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 + CO 2

The parts of a cell

Ps & Rs Comparison Photosynthesis Occurs only in green cells Occurs in chloroplasts Occurs only in light Requires light, CO 2, H 2 O Produces O 2 and sugar ATP produced by photophosphorylation (used to make sugar) Results in biomass gain Respiration Occurs in all living cells Occurs in mitochondria Occurs 24/7 Requires O 2 and sugar Produces CO 2, H 2 O ATP produced by oxidative phosphorylation (‘burning’ sugar to make other products) Results in biomass loss

Temperature Effects on Ps & Rs Temperature (C) Relative Response (%)

Temperature Effects on Ps & Rs Temperature (C) Relative Response (%) Net Ps

Terms Cool season crops Warm season crops Cold-hardiness Dormancy Endo- Eco- Para- Chilling requirement Growing degree day GDD) Stratification Scarification Vernalization Heat-zone map Hardiness zone map

Cool season crops Prefers air temperatures: o C –Soil temperatures: o C Crops: –Lettuce− Kentucky bluegrass –Cole crops− Christmas trees –Carrots− Wheat –Spinach − Barley

Warm season crops Prefers air temperatures: o C –Soil temperatures: o C Crops: –Tomato− Bermuda grass –Sorghum− Corn –Soybean− Chile –Afghan pine− Pineapple

Cold-hardiness Definition: ability to survive temperatures below 0 o C. Function of tissue, season, growth stage –Shoots <-40 o C− Roots ~ -10 o C N.B. Chilling injury is injury to tropical fruits caused by temperatures between 0-5 o C

Basic Plant Biology Factors Affecting Acclimation-Size Spring Buds = -3 o Cambium = -4 o Roots = -4 o Seedling = -3 o Germinant = -2 o Winter Buds = -25 o Cambium = -50 o Roots = -10 o Seedling = -30 o

Basic Plant Biology Factors Affecting Acclimation- Genetics Tolerant Pinus pinea –Shoots = -40 o C –Roots = -10 o C Intolerant Eucalyptus camaldulensis –Shoots = -10 o C –Roots = -3 o C

Basic Plant Biology Mesquite/ April 2003

Dormancy & Cold-hardiness Cold - Hardiness of Apple Blooms Approximate Calendar Date LT 50 ( o C)

Dormant Silver Tip 12mm Green Green Tip Tight Cluster Full Pink Full Bloom Growing Degree Hours ( o C) LT 50 ( o C) Photos by: Basic Plant Biology Cold - Hardiness of Apple Blooms

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 0-10 o C), and sufficient GDD accumulate –Paradormancy- regulated by other buds Remove the controlling bud and ‘whalaa’

Dormancy & Cold-hardiness Dormancy of Apple Blooms Temperature ( o C) Chilling Units Growth Units

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 = 146 divided by 2 = 73 – 50 = 23 GDD.

National Climate Zone Map E Gregory McPherson

Plant Hardiness Zone Map

USDA Hardiness Zone Map

Plant Heat Zone Map

Nursery Industry Heat-Zone Map/ AmHortSoc Days/yr> 86F Zone 9

New Mexico Maps Zone 9 Days/yr> 86F

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, LT 50 ) 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 Military Time (hr) Temperature ( o F)