ENH102

Physiological Principles in Environmental Horticulture

Matthew Gilbert (megilbert@ucdavis.edu)

• ENH 102. Physiological Principles in Environmental Horticulture (4)

• Lecture—3 hours; discussion—1 hour. Prerequisite: Biological Sciences 1C. Physiological principles and processes essential to floriculture, nursery crop production, turfculture and landscape horticulture. Emphasis on the control of vegetative and reproductive development for a broad species range in greenhouse and extensive landscape environments. GE credit: SE.—I. (I.) Burger Gilbert

Who am I?

• Matthew Gilbert • Department of Plant Sciences

– 2314 Plant and Environmental Sciences Building – megilbert@ucdavis.edu – Office Hours:

• Mondays 2pm-4:30pm (email me otherwise) • PES 2314

Who am I?

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What is Environmental Horticulture?

• Department of Plant Biology – Basic plant research (?focusing on small scales?)

• Department of Plant Sciences – Agronomy and Vegetable Crops – Pomology – Rangeland Science – Environmental Horticulture

Goals for the Course • To provide students with an integrative overview of

major physiological plant processes spanning the biochemical, cellular, tissue, organ and whole plant levels of organization.

• To build a physiological basis upon which students can understand the effects on and responses of plants to their environment.

“Horticulturists know how to grow plants; physiologists know how plants grow.” • To provide you with (intellectual) tools to observe

and understand the plants that surround you.

http://berxblog.blogspot.com/2012/03/creating-my-mobile-toolbox-for-windows.html

Goals for the Course

• Back of the envelope calculations • Critical thought using plant physiology • Critical reading of scientific papers

http://en.wikipedia.org/wiki/File:HouseCastSeason1.jpg

http://12160.info/group/marijuanagodsplant/forum/topics/famous-stoners-throughout-history

http://en.wikipedia.org/wiki/File:Goldman_Sachs.svg

http://en.wikipedia.org/wiki/File:Orchid_plants.jpg

Introduction

Plant Physiology?

• An integrative science – Biology – Chemistry – Physics – Math – Anatomy – Morphology

Introduction

Plant Physiology?

• The science concerned with processes and functions

• Processes – Photosynthesis – Respiration – Ion uptake – Translocation – Transpiration – Flowering – Seed formation

Introduction

Unifying Concepts • Importance of water • Membranes • Energy

– Chemical potential • Photosynthesis

– ATP, NADPH • Respiration

– Water potential • Internal control mechanisms of plants • Environmental responses of plants • Mechanisms of adaptability

Introduction

Unifying Principles of Plants • Convert light energy into chemical energy

– Photosynthesis • Non-motile • Must evolve or adapt or else • Have cell walls

– Structural reinforcement • Continuously uptake, transport and lose water

– Transpiration – Evaporation

• Developed means of nutrient and photosynthate translocation

He’s forgotten genetics!

Structure Enzymes/ protein

Resource cycles

H2O NADPH

Genes

http://www.thehistoryblog.com/wp-content/uploads/2013/05/Watson-Crick-DNA-model.jpg

Course format

• Lectures (22 topics) • No lab (video’s + demonstrations + examples) • Evaluations:

– One final exam (150) – One (two?) midterms (100) – Group discussion exercises (125) – Arboretum tour (25) – One minute evaluations (evaluation of progress)

• 1 – Introduction and Environment • 2 – Anatomy • 3 – Membranes • 4 – Bioenergetics • 5- Photosynthesis – Light dependent

reactions • 6- Photosynthesis – Light

independent reactions • 7 – Factors affecting photosynthesis • 8 – Respiration • 9 – Water relations • 10- SPAC • 11- Transpiration • 12- Water stress

• 13- Translocation • 14 – Mineral nutrition • 15 – Uptake and assimilation • 16 – Nutrient deficiency • 17 – Growth • 18 – Differentiation and

Development • 19 – Growth regulators: Auxin,

Cytokinin, Gibberellin, Growth inhibitors, Ethylene

• 20 – Developmental physiology • 21 – Postharvest • 22 – Stress physiology

Reference material • No textbook – so will post lecture slides on

Smartsite • Will post websites at lectures • Taiz and Zeiger - on reserve, any edition is fine • Alternatives abound:

– Salisbury and Ross Plant Physiology – Hopkins and Huner Introduction to Plant Physiology

• If you see a career as an plant physiologist, then these graduate student-level books are useful:

– Lambers et al. Plant Physiological Ecology (PDF available on UCD library website)

– Nobel Physicochemical and Environmental Plant Physiology (serious physics)

Any questions?

Why study the environment, when this is a Plant Physiology course?

• What is a plant’s environment? • Radiation • Temperature • Humidity • Wind • Atmosphere

Temperature

• oC, F or K • Temperature affects:

– Growth and development – Water loss – Photosynthesis and enzymatic processes

• Zwieniecki’s First Law: Temperature affects everything e.g. PV=nRT

Relative humidity • RH is a function of vapor pressure, temperature and atmospheric

pressure (~altitude)

• 0-100% relative humidity of air • 100% is saturation at which condensation occurs • RH=100*ea/esat

– ea = pressure of H2O vapor – esat = saturation pressure of H2O vapor

• But esat = f(Tair) • Is relative humidity very useful?

• http://en.wikipedia.org/wiki/Relative_humidity

http://en.wikipedia.org/wiki/File: Atmosphere_gas_proportions.svg

RH=ea/esat*100

Dry bulb, wet bulb and dew point temperatures • Dry bulb temperature – (shielded) air temperature of dry

thermometer – used in weather reports

• Wet bulb temperature – temperature of thermometer when cooled by evaporating water – used to calculate humidity, or used to evaluate cooling potential of

evaporation

• Dew point temperature or saturation temperature – temperature of air or substance that results in condensation of water vapor – used to control temperatures to prevent or cause condensation

• Great and simple explanation: http://www.ianrpubs.unl.edu/pages/publicationD.jsp?publicationId=1000

• Measurement: using electric RH and Tair meter • Sling psychrometer: http://www.youtube.com/watch?v=Sxm6yq268Bc

ftp://ftp.licor.com/perm/env/LI-610/Manual/610card.pdf

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Relative humidty

Water vapor pressure and dewpoint estimation at sea-level:1) Saturated vapor pressure -where air temperature meets 100%RH curve 2) Water vapor pressure - find intersection of air temperature line and and RH curve, read vapor pressure off y-axis 3) Dewpoint temperature -calculate vapor pressure as in (2) find intersection with 100%RH curve.

A good reference:

Vapor pressure deficit From FAO56

Leaf water loss is roughly proportional to the difference in the atmospheric partial pressure of water in the leaf and outside the leaf

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Air temperature (oC)

100%

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20%

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Relative humidty

Water vapor pressure and dewpoint estimation at sea-level:1) Saturated vapor pressure -where air temperature meets 100%RH curve 2) Water vapor pressure - find intersection of air temperature line and and RH curve, read vapor pressure off y-axis 3) Dewpoint temperature -calculate vapor pressure as in (2) find intersection with 100%RH curve.

VPD = esat(@Tleaf)-ea(@Tair) 1.7 2.5

VPD 9AM = 2.5-1.7 = 0.8 kPa

Vapor pressure deficit From FAO56

Leaf water loss is roughly proportional to the difference in the atmospheric partial pressure of water in the leaf and outside the leaf

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0 5 10 15 20 25 30 35 40 45

Wat

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Air temperature (oC)

100%

90%

80%

70%

60%

50%

40%

30%

20%

10%

Relative humidty

Water vapor pressure and dewpoint estimation at sea-level:1) Saturated vapor pressure -where air temperature meets 100%RH curve 2) Water vapor pressure - find intersection of air temperature line and and RH curve, read vapor pressure off y-axis 3) Dewpoint temperature -calculate vapor pressure as in (2) find intersection with 100%RH curve.

VPD = esat(@Tleaf)-ea(@Tair)

4.9

1.7 2.5

VPD 9AM = 2.5-1.7 = 0.8 kPa VPD 3PM = 4.9-1.7 =

From: http://en.wikipedia.org/wiki/Psychrometrics

Wind

• http://en.wikipedia.org/wiki/Beaufort_scale • Growth chambers/greenhouses have circulation • Wind couples things (leaves) with air

– enhances water loss – changes temperature

What is light?

http://en.wikipedia.org/wiki/File:Linear_visible_spectrum.svg

What is light?

Solar radiation: W m-2 = J s-1 m-2

Wavelength: 250nm – 2.5µm Intensity: full sunlight 1000 W m-2

http://en.wikipedia.org/wiki/File:Linear_visible_spectrum.svg

Light: Lux (weighted according to human perception) Wavelength: 380nm – 750nm Intensity: full sunlight 100000 lux

Power or energy

Light for plants

http://en.wikipedia.org/wiki/File:Par_action_spectrum.gif

PAR, PPF and PPFD: µmol * m-2 s-1

Wavelength: 400nm – 700nm Intensity: full sunlight 2000 µmol m-2 s-1

* That is micro mols of photosynthetically active photons per m2 per s Why express PAR as a quantum unit rather than energy (W m-2)?

Photosynthetically Active Radiation, Photosynthetic Photon Flux and Photosynthetic Photon Flux Density

http://en.wikipedia.org/wiki/File:Linear_visible_spectrum.svg

http://en.wikipedia.org/wiki/File:Linear_visible_spectrum.svg

Which is the best artificial light source for growing plants?

Source: LICOR6400XT manual

700nm - > beyond here lies heat UV <- 400nm

Atmosphere

• Sea level: 101.35 kPa • O2 20.9% ~21kPa • H2O 0-5% ~ 0-5kPa • CO2 0.04% ~ 40Pa ~ 400ppm

• O3 low

• pollution

http://en.wikipedia.org/wiki/File: Atmosphere_gas_proportions.svg

What factors influence plant water loss?

• Environmental: – Solar radiation – Wind – VPD (RH and temperature)

• Plant characteristics – Leaf and canopy shape – How wide the stomata are open and their density

From FAO56

ETo = reference evapotranspiration

Landscape coefficient/crop coefienct

ETo = reference evapotranspiration

• Penman-Monteith equation:

• Main publication: FAO56 http://www.kimberly.uidaho.edu/ref-et/fao56.pdf

From FAO56

Wind speed

ETo applied to landscapes

http://www.water.ca.gov/wateruseefficiency/docs/wucols00.pdf

http://en.wikipedia.org/wiki/File:Lysimeter_g1.svg http://dateline.ucdavis.edu/071996/071996no1.html

http://wwwcimis.water.ca.gov/cimis/frontMapView.do?urlImg=eto

Exercise #1

http://crf.ucdavis.edu/virtual-tour /conviron-growth-chamber/

ftp://ftp.licor.com/perm/env/LI-610/Manual/610card.pdf

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Wat

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Pa)

Air temperature (oC)

100%

90%

80%

70%

60%

50%

40%

30%

20%

10%

Relative humidty

Water vapor pressure and dewpoint estimation at sea-level:1) Saturated vapor pressure -where air temperature meets 100%RH curve 2) Water vapor pressure - find intersection of air temperature line and and RH curve, read vapor pressure off y-axis 3) Dewpoint temperature -calculate vapor pressure as in (2) find intersection with 100%RH curve.

A good reference: