants, and eventually chlorosis of the whole leaf. The veins of the plant appear very sharply defined next to the yellowing leaves.

Manganese - Manganese is a plant nutrient important for the chloroplast. Symptoms of a manganese deficiency include yellowing of the leaves between veins, dead spots on the leaves, smaller plant parts, and fronds having slowed or stopped growth (called frizzle top).

Molybdenum - Molybdenum is needed for enzyme activation and nitrogen fixation in some plants. Molybdenum deficiencies often have similar symptoms to a nitrogen deficiency, due to how it is used.

Zinc - Zinc is a plant nutrient used in the production of plant growth factors (or plant hormones). Symptoms of a zinc deficiency include yellowing of leaves between veins and sever chlorosis, turning the leaves to a pale green color, or even white if the deficiency is bad enough.


Agricultural Science

Agricultural Practices

Participants will be tested on crop cultivation method types and their impacts on yields and the environment around the crop. Microtechniques, such as grafting, may also be asked about. Fertilizer and pesticide use is an important component of this section and ties in closely with Integrated Pest Management. Additionally, pollinators and hydroponics are topics available to be tested on.

Genetic Experiments

Throughout history, genetic experiments have been popular amongst scientists. From Shull and McClintock and the famous Mendel, plants have been an essential test subject for geneticists. Participants will use their knowledge of these epxiremnts and other major contributions to answer questions


Resources