BASICS OF VERNALISAT MOLECULAR BASIS OF VERNALISATION

VIETNAM GENERAL CONFEDERATION OF LABOUR TON DUC THANG UNIVERSITY FACULTY OF APPLIED SCIENCE PLANT PHYSIOLOGY REPORT VERNALISATION AND FLOWERING Instructing lecturer: ph.D Trần Thị Dung Group: 10 Hà Minh Đạt – 620H0021 Lương Thị Quỳnh Mai – 620H0273 Ho Chi Minh City, 2022 i ACKNOWLEGDEMENT First, I would like to thank Ton Duc Thang University for giving me the opportunity to access learning Biosafety In particular, I would like to express my deep thanks to my lecturer – Tran Thi Dung for imparting valuable, influential and highly applicable lessons From what you conveyed, I gradually expand my knowledge, comprehend the small world that the naked eye could not see, understand the world of plant Perhaps knowledge is endless and each person's acquisition has certain limitations For over the year, our country has also been heavily affected by the Covid-19 pandemic leading to our knowledge disruption Therefore, in the process of completing the report, it is inevitable to avoid the shortcomings or mistakes I look forward to receiving comments from you to gain more experience for later reports and essays I would like to sincerely thank and wish you and other teachers have excellent health to overcome this pandemic together ii TABLE OF CONTENTS ACKNOWLEGDEMENT i TABLE OF CONTENTS ii LIST OF ABBREVIATIONS iii LIST OF TABLES iii LIST OF PICTURES iv INTRODUCTION v CHAPTER 1: BASICS OF VERNALISATION 1.1 Definition of vernalization 1.2 Vernalization category 1.3 Factors Affecting Vernalization CHAPTER 2: FLOWERING 2.1 Abstract 2.2 Stages of flowering CHAPTER 3: VERNALISATION IN FLOWERING 3.1 Receptor organ 3.2 Giai đoạn xuân hóa 3.3 Cơ sở phân tử tượng xuân hoá 3.4 Devernalisation CHAPTER 4: PRACTICALAPPLICATION & CONCLUSION 3.1 3.2 Application in manufacturing Conclusion REFERENCES 10 iii LIST OF PICTURES Chapter 1: BASICS OF VERNALISAT Y Figure 1.1 Effect of vernalisation Figure 1.2 Distributed temperature sensitive in vernaltisaion Chapter 2: FLOWERING Figure 2.1 Jasmine Figure 2.2 Canabis flowering phase Chapter 3: MOLECULAR BASIS OF VERNALISATION Figure 3.1 Vernalisation process Figure 3.2 Receptor of plant Figure 3.3 Vernalisation phase Figure 3.4 How to make vernalisation? 10 Figure 3.5 The molecular basis of vernalization: The central role of FLOWERING LOCUS C (FLC) 11 iv INTRODUCTION When a plant reaches a certain stage of vegetative growth, profound changes take place in its structure and function and it starts flowering The apex of the branch on plant, is induced to form a flower instead of other branches or leaves Significant changes take place at cellular and metabolic levels, during these modification All these changes are finally manifested into morphological changes , the vegetative bud is transformed into a reproductive or floral bud A flower is nothing but a compressed, determinate shoot bearing sepals, petals, stamens and carpels as lateral organs instead of leaves Among various environmental factors, the day length, the quality and intensity of light and temperature are the most important variables affecting the timing and intensity of flowering The purpose of our group through this report is giving the detailed information about flowering: This report consists of two chapters: Chapter 1: Definition of gene regulation Chapter 2: Gene regulation in Eukaryotes CHAPTER 1: BASICS OF VERNALISATION 1.1 Definition of vernalization Vernalization, the artificial exposure of plants (or seeds) to low temperatures in order to stimulate flowering or to enhance seed production By satisfying the cold requirement of many temperate-zone plants, flowering can be induced to occur earlier than normal or in warm climates lacking the requisite seasonal chilling [1] The word “vernalization” comes from the Latin word “ver” meaning green, and “nalizare” meaning to make grow or produce Vernalization is also known as wintering, which means it is used in plants that are not native to areas with cold winters [2] Vernalization can be induced by either natural conditions such as temperature and day length or by artificial conditions such as low temperature, high humidity and darkness The process of vernalization can take anywhere from weeks to months depending on the type of plant it is being induced [2] Figure11.1Efffectofofvernalisation 1.2 Vernalization category Vernalization does not have any types But based on the requirement to vernalization, plants are divided into Obligate, Facultative plants and certain plants are unresponsive for vernalization [1] Obligate Plants: vernalization is essential for flower production (i.e.) transition from vegetative to reproductive phase of the plant without which plant remains in vegetative phase or may die Example: henbane – Hyoscyamus niger, sugar beet – Beta vulgaris [1] Facultative Plants: Facultative plants does not completely depend on vernalization for flowering but on exposure to vernalization will accelerate and becomes efficient in flowering The transition from vegetative to reproductive phase does not require the vernalizing phenomenon [1] 1.3 Factors Affecting Vernalization Age of the Plants: Different types of plants has different receptive capacity of the stimulus Winter Annuals are capable of producing shoot at the stage of Seedling where it is imbibed with water on the other hand, Perennials and Biennials require at least 5-week-old to be effective to receive cold stimulus [1] Temperature: The vernalizing stimulus is effective and receptive under an optimal temperature around 1-6oC and the temperature above and below the optimum levels will decrease the receptive capacity of the plants Plants will have types of basic induction temperature requirements: The effect of low temperatures is mandatory and the effect of low temperatures is not required [3] Figure 1.1 Distributed temperature sensitive in vernaltisaion The effects of low temperatures are mandatory: Plants of this species will usually only flower at a certain stage of development at a low temperature suitable for them If the ambient temperature they are in is higher than the springing temperature of this group of plants, they will not flower [3] The effects of low temperatures are not mandatory: These plants differ from the obligatory temperature-affected species that this group of plants will flower at temperatures higher than their springing temperatures, but the rate of flowering will be slow [3] Site of the Plant: the phenomenon requires continuously dividing mitotic apical meristem to transit the stem or leaf primordia to flower primordia Hence, the stimulus is receptive at the apices and not induced on lateral side of the plants [1] Exposure to light: Following vernalization, the plant must be exposed to long light before the effect of vernalization wears off to support the production of efficient reproductive organ [1] Oxygen: Vernalization takes place under aerobic condition When devoid of oxygen the plants get devernalized and develops the reproductive phase and the production may or may not be successful in virilization dependent plants [1] Water: In Winter annuals vernalization has effects on germinating seedling imbibed with water Dry seeds never respond to vernalization [1] CHAPTER 2: FLOWERING 2.1 Abstract The initiation of flowering is a critical life-history trait; plants have presumably evolved to flower at a time of year that ensures maximal reproductive success in a given region [4] The flowering in plants is influenced by various environmental and nutritional factors In most cases, a specifc environment is necessary for flowering to occur [5] The specific environment acts as a floral stimulus, only when the plant has reached a certain stage of maturity [4] Very young plants as being in juvenile phase, cannot flower, even if all other factors are favourable They are receptive to floral stimuli when they have reached puberty [5] Figure 2.1 Jasmine Decades of physiological studies have revealed that flowering is initiated in response to both environmental cues and endogenous pathways Commonly studied environmental cues include changes in temperature and daylength Endogenous pathways function independently of environmental signals and are related to the developmental state of the plant [4] The recent addition of molecular genetics to the range of approaches used to study the initiation of flowering has provided some molecular insights into these endogenous and environment-sensing pathways and has revealed how inputs from multiple pathways are integrated into the flowering decision [4] 2.2 Stages of flowering The development of plants is the process of flowering, pollination, fertilization, fruiting which is mainly the flowering process of plants [3] - Induction flower formation - Formation of hoa sprouts - The growth of flowers and sexual discrimination The most important stage for flower formation is the induction of flower formation The main factors affecting the induction stage of flower formation include: low temperature (springing), light (photoperiodism), Flowering hormone (Florigen) [3] Figure 2.2 Canabis flowering phase CHAPTER 3: VERNALISATION IN FLOWERING Figure 3.1 Vernalisation process 3.1 Receptor organ In plants the receptor organ for vernalisation found at the top growth of the plant [3] When the growth of the plant is inhibited by temperature, plant lose its respiration at this time the process of deconstructing protein and reserves will be consciously pushed to improve assimilation to give the bud top This results in just a low temperature enough to make the growth peak affected without having to affect the temperature on other organs.[3] In organs such as embryos or shoots, they will begin to start the decomposition activity when a tissue has been decomposed, at which point the shoots will begin the process of vernalisation [3] Figure 3.2 Receptor of plant 3.2 Vernalisation phase Different plants will have periods of sensitivity to different environmental temperatures For sensitive plants, their flowering will defy the time and temperature of the farming environment, and with less sensitivity, it will only flower when the growth time is met For example, keep the soaked seeds at 10oC for Figure 3.3 Vernalisation phase month in artificial conditions then sow in the spring, thereby turning winter wheat into spring wheat [3] Figure 3.4 How to make vernalisation? 3.3 Molecular basis of vernalisation Under the influence of low temperatures, in the growth peak produces a substance of a hormone nature (Vernalin – vernalisation substance) [3] This substance will transport to the parts necessary to stimulate and cause the gene differentiation activation necessary for the differentiation of flower germs at the growth peak of the stem Tree grafting experiments have shown that if you graft a branch of a tree that has been experient vernalisation phase onto a tree that has not yet in vernalisation, the 10 other branches all flower Thus, the vernalisation substance can be transported to untreated branches to stimulate the vernalisation of flower germs [3] Figure 3.5 The molecular basis of vernalization: The central role of FLOWERING LOCUS C (FLC) 11 3.4 Devernalisation The duration of the impact of low temperatures needs to be continuous for a certain period of time depending on the breed If the vernalisation is not over, the impact of high temperatures will lose the effect of vernalisation, the plant does not flower [6] In brief, the reversion of vernalization by high temperature treatment is called devernalization Lang et al (1957) demonstrated that application of gibberlins can replace the cold treatment for vernalization in certain biennial plants [6] Devernalization is effected by treating the vernalized seeds or buds with high temperature Diagram of devernalisation : [3] A ↔ A’ B A It is a precursor to vernalisation A’ It's an unstable product B It is a stable product of vernalisation A↔A’: Vernalisation occurs at low temperatures and deverrnalisation occurs at high temperatures until vernalisation is not yet over When the springing process has ended leading to the formation of a stable product B, the effectiveness of deverrnalisation is negligible [3] 12 CHAPTER 4: PRACTICAL APPLICATION & CONCLUSION 3.1 Application in manufacturing Vernalisation can help in shortening the juvenile or vegetative period of plant and induce early flowering It is applicable to not only temperate plants but also to tropical plants, e.g., wheat, rice, millets, cotton [7] By treating low temperatures one can turn winter wheat into spring wheat, two-year trees into 1-year trees [7] With most crops, the treatment and storage of seeds and tubers at low temperatures (in the refrigerator or cold storage) will have a very good effect for the next generation, shortening the time of growth, rapid flowering, increasing productivity and harvest qualities For example: the low temperature treatment for the bulbs of lilies can create lilies off-season on the Lunar New Year, increasing economic efficiency for flower producers If storing potato bulbs in low temperature conditions, the quality of bulbs is very high, the plant grows well and the yield of potatoes is higher 3.2 Conclusion Low temperatures act as a trigger for flowering The low temperature in the preservation of bulbs inhibits the aging of young tubers physiologically In the springing temperature range, the lower the temperature, the shorter the exposure time and vice versa It is possible to handle low temperatures at the tuber stage to create fruit for lilies By passing genes that control springing in our trees, we can create trees that didn't bloom in the winter 13 REFERENCES Internet: [1] Vinepair staff, Vernalization: Definition, Mechanism, and Factors, (Retrieved: 01:31 PM, 01/03/2022) From: https://researchtweet.com/vernalization-definition-mechanism-factors/ [2] J Cell Sci, Vernalization – a cold-induced epigenetic switch 2012 Aug 15;125 (Pt 16):3723-31 [3] “Sinh lý thực vật”, (Retrieved: 03:21 PM, 19/02/2022) From: https://nslide.com/giao-an/sinh-ly-thuc-vat.98m9vq.html? fbclid=IwAR3m8HG4d_nHhwX6H47XGQ2vxrGVOL3PoQBQqq6J0zLnzL3 vbGbIgrLjvR4 [4] Richard M Amasino, Scott D Michaels, The Timing of Flowering, (Retrieved: 03:21 PM, 19/02/2022) From: https://academic.oup.com/plphys/article/154/2/516/6111461 [5] Theory of flowering, (Retrieved: 03:21 PM, 19/02/2022 From: http://www.isca.co.in/BIO_SCI/book/ISBN%20978-93-86675-26-2.pdf [6] Vernalization Promoting flowering with cold, (Retrieved: 03:21 PM, 19/02/2022) From: https://www.mpgmahavidyalaya.org/userfiles/vernalization-143.pdf [7] Srinibas Kumar, Vernalisation in Plants: Site, Requirements, Mechanism and Importance, From: https://www.biologydiscussion.com/plants/vernalisation/vernalisationin-plants-site-requirements-mechanism-and-importance/15815 ... 3: MOLECULAR BASIS OF VERNALISATION Figure 3.1 Vernalisation process Figure 3.2 Receptor of plant Figure 3.3 Vernalisation phase Figure 3.4 How to make vernalisation? ... 3.4 How to make vernalisation? 3.3 Molecular basis of vernalisation Under the influence of low temperatures, in the growth peak produces a substance of a hormone nature (Vernalin – vernalisation. .. high temperature Diagram of devernalisation : [3] A ↔ A’ B A It is a precursor to vernalisation A’ It''s an unstable product B It is a stable product of vernalisation A↔A’: Vernalisation occurs at