Phytochromes are light-sensing pigment proteins found in plants that exist in two forms, Pr and Pfr, which are interconvertible by red and far-red light. Phytochromes perceive light and initiate downstream signaling pathways regulating various physiological processes in plants like seed germination, flowering, chlorophyll synthesis and enzyme activity. They control plant responses to daylength and entrain the circadian clock. Phytochromes are encoded by multiple gene families and interact with other proteins to regulate gene expression changes in response to light.
intro-hostory and discovery-characteristics of phytochrome-chemical nature of phytochrome-mode of action-mechanism-phytochrome mediated physiological responses-phytochrome is a pigment system:some evidences-role of phytochrome
Everything about photoperiodism from scratch to smart, from the oldest models to the latest models as well as proposed one, exclusive and elusive illustrations and models for proper understanding
molecular and genetic analysis of floral induction is an integrated approach, taking into consideration various genes involved in the four major pathways of flowering process
PHOTOPERIODISM IN PLANTS
• The concept of photoperiodism was given by W.W. Garner & H.A. Allard of the U.S Department of Agriculture, studied flowering in Maryland's mammoth variety of Tobacco plant in 1920.
• ‘PHOTOPERIODISM':-derived from 2 Greek words i.e.,'photos' (light) & periods (length of time).
• With a few exceptions, virtually all organisms (plant & animals) need exposure to light for a given number of hours per day for a variety of growth and reproductive functions. This day length is called PHOTOPERIOD & the phenomenon is called PHOTOPERIODISM.
• The flowering plant comprises 2 phases i.e, vegetative & reproductive.
• Under an appropriate photoperiod, plant switches from vegetative to reproductive phase, responding to the synthesis of flowering hormones & its subsequent translocation to buds. (Bartholomew,1977)
• The effect of daily duration of light hours(& dark periods) on the growth & development of plants, especially flowering is called photoperiodism.
CRITICAL DAY LENGTH
• Critical day length is the photoperiod required to induce flowering.
• It varies from species to species.
• e.g-Xanthium (SDP) requires a critical day length of 15.5hrs (15.5 light/8.5 dark).
• Critical photoperiod mustn't be exceeded in short-day plants & should always be exceeded in long-day plants.
• A single photoperiodic cycle that induces flowering-Inductive cycle & its effect is called Photoperiodic induction.
Depending upon the duration of the photoperiod, plants are classified into 3 categories:
1. Short Day Plants (SDP):
These plants require a relatively short daylight period (usually 8-10 hours) and a continuous dark period of about 14-16 hours for subsequent flowering.E.g.:-Strawberry, coffee, pineapple, etc.
o These plants are also known as long-night-plants.
2. Long day plants (LDP):
These plants require a longer daylight period (usually 14-16 hours) in a 24 hours cycle for subsequent flowering.
o Also called as short night plants.
E.g.:-Apple, passion fruit, etc..
3. A day-neutral plant (DNP):
This plants flower in all photoperiods ranging from 5 hrs to
24 hrs of continuous exposure.
e.g.:- Banana, guava, tomato, brinjal, etc…
-Dual Day Length Plants
Long Short Day Plants(LSDP):
These are short-day plants but must be exposed to long days during early periods of growth for subsequent flowering.
e.g.:- species of Bryophyllum, night jasmine, etc..
Short-Long Day Plants(SLDP):
These are long-day plants but must be exposed to short days during early periods of growth for subsequent flowering.
e.g.:- Wheat (Triticum), Rye (Secale), etc.
-MECHANISM OF PHOTOPERIODISM
-Florigen concept
-Phytochrome concept
-IMPORTANCE OF PHOTOPERIODISM
photoperiodism its discovery,significance,classifications,mechanism,critical day length,quality of light, night break phenomenon,phytochrome.florigen,floering genes, circadian rhythm
intro-hostory and discovery-characteristics of phytochrome-chemical nature of phytochrome-mode of action-mechanism-phytochrome mediated physiological responses-phytochrome is a pigment system:some evidences-role of phytochrome
Everything about photoperiodism from scratch to smart, from the oldest models to the latest models as well as proposed one, exclusive and elusive illustrations and models for proper understanding
molecular and genetic analysis of floral induction is an integrated approach, taking into consideration various genes involved in the four major pathways of flowering process
PHOTOPERIODISM IN PLANTS
• The concept of photoperiodism was given by W.W. Garner & H.A. Allard of the U.S Department of Agriculture, studied flowering in Maryland's mammoth variety of Tobacco plant in 1920.
• ‘PHOTOPERIODISM':-derived from 2 Greek words i.e.,'photos' (light) & periods (length of time).
• With a few exceptions, virtually all organisms (plant & animals) need exposure to light for a given number of hours per day for a variety of growth and reproductive functions. This day length is called PHOTOPERIOD & the phenomenon is called PHOTOPERIODISM.
• The flowering plant comprises 2 phases i.e, vegetative & reproductive.
• Under an appropriate photoperiod, plant switches from vegetative to reproductive phase, responding to the synthesis of flowering hormones & its subsequent translocation to buds. (Bartholomew,1977)
• The effect of daily duration of light hours(& dark periods) on the growth & development of plants, especially flowering is called photoperiodism.
CRITICAL DAY LENGTH
• Critical day length is the photoperiod required to induce flowering.
• It varies from species to species.
• e.g-Xanthium (SDP) requires a critical day length of 15.5hrs (15.5 light/8.5 dark).
• Critical photoperiod mustn't be exceeded in short-day plants & should always be exceeded in long-day plants.
• A single photoperiodic cycle that induces flowering-Inductive cycle & its effect is called Photoperiodic induction.
Depending upon the duration of the photoperiod, plants are classified into 3 categories:
1. Short Day Plants (SDP):
These plants require a relatively short daylight period (usually 8-10 hours) and a continuous dark period of about 14-16 hours for subsequent flowering.E.g.:-Strawberry, coffee, pineapple, etc.
o These plants are also known as long-night-plants.
2. Long day plants (LDP):
These plants require a longer daylight period (usually 14-16 hours) in a 24 hours cycle for subsequent flowering.
o Also called as short night plants.
E.g.:-Apple, passion fruit, etc..
3. A day-neutral plant (DNP):
This plants flower in all photoperiods ranging from 5 hrs to
24 hrs of continuous exposure.
e.g.:- Banana, guava, tomato, brinjal, etc…
-Dual Day Length Plants
Long Short Day Plants(LSDP):
These are short-day plants but must be exposed to long days during early periods of growth for subsequent flowering.
e.g.:- species of Bryophyllum, night jasmine, etc..
Short-Long Day Plants(SLDP):
These are long-day plants but must be exposed to short days during early periods of growth for subsequent flowering.
e.g.:- Wheat (Triticum), Rye (Secale), etc.
-MECHANISM OF PHOTOPERIODISM
-Florigen concept
-Phytochrome concept
-IMPORTANCE OF PHOTOPERIODISM
photoperiodism its discovery,significance,classifications,mechanism,critical day length,quality of light, night break phenomenon,phytochrome.florigen,floering genes, circadian rhythm
Phytochrome is a photoreceptor.it is the blue light receptor in plants.phytochrome have many roles such as in shade tolerance,phototropism ,flowering,seed germination,hook formation,de etiolation etc.phytochrome is involved in lal light related developmental processes in plants.
Here is the presentation about Skotomorphogenesis & Photomorphogensis.
A seedling that emerge in darkness is known as skotomorphogenesis which is characterized by etiolation. A seedling that emerge in light is known as photomorphogenesis which is characterized by de-etiolation. effect of duration of photoperiod on floral indication is known as Photoperiodism. Phytochrome present in the chloroplast is responsible for the photoperiodic responses. Phytochromes in chloroplast exist in two interconvertible forms. That is PR and PFR. The sunlight converts PR into PFR that results to initiate transcription of a variety of genes that eventually effect the process of photoperiodism.
Autofluorescence - natural emission of light by biological structures when they have absorbed light.
The most commonly observed autofluorescencing molecules are NADPG and flavins.
Generally, proteins containing an increased amount of the amino acids tryptophan, tyrosine and phenylalanine show some degree of autofluorescence.
To overcome cons of labeling for in-vivo applications mostly, naturally fluorescent proteins are used.
Pigments which are not directly involved in photosynthesis but have the ability to absorb light and transfer it to the principal photosynthetic pigments are called as Accessory pigments. Phycobilins are water soluble pigments that are fairly joined to a protein, which acts as a accessory pigment in photosynthesis. Phycocyanobilin and Phycoerythrobilin are major phycobilins.
Palestine last event orientationfvgnh .pptxRaedMohamed3
An EFL lesson about the current events in Palestine. It is intended to be for intermediate students who wish to increase their listening skills through a short lesson in power point.
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
Embracing GenAI - A Strategic ImperativePeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
Operation “Blue Star” is the only event in the history of Independent India where the state went into war with its own people. Even after about 40 years it is not clear if it was culmination of states anger over people of the region, a political game of power or start of dictatorial chapter in the democratic setup.
The people of Punjab felt alienated from main stream due to denial of their just demands during a long democratic struggle since independence. As it happen all over the word, it led to militant struggle with great loss of lives of military, police and civilian personnel. Killing of Indira Gandhi and massacre of innocent Sikhs in Delhi and other India cities was also associated with this movement.
Read| The latest issue of The Challenger is here! We are thrilled to announce that our school paper has qualified for the NATIONAL SCHOOLS PRESS CONFERENCE (NSPC) 2024. Thank you for your unwavering support and trust. Dive into the stories that made us stand out!
Acetabularia Information For Class 9 .docxvaibhavrinwa19
Acetabularia acetabulum is a single-celled green alga that in its vegetative state is morphologically differentiated into a basal rhizoid and an axially elongated stalk, which bears whorls of branching hairs. The single diploid nucleus resides in the rhizoid.
Synthetic Fiber Construction in lab .pptxPavel ( NSTU)
Synthetic fiber production is a fascinating and complex field that blends chemistry, engineering, and environmental science. By understanding these aspects, students can gain a comprehensive view of synthetic fiber production, its impact on society and the environment, and the potential for future innovations. Synthetic fibers play a crucial role in modern society, impacting various aspects of daily life, industry, and the environment. ynthetic fibers are integral to modern life, offering a range of benefits from cost-effectiveness and versatility to innovative applications and performance characteristics. While they pose environmental challenges, ongoing research and development aim to create more sustainable and eco-friendly alternatives. Understanding the importance of synthetic fibers helps in appreciating their role in the economy, industry, and daily life, while also emphasizing the need for sustainable practices and innovation.
A Strategic Approach: GenAI in EducationPeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
Unit 8 - Information and Communication Technology (Paper I).pdfThiyagu K
This slides describes the basic concepts of ICT, basics of Email, Emerging Technology and Digital Initiatives in Education. This presentations aligns with the UGC Paper I syllabus.
2. PHYTOCHROME
• Proteinaceous Pigment
• Phytochrome photoreceptors presence
• They are almost ubiquitous in green plants.
• The phytochromes absorb light with wavelength of 600-730
nm .
• Exist in two forms pfr and pr form.
• Two structures Apoprotein and chromophore.
3. FORMS
• It exist in two forms Pr (650-680nm) and Pfr (700-740nm)
form, both are interconvertable.
• The Pr form:
• Absorbs at a peak of 665 nm
• Is the form synthesized in dark-grown seedlings.
• When Pr absorbs red light, it is converted to the Pfr form.
4. The Pfr form:
• The Pfr form is the active form that initiates biological
responses
• Absorbs at a peak of 730 nm
• When Pfr absorbs far red light, it is converted to the Pr form
• Pfr can also spontaneously revert to the Pr form in the dark
over time = dark reversion.
5. STRUCTURE
• It is a soluble protein with a molecularweight of about 250
kDa.
• A light-absorbing pigment molecule called the chromophore,
and a polypeptide chain called the apoprotein.
• The apoprotein monomer has a
molecular mass of about 125 kDa.
6. COOH
Chromophore
The apoprotein and its chromophore make up the holoprotein.
Light can be absorbed only when the polypeptide is covalently
linked with phytochromobilin to form the holoprotein.
There is only one chromophore per monomer of apoprotein, and
it is attached to the protein through a thioether linkage to a
cysteine residue.
NH2
7. • After absorption of light, the Pr chromophore undergoes a
cis–trans isomerization of the double bond between carbons
15 and 16.
• Phytochrome is encoded by divergent genes consist of two
types of proteins: Type I and Type II.
• Type I encoded by the PHYA gene, is abundant in etiolated
tissue. Low levels in light-grown plants because of its
instability in the Pfr form.
• Type II phytochrome (encoded by the PHYB, PHYC, PHYD, and
PHYE genes) is present at low levels in both light-grown and
dark-grown plants because its genes are constitutively
expressed at low levels.
8. The smaller C-terminal domain is approximately 55 kDa and contains the site
where the two monomers associate with each other to form the dimer.
The C-terminal domain contains a dimerization site, a ubiquitination site, and a
regulatory region.
9.
10.
11.
12.
13. Light perception and signalling in
higher plants
• Light-induced signal transduction.
• Perception of light by these specialised
photoreceptors.
• Ends in the regulation of the expression of genes
• Plants response at the physiological level.
15. • To entrain the clock to be in sync with the diurnal cycle,
various photoreceptors act singularly or together to transduce
the light signal into the clock.
• Several genes involved in both phytochrome-mediated light
signaling and clock function have been reported, including
GIGANTEA (GI),
EARLY FLOWERING 3 (ELF3),
ELF4,
TIME FOR COFFEE (TIC),
LIGHT INSENSITIVE PERIOD1 (LIP1)
• Elongation of hypocotyl,shoot branching,Flowering time
17. LDP SDP
Long day: More Pfr
Pfr promotes flowering for LDPs
Pfr inhibits flowering for SDPs
Short day: Less Pfr
Promote flowering for SDPs
Inhibit flowering for LDPs
18.
19. A partner protein for PhyB
called PIF3 (PhyB-Interacting
Factor 3).
Red light causes PhyB to move into
nucleus and interact with PIF3, a
transcription factor that activates the
genes encoding other transcription
factors for activation of
photosynthetic genes.
20. Localization of
Phytochromes in Two
Distinct Forms
of Nuclear Bodies.
(A and B) Transient phyA
NBs are formed upon
pulses (5 min) of R (A) or
FR (B) light treatment.
(C) Stable phyA NBs after
being exposed to
prolonged (5 h) FR light.
(D and E) Transient phyB
NBs are formed after
pulses (5 min) of R (D),
but not FR (E) treatment.
(F) Prolonged R light
exposure (4 days) induces
the formation of stable
phyB NBs.
Note that transient NBs
are smaller and more
21.
22. References
• Phytochrome-mediated light signalling in
Arabidopsis.(www,sciencedirect.com)
• Phytochrome Signaling: Time to Tighten up theLoose Ends
Hai Wang and Haiyang Wang
• Biotechnology Research Institute, Chinese Academy of
Agricultural Sciences
