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"COMPETITION FOR CARBOHYDRATES has been reported between petals of one flower, and among the opening flowers and flower buds. In cut Madelon roses, removal of the outer petals directly after harvest resulted in an increase in the surface area and in the sugar content of the innermost petals once they had fully developed. Competition between buds follows from standard horticultural practice, where flower buds are removed in order to produce larger sized single flowers." http://jxb.oxfordjournals.org/content/54/389/1801.full View in LinkedIn

"FLOWER OPENING may be due to a combination of sugar uptake and degradation of various polysaccharides. In gladiolus florets, where starch was a source of soluble carbohydrate, the increase in sugar content was 7–8 times higher than the decrease in starch content, which is indicative of sugar uptake." http://jxb.oxfordjournals.org/content/54/389/1801.full View in LinkedIn

HYBRID STRATEGY. "Some petals contain both starch and fructan. In chrysanthemum petals, for example, both polysaccharides were degraded during petal expansion. Finally, some flowers reportedly contain neither fructan nor starch (or only very low starch concentrations) just prior to opening." http://jxb.oxfordjournals.org/content/54/389/1801.full View in LinkedIn

ALTERNATIVE STRATEGY. "Petals of unopened daylily (Hemerocallis sp.) flowers, in contrast, contained no starch but a high concentration of fructan, an oligosaccharide with a high number of fructose monomers. Upon flower opening, fructan was rapidly degraded. Fructan also accumulated in the petals of Phipssia algida and Campanula rapunculoides, prior to opening." http://jxb.oxfordjournals.org/content/54/389/1801.full View in LinkedIn

RAPID CONVERSION OF STORES. "In most species, the mobilization of storage carbohydrates and/or the import of sucrose accompanies flower opening. Young petal cells of many species contain considerable amounts of starch which, shortly before opening, is rapidly converted to glucose and fructose." http://jxb.oxfordjournals.org/content/54/389/1801.full View in LinkedIn

TURGOR CHEMISTRY. "Floral movements are based on changes in osmotic pressure in cells that do not elongate, or on differential elongation growth. Both involve an increase in osmotic pressure, followed by water uptake. Prior to opening, osmotic solute levels increased, for example by the conversion of polysaccharides (starch or fructan) to monosaccharides, and/or the uptake of sugars from the apoplast." https://lnkd.in/eTEzGE9 View in LinkedIn

FRAGMENT FROM NATURE continues from last weekend on the topic of flower opening and closing, which is so much more than tubes and pumps and fluid dynamics. The biochemistry, genetics and circadian controls behind these fluid mechanics are where it starts to get interesting. Complex changes in cellular viscosity are caused by a cascade of events from the genes to the osmolytes, which change on a diurnal basis, thus controlling flower opening and closure. 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

RNA DRIVEN. "It appears that all the detailed steps of evolution stored in DNA that are read, transcribed, and translated in every developmental and growth process of each individual cell depend on RNA-mediated processes, in most cases interconnected with other RNAs and their associated protein complexes and functions in a strict hierarchy of temporal and spatial steps." https://lnkd.in/euyhznh 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