Month: September 2022

TEMPERATURE DIFFERENTIAL. "In tulip petals, for example, the upper and lower sides of the mesophyll exhibit a 10 °C difference in optimum temperature for elongation growth, resulting in opening in the morning and closure in the evening." http://jxb.oxfordjournals.org/content/54/389/1801.full View in LinkedIn

CLOCK DRIVEN. "Approximately 25% of the Arabidopsis genes that encode proteins with several functions are regulated by the circadian clock. Amongst its functions are the regulation of germination, enzymatic activity, stomatal movements and gas exchanges, photosynthesis, flower blossoming and the emission of fragrances." https://lnkd.in/ecWYRcG View in LinkedIn

PHOTORECEPTORS. "The perception of the luminous sign in plants is made by photoreceptors, which include phytochromes (phy), cryptochromes, phototropins, ZTL/ADO family proteins, in addition to a protein family of photoreceptors responsible for absorbing the ultraviolet light (UV-B). Phytochromes are the main photoreceptors, and they are responsible for absorbing the red (R) and far-red (FR) radiation." http://www.scielo.br/scielo.php?pid=S0100-83582016000100191&script=sci_arttext View in LinkedIn

CLOCK PIECES. "Up to now, over 20 components related to the circadian clock in Arabidopsis were identified, and homologous genes in other plants have been observed, indicating that this system is highly preserved in plants. The proteins that belong to the circadian clock act at different times during the night and the day, reciprocally regulating the expression of other genes, on the transcriptional and post transcriptional level." http://www.scielo.br/scielo.php?pid=S0100-83582016000100191&script=sci_arttext View in LinkedIn

MOLECULAR ACTIVATORS. "The leaves of Mimosa pudica L. are well known for their rapid movement when touched. Recently, we were able to isolate an excitatory substance in small quantities from this plant, which consists of three different components (potassium L-malate, magnesium trans-aconitate, and dimethylammonium salt)." https://lnkd.in/eHVDKsZ View in LinkedIn

OPPOSED ACTIONS. "Based on our experiments on these bioactive substances, we found that the circadian rhythmic leaf movement of these plants is initiated by the regulated balance of LOSs and LCSs. The balance of concentration between the two leaf-movement factors (LMFs) is inversed during the day. The glycoside-type LMF is hydrolyzed with β-glucosidase, the activity of which is regulated by the biological clock. The circadian rhythm observed in the leaf movement is introduced by activation of β-glucosidase regulated by the biological clock." (LOSs = leaf opening substances; LCSs = leaf closing substances). https://lnkd.in/eHVDKsZ View in LinkedIn

CLOCK FACTORS. "The nyctinastic leaf movement is induced by a pair of leaf-movement factors, and one of each pair is a glucoside. There are two key proteins that are involved in the control of nyctinasty. One is β-glucosidase: a biological clock regulates the activity of β-glucosidase, which deactivates the glucoside-type leaf-movement factor, controlling the balance in the concentrations of the leaf-closing and -opening factors. The other is the specific receptor for each leaf-movement factor." https://lnkd.in/bF4kXPr View in LinkedIn

CIRCADIAN MOVEMENT. Tribulus cistoides. "Its bright yellow flowers come to life at sunrise and face into the sun. During the day, as the sun appears to move across the sky, the flowers of Tribulus track the sun like little satellite dishes, reorienting themselves so that they always face into the sun. When the sun drops below the horizon, the flowers close. Some species of day-flowering plants can open and close their flowers for several days in succession." https://lnkd.in/bgcAj66 View in LinkedIn

QUIRKY HABITS. "The setting of the sun does not always bring about the closure of flowers. Indeed, it can have quite the opposite effect. Nightfall is the cue for many plants to begin reproductive activity. Four-o’clocks (Mirabilis jalapa) earn their common name from the time at which their flowers open, about four o’clock in the afternoon. (The ones in my garden, for some reason, seem to be on Greenwich Mean Time — they don't open until around nine o’clock at night.) Four-o’clocks are pollinated by evening-flying moths that are attracted to the sweet fragrance of the flowers." https://lnkd.in/bgcAj66 View in LinkedIn

DAY TETHERING. "Floral opening in several species is apparently independent of specific external regulation as it occurs at any time of the day. Floral opening in other species, belonging to a large number of families, show a relationship with the time of day. Flower closure may similarly be independent or dependent of the time of the day, depending on the species. This dependence on the time of the day may be regulated by external cues such as temperature, humidity, and light and/or by an internal rhythm." https://lnkd.in/eTEzGE9 View in LinkedIn