高级植物生理学课件第七章植物的生殖生理培训资料
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• long day (LD): plants are stimulated to flower when the length of day exceeds a threshold
• Day neutral (DN): plants flower indifference to the changes of day length.
vegetative or reproductive growth?
• the flowering signal is generated in
SAM
the leaf
• the signal goes one way: from the leaf to the apex
• Grafting transmittable
• Intermediate-daylength: not flowering if the daylength is too short or too long.
17
Plants that respond to lengthening days and flower in the spring or early summer are known as long-day (LD) plants. Short-day (SD) plants flower in the late summer or autumn in response to shortening days and lengthening nights
• FT-like genes ( FD, FVE, FCA, FY, and FPA) are ubiquitous in plants and have been found to regulate flowering in a variety of species including wheat and poplar
Vegetative meristem Inflorescence meristem
• Genes (flowering-time genes and floral identity genes)
• Light (photoperiod) • The biological clock • Temperature • Hormones
period all flowered about the same time
13
Many more experiments were followed: • Eliminate a variety of environmental conditions:
Nutrition, temperature, and light intensity • Relative length of day and night decides the
affecting formation of inflorescence and floral meristems
Flower (from Floral meristem)
Inflorescence (from Inflorescence meristem)
8
Mutations in floral identity genes
Floral meristem 6
Flowering-time genes
affecting the transition of vegetative growth to reproductive growth
WT
emf1
emf2
embryonic flower
7
Floral identity genes
CD is MORE than 11 hours.
16
Plants are induced to flower by different photoperiods
• short day (SD) : plants are stimulated to flower when the length of day falls below a threshold
terminal flower 1 (tfl1):
Convert the inflorescence meristem to the flower meristem.
leafy (lfy): produce more
inflorescences, delayed flowering
9
tfl1
• [FUNCTION] Controls inflorescence meristem identity and is required for maintenance of a indeterminate inflorescence. Prevents the expression of 'APETALA1' and 'LEAFY'. Also plays a role in the regulation of the time of flowering in the long-day flowering pathway. May form complexes with phosphorylated ligands by interfering with kinases and their effectors] Expressed below the apical dome of inflorescence and coflorescence meristems, and in inflorescence stem. Weakly expressed in vegetative phase from day 2 or day 3. Increased expression after commitment to flowering from day 7 on.
Florigen
Florigen
?
Florigen
25
• Recent studies in Arabidopsis and rice have made a strong case that florigen, or at least acomponent of the floral stimulus, is the floral integrator FT.
• EXPRESSED IN: shoot apex, leaf whorl, embryo, flower, seed; EXPRESSED DURING: 7 growth stages;
Factors regulating the transition to reproduction
EMF LFY
Vegetative meristem
Inflorescence meristem
Floral meristem
TF1
12
The discovery of photoperiodism
Garner and Allard (1920’s)
Soybeans (Glycine max) planted over a three-month
• The FT gene is expressed in leaves, and the protein travels to the meristem where it interacts with another integrator, FD, to initiate the floral transition
• Short interruption of dark period,
even by a pulse of light as short as 1
minute delays flowering. • The relative length of dark is not
the determining factor.
Do plants really measure the length of the daylength?
19
Hamner and Bonner (1938): Xanthium strumarium(苍耳）, a SD
plant with CD = 15.5 hours
• Xanthium flowers when the dark period exceeds 8.5 hours.
15
Critical daylength
Critical Daylength
(CD)
Xanthium(苍耳）: a short day plant, flowers when CD is LESS than 15.5 hours.
Hyoscyamus(茛菪 ): a long day plant, flowers when
22
Exp. 1: The leaf or apex of Perilla（紫苏 ） (a short day plant)
was exposed to different daylength.
23
Exp. 2: Grafting experiment with Perilla
24
The flowering signal: florigen
2. Convert inflorescence meristem to floral meristem (terminal, flowers)
SC: stem cell P: organ primordia Se: sepal
5
Factors regulating the transitions
3
Production of flowers involves two transitions in Arabidopsis
1. Convert SAM （ Shoot Apical Meristem) to inflorescence meristem (infinite, making lateral organs)
flowering time
Photoperiodism: ability of an organism to measure the proportion of daylight during a 24-hour period
14
Photoperiod
Varies according to the latitude and seasonal changes.
• Long-short-day: flowering requires certain number of short days are preceded by a certain number of long days.
• Short-long-day: flowering requires certain number of long days are preceded by a certain number of short days.
LEAFY;
• LFY, FUNCTIONS IN: chromatin DNA binding, transcription factor activity, sequence-specific DNA binding; INVOLVED IN: flower development, maintenance of inflorescence meristem identity, response to gibberellin stimulus, gibberellic acid mediated signaling; LOCATED IN: nucleus;
20
Similar results were obtained with other SD plants. For LD plants
A longer dark period inhibits flowering. Light break induces flowering.
21
What tissues/organs perceive photoperiod?
Plant Reproduction
Zichao Mao
1
ห้องสมุดไป่ตู้
Life cycle of plant
2
Plant Reproduction • Transition to reproduction • Flower organ development • Gametogenesis and fertilization
• Day neutral (DN): plants flower indifference to the changes of day length.
vegetative or reproductive growth?
• the flowering signal is generated in
SAM
the leaf
• the signal goes one way: from the leaf to the apex
• Grafting transmittable
• Intermediate-daylength: not flowering if the daylength is too short or too long.
17
Plants that respond to lengthening days and flower in the spring or early summer are known as long-day (LD) plants. Short-day (SD) plants flower in the late summer or autumn in response to shortening days and lengthening nights
• FT-like genes ( FD, FVE, FCA, FY, and FPA) are ubiquitous in plants and have been found to regulate flowering in a variety of species including wheat and poplar
Vegetative meristem Inflorescence meristem
• Genes (flowering-time genes and floral identity genes)
• Light (photoperiod) • The biological clock • Temperature • Hormones
period all flowered about the same time
13
Many more experiments were followed: • Eliminate a variety of environmental conditions:
Nutrition, temperature, and light intensity • Relative length of day and night decides the
affecting formation of inflorescence and floral meristems
Flower (from Floral meristem)
Inflorescence (from Inflorescence meristem)
8
Mutations in floral identity genes
Floral meristem 6
Flowering-time genes
affecting the transition of vegetative growth to reproductive growth
WT
emf1
emf2
embryonic flower
7
Floral identity genes
CD is MORE than 11 hours.
16
Plants are induced to flower by different photoperiods
• short day (SD) : plants are stimulated to flower when the length of day falls below a threshold
terminal flower 1 (tfl1):
Convert the inflorescence meristem to the flower meristem.
leafy (lfy): produce more
inflorescences, delayed flowering
9
tfl1
• [FUNCTION] Controls inflorescence meristem identity and is required for maintenance of a indeterminate inflorescence. Prevents the expression of 'APETALA1' and 'LEAFY'. Also plays a role in the regulation of the time of flowering in the long-day flowering pathway. May form complexes with phosphorylated ligands by interfering with kinases and their effectors] Expressed below the apical dome of inflorescence and coflorescence meristems, and in inflorescence stem. Weakly expressed in vegetative phase from day 2 or day 3. Increased expression after commitment to flowering from day 7 on.
Florigen
Florigen
?
Florigen
25
• Recent studies in Arabidopsis and rice have made a strong case that florigen, or at least acomponent of the floral stimulus, is the floral integrator FT.
• EXPRESSED IN: shoot apex, leaf whorl, embryo, flower, seed; EXPRESSED DURING: 7 growth stages;
Factors regulating the transition to reproduction
EMF LFY
Vegetative meristem
Inflorescence meristem
Floral meristem
TF1
12
The discovery of photoperiodism
Garner and Allard (1920’s)
Soybeans (Glycine max) planted over a three-month
• The FT gene is expressed in leaves, and the protein travels to the meristem where it interacts with another integrator, FD, to initiate the floral transition
• Short interruption of dark period,
even by a pulse of light as short as 1
minute delays flowering. • The relative length of dark is not
the determining factor.
Do plants really measure the length of the daylength?
19
Hamner and Bonner (1938): Xanthium strumarium(苍耳）, a SD
plant with CD = 15.5 hours
• Xanthium flowers when the dark period exceeds 8.5 hours.
15
Critical daylength
Critical Daylength
(CD)
Xanthium(苍耳）: a short day plant, flowers when CD is LESS than 15.5 hours.
Hyoscyamus(茛菪 ): a long day plant, flowers when
22
Exp. 1: The leaf or apex of Perilla（紫苏 ） (a short day plant)
was exposed to different daylength.
23
Exp. 2: Grafting experiment with Perilla
24
The flowering signal: florigen
2. Convert inflorescence meristem to floral meristem (terminal, flowers)
SC: stem cell P: organ primordia Se: sepal
5
Factors regulating the transitions
3
Production of flowers involves two transitions in Arabidopsis
1. Convert SAM （ Shoot Apical Meristem) to inflorescence meristem (infinite, making lateral organs)
flowering time
Photoperiodism: ability of an organism to measure the proportion of daylight during a 24-hour period
14
Photoperiod
Varies according to the latitude and seasonal changes.
• Long-short-day: flowering requires certain number of short days are preceded by a certain number of long days.
• Short-long-day: flowering requires certain number of long days are preceded by a certain number of short days.
LEAFY;
• LFY, FUNCTIONS IN: chromatin DNA binding, transcription factor activity, sequence-specific DNA binding; INVOLVED IN: flower development, maintenance of inflorescence meristem identity, response to gibberellin stimulus, gibberellic acid mediated signaling; LOCATED IN: nucleus;
20
Similar results were obtained with other SD plants. For LD plants
A longer dark period inhibits flowering. Light break induces flowering.
21
What tissues/organs perceive photoperiod?
Plant Reproduction
Zichao Mao
1
ห้องสมุดไป่ตู้
Life cycle of plant
2
Plant Reproduction • Transition to reproduction • Flower organ development • Gametogenesis and fertilization