environmental conditions in cutting...
TRANSCRIPT
Prof. Dr. Károly Hrotkó
SZIU Faculty of Horticultural Science
Environmental conditions in cutting
propagation
Dr. Hrotkó Károly Environmental conditions and rooting of cuttings 2
Different requirements in the phases of technology I. Environmental conditions of stockplants
II. Requirements of rooting cuttings
III. Requirements of rooted cuttings
Dr. Hrotkó Károly Environmental conditions and rooting of cuttings 3
I. Environmental conditions and stockplants Turgor, water content.
Temperature
Light - shading, etiolation
Nutrition
CO2 enrichment
Dr. Hrotkó Károly Environmental conditions and rooting of cuttings 4
Water supply of stockplant and water content of cuttings Optimal water supply is required.
Taking cuttings earlier (before 9 am) results higher turgor.
Water deficit of stockplants results low rooting capacity and susceptibility to infections.
Water loss of hardwood cuttings improves the uptake of hormonal soultion.
Dr. Hrotkó Károly Environmental conditions and rooting of cuttings 5
16.05.2008
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Korponay 4/8 Korponay 4/10
Dynamics of transpiration of
leaves on Prunus avium
in May 2008.
(2008. 05. 16. és 2008. 05. 26.)
Dr. Hrotkó Károly Environmental conditions and rooting of cuttings 6
Water content
influence the
rooting of cuttings;
above 50% more
favorable
Sainte Julien GF 655/2
0
10
20
30
40
50
60
70
80
40 45 50 55 60
Water (%)
Rooti
ng (
%)
Gyökeresedés
Lineáris (Gyökeresedés)
Rooting of plum hardwood cuttings related to
water content of cuttings
Dr. Hrotkó Károly Environmental conditions and rooting of cuttings 7
Temperature at taking of cuttings Complex effects, related to other conditions (sunshine
hours, hormonal factors, etc.).
Faster growth of shoots on apple and plum at higher temperature; results more thin shoots and higher rooting percentage.
Higher temperature on the day of taking hardwood cuttings of plum results higher rooting. Reason is unknown, probably complex.
Dr. Hrotkó Károly Environmental conditions and rooting of cuttings 8
PPO-
activity
cold unit
water
content leaf fall POD-activity
phenolics
sproutin
g
rooting
temperature
Effects on rooting of plum rootstocks hardwood cuttings
Dr. Hrotkó Károly Environmental conditions and rooting of cuttings 9
Marianna GF 8-1
0
10
20
30
40
50
60
70
80
90
-250 0 250 500 750 1000 1250 1500 1750 2000
Cold unit (CU)
ro
oti
ng
(%
)
gyökeresedés
Lineáris (gyökeresedés)
– No direct link
between dayly
average
temperature and
rooting
– Low cold unit
quantity befora
taking cuttings
(below 500 CU) is
more favorable
Temperature and cold unit (CU) on plum rootstocks’
hardwood cuttings
Dr. Hrotkó Károly Environmental conditions and rooting of cuttings 10
Rooting of plum rootstocks’ hardwood cuttings
Phenolics and
rooting
– favorable:
Fehér besztercei:
above 10 μg/mg
St. Julien GF 655/2:
10-30 μg/mg
Marianna GF 8-1:
15-40 μg/mg
Marianna GF 8-1
0
10
20
30
40
50
60
70
80
90
100
0 5 10 15 20 25 30 35 40 45 50
phenol content in buds (μg/mg)
roo
tin
g (
%)
Gyökeresedés
Polinom. (Gyökeresedés)
Dr. Hrotkó Károly Environmental conditions and rooting of cuttings 11
POD activity and
rooting
– Low activity is more
favourable
– Fehér besztercei (bud)
St. Julien GF 655/2
(cutting): under 4 U/mg,
Marianna GF 8-1
(cutting): under 3 U/mg
Marianna 8-1
0
10
20
30
40
50
60
70
80
90
100
0 1 2 3 4 5 6 7
POD activity (U/mg protein)
Rooti
ng (
%)
Gyökeresedés
Lineáris (Gyökeresedés)
Rooting of plum hardwood cuttings
Dr. Hrotkó Károly Environmental conditions and rooting of cuttings 12
0
10
20
30
40
50
60
70
80
90
9. 1. 10. 1. 11. 1. 12. 1. 1. 1. 2. 1. 3. 1.
taking of cuttings (date)
roo
tin
g (
%)
Fehér besztercei
Sainte Julien GF
655/2
Marianna GF 8-1
Polinom. (Fehér
besztercei)
Polinom. (Marianna
GF 8-1)
Polinom. (Sainte
Julien GF 655/2)
Dr. Hrotkó Károly Environmental conditions and rooting of cuttings 13
Effect of light on stockplants Daylength
- affetc photosysnthesis: carbohidrate accumulation - fotomorfogenetic effect : increasing daylength affect positive the vegetative growth and rooting of Chrisanthemum.
Wawelength no consistent results: red light stimulate the phytochrom system and rooting, but some results indicate that blue light also positive.
Dr. Hrotkó Károly Environmental conditions and rooting of cuttings 14
Etiolation and shading of stockplants Etiolation: excluded solar radiation. During preconditioning different level of shading
is more applied in practice. Local etiolation using black strips or Alu folie. Effect
- starch accumulation, - reduced formation of schlerenchima, - reduced lignin production – phenolics may be used for rooting, - etiolated tissue react more efficient to auxine treatments.
Dr. Hrotkó Károly Environmental conditions and rooting of cuttings 15
Rejuvenalization
grafting subsequently
on seedlings →
Etiolated and shaded
stockplants
Dr. Hrotkó Károly Environmental conditions and rooting of cuttings 16
Dr. Hrotkó Károly Environmental conditions and rooting of cuttings 17
CO2 enrichment Increased photosynthese – more shoots appropriate
for cuttings.
Only in closed systems (greenhouse) is possible.
In winter effectivity should be increased usin supplementary lighting.
Dr. Hrotkó Károly Environmental conditions and rooting of cuttings 18
Nutrition of stockplants Shott mass and its nutrient content is determining
to the regeneration process (related to the anatomy structure too)
Factors of nutrient balance during rooting: + absorption from substrate (no importance!) + assimilation (only leafy cuttings!) - respiration during rooting (increase due auxine application) - leaching due to irrigation, mist application
Dr. Hrotkó Károly Environmental conditions and rooting of cuttings 19
Principles of nitrogen and carbohydrate metabolism in cuttings Lack of roots – no nitrogen uptake and assimilation
Amino acid sources for root formation: - Amino acid reserve - proteolitic processes (decomposition of proteins)
Carbohydrates: energy reserves and sources for structural carbohydrates (cellulose)
Optimal concentration of non-structural carbohydrates (sugar, starch) is required for rooting
Starch content test on hardwood cuttings (jódos-jódkáli 0,2%)
Dr. Hrotkó Károly Environmental conditions and rooting of cuttings 20
Importance of Carbohydrate / Nitrogen ratio Carbohydrates: energy reserves and sources for
structural carbohydrates (cellulose)
Indirect effects!
Higher C / N ratio in stockplant shoots is favourable.
Exceed nitrogen reduction decreases the shoot (cuttings) production.
In thin shoots, secondary shoots the C/N ratio and rooting is higher.
Dr. Hrotkó Károly Environmental conditions and rooting of cuttings 21
Management of stockplant in order to improve C/N ratio in practice Decreased N- supply; increased K and P supply
Root restriction: close planting, root pruning
Pruning back the primary shoots (increased C/N ratio in secondary shoots)
Moving away from shoot basis C/N ratio decreases
Maintaining healthy leaf surface
Positive effect of ringing, etiolation
Dr. Hrotkó Károly Environmental conditions and rooting of cuttings 22
Rooting of Vitis cuttings of potted plants with excluded nutrients
Missing nutrient in substrate Rooting percent
Nitrogen 91%
Potassium 42%
Phosphorus 37%
Magnesium 35%
Calcium 0%
Dr. Hrotkó Károly Environmental conditions and rooting of cuttings 23
Role of other nutrients in rooting process Ca - activates peroxidase, essential for growing of root
primordium
Zn - cathalitic effect on triptophan synthesys → formation of native auxine
Mn - activates oxidative enzymes
B - influences the permeability of membrane, sugar transport, activates enzyme, carbohydrate metabolism, metabolism of phenolics, formation of auxine, and nucleic acids
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Dr. Hrotkó Károly Environmental conditions and rooting of cuttings 25
Shoot position and type of cuttings is related to nutrient content Considerable morphological and nutrient content
differences along the shoot from basis to shoot tip. Secondary shoots, branches root better, but
consider plagiotropic shoots. Basal cuttings generally root better:
- more ripe and lignificated shoots, higher C/N ratio, - meristematic cell groups in branch collar, - number of preformed roots considerable decreases towards the shoot tip.
Shoots with flower buds root less (blueberry, Abelia, Ligustrum, Ilex, etc.)
Dr. Hrotkó Károly Environmental conditions and rooting of cuttings 26
Shoot meristem in shoot tip
Section of subterminal growth
Rhytidom typical to species,
leaf fall, → leafless shoot
Secondary thickening,
lignification
Secondary thickening,
complete cambial ring,
formation of secondary
xylem
schlerenchyma
(lignification starts)
Dr. Hrotkó Károly Environmental conditions and rooting of cuttings 27
← terminal cutting
← basal cutting
Hradwood cutting
Dr. Hrotkó Károly Environmental conditions and rooting of cuttings 28
Autovegetatív szaporítások
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Dr. Hrotkó Károly Environmental conditions and rooting of cuttings 30
Effect of storage conditions on rooting of cuttings Requirements during cutting storage depends on
species and cutting type.
Avoid water deficit, mass decrease and disease infection.
Temperature as low as the species can tolarate.
Maximum air humidity, moistured substrate, or covering material.
Decreased oxigen and etilen concentration, increased CO2 level.
Storage length from few days to more month.
Dr. Hrotkó Károly Environmental conditions and rooting of cuttings 31
II. Environmental conditions during rooting Leaf water content and turgor
Transpiration activity and water supply
Photosynthetic activity and solar radiation
Dr. Hrotkó Károly Environmental conditions and rooting of cuttings 32
Problems of water management in leafy cuttings: contradicting requirements Reduce the water loss through transpiration activity,
maintaining turgor
Maintaining the photosynthetic activity – required solar radiation
Avoid heat stress in leaves
Optimal temperature in rooting zone
Dr. Hrotkó Károly Environmental conditions and rooting of cuttings 33
Factors in water management in leafy cuttings Water loss due to transpiration.
Water uptake - no roots , - basal part of tracheas, tracheids are blocked, no water transport, - minimal water uptake through leaves, - more water uptake through basal part of cuttings.
Water deficit→ stomatal conductance reduced→ no CO2 uptake→reduced photosyntesis
Dr. Hrotkó Károly Environmental conditions and rooting of cuttings 34
How to control water loss of cuttings? Water loss depends on difference in vapour
pressure of leaf and environmental air.
Difference could be deminish - leaf temperature and vapour pressure of leaves - increased vapour content in environmental air, - combination of both factors.
Vapour pressure of leaves is function of - leaf temperature and - difference between leaf temperature and the leaf-air temperature difference (Δt).
Dr. Hrotkó Károly Environmental conditions and rooting of cuttings 35
Importance of solar radiation When solar radiation intensity is larger than 0,8 J
cm-2 min-1 (Klougart 1975) shading is required. Large fluctuation in solar radiation
in May 250 – 540 J cm-2
in Agust 250 – 2100 J cm-2 (Klougart 1975). Shading reduces insolation at 70-80%. Long wave radiation gets throug PE tent →plant
temperature is higher than under glass, but during the night the temperature decrease more.
White plastic foil reflects 40-60% of solar radiation.
Dr. Hrotkó Károly Environmental conditions and rooting of cuttings 36
Options in reducing water loss of leafy cuttings in propagation technology Using closed propagation units
(polythene tent, closed systems inside the glasshouse, polythene tent, shading, contact plastic cover, wet cover)
Intermittent mist (open and closed propagation units)
Fog system
Dr. Hrotkó Károly Environmental conditions and rooting of cuttings 37
Closed propagation units: advantages and shortcomings Simple and cheap (glass, polythene tent, etc.) Heat trap effect → increasing leaf – air vapor pressure
difference → water loss. Shading is required:
- PE-inner cover, modifyed PE foils (vinil-acetate, Al- or Mg-silicate added) long wave radiation in reflected - flies
Additional mist or fog systems could be installed. Contact foil cover: advantageous when radiation and
temperature is controlled, condeansation of vapour contributrs to wetting of leaves. Recommended for less sensitive leaves (evergreens – thick epidermis – danger of drying out is lower).
Dr. Hrotkó Károly Environmental conditions and rooting of cuttings 38
Double cover inside the polythene tent
Dr. Hrotkó Károly Environmental conditions and rooting of cuttings 39
Shading is required !
Dr. Hrotkó Károly Environmental conditions and rooting of cuttings 40
Intermittent mist: benefits and shortcomings Water film on leaves reduces leaf temperature → reduced
leaf vapour pressure – minimal difference in vapor pressure between leaves and air → reduced leaf transpiaration.
Intermittent mist reduces the air temperature due to evaporation → advective cooling of leaves.
High air vapour content (80-95% relative humidity) reduces the Δ RH.
Reduces the temperature in rooting zone – bottom heat is required.
Leaching of nutrients from leaves and cuttings. Applyed in closed propagation units.
(Environmental factors in open systems are less controllable, nowadays are not utilized in practice.)
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Dr. Hrotkó Károly Environmental conditions and rooting of cuttings 42
Dr. Hrotkó Károly Environmental conditions and rooting of cuttings 43
Propagation unit with intermittent mist and shading
Dr. Hrotkó Károly Environmental conditions and rooting of cuttings 44
Application of intermittent mist and shading in PE tent and glasshouse
Dr. Hrotkó Károly Environmental conditions and rooting of cuttings 45
Dr. Hrotkó Károly Environmental conditions and rooting of cuttings 46
Dr. Hrotkó Károly Environmental conditions and rooting of cuttings 47
Fog systems High air relative humidity.
Fog systems spray at 40-60 bar pressure water drops of 15 μm size into air, which remain flotating.
Reduces leaching of nutrients.
No temperature decrease in rooting zone.
Larger costs in investment and maintenance .
Applicable for acclimatization of in-vitro plants also.
Dr. Hrotkó Károly Environmental conditions and rooting of cuttings 48
Propagation unit with fog system
Dr. Hrotkó Károly Environmental conditions and rooting of cuttings 49
Importance of temperature Optimum temperature at temperate zone plants 18-25
˚C, at tropical and subtropical plants 25-32 °C
Higher temperature at daytime (21-27 °C), lower at night (15 °C) .
Higher temperature increases the shoot growth in contrary root formation; by using bottom heat could be balanced.
At root growth higher roote zone temperature is recommended while for formation of root initials lower temperature is favourable.
Dr. Hrotkó Károly Environmental conditions and rooting of cuttings 50
Role of light in rooting of cuttings Rooting requires relative low solar radiation.
Cuttings of some herbaceous plants (Chrisanthemum, Pelargonium, Poinsettia) root better at increased solar radiation (116 Wm-2), optimum differrs by species (20-100 Wm-2).
Cuttings of some ornamental plants root better at long-day conditions.
Long day conditons are preferable for growth of rooted cuttings eg. Rododendrons (additional lighting in wintertime is favourable).
Red and fare-red wavelength is favourable for rooting (rooting is linked to phytochrom-system!).
Dr. Hrotkó Károly Environmental conditions and rooting of cuttings 51
Photosysnthetic activity of cuttings For rooting no highest photosysnthetic activity is
required, too high PAR increase the danger of drying out of cuttings.
After rooting intensive photosynthetic activity is required for growth of cuttings.
Citokinin-formation of cuttings increase the stomatal conductance and the intensity of photosynthesis.
Dr. Hrotkó Károly Environmental conditions and rooting of cuttings 52
Dr. Hrotkó Károly Environmental conditions and rooting of cuttings 53
Benefits and shortcomings of different propagation systems in technology Working with cuttings placed on ground is difficult. Replanting, potting of rooted cuttings is not economical. Mist propagation when using high Fe and Mg containing
water cause stayning by salt – cuttings are not attractive. Bottom heat is required when using mist beacause of
temperature decrease in rooting zone. Nutrient leaching from cuttings could not be balanced by
spray with fertilizers. White (milk foil) cover reflects of 40-60% of radiation,
isothermal condition, minimal vapour condensation. Using propagatin trays nutrient sprays after rooting
improves the growth of cuttings.
Dr. Hrotkó Károly Environmental conditions and rooting of cuttings 54
Dr. Hrotkó Károly Environmental conditions and rooting of cuttings 55
Dr. Hrotkó Károly Environmental conditions and rooting of cuttings 56
Improved raising technology Cyclical growth and winter dormancy of woody plants
should be considered.
Optimal environment conditions should be prepared to each growth cycle in propagation units : control of daylength, water supply, temperature, CO2, nutrients, mycorrhiza, substrate, etc.
Lighting, CO2 application to mist system or fog, fertilizers, etc.
Dr. Hrotkó Károly Environmental conditions and rooting of cuttings 57
St. Julien A hardwood cuttings
in open ground conditions