So it's day 45 and not much has happened... pollinated them last week with blue silverhaze auto pollen... She don't make fat buds anymore... From now on, she will concentrate more on her offspring. So her being there was not completely in vain and her girls may be able to do it even better. Thanks for looking.. nor is it fun. There is always one who doesn't go so well. And nobody can do anything about the bad Werther or geoe... projects. Happy Growing Everyone!

Sooooo this has been an amazing and exciting week! Ive been patient with this last plant and really checking the trichomes i inly wanted a few amber caps on the nugs, was looking for milky on this one! Shes smelling amazing and the color change was such a sight to see! She did so well with the nutrients and loved the 2 week flush i did! I cut her down did a wet trim and have em in the drying rack! Im excited to see how she cures and drys ready for the smoke reveal! Much love and happy growing!!! *check out the examples of the rewards from the traing i did with lst, hst, desolation love seeing this!!* learning this craft and style of growing is a blast! And everyone should try it!

King tut is foxtailing, I had two hours where the temps got to 90 in the tent three days in a row. I've seen some others mention foxtailing on king tut in general. With the ROI-E680 a few people complained about foxtailing on the first couple grows. I turned the light down to 60% from 80 and the dehumidifier set on low so it would stop spiking the tent temp and keep the humidity in the 50s as best I can. Fingers crossed!

Week 2 Apricot left 4 Strawberry gorilla right 4

All in all every strain is doing great! Blueberry is the closes to finishing followed by chemdawg and lastly the Somango I just flipped little over a week ago so still have a little while to go with her! Blueberry has a pungent and fresh berries/citrus aroma going on while the chemdawg has the infamous og odor no doubt og is related to it haha. Thanks for checking it out! XD ..sorry for the delayed update

47th Parallel Crowly's Comet 🔹⊱╮🔹╰⊰🔹 GROW Started 03.10.24 INFORMATION 🔹╰⊰´🔹⊱╮🔹 🌞Environment - Maintaining 80F and 65%Humidity 🌾Training - Nothing this week, just letting the flowers stack up; they are getting fat, sticky, and stinky! ⚱️3-Gallon 📊6.2 PH 💧 Feeding - Using Horti Grow 8-11-21, Bloom 5-15-26, Late Bloom 0-24-26, Cal 12-0-0 🌞Medic Grow Smart 8 760 Watts 🕷️ IPM - CannControl from Mammoth and Mosquito Bits as needed 🔹⊱╮🔹╰⊰🔹 PLANT UPDATES 🔹╰⊰´🔹⊱╮🔹 📝 On 05.11.24, This week, we are on Auto-Pilot and just Fertigating as needed; the ladies are stacking up nicely. I am surprised, but they are looking great! 📝Fertigation injects fertilizers into an irrigation system to supply dissolved nutrients to crops. 🗓️05.11.24 Just feeding daily, sometimes twice; today, fed with Hort-Bloom @ 2.7 GRMS Per Gal and Horti-Cal @ 2.5 GRMS Per Gal. 🗓️05.12.24 Just feeding daily, sometimes twice; today, fed with Hort-Bloom @ 2.7 GRMS Per Gal and Horti-Cal @ 2.5 GRMS Per Gal. 🗓️05.13.24 Just feeding daily, sometimes twice; today, fed with Hort-Bloom @ 2.7 GRMS Per Gal and Horti-Cal @ 2.5 GRMS Per Gal. 🗓️05.14.24 Just feeding daily, sometimes twice; today, fed with Hort-Bloom @ 2.7 GRMS Per Gal and Horti-Cal @ 2.5 GRMS Per Gal. 🗓️05.15.24 Just feeding daily, sometimes twice; today, fed with Hort-Bloom @ 2.7 GRMS Per Gal and Horti-Cal @ 2.5 GRMS Per Gal. 🗓️05.16.24 Just feeding daily, sometimes twice; today, fed with Hort-Bloom @ 2.7 GRMS Per Gal and Horti-Cal @ 2.5 GRMS Per Gal. 🗓️05.17.24 Just feeding daily, sometimes twice; today, fed with Hort-Bloom @ 2.7 GRMS Per Gal and Horti-Cal @ 2.5 GRMS Per Gal. ╰⊰🔹╰⊰´🔹⊱╮🔹╰⊰🔹╰⊰🔹STRAIN INFORMATION🔹⊱╮🔹╰⊰🔹╰⊰🔹╰⊰🔹⊱╮ Crowley's Comet / https://www.47thgenetics.com/product-page/crowley-s-comet-10-fem-birdseeds It's everyone's favorite piece of space rock, Crowley's Comet! The culmination of reversing our Matterhorn cut off Mr. Crowley to Intergalactic Runtz, and the results were out of this world (I had to do it). These ladies were slow to start, but once they hit their stride, they put any worries we had to rest. Compact, short-framed, and robust. They pack beautifully boulder-like flowers that reek of garlic and sickly sweet cotton candy. Dark green to a mosaic of purples, yellows, and silvers. Frost production is off the charts, the internode spacing is tight, and they certainly will impress in their last few weeks of flower. This is one of our favorite crosses in the new fem lineup. If you're looking for your hype fix, here you go. Yield: Heavy to XL Flower Time: 63 days Feeding Schedule: Heavy

Day 1. Hope all goes well. This time I have my substrate ready, unlike strawberry pie. It took off so fast didn't expect it to break ground in 2 days. Which I just transplanted.

D50/F06 - 20/05/23 - Nothing to report D51/F07 - 21/05/23 - Added water and nutes EC=1.1 pH=5.7 D52/F08 - 22/05/23 - Nothing to report D53/F09 - 23/05/23 - Added water. EC=1.1 pH=6.4 D54/F10 - 24/05/23 - Added water and nutes EC=1.0 pH=6.3 D55/F11 - 25/05/23 - Start the week out. I set up a system to feeding Nora during my stay out (I'll take some picture about...) D56/F12 - 26/05/23 - I leave today, 1 week away

Lots and lots of flowers. 😍 They are smelling really awesome. The buds are getting extremely sticky and its only day 53 sohey have plenty of time too swell up. I know my light set up isn't optimal but these girls don't seem to mind much. My yield might suffer slightly but the girls are happy and that's what matters most. Let me tell you guys a secret.... I have tried Ocean Forest and Happy Frog and... Fox Farm Strawberry Fields Potting Soil is the bomb for Autoflowers. This is just my first time using it so more research is needed but wow this stuff seems to grow um massive.

desarrollo optimo de mi Euphoria CBD, una cepa que sedesarrolla muy rapidamente ya secomeienza a desarrollar la resinaen sus hojas, realmente me enamora

Natural grow with all the cloudy,rain und Sun hours

Die Ernre war mal der Wahnsinn! Also erstmal: Ich habe 3 Paar Handschuhe verbraucht. Normalerweise reicht ein, max. zwei... hier war ich kurz vor Paar 4! Harzig wie blöd, überall Trichome! Was aber bei dieser Genetik auffällt: Es bilden sich sogar Blüten auf den Sonnensegeln!!! Bei ganz frechen Genetiken habe ich mal Trichome auf den Stielen und Blättern... aber nicht ganze Blüten. Safe the fan leafs, they carry!!! Der Geruch ist zu 100% Skunk... aber mit einem kleinen Twist. Die Cherry kommt schon etwas von der Farbe durch.

segui regando demaciado y al tener mucha humedad se me genero moho, apesar de eso resistieron.

Nothing much happened since last week. The foxtailing continues on the NYC and BJ. Mostly white pistils still. Found another banana on the SAD. It's definitely going to take a few more weeks.

GENERAL COMMENT The SKR is dry and starting the cure in jars, and the NL is done. RQS NORTHERN LIGHTS AUTO COMMENT. This is the final week, next time will be the harvest, this girl just got mature from a day to the other, lost 70% of the top bud due to rot i haven t seen. So i could get virtually 30-40% yield from this girl Without the locks or rot, anyhow still looking ok as far as harvest, quality will be a bit compromise, not the end of times though lol! 🙃👊🏻👍🏻

day 42 images are in last week, I can not count XD. bridal is stacking a lot of weight and is constantly shifting/leaning every morning, good things. I would chop any day but I will wait it out. water, tiny bit of humic and folvic to reduce chloromine, chlorine- air stones day 45 took a few nugs off on day 42, dried for 3 days. Tried bridal and blackberry. As a heavy recreational, thc is up there! bridal felt like having a blindfold over your eyes somewhat sativa uplift but heavy weight feelings. Very good. Lasted as good as 30%'s. Dr. Thunder was also very nice, nug was smaller so mixed with blackberry to have a small j. Also feels very good indica. Both trials were chopped on week 6 day 1. Very pleased with the results. I was worried bridal was more sativa; which charasteristica I am not looking for. So I believe this is a very good heavy hitter run with 4 plants. I can chop any day, but I am waiting for pink paradise to finish seeds. day45 took top nugs from bridal party, blackberry oreo bigstuff and dr. thunder. No touching pink paradise!! day 46 can chop anytime just waiting on pink paradise seeds to finish, bridal party leaning more day 47 bridal leaning hard from weight. day 48 stacking, day 48 video

Yellow butterfly came to see me the other day; that was nice. Starting to show signs of stress on the odd leaf, localized isolated blips, blemishes, who said growing up was going to be easy! Smaller leaves have less surface area for stomata to occupy, so the stomata are packed more densely to maintain adequate gas exchange. Smaller leaves might have higher stomatal density to compensate for their smaller size, potentially maximizing carbon uptake and minimizing water loss. Environmental conditions like light intensity and water availability can influence stomatal density, and these factors can affect leaf size as well. Leaf development involves cell division and expansion, and stomatal differentiation is sensitive to these processes. In essence, the smaller leaf size can lead to a higher stomatal density due to the constraints of available space and the need to optimize gas exchange for photosynthesis and transpiration. In the long term, UV-B radiation can lead to more complex changes in stomatal morphology, including effects on both stomatal density and size, potentially impacting carbon sequestration and water use. In essence, UV-B can be a double-edged sword for stomata: It can induce stomatal closure and potentially reduce stomatal size, but it may also trigger an increase in stomatal density as a compensatory mechanism. It is generally more efficient for gas exchange to have smaller leaves with a higher stomatal density, rather than large leaves with lower stomatal density. This is because smaller stomata can facilitate faster gas exchange due to shorter diffusion pathways, even though they may have the same total pore area as fewer, larger stomata. Leaf size tends to decrease in colder climates to reduce heat loss, while larger leaves are more common in warmer, humid environments. Plants in arid regions often develop smaller leaves with a thicker cuticle and/or hairs to minimize water loss through transpiration. Conversely, plants in wet environments may have larger leaves and drip tips to facilitate water runoff. Leaf size and shape can vary based on light availability. For example, leaves in shaded areas may be larger and thinner to maximize light absorption. Leaf mass per area (LMA) can be higher in stressful environments with limited nutrients, indicating a greater investment in structural components for protection and critical resource conservation. Wind speed, humidity, and soil conditions can also influence leaf morphology, leading to variations in leaf shape, size, and surface characteristics. Small leaves: Reduce water loss in arid or cold climates. Environmental conditions significantly affect gene expression in plants. Plants are sessile organisms, meaning they cannot move to escape unfavorable conditions, so they rely on gene expression to adapt to their surroundings. Environmental factors like light, temperature, water, and nutrient availability can trigger changes in gene expression, allowing plants to respond to and survive in diverse environments. Depending on the environment a young seedling encounters, the developmental program following seed germination could be skotomorphogenesis in the dark or photomorphogenesis in the light. Light signals are interpreted by a repertoire of photoreceptors followed by sophisticated gene expression networks, eventually resulting in developmental changes. The expression and functions of photoreceptors and key signaling molecules are highly coordinated and regulated at multiple levels of the central dogma in molecular biology. Light activates gene expression through the actions of positive transcriptional regulators and the relaxation of chromatin by histone acetylation. Small regulatory RNAs help attenuate the expression of light-responsive genes. Alternative splicing, protein phosphorylation/dephosphorylation, the formation of diverse transcriptional complexes, and selective protein degradation all contribute to proteome diversity and change the functions of individual proteins. Photomorphogenesis, the light-driven developmental changes in plants, significantly impacts gene expression. It involves a cascade of events where light signals, perceived by photoreceptors, trigger changes in gene expression patterns, ultimately leading to the development of a plant in response to its light environment. Genes are expressed, not dictated! While having the potential to encode proteins, genes are not automatically and constantly active. Instead, their expression (the process of turning them into proteins) is carefully regulated by the cell, responding to internal and external signals. This means that genes can be "turned on" or "turned off," and the level of expression can be adjusted, depending on the cell's needs and the surrounding environment. In plants, genes are not simply "on" or "off" but rather their expression is carefully regulated based on various factors, including the cell type, developmental stage, and environmental conditions. This means that while all cells in a plant contain the same genetic information (the same genes), different cells will express different subsets of those genes at different times. This regulation is crucial for the proper functioning and development of the plant. When a green plant is exposed to red light, much of the red light is absorbed, but some is also reflected back. The reflected red light, along with any blue light reflected from other parts of the plant, can be perceived by our eyes as purple. Carotenoids absorb light in blue-green region of the visible spectrum, complementing chlorophyll's absorption in the red region. They safeguard the photosynthetic machinery from excessive light by activating singlet oxygen, an oxidant formed during photosynthesis. Carotenoids also quench triplet chlorophyll, which can negatively affect photosynthesis, and scavenge reactive oxygen species (ROS) that can damage cellular proteins. Additionally, carotenoid derivatives signal plant development and responses to environmental cues. They serve as precursors for the biosynthesis of phytohormones such as abscisic acid () and strigolactones (SLs). These pigments are responsible for the orange, red, and yellow hues of fruits and vegetables, while acting as free scavengers to protect plants during photosynthesis. Singlet oxygen (¹O₂) is an electronically excited state of molecular oxygen (O₂). Singlet oxygen is produced as a byproduct during photosynthesis, primarily within the photosystem II (PSII) reaction center and light-harvesting antenna complex. This occurs when excess energy from excited chlorophyll molecules is transferred to molecular oxygen. While singlet oxygen can cause oxidative damage, plants have mechanisms to manage its production and mitigate its harmful effects. Singlet oxygen (¹O₂) is considered a reactive oxygen species (ROS). It's a form of oxygen with higher energy and reactivity compared to the more common triplet oxygen found in its ground state. Singlet oxygen is generated both in biological systems, such as during photosynthesis in plants, and in cellular processes, and through chemical and photochemical reactions. While singlet oxygen is a ROS, it's important to note that it differs from other ROS like superoxide (O₂⁻), hydrogen peroxide (H₂O₂), and hydroxyl radicals (OH) in its formation, reactivity, and specific biological roles. Non-photochemical quenching (NPQ) protects plants from damage caused by reactive oxygen species (ROS) by dissipating excess light energy as heat. This process reduces the overexcitation of photosynthetic pigments, which can lead to the production of ROS, thus mitigating the potential for photodamage. Zeaxanthin, a carotenoid pigment, plays a crucial role in photoprotection in plants by both enhancing non-photochemical quenching (NPQ) and scavenging reactive oxygen species (ROS). In high-light conditions, zeaxanthin is synthesized from violaxanthin through the xanthophyll cycle, and this zeaxanthin then facilitates heat dissipation of excess light energy (NPQ) and quenches harmful ROS. The Issue of Singlet Oxygen!! ROS Formation: Blue light, with its higher energy photons, can promote the formation of reactive oxygen species (ROS), including singlet oxygen, within the plant. Potential Damage: High levels of ROS can damage cellular components, including proteins, lipids, and DNA, potentially impacting plant health and productivity. Balancing Act: A balanced spectrum of light, including both blue and red light, is crucial for mitigating the harmful effects of excessive blue light and promoting optimal plant growth and stress tolerance. The Importance of Red Light: Red light (especially far-red) can help to mitigate the negative effects of excessive blue light by: Balancing the Photoreceptor Response: Red light can influence the activity of photoreceptors like phytochrome, which are involved in regulating plant responses to different light wavelengths. Enhancing Antioxidant Production: Red and blue light can stimulate the production of antioxidants, which help to neutralize ROS and protect the plant from oxidative damage. Optimizing Photosynthesis: Red light is efficiently used in photosynthesis, and its combination with blue light can lead to increased photosynthetic efficiency and biomass production. In controlled environments like greenhouses and vertical farms, optimizing the ratio of blue and red light is a key strategy for promoting healthy plant growth and yield. Understanding the interplay between blue light signaling, ROS production, and antioxidant defense mechanisms can inform breeding programs and biotechnological interventions aimed at improving plant stress resistance. In summary, while blue light is essential for plant development and photosynthesis, it's crucial to balance it with other light wavelengths, particularly red light, to prevent excessive ROS formation and promote overall plant health. Oxidative damage in plants occurs when there's an imbalance between the production of reactive oxygen species (ROS) and the plant's ability to neutralize them, leading to cellular damage. This imbalance, known as oxidative stress, can result from various environmental stressors, affecting plant growth, development, and overall productivity. Causes of Oxidative Damage: Abiotic stresses: These include extreme temperatures (heat and cold), drought, salinity, heavy metal toxicity, and excessive light. Biotic stresses: Pathogen attacks and insect infestations can also trigger oxidative stress. Metabolic processes: Normal cellular activities, particularly in chloroplasts, mitochondria, and peroxisomes, can generate ROS as byproducts. Certain chlorophyll biosynthesis intermediates can produce singlet oxygen (1O2), a potent ROS, leading to oxidative damage. ROS can damage lipids (lipid peroxidation), proteins, carbohydrates, and nucleic acids (DNA). Oxidative stress can compromise the integrity of cell membranes, affecting their function and permeability. Oxidative damage can interfere with essential cellular functions, including photosynthesis, respiration, and signal transduction. In severe cases, oxidative stress can trigger programmed cell death (apoptosis). Oxidative damage can lead to stunted growth, reduced biomass, and lower crop yields. Plants have evolved intricate antioxidant defense systems to counteract oxidative stress. These include: Enzymes like superoxide dismutase (SOD), catalase (CAT), and various peroxidases scavenge ROS and neutralize their damaging effects. Antioxidant molecules like glutathione, ascorbic acid (vitamin C), C60 fullerene, and carotenoids directly neutralize ROS. Developing plant varieties with gene expression focused on enhanced antioxidant capacity and stress tolerance is crucial. Optimizing irrigation, fertilization, and other management practices can help minimize stress and oxidative damage. Applying antioxidant compounds or elicitors can help plants cope with oxidative stress. Introducing genes for enhanced antioxidant enzymes or stress-related proteins over generations. Phytohormones, also known as plant hormones, are a group of naturally occurring organic compounds that regulate plant growth, development, and various physiological processes. The five major classes of phytohormones are: auxins, gibberellins, cytokinins, ethylene, and abscisic acid. In addition to these, other phytohormones like brassinosteroids, jasmonates, and salicylates also play significant roles. Here's a breakdown of the key phytohormones: Auxins: Primarily involved in cell elongation, root initiation, and apical dominance. Gibberellins: Promote stem elongation, seed germination, and flowering. Cytokinins: Stimulate cell division and differentiation, and delay leaf senescence. Ethylene: Regulates fruit ripening, leaf abscission, and senescence. Abscisic acid (ABA): Plays a role in seed dormancy, stomatal closure, and stress responses. Brassinosteroids: Involved in cell elongation, division, and stress responses. Jasmonates: Regulate plant defense against pathogens and herbivores, as well as other processes. Salicylic acid: Plays a role in plant defense against pathogens. 1. Red and Far-Red Light (Phytochromes): Red light: Primarily activates the phytochrome system, converting it to its active form (Pfr), which promotes processes like stem elongation and flowering. Far-red light: Inhibits the phytochrome system by converting the active Pfr form back to the inactive Pr form. This can trigger shade avoidance responses and inhibit germination. Phytohormones: Red and far-red light regulate phytohormones like auxin and gibberellins, which are involved in stem elongation and other growth processes. 2. Blue Light (Cryptochromes and Phototropins): Blue light: Activates cryptochromes and phototropins, which are involved in various processes like stomatal opening, seedling de-etiolation, and phototropism (growth towards light). Phytohormones: Blue light affects auxin levels, influencing stem growth, and also impacts other phytohormones involved in these processes. Example: Blue light can promote vegetative growth and can interact with red light to promote flowering. 3. UV-B Light (UV-B Receptors): UV-B light: Perceived by UVR8 receptors, it can affect plant growth and development and has roles in stress responses, like UV protection. Phytohormones: UV-B light can influence phytohormones involved in stress responses, potentially affecting growth and development. 4. Other Colors: Green light: Plants are generally less sensitive to green light, as chlorophyll reflects it. Other wavelengths: While less studied, other wavelengths can also influence plant growth and development through interactions with different photoreceptors and phytohormones. Key Points: Cross-Signaling: Plants often experience a mix of light wavelengths, leading to complex interactions between different photoreceptors and phytohormones. Species Variability: The precise effects of light color on phytohormones can vary between different plant species. Hormonal Interactions: Phytohormones don't act in isolation; their interactions and interplay with other phytohormones and environmental signals are critical for plant responses. The spectral ratio of light (the composition of different colors of light) significantly influences a plant's hormonal balance. Different wavelengths of light are perceived by specific photoreceptors in plants, which in turn regulate the production and activity of various plant hormones (phytohormones). These hormones then control a wide range of developmental processes.

Holaa, cuarta semana de la Negra44. Esta semana hubieron varios cambios. Primero hice el segundo y ultimo transplante a una maceta de 7 lt al hacer esto aplique Great white en contacto directo con las raíces. Luego le hice LST y al día siguiente le realice una defoliación para dar mas espacio a las ramas que pretendo mantener. Hago los riegos 1/1, uno solo con agua(EC: 0.4) y el otro con los fertilizantes. En los riegos estoy utilizando Sensi cal-mag para llegar a una EC base de 0.4 y luego aplicar los fertilizantes. Regulo el PH con los reguladores de BioBizz. Decidí sacar la malla para Scrog por la poca homogeneidad de las plantas en la carpa. Pretendo hacer esta semana la primera aplicación de Delta9 (estimulante floral) la cual será de manera foliar, está se hace 10 días antes de cambiar el ciclo de luz a 12/12. Va quedando menos para la esperada floración. Estos días está haciendo más frio por lo que la temperatura en mí carpa a bajado, no puedo hacer mucho frente a esto así que espero que no afecte tanto. La única solución seria alguna fuente de calor pero la cuenta de luz se me dispararía. Por lo demás todo va bien, no presenta carencias ni ningún posible problema. Se a adaptado muy bien a los cambios de esta semana y ya esta creciendo con mas vigorosidad. Cualquier recomendación sera bien recibida!! *Great White se mide en gramos. (Dosis: 1gr/3lt)

ANTHOCYANIN production is primarily controlled by the Cryptochrome (CR1) Photoreceptor ( !! UV and Blue Spectrums are primary drivers in the production of the pigment that replaces chlorophyll, isn't that awesome! 1. Diverse photoreceptors in plants Many civilizations, including the sun god of ancient Egypt, thought that the blessings of sunlight were the source of life. In fact, the survival of all life, including humans, is supported by the photosynthesis of plants that capture solar energy. Plants that perform photosynthesis have no means of transportation except for some algae. Therefore, it is necessary to monitor various changes in the external environment and respond appropriately to the place to survive. Among various environmental information, light is especially important information for plants that perform photosynthesis. In the process of evolution, plants acquired phytochrome, which mainly receives light in the red light region, and multiple blue light receptors, including his hytropin and phototropin, in order to sense the light environment. .. In addition to these, an ultraviolet light receptor named UVR8 was recently discovered. The latest image of the molecular structure and function of these various plant photoreceptors (Fig. 1), focusing on phytochrome and phototropin. Figure 1 Ultraviolet-visible absorption spectra of phytochrome, cryptochrome, phototropin, and UVR8. The dashed line represents each bioactive absorption spectrum. 2. Phytochrome; red-far red photoreversible molecular switch What is phytochrome? Phytochrome is a photochromic photoreceptor, and has two absorption types, a red light absorption type Pr (absorption maximum wavelength of about 665 nm) and a far-red light absorption type Pfr (730 nm). Reversible light conversion between the two by red light and far-red light, respectively(Fig. 1A, solid line and broken line). In general, Pfr is the active form that causes a physiological response. With some exceptions, phytochrome can be said to function as a photoreversible molecular switch. The background of the discovery is as follows. There are some types of plants that require light for germination (light seed germination). From that study, it was found that germination was induced by red light, the effect was inhibited by subsequent far-red light irradiation, and this could be repeated, and the existence of photoreceptors that reversibly photoconvert was predicted. In 1959, its existence was confirmed by the absorption spectrum measurement of the yellow sprout tissue, and it was named phytochrome. Why does the plant have a sensor to distinguish between such red light and far-red light? There is no big difference between the red and far-red light regions in the open-field spectrum of sunlight, but the proportion of red light is greatly reduced due to the absorption of chloroplasts in the shade of plants. Similar changes in light quality occur in the evening sunlight. Plants perceive this difference in light quality as the ratio of Pr and Pfr, recognize the light environment, and respond to it. Subsequent studies have revealed that it is responsible for various photomorphogenic reactions such as photoperiodic flowering induction, shade repellent, and deyellowing (greening). Furthermore, with the introduction of the model plant Arabidopsis thaliana (At) and the development of molecular biological analysis methods, research has progressed dramatically, and his five types of phytochromes (phyA-E) are present in Arabidopsis thaliana. all right. With the progress of the genome project, Fi’s tochrome-like photoreceptors were found in cyanobacteria, a photosynthetic prokaryotes other than plants. Furthermore, in non-photosynthetic bacteria, a homologue molecule called bacteriophytochrome photoreceptor (BphP) was found in Pseudomonas aeruginosa (Pa) and radiation-resistant bacteria (Deinococcus radiodurans, Dr). Domain structure of phytochrome molecule Phytochrome molecule can be roughly divided into N-terminal side and C-terminal side region. PAS (Per / Arndt / Sim: blue), GAF (cGMP phosphodiesterase / adenylyl cyclase / FhlA: green), PHY (phyto-chrome: purple) 3 in the N-terminal region of plant phytochrome (Fig. 2A) There are two domains and an N-terminal extension region (NTE: dark blue), and phytochromobilin (PΦB), which is one of the ring-opening tetrapyrroles, is thioether-bonded to the system stored in GAF as a chromophore. ing. PAS is a domain involved in the interaction between signal transduction-related proteins, and PHY is a phytochrome-specific domain. There are two PASs and her histidine kinase-related (HKR) domain (red) in the C-terminal region, but the histidine essential for kinase activity is not conserved. 3. Phototropin; photosynthetic efficiency optimized blue light receptor What is phototropin? Charles Darwin, who is famous for his theory of evolution, wrote in his book “The power of move-ment in plants” published in 1882 that plants bend toward blue light. Approximately 100 years later, the protein nph1 (nonphoto-tropic hypocotyl 1) encoded by one of the causative genes of Arabidopsis mutants causing phototropic abnormalities was identified as a blue photoreceptor. Later, another isotype npl1 was found and renamed phototropin 1 (phot1) and 2 (phot2), respectively. In addition to phototropism, phototropin is damaged by chloroplast photolocalization (chloroplasts move through the epidermal cells of the leaves and gather on the cell surface under appropriate light intensity for photosynthesis. As a photoreceptor for reactions such as escaping to the side of cells under dangerous strong light) and stomata (reactions that open stomata to optimize the uptake of carbon dioxide, which is the rate-determining process of photosynthetic reactions). It became clear that it worked. In this way, phototropin can be said to be a blue light receptor responsible for optimizing photosynthetic efficiency. Domain structure and LOV photoreaction of phototropin molecule Phototropin molecule has two photoreceptive domains (LOV1 and LOV2) called LOV (Light-Oxygen-Voltage sensing) on the N-terminal side, and serine / on the C-terminal side. It is a protein kinase that forms threonine kinase (STK) (Fig. 4Aa) and whose activity is regulated by light. LOV is one molecule as a chromophore, he binds FMN (flavin mononucleotide) non-covalently. The LOV forms an α/βfold, and the FMN is located on a β-sheet consisting of five antiparallel β-strands (Fig. 4B). The FMN in the ground state LOV shows the absorption spectrum of a typical oxidized flavin protein with a triplet oscillation structure and an absorption maximum wavelength of 450 nm, and is called D450 (Fig. 1C and Fig. 4E). After being excited to the singlet excited state by blue light, the FMN shifts to the triplet excited state (L660t *) due to intersystem crossing, and then the C4 (Fig. 4C) of the isoaroxazine ring of the FMN is conserved in the vicinity. It forms a transient accretionary prism with the tain (red part in Fig. 4B Eα) (S390I). When this cysteine is replaced with alanine (C / A substitution), the addition reaction does not occur. The effect of adduct formation propagates to the protein moiety, causing kinase activation (S390II). After that, the formed cysteine-flavin adduct spontaneously dissociates and returns to the original D450 (Fig. 4E, dark regression reaction). Phototropin kinase activity control mechanism by LOV2 Why does phototropin have two LOVs? Atphot1 was found as a protein that is rapidly autophosphorylated when irradiated with blue light. The effect of the above C / A substitution on this self-phosphorylation reaction and phototropism was investigated, and LOV2 is the main photomolecular switch in both self-phosphorylation and phototropism. It turns out that it functions as. After that, from experiments using artificial substrates, STK has a constitutive activity, LOV2 functions as an inhibitory domain of this activity, and the inhibition is eliminated by photoreaction, while LOV1 is kinase light. It was shown to modify the photosensitivity of the activation reaction. In addition to this, LOV1 was found to act as a dimerization site from the crystal structure and his SAXS. What kind of molecular mechanism does LOV2 use to photoregulate kinase activity? The following two modules play important roles in this intramolecular signal transduction. Figure 4 (A) Domain structure of LOV photoreceptors. a: Phototropin b: Neochrome c: FKF1 family protein d: Aureochrome (B) Crystal structure of auto barley phot1 LOV2. (C) Structure of FMN isoaroxazine ring. (D) Schematic diagram of the functional domain and module of Arabidopsis thaliana phot1. L, A’α, and Jα represent linker, A’α helix, and Jα helix, respectively. (E) LOV photoreaction. (F) Molecular structure model (mesh) of the LOV2-STK sample (black line) containing A’α of phot2 obtained based on SAXS under dark (top) and under bright (bottom). The yellow, red, and green space-filled models represent the crystal structures of LOV2-Jα, protein kinase A N-lobe, and C-robe, respectively, and black represents FMN. See the text for details. 1) Jα. LOV2 C of oat phot1-to α immediately after the terminus Rix (Jα) is present (Fig. 4D), which interacts with the β-sheet (Fig. 4B) that forms the FMN-bound scaffold of LOV2 in the dark, but unfolds and dissociates from the β-sheet with photoreaction. It was shown by NMR that it does. According to the crystal structure of LOV2-Jα, this Jα is located on the back surface of the β sheet and mainly has a hydrophobic interaction. The formation of S390II causes twisting of the isoaroxazine ring and protonation of N5 (Fig. 4C). As a result, the glutamine side chain present on his Iβ strand (Fig. 4B) in the β-sheet rotates to form a hydrogen bond with this protonated N5. Jα interacts with this his Iβ strand, and these changes are thought to cause the unfold-ing of Jα and dissociation from the β-sheet described above. Experiments such as amino acid substitution of Iβ strands revealed that kinases exhibit constitutive activity when this interaction is eliminated, and that Jα plays an important role in photoactivation of kinases. 2) A’α / Aβ gap. Recently, several results have been reported showing the involvement of amino acids near the A’α helix (Fig. 4D) located upstream of the N-terminal of LOV2 in kinase photoactivation. Therefore, he investigated the role of this A’α and its neighboring amino acids in kinase photoactivation, photoreaction, and Jα structural change for Atphot1. The LOV2-STK polypeptide (Fig. 4D, underlined in black) was used as a photocontrollable kinase for kinase activity analysis. As a result, it was found that the photoactivation of the kinase was abolished when amino acid substitution was introduced into the A’α / Aβ gap between A’α and Aβ of the LOV2 core. Interestingly, he had no effect on the structural changes in Jα examined on the peptide map due to the photoreaction of LOV2 or trypsin degradation. Therefore, the A’α / Aβ gap is considered to play an important role in intramolecular signal transduction after Jα. Structural changes detected by SAXS Structural changes of Jα have been detected by various biophysical methods other than NMR, but structural information on samples including up to STK is reported only by his results to his SAXS. Not. The SAXS measurement of the Atphot2 LOV2-STK polypeptide showed that the radius of inertia increased from 32.4 Å to 34.8 Å, and the molecular model (Fig. 4F) obtained by the ab initio modeling software GASBOR is that of LOV2 and STK. It was shown that the N lobes and C lobes lined up in tandem, and the relative position of LOV2 with respect to STK shifted by about 13 Å under light irradiation. The difference in the molecular model between the two is considered to reflect the structural changes that occur in the Jα and A’α / Aβ gaps mentioned above. Two phototropins with different photosensitivity In the phototropic reaction of Arabidopsis Arabidopsis, Arabidopsis responds to a very wide range of light intensities from 10–4 to 102 μmol photon / sec / m2. At that time, phot1 functions as an optical sensor in a wide range from low light to strong light, while phot2 reacts with light stronger than 1 μmol photon / sec / m2. What is the origin of these differences? As is well known, animal photoreceptors have a high photosensitivity due to the abundance of rhodopsin and the presence of biochemical amplification mechanisms. The exact abundance of phot1 and phot2 in vivo is unknown, but interesting results have been obtained in terms of amplification. The light intensity dependence of the photoactivation of the LOV2-STK polypeptide used in the above kinase analysis was investigated. It was found that phot1 was about 10 times more photosensitive than phot2. On the other hand, when the photochemical reactions of both were examined, it was found that the rate of the dark return reaction of phot1 was about 10 times slower than that of phot2. This result indicates that the longer the lifetime of S390II, which is in the kinase-activated state, the higher the photosensitivity of kinase activation. This correlation was further confirmed by extending the lifespan of her S390II with amino acid substitutions. This alone cannot explain the widespread differences in photosensitivity between phot1 and phot2, but it may explain some of them. Furthermore, it is necessary to investigate in detail protein modifications such as phosphorylation and the effects of phot interacting factors on photosensitivity. Other LOV photoreceptors Among fern plants and green algae, phytochrome ɾphotosensory module (PSM) on the N-terminal side and chimera photoreceptor with full-length phototropin on the C-terminal side, neochrome (Fig. There are types with 4Ab). It has been reported that some neochromes play a role in chloroplast photolocalization as a red light receiver. It is considered that fern plants have such a chimera photoreceptor in order to survive in a habitat such as undergrowth in a jungle where only red light reaches. In addition to this, plants have only one LOV domain, and three proteins involved in the degradation of photomorphogenesis-related proteins, FKF1 (Flavin-binding, Kelch repeat, F-box 1, ZTL (ZEITLUPE)), LKP2 ( There are LOV Kelch Protein2) (Fig. 4Ac) and aureochrome (Fig. 4Ad), which has a bZip domain on the N-terminal side of LOV and functions as a gene transcription factor. 4. Cryptochrome and UVR8 Cryptochrome is one of the blue photoreceptors and forms a superfamily with the DNA photoreceptor photolyase. It has FAD (flavin adenine dinucle-otide) as a chromophore and tetrahydrofolic acid, which is a condensing pigment. The ground state of FAD is considered to be the oxidized type, and the radical type (broken line in Fig. 1B) generated by blue light irradiation is considered to be the signaling state. The radical type also absorbs in the green to orange light region, and may widen the wavelength region of the plant morphogenesis reaction spectrum. Cryptochrome uses blue light to control physiological functions similar to phytochrome. It was identified as a photoreceptor from one of the causative genes of UVR8 Arabidopsis thaliana, and the chromophore is absorbed in the UVB region by a Trp triad consisting of three tryptophans (Fig. 1D). It is involved in the biosynthesis of flavonoids and anthocyanins that function as UV scavengers in plants. Conclusion It is thought that plants have acquired various photoreceptors necessary for their survival during a long evolutionary process. The photoreceptors that cover the existing far-red light to UVB mentioned here are considered to be some of them. More and more diverse photoreceptor genes are conserved in cyanobacteria and marine plankton. By examining these, it is thought that the understanding of plant photoreceptors will be further deepened.