Plants perform a wonder that has attracted the admiration of scholars from ancient Egypt, Greece and Rome to modern times: the ability to reproduce mathematically perfect patterns. This ability, called phyllotaxis, can be described mathematically with the Fibonacci Series and the Golden Angle. The beautiful spirals in sunflowers, artichokes, cacti, dandelion heads and other plants continue to fascinate children and adults today, but those are not the only examples. Leaves on a stem can emerge in phyllotactic patterns like a spiral staircase, and depending on the environment, plants can switch patterns at different stages in development. Scientists have learned a lot about the players in the phyllotaxis game, but still do not understand the script. The details of how genes and proteins produce the patterns remain elusive. In Current Biology,1 French biologists Jean-Christophe Palauqui and Patrick Laufs recounted some of the theories that have tried to explain phyllotaxis. Scientists know that the plant hormone auxin becomes concentrated in the shoot meristem where new organ primordia emerge, and that the PIN1 auxin transporter is able to polarize the localization of auxin. New work reported in the same issue of Current Biology implicates the PLETHORA (PLT) gene family, known to be active with root formation, with the processes going on in the meristem. Tinkering with the players can enhance or inhibit pattern formation. Just how these players interact, though, is not well understood. It’s not a simple case of gene turning on protein turning on hormone; each of the players signal each other back and forth in a complex choreography. In addition, the PLT genes seem able to stimulate mechanical forces in the primordia by the way they regulate PIN1 polarity and hence auxin distribution. There are also time delays between gene expression and downstream effects, such as 4 hours from the time PLT genes activate to the time PIN1 transcript levels are seen to increase. But then, auxin level can also feed back to regulate PIN1 expression. It appears, therefore, that the intra-player signaling is indirect and complex. The authors stated that the bewildering interactions of these players keeps biologists busy: “Elucidating the mechanism underlying PLT-mediated control of phyllotaxis will be challenging and likely depend on quantitative descriptions and modeling of PLT expression, PIN1 levels and polarization, auxin distribution, growth and mechanics,” they said. Even if these problems are solved with mechanistic theories some day, questions may still remain about how a seed with no phyllotaxis results in a mature plant with it. And beyond that, philosophers of aesthetics may continue to ponder how plants – and many other phenomena in nature unrelated to them, like spiral galaxies, hurricanes, conch shells, and the cochlea in the human ear – reproduce “divine proportions” that humans find beautiful (see article by Fred Willson at ICR and the 11/20/2003 entry). 1. Jean-Christophe Palauqui, Patrick Laufs, “Phyllotaxis: In Search of the Golden Angle,” Current Biology, Volume 21, Issue 13, R502-R504, 12 July 2011, DOI 10.1016/j.cub.2011.05.054. Explaining the mechanics of something does not explain its origin. You can understand how a robot on an assembly line works, and describe its structures and functions with flowcharts, equations and blueprints. That knowledge will not explain why it produces a Mercedes. Wikipedia trivializes the explanation as a consequence of natural selection, claiming that the solution was found within a decade of Darwin by Wilhelm Hofmeister. “Questions remain about the details,” the entry oversimplifies. If that were true, the scientists publishing in this week’s Current Biology would not remain baffled by it. The devil is often in the details. Hofmeister knew nothing of PIN1 and PLT, let alone the genetic code. His simplistic model of competing mechanical forces is so 1896; it cannot satisfy observers today, with our newer knowledge of genetic codes, proteins, and cell signals. If evolutionists do some day get all the mechanics worked out, the questions stated above will still remain. Considering that not all plants employ phyllotaxis, and that the patterns seem unnecessary for survival, unguided evolution reduces to an empty hand-waving story that “amazing stuff happens sometimes.” The same criticism can be leveled at any explanation employing impersonal, material causes. Take a deeper look at that sunflower. Here is a natural wonder that calls out for better science, deeper philosophy, and perhaps most of all, sound theology.(Visited 38 times, 1 visits today)FacebookTwitterPinterestSave分享0
With a star-studded 21-man field consisting of the world’s best riders, the race was destined to be a hard one with no quarter asked or given. The 26-year-old from Franschhoek, who currently resides in Johannesburg, rode a well-controlled race and pulled out something extra at the end to close down the gap on an escaping group. 5 April 2012 SAinfo reporter ‘Tried to play it cool’“I knew somebody was going to attack in the finish, and just tried to play it cool and make other people chase. It’s definitely the hardest I’ve ever had to work for a track cycling race,” the aptly named Swift said afterwards. Talent and class Hoffman, around 10 lengths behind Swift at the bell lap, showed his immense talent and undoubted class when he turned the burners on the second last corner to pass five riders. South African sprint sensation Nolan Hoffman delivered the performance of his life to clinch a silver medal in the 15km scratch race at the 2012 UCI Track World Champs in Melbourne, Australia on Wednesday. Would you like to use this article in your publication or on your website? See: Using SAinfo material Swift’s win was the first British gold medal for the event since it was introduced at the 2002 World Championships, while it was South Africa’s first medal in the men’s scratch event. Around the last bend, it was clear that a podium finish was within reach for the South African. He put in an almighty effort to try and catch Swift, but it was not to be. Nonetheless, Hoffman’s enormous final lunge saw him miss out on the gold medal by a mere half a wheel. He was ecstatic to cross the line in second place. Hoffman believed it was a breakthrough performance at his first elite World Championships. “I’ve been to all the World Cups and I’ve struggled a bit and I always thought the World Champs is going to be hard,” he said with some surprise. Austrian Andreas Muller made a break with with six laps of the 60 remaining to open up a-third-of-a-lap lead. Czech rider Martin Blaha, Italian Elia Viviani and Briton Ben Swift chased down Mueller to catch him with less than two laps left before the British rider kicked to open a lead in the final back straight.
Brace for potentially devastating typhoon approaching PH – NDRRMC MOST READ Read Next Typhoon Kammuri accelerates, gains strength en route to PH AFP official booed out of forum Philippines’ Asa Miller competes in the Men’s Giant Slalom at the Jeongseon Alpine Center during the Pyeongchang 2018 Winter Olympic Games in Pyeongchang on February 18, 2018. / AFP PHOTO / Fabrice COFFRINIAsa Miller made a huge leap in his second run to finish 70th overall in the men’s giant slalom event in alpine skiing Sunday in the 2018 PyeongChang Winter OIympics at Yongpyong Alpine Centre.Seeking to improve his time of 1:27.52 after finishing 81st in Run 1, the Fil-Am alpine skier performed better in Run 2, completing the course in 1:22.43, the 68th-best in the round.ADVERTISEMENT Slow and steady hope for near-extinct Bangladesh tortoises View comments LATEST STORIES That showing hiked his total time to 2:49.95, still 31.91 seconds behind the leader but enough to get him a spot in the top 70 among 108 competitors.Marcel Hirscher of Austria claimed the gold medal after topping the field with a total time of 2:18.04.FEATURED STORIESSPORTSWATCH: Drones light up sky in final leg of SEA Games torch runSPORTSLillard, Anthony lead Blazers over ThunderSPORTSMalditas save PH from shutoutHenrik Kristoffersen of Norway made a huge run in Run 2 to take home the silver with his 2:19.31, while Alexis Pinturault of France settled for bronze with his time of 2:19.35.Miller will compete in the men’s slalom event on Thursday. UE should have a ‘win now’ mentality, says Adorador Onyok Velasco see bright future for PH boxing in Olympics PLAY LIST 00:45Onyok Velasco see bright future for PH boxing in Olympics00:50Trending Articles00:50Trending Articles01:29Police teams find crossbows, bows in HK university01:35Panelo suggests discounted SEA Games tickets for students02:49Robredo: True leaders perform well despite having ‘uninspiring’ boss02:42PH underwater hockey team aims to make waves in SEA Games01:44Philippines marks anniversary of massacre with calls for justice01:19Fire erupts in Barangay Tatalon in Quezon City NEXT BLOCK ASIA 2.0 introduces GURUS AWARDS to recognize and reward industry influencers 2 ‘newbie’ drug pushers fall in Lucena sting John Lloyd Cruz a dashing guest at Vhong Navarro’s wedding Don’t miss out on the latest news and information. Globe Business launches leading cloud-enabled and hardware-agnostic conferencing platform in PH