Fruit & veg Flashcards
Sunshine hours
time during which the direct solar radiation exceeds 120 W/m²
Most sunshine hours at
the equator and in the tropics
conversion efficiency from sunlight to food
Total solar energy (-60% non absorbed wavelength) (- 8% reflection- transmittion) (- 8% heat dissipation) (-19% metabolism) > 5% carbohydrate
Efficiency of food production from solar energy to people
0.42% of solar energy is converted into winter wheat grain.
Conversion of grain into energy stores within the body of animals or humans = 10% efficiency.
10x more grain is required if people obtain their energy by consuming meat.
Daily per capita food availability
Global food production has been adequate every year since 1974 to meet minimal calorie requirements for everyone on earth (FAO).
Protein in the diet
% from what source
55% from grain staples
20% from animal products
13% from legumes
Adult daily protein intake should be
at least 50g/day
Legumes and grains provide which 4 proteins
= Ile L = Lys L
= Met G =Try G
Isoleucine Lysine
Methionine tryptophan
World food programmes (WFP) disaster food basket
400g of cereal flour/rice/bulgur 60gof pulses 25 g of oil (vit. A fortified) 50 g of fortified blended foods (Corn Soya Blend) 15g of sugar 15g of iodized salt
Nutritional value of WFP disaster food basket
Energy 2,100 Kcal
Protein 58 g
Fat 43g
Nutritional value of Peanut paste
Energy 545Kcal
Protein 13.6g
Fat 35.7g
Increases in world meat production
Rising incomes have increased meat consumption.
Chicken consumption is increasing in the US as people swap from eating red to white meat.
Strategies for reproduction
R strategy & k strategy
[Bennett et al., 2012]
R strategy selected
- Mature rapidly
- Short lived: Most die before they reproduce
- Many offspring: Tend to overproduce
- Most pest species
- Population not regulated by density: boom and bust figures
- Opportunistic: invade new areas
K strategy selected
- Mature slowly
- Long lived: Low juvenile mortality rate
- Few offspring at a time
- Most endangered species
- Population stabilises near carrying capacity
- Maintain numbers in stable ecosystems
Abiotic stress
Non-living =
oxygen Soil quality Temperature
Water status Mineral nutritions
Toxic minerals & allelochemicals Gravity
Humidity C2H4 (ethylene) Wind
Photoperiod Photosynthetic light
Photomorphogenic light
biotic stress
life and living organisms =
Herbivores Pathogens
Soil microorganisms Parasites
How short day rice variety response to light hour
Flowers if short daylight and long night without flash of light
How long day plant response to light hour
Flowers if long period of daylight or short day light with flash of light at night
Yield loss may due to
pests and unfavourable abiotic conditions
Plant defences against herbivores
= Chemical (secondary metabolites)
= Physiological
= Morphological
Example of chemical defence
- Nitrogen compounds
- Phenoloics
- Polyacetylenes
- Proteins
- Terpenes
- Other
Example of morphological defence
- Bark and cell wall thickening
- Spines and hairs
- Waxy silica covered surfaces
Example of physiological defence
- Compensate for yield loss
- Rapid repair of injured tissue
Pest outbreaks occur with changes in the environment
- Physical environment becomes more favourable for pest reproduction, survival and growth.
- Food plants become more abundant/ nutritious for pests
- Natural enemies of the pest become less common
- Competing species become less common
- Environmental induces physiological, reproductive or genetic changes in the pest to make it better adapted to the environment/ crop