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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

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

"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

SUPER-FAST EVOLUTION. "RNA-based life forms could evolve millions of times faster than DNA-based systems. This was an advantage for the exploration and invention of new sequence space, i.e. new genomic content with phenotypic competences and functions." https://lnkd.in/ekWBG2q View in LinkedIn