Plants and Society Midterm Study Guide

The Scientific Method

  • make observation

  • ask questions

  • background research

  • develop hypothesis 

  • test the experiment 

  • analyze results & draw conclusions 

  • if results are false, construct another hypothesis 

Science: knowledge attained through study or practice 

Scientific Knowledge: proven knowledge acquires through the Scientific Method 

Plants and Humans 

  • Three Cereal Crops widely consumed in the world: rice, wheat, corn 

  • 10% of efficient energy transfer from one level to the next in food chain 

  • Macronutrients (large quantities): carbohydrates, proteins, lipids (fat) 

  • Micronutrients (small quantities): vitamins, minerals (17 essential minerals) 

  • Cereal and Pseudocereals: cereals are fruits of grasses and belong to the family Poaceae and they assemble appearance with pseudocereals (don’t belong in same family) 

  • Examples of cereal grains include wheat, rice, and corn, while pseudocereals include quinoa and amaranth, which are valued for their high protein content and gluten-free properties.

  • Simple carbohydrates: glucose, fructose, sucrose (doesn’t need to be digested) 

  • Rich in complex carbohydrates: carrots, sugarcane

  • Modified stems: have nodes, internodes, serve as a protected food reserve (ex: potato tubers) 

  • Tuberous Roots: modified roots that become fleshy and enlarged with food reserves (ex: sweet potato, carrots)

  • Certain amino acids are considered essential for humans because humans cannot make ass the amino acids required for protein synthesis and need to obtain 9 essential amino acids 

  • Protein is the macronutrient that is abundant in legumes 

  • Triacylglycerols: type of plant lipid that serves as a source of dietary energy for humans  

What Wrong With What We Eat

  • livestock is the second biggest contributor to CO2 emission to the atmosphere and increases global warming 

  • cow fart releases methane 

  • overconsumption is not good 

  • eat more plant, means you live longer 

  • locavore: people who ate local foods 

Vitamins

  • essential organic compounds required in small amounts 

  • involved in fundamental functions to the body, such as metabolism, immune function, and overall health maintenance.

Fat Soluble Vitamins: Vitamin A, D, E, K 

Water Soluble Vitamins: Vitamin C and B 

Phytonutrients: 

  • phyto: plant 

  • plant derived chemicals that impact human nutrition and health 

  • also known as phytochemicals, plant natural sources 

  • three major classes: terpenoids, nitrogen-containing compounds, phenolics

Functions: 

Floral pigments: plant pollinator attraction interaction 

Major floral pigments: carotenoids, anthocyanins 

Floral scent constituents: plant pollinator, present in leaves and fruits 

Volatiles: terpenoid, phenolic derivatives 

  • phytonutrients (phenolics and carotenoids) protect plants from high UV radiation 

  • Phenolics acts as plant signals in legume rhizobia interactions 

Nutraceuticals: provide long term health benefits 

Phytomedicines: target a specific health problem 

Knowledge of medicinal plants been acquired throughout human history by: 

  • trial & error: original experience 

  • religious beliefs

  • doctrine of signatures: part of a plant has the shape of a part of human body, it would be useful in treating a disease of human part it closely resembles (ex: carrots → eyes, onions → cells, kidney beans → kidney) 

Medicinal Plants in Modern Healthcare

  • up to 80% of world’s population still relies heavily on produced medicine 

  • pharmaceutical drugs are unavailable or too expensive to use by one-third of world’s population 

  • over 25% of our common medicine contain at least some compounds obtained from plants 

  • in the US, about 10% of major drugs have plant extracts as active ingredients 

Allelopathy: plants secret chemicals from their roots or other tissues that prevent germination or growth of other plants in their root zone to decrease competition with other plants 

Process of Drug Discovery: 

  • identify potential plants 

  • screening for biological activities 

  • chemically analyze the extract 

  • large scale extraction from plants or chemical synthesis 

  • preclinical research, clinical trials, government reviews 

Advantages and Limitations of synthetic drugs compared to natural plants produced chemicals 

  • synthetic drugs don’t depend on plant collectors or growers as a source or the long term survival of a plant 

  • synthetic drugs can be patented, natural compounds can’t 

  • sometimes chemical synthesis of the desired compound is difficult 

  • camptotheca and yew tree: examples of anti-cancer drugs derived 

Key Risks threatening medicinal plants: 

  • overharvesting

  • habitat destruction

  • knowledge of plants not passed onto next generation 

  • 54.2 million hectares lost in 20 years 

  • wildfires in Amazon rainforest 

  • deforestation by land conversion and urbanization 

Conservation of Medicinal Plants

  • in-situ conservation: identify ecosystems with diverse medicinal plant species 

  • ex-situ conservation/cultivation: seed storage 

Ethnobotany: study of how people of a particular culture/region make use of indigenous plants 

  • UC Davis is located on the Patwin’s land

Ayahuasca:

  • contains a potent hallucinogen dimethyltryptamine 

  • tradition medicine to treat emotional disorders 

  • secure the help of great spirit to the entire community 

  • used in rituals and ceremonies (medicine man and shaman) 

Bioprospecting: scientific studies that search for a useful application, process or product in nature 

  • issues: biopiracy → exploits the distinctiveness of a country
    controversies about the Ayahuasca and Turmeric patents.

  • ayahuasca have attracted international attention, issued patent for a unique variety of the hallucinogenic vine 

  • tumeric: patent related to wound healing property
    Three objectives of the Convention on Biodiversity (CBD).

  • the convention of biological diversity

  • the sustainable use of the components of biological diversity 

  • the fair and equitable sharing of the benefits arising out of the utilization of genetic sources

    • Compare and contrast the use of petroleum-based and plant-based raw materials in the production of industrial chemicals.

  • Petroleum based: more experience, material imported → increase in price, major source of pollution, chemical diversity limited 

  • plant based: less experience, cost is declined, less pollution, diversity unlimited
            examples of plant-based materials used to make bioplastics.

  • cellulose, starch, lipid (corn starch, sugarcane, cassava starch)
             concept of a biorefinery and be able to give examples of bio-based products derived from biorefining processes.

  • a facility that, like a petroleum refinery, processes biomass to produce a range of products such as biofuels, chemicals, power, and other value-added materials (ethanol, corn oil, acetone) 

    • What are the advantages of using plant tissue or cell cultures to produce phytochemicals?

  • year round availability of plant material 

  • absence of interfering microorganisms in soil 

  • compressed vegetative cycle, plant cell cultures can synthesize large amounts of phytochemicals within two week culture period
    Plants and the environment
    What are the benefits of seed dormancy? What methods can be used to break seed dormancy?

  • natural process that delays germination until environmental conditions are favorable for seed growth 

  • stratification (store seeds at 4 degrees celsius for a few days) 

  • scarification (mechanical abrasion, acid treatment)
            process of double fertilization in flowering plants.

  • one sperm combines with egg → embryo 

  • another sperm + polar nuclei → endosperm     

    • examples of major seed crops used worldwide.

  • wheat, rice, corn, barley, sorghum, soybean, common bean, coconut
            What are some of the issues associated with relying on only a few plant species for food?

  • nutritional risks → malnutrition and hidden hunger 

  • growing large amounts of the same crop increases their vulnerability to pests, diseases, and changes in environmental conditions
            Understand the important role seed banks play in preserving global plant biodiversity.

  • collects, preserves, and store seeds of various plants species for long term conservation and future use 

  • conservation of genetic diversity 

  • preservation of endangered species 

  • ecological research 

  • scientific research
            Define recalcitrant seeds. Explain the conservation strategies used for plant species that produce

  • seeds that do not survive drying or freezing (cocoa, mango, avocado) 

  • keep in moist conditions

             What are biotic and abiotic stresses in plants? Give some examples of each.

  • Biotic: stress caused by living organisms ( fungal, virus, bacteria, competition, herbivores, insects, pathogens) 

  • abiotic: extreme temperature, flood, drought, excessive soil salinity, light, chemicals, nutrient deficiencies
            Understand the stress escape strategies used by certain plants.

  • plants complete life cycle before the onset of stress

  • ex: desert sunflowers grow, flower, and dies during rainy seasons 

  • plants elongate shoots to escape shade 

  • plant roots grow away from saline soil
            Understand the importance of mineral nutrients for plant growth and development.

  • Nitrogen: component of amino acids, proteins, nuclei acid 

  • Phosphorus: key role in reactions that involve ATP, nucleic acids, sugar phosphate, phospholipids 

  • Potassium: cofactor for over 40 enzymes 

  • magnesium: constituent for chlorophylls
            Describe the sources of minerals in soil that are available for plant uptake.

  • minerals in rocks, natural fertilizers, artificial fertilizer
    What are the potential causes of plant nutrient deficiencies? Explain how soil pH affects plant mineral nutrition.

  • mineral nutrients are not present in soil 

  • crop competition 

  • unfavorable soil pH 

  • soil pH affects the availability of plant mineral nutrient uptake, can be too toxic
    Give examples of how plants interact with other living organisms in their “social networks”.

  • Mutualistic and symbiotic interactions (enhances reproduction and nutrient uptake, pollination, seed dispersal, nitrogen fixation) 

  • Defense against pathogens and pests

  • Competitive and cooperative interactions with other plants

  • Plants and people: plants as food and medicine, and anthropogenic climate change
    In legume-rhizobia symbiosis, what do the legume plants and rhizobia each receive?

  • Plants receive nitrogen -> ammonium 

  • Rhizobia receive photosynthetic products and a well controlled and protected environment for nodules to grow in
    How can non-legume plants benefit from the legume-rhizobia symbiosis?

  • From soil enriching properties (crop rotation) the practice of planting different types of crops in the same area in sequential seasons
    Name the different groups of microorganisms that can cause diseases in plants.

  • Virus, bacterium, fungus, nematode
    Know the concept and importance of the plant disease triangle. Understand the principles of plant disease control based on the disease triangle.

  • 3 factors must exist for plant disease to occur: susceptible host, favorable environment, pathogen (to understand why diseases happen, how to prevent and keep plants healthy by breaking one or more sides) 

  • Susceptible host: has genetic makeup that permits the development of a particular disease 

  • Plants have developed physical and chemical defense (physical barriers: cuticles, cell wall, spines, and thorns) (chemical: antimicrobial and antifungal chemicals) some plants carry resistance R genes against specific pathogens 

  • Favorable environment conditions: specific conditions must exist for pathogen to cause infections (ex: high moisture and specific temperature ranges necessary for many fungal diseases) 

Principles of Plant Disease Control 

  • Exclusion:  Preventing the introduction of pathogens to farms, orchards etc.

  • Eradication: Eliminating a pathogen after it is introduced into an area but before it has become well established or widely spread

  • Host resistance: selecting disease resistant varieties 

  • Protection: creating a barrier between plants and pathogens (ex: bananas covered with plastic bags, pesticide application

    • What are the advantages and limitations of monocultures? What are the benefits of polycultures?

  • monocultures : genetically similar crops planted over large acreages but are sensitive to weather pattern changes and crop diseases 

  • Polycultures: provide more diverse pollen and nectar sources that can attract natural enemies of crop pathogens and the greater variety of crops provides habitat for more species and increase biodiversity
    Give examples of competitive or cooperative relationships among different plant species.

  • Competitive: light (tall trees take light from smaller plants), plants produce allelopathic chemicals that interfere with growth of nearby plants, parasitize others 

  • Cooperative: the three sisters method (beans → nitrogen, corn → structure, squash → keep moisture and block light)
    Give examples of sources of environmental contaminants.

  • Volcanic eruptions, forest fires, pollution caused by human activities, pesticide contaminants
    Describe the biotic migration of contaminants in the environment.

  • The transfer and concentration of a toxic material along a food chain

  • Ex: DDT (pesticide used to kill mosquitoes, slow to degrade, and soluble in lipids, increase in concentration as it goes up the food chain
    What are the environmental risks linked to the use of inorganic fertilizers in agriculture?

  • Eutrophication (leaching of nitrate into ground water, algal blooms can lead to dead zones)
    Understand the physical, chemical, and biological methods used to remediate environmental pollutants. 

  • Chemical method: involve oxidation and reduction reactions to treat inorganic and organic contaminants 

  • Physical and chemical: serve as pretreatment steps before applying biological treatments 

  • biological : A process that uses living organisms (e.g. microorganisms, green plants) to reduce or eliminate environmental hazards.
    What is phytoremediation? Describe and distinguish the various mechanisms plants use to remediate contaminated soil and water.

  • Phytoremediation is a process that uses plants to remove, stabilize, or degrade contaminants in soil and water

  • Phytovolatilization is the process by which plants take up contaminants and release them into the air in a volatile form, either directly or after chemical modification.

  • Phytoextraction: Uptake of soil contaminants by plant roots followed by translocation to the aboveground part of the plants.

  • Phytostabilization reduces the movement and spread of contaminants. It involves immobilizing contaminants in soil or groundwater through root uptake andaccumulation, root surface adsorption, root-zone precipitation, or soil stabilization to prevent their spread

  • Phytodegradation (also known as phytotransformation) is the breakdown of contaminants taken up by plants through metabolic processes occurring within the plant
    What are the ecological benefits of fire in nature?

  • recycle nutrients and promote new plant growth

  • control pests and diseases 

  • stimulate seed germination 

  • create open habitat for wildlife 
    How have plants evolved to survive fires?

  • thick barks can protect living tissues

  • certain plants resprout from buds located in underground structures such as the root crown or underground stems (rhizomes) 

  • jack pine has developed serotinous cones that depend upon high heat to open and release the seeds 
         What are some traditional indigenous burning practices and how have they been used for fire management?

  • small, low intensity fires are set under specific weather condition and at precise time of the year 

  • patch burning (habitat mosaics) - fires are lit in mosaic patterns to create patches of burnt and unburnt areas to support diverse habitats and plant regeneration 
         What is the fire suppression paradox and why does it lead to more dangerous wildfires?

  • refers to a counter intuitive phenomenon in which the active suppression of wildfires such as through firefighting efforts, can lead to more severe and destructive fires in the long run 

  • fire is removed from the cycle and ecosystems begin to get out of balance 
    Understand the key points of the AB-706 bill presented by your classmate Ethan     

  • establishes the forest and wildfire prevention fund to reduce wildfire risk by funding the procurement, transport, and beneficial use of forest biomass waste 

  • local relevance; from the 4th assembly district and the major leader is Aguiar Curry

    • Controlled Environments to Manipulate Plants

  • place plants in nets, color light room, green house

  • protected cultivation systems are used for outdoor threats

  • nursery: cultivation, propagation, and management of crops before transplanting

  • Other than nursery: food production, ornamentals, medicinal and cosmetics

  • Applications: space science, research tool

Controlled environment agriculture

  • no environmental influences

  • produced locally

  • less natural sources exploitation

  • can be sustainable

Controlled environment for plant’s needs:

  • photosynthesis

  • limiting factors: light, CO2, temperature (enzymes)

Control of input (resources)

  • optimal

  • homogeneous

  • targeted treatments

Control of output (plant growth and quality)

  • yield

  • timing

  • morphology

  • nutrition

Light:

  • perceived by plants varies in: irradiance, photoperiod, spectral quality

  • fundamental for plants: allows for photosynthesis (photosynthetically active radiation 400-700 nm) and photomorphogenesis (broader range of the spectrum 300-800 nm)

  • adaptive mechanisms to increase or decrease: light interception, light absorption, light use (affects the quality of the plant, leaf, and cell)

  • morphology: color, size, texture

  • nutritional content: content of specific compounds such as antioxidants, sugars, and vitamins

  • organoleptic properties: aroma, smell, taste, texture

Quality of red leaf lettuce

  • morphology: red leaf

  • nutritional content: anthocyanins

  • shelf life (longer), organoleptic properties (bitterness)

Accumulation of biomass and biosynthesis of antioxidants are competitive processes

  • Light controls yield, nutritional quality and energy efficiency

Tomatoes

Morning: nutritional quality higher

night: flavor quality higher

  • Blue light delays ripening of chili peppers