1 Flashcards
What are phytonutrients?
Often secondary metabolites of plants that have beneficial effects that promote good health, e.g antioxidants.
Name one downside of the greenrevolutions goal of increasing yield?
Meant that the cereals which were targeted to increase yield were preferentially chosen by farmers over nutrient rich pulse and legume crops. Contributing to nutritional deficiency in those areas.
What are three methods of biofortification?
Biofortification:
* Improving take up via fertiliser, doesn’t work for all minerals, but e.g. Zinc fertilizer increased zinc content
- Genetic biofortification, through breed, but need these traits already in the population
- Transgeneic biofortification, GM, i.e. increased iron transporters
What is golden rice increasing in the grain?
Beta-carotene
Introduces a new metabolic pathway which converts the naturally occurring beta-carotene precursor into pro-vitamine A
Which is converted into Vit A in our body.
What are three sections we have to consider when trying to biofortify via GM?
- Aware of assimilation processes
- Aware of processes that control the accumulation of nutrients in the part we eat
- The mobilisation of that into our intestinal tissues
Describe the rhizosphere
Describe iron availbility in the soil
How can iron assimilation be improved?
- target better root growth
- increase bioavailbility by lowering pH
- enhanced scavenging via strategy one
Describe how plants increase bioavailability of iron via lowering pH
- Uses atp hydrolysis to move protons out of the cell, increasing the acidity
- Efflux co2 out which increases acidity but also the H+ ions displace positive charged metal ions from negatively charged soil particles allowing uptake
Describe the ‘strategy 1’ method for increasing iron uptake
- Strategy 1
- Propton pump, acidifying exterior solution
- Reductase enzyme which drive fe3 to fe2, aided by secretion of chelate, which bind oxidised iron
- Once bound to chelate, enzyme uses reducing power of nadh to reduce iron form fe3 to fe2, which can be converted into irons due to acidification in soil solution
- Able to be taking up via iron transporter
What specific genes have been edited to increase iron content/uptake in crops?
Upregulation of IRT1, an iron transporter in the roots
* Overexpression of IRT1 increased iron content but didnt improve plant growth
* No significant increase in the grain
Adding chelate reductase gene from yeast
* increases ferric (feiii) reductase
* Under low iron, grew much better, increased yeild
* No significant change in seed iron content
Difficulty getting it into the grain
Describe how shade avoidance is regulated by phytochrome B and PIF transcription factors
What is SAS? and is it in all plants?
Shade avoidance syndrome
What is the effect of SAS on fitness?
Increases fitness at high densities but reduced fitness at low densities
Reduces yield due to more energy spent on stem elongation.
How do plants anticipate a need for shade avoidance?
Increased far-red light reflected from other plants
What is the perfect storm that’s arising?
Changing towards a meat based diet
Changing climates changing what crops can be grown where
Increasing population
Reduced arable land due to competition with biofuels etc
How can higher yield farming help spare nature?
- Increasing intensity and therefore yeild to make room for more wildlife areas (snow leopards in Pakistan)
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Define a Nastic movement
A movement largely independent of outside stimulus or a directionless stimulus.
As opposed to tropism.
Define thermonasty
controlled by temperature
Name six tropisms
Gravitropism
Chemotropism
Thigmotropism
Phototropism
Thermotropism
Hydrotropism
Can be positive or negative
How does the circadian clock aid phototropism to increase photosynthesis efficiency
Allows optimisation/anticipation to move leaves the correct position in advance of sunrise/sun movement
What is an example of plants using electronic signalling?
Electronic signals produced when leaves of arabadopsis eaten by cotton worm which initiated defensive response genes in surrounding leaves.
