Temperature & Respiration
A/H 100G
J.G. Mexal
HORT Humor
Take Home Quiz (due Monday 2/27/06)
What will be the impact of global climate
change to:
• Natural ecosystems
• Agriculture in the southwest
• Urban landscapes, esp. golf courses
– Discuss these in terms of near-term
consequences (10-20 years) and long-term (>
30 years)
What is ‘Respiration’?
• The conversion of stored energy (sugar) into
metabolic energy (ATP)
• Occurs in mitochondria
• Requires sugar
• Generates ATP + CO2
The parts of a cell
Ps & Rs Comparison
Photosynthesis
Respiration
•
•
•
•
•
•
•
•
•
•
•
•
Occurs only in green cells
Occurs in chloroplasts
Occurs only in light
Requires light, CO2, H2O
Produces O2 and sugar
ATP produced by
photophosphorylation
(used to make sugar)
• Results in biomass gain
Occurs in all living cells
Occurs in mitochondria
Occurs 24/7
Requires O2 and sugar
Produces CO2, H2O
ATP produced by
oxidative phosphorylation
(‘burning’ sugar to make
other products)
• Results in biomass loss
Temperature Effects on Ps & Rs
Relative Response (%)
100
Photosynthsis
Respiration
80
60
40
20
0
0
10
20
30
Temperature (C)
40
50
Temperature Effects on Ps & Rs
Relative Response (%)
100
Photosynthsis
Respiration
80
60
Net Ps
40
20
0
0
10
20
30
Temperature (C)
40
50
Terms
•Cool season crops
•Warm season crops
•Cold-hardiness
•Dormancy
•Endo•Eco•Para-
•Stratification
•Scarification
•Vernalization
•Heat-zone map
•Hardiness zone map
•Chilling requirement
•Growing degree day GDD)
Cool season crops
• Prefers air temperatures: 20-25oC
– Soil temperatures: 15-22oC
• Crops:
– Lettuce
– Cole crops
– Carrots
– Spinach
− Kentucky bluegrass
− Christmas trees
− Wheat
− Barley
Warm season crops
• Prefers air temperatures: 25-35oC
– Soil temperatures: 20-28oC
• Crops:
– Tomato
– Sorghum
– Soybean
– Afghan pine
− Bermuda grass
− Corn
− Chile
− Pineapple
Cold-hardiness
• Definition: ability to survive temperatures
below 0oC.
• Function of tissue, season, growth stage
– Shoots <-40oC
− Roots ~ -10oC
• N.B. Chilling injury is injury to tropical fruits
caused by temperatures between 0-5oC
Basic Plant Biology
Factors Affecting Acclimation-Size
Winter
Spring
• Buds
= -25o
• Cambium = -50o
• Roots
= -10o
• Buds
= -3o
• Cambium = -4o
• Roots
= -4o
• Seedling = -30o
• Seedling
= -3o
• Germinant = -2o
Basic Plant Biology
Factors Affecting Acclimation- Genetics
Intolerant
• Eucalyptus
camaldulensis
– Shoots = -10oC
– Roots = -3oC
Tolerant
• Pinus pinea
– Shoots = -40oC
– Roots = -10oC
Basic Plant Biology
Mesquite/ April 2003
Dormancy & Cold-hardiness
Cold - Hardiness of Apple Blooms
LT50 (oC)
0
-2
-4
-6
-8
LT50
LT10
LT90
-10
-12
-14
-16
ov
15
-N
ov
30
-N
ov
15
-D
ec
30
-D
ec
15
-J
an
30
-J
an
15
-F
eb
28
-F
eb
15
-M
a
30 r
-M
ar
15
-A
p
15 r
-M
ay
30
-M
ay
ct
1N
15
-O
1O
ct
-18
Approximate Calendar Date
Basic Plant Biology
Cold - Hardiness of Apple Blooms
LT50 (oC)
1000
0
2000
3000
4000
5000
6000
7000
Tight Cluster
-2
12mm Green
-4
-6
Green Tip
Full Pink
Full Bloom
-8
-10
Dormant
-12
-14
Photos by:
Silver Tip
Growing Degree Hours (oC)
Basic Plant Biology
How a Tree Grows
• Dormancy-lack of visible growth
– Ecodormancy- environmental stress
induced• Growth resumes when stress removed
– Endodormancy- requires chilling
• Growth resumes after chilling requirement met
(h between 0-10oC), and sufficient GDD
accumulate
– Paradormancy- regulated by other buds
• Remove the controlling bud and ‘whalaa’
Dormancy & Cold-hardiness
Dormancy of Apple Blooms
Growth Units
20
Chilling Units
1.0
0.5
15
0
10
-0.5
5
-1.0
0
0
5
10
15
20
Temperature (oC)
25
30
Growing degree days (GDD)
• Growing degree days (GDD) is a
measure of temperature requirements for
plants and can be used to estimate growth
and development.
• The basic concept of growing degree days
is that plant development will occur when
temperatures exceed a base temperature.
Growing degree days (GDD)
• Corn: the maximum temperature plus
the minimum temperature in a day
divided by 2 minus 50.
• Fifty is selected as the constant
because corn grows little at 50°F or
below.
• 86°F is the maximum temperature
Growing degree days (GDD)
• Example: If a low temperature was
60°F and the high was 90°F, the GDD
would be 60 + 86 = 146 divided by 2
= 73 – 50 = 23 GDD.
National Climate Zone Map
E Gregory McPherson <[email protected]>
Plant Hardiness Zone Map
USDA Hardiness Zone Map
Plant Heat Zone Map
Nursery Industry
Heat-Zone Map/ AmHortSoc
Days/yr> 86F
7-14
14-30
30-45
45-60
60-90
90-120
120-150
Zone 9
New Mexico Maps
Days/yr> 86F
7-14
14-30
30-45
45-60
60-90
90-120
120-150
Zone 9
Seed Dormancy
• Stratification
– Overcoming physiological dormancy by
exposure to cold temperatures (wet or dry)
• Scarification
– Overcoming physical dormancy by
mechanical abrasion
•
•
•
•
Mechanical
Chemical (acid)
Thermal (hot water)
Percussion (certain species)
Vernalization
• Chilling to induce transition from
vegetative growth to reproductive growth
• Examples:
– Winter wheat
– Onions (biennial)
– Bulbs (daffodil, tulip)
Things to know:
•Cool season crops (T & e.g.)
•Warm season crops (T & e.g.)
•Cold-hardiness (definition, LT50)
•Dormancy
•Endo•Eco•Para-
•Chilling requirement
•Growing degree day GDD)
Things to know:
•
•
•
•
•
Stratification (e.g.)
Scarification (e.g.)
Vernalization (e.g.)
Heat-zone map (what it means)
Hardiness zone map (what it means)
Infrared Surface Temperature Influenced
by Surface Cover
Temperature (oF)
160
Turf
Asphalt
Artificial Turf
140
120
100
80
60
40
6
8
10
12
14
16
18
Military Time (hr)
20
22
24