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Root growth
- Elongation: apical meristem
- Girth: lateral meristem (dicots mostly)
- Low CHO: root growth goes way down
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Stem Growth
- Apical meristem: initiating nodes, internodes, small amount of elongation
- Intercalary meristem: most of growth
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Leaf growth (monocots)
leaf intercalary meristem
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Difference btw root stem and leaf in Dicot/monocot
- Root: D- apical, lateral M- apical
- Stem: D&M- apical, Intercalary
- Leaf: D- apical, Marginal M- Apical, Intercalary
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where does growth happen
lowest 3 cm of the leaf
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Dicot leaf growth is really
basal oriented
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Tall fescue leaf growth habits
- Forage type: more cells dividing and elongating further away from the leaf base
- Turf type: slower growth, division and elongation closer to stem base.
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Leaf growth and cell division under shade
goes down
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12 hour night with flash
- Pfr is decaying to Pr but flash sends all back to Pr and decay process has to start over again
- therefore Pfr is around and short day plants can't flower
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plastochron
interval btw appearances of new leaf
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calculating division/ cell column/day
- 1 mm = 1000 µm
- cells/leaf x .% of growth
- cells/leaf = leaf length mm/(cell length/1000)
- .% of growth = leaf elongation/length of leaf
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Serial Sampling
- Isn't very good b/c plant-plant variablity
- range can be 3 fold
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CGR
- ∆w/∆t
- not linear = use calculus for dry weight (derivative)
- if x2 + 6x - 4.9 use 2t + 6
- For CGR use integration
- = LAI x NAR
- increase yield by keeping CGR higher, longer
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Negative CGR?
- hail, drought cut
- night
- germination
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NAR
- Net assimilation rate
- estimate of efficiency
- = (w2-w1)(lnLA2-lnLA1)/(LA2-LA1)(t2-t1)
- Affected by dark respiration, exudates, stored reserves, and age
- decreases with increased leaf area
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Change CGR
- Increase N = sharper initial uptake
- increase water = better growth rate
- closely tied with yield
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CGR v. LAI
- There is a critical leaf area
- law of diminishing returns ~ 95%
- CGR:interception = 1:1
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LAR
- Leaf Area Ratio
- Partitioning of dry matter into leaf
- LAR = 1/2(a1/w1 + a2/w2)
- After planting values are low (b/c roots first)
- dm2/g
- graph is exponetial to plateau after 2-3 weeks
- C3 tend to have greater LAR, perhaps compensating
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RGR
- Relative Growth Rate
- Use when plants differ in inital size
- Growth efficiencies
- g of dry matter / grams of existing / time (g/g/day)
- RGR = (lnw2-lnw1)/(t2-t1)
- values up to 60%
- small changes = big difference
- RGR = LAR (partitioning) x NAR (efficiency)
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Winter wheat v. Spring wheat
- CGR is higher for winter- more leaf area
- spring wheat peck is further back
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NAR v. CGR in winter wheat
- NAR down for winter w/ N b/c shading
- CGR is higher because more LAI
- Spring has higher NAR but lower LAI so growth rate is down
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NAR over time
- declines b/c
- increase shading
- increased average age = Ps down
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NAR v. RGR
- Very similar, LAR is similar
- Lower Rd has higher efficiency in both
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RGR v. LAR
- as RGR increases so does LAR
- C3 have higher LAR to increase CGR
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C3 v. C4 CGR
- C4 higher & steeper curve
- NAR higher (Ps)
- Don't take over b/c cold sensitive
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Term for no G x E
homoeostatsis
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Protein Kinase
What puts the P on Nitrate reductase
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