Why weeping willows bend and poison ivy doesn’t

first_img Growing plant stems and shoots exhibit a variety of shapes that embody growth in response to various stimuli. Building on experimental observations, researchers from the Harvard John A. Paulson School of Engineering and Applied Sciences can provide a quantitative biophysical theory for these shapes by accounting for the inherent observed passive and active effects. Credit: Harvard John A. Paulson School of Engineering and Applied Sciences The research is published in the Journal of the Royal Society Interface.“We have combined, in one theory, a plant’s ability to sense itself and its environment while being constrained by gravity and its elastic nature,” said L. Mahadevan, the Lola England de Valpine Professor of Applied Mathematics, of Organismic and Evolutionary Biology, and of Physics. “By accounting for these factors, we can explain the range of shapes seen in nature without the need for complex growth strategies. This, in turn, implies that the diversity of morphologies seen in your garden may follow from very simple causes.”Mahadevan and co-author Raghunath Chelakkot describe plant shoots as “sentient,” meaning they can sense their own shapes and the direction of gravity and light through mechanochemical pathways.When these pathways are triggered by stimuli, one part of the shoot may grow relative to another and change shape. The shoots of the weeping willow, for example, try to grow upward, away from gravity and toward light. But, because they are so soft, the shoots sag under the weight of gravity and cascade toward the ground. On the other hand, poison ivy shoots start by growing downward before turning upward.How organisms sense and respond to these outside signals is important to understanding everything from plant growth to human development.“Different organs in our body grow and take on their characteristic shapes by responding to both internal and external signals, such as gravity,” said Mahadevan. “We do not yet understand how large-scale shape changes arise from a combination of sensing and growth, and our study attempts to look at one example of this.”Mahadevan is also a core faculty member of the Wyss Institute for Biologically Inspired Engineering at Harvard.The research was supported in part by the MacArthur Foundation. It is well known that as plants grow, their stems and shoots respond to outside signals such as light and gravity. But if all plants have similar stimuli, why are there so many different stem shapes? Why do a weeping willow branches grow downward while nearby poison ivy shoots upward?Using simple mathematical ideas, researchers from the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) constructed a framework that explains and quantifies the different shapes of plant stems.A stem’s ‘sense of self’ contributes to plant shape <a href=”https://www.youtube.com/watch?v=VSY1Non2NAI” rel=”nofollow” target=”_blank”> <img src=”https://img.youtube.com/vi/VSY1Non2NAI/0.jpg” alt=”0″ title=”How To Choose The Correct Channel Type For Your Video Content ” /> </a>last_img read more

Continue Reading

Parts of North Jakarta at risk of tidal floods as heavy rainfall hits Jakarta

first_img“Beware of the potential rainfall accompanied by lightning in the South and East Jakarta areas in the afternoon until late at night, and in the Thousand Islands regency at night until early morning,” the agency tweeted on Thursday morning.Read also: High intensity rain triggers flooding in parts of Aceh, Central KalimantanBPBD Jakarta said areas that were at risk of tidal flooding included Kamal Muara, Kapuk Muara, Penjaringan, Pluit, Ancol, Marunda, Cilincing and Kalibaru in North Jakarta, as well as Kamal in West Jakarta.The agency has disseminated information on the water level increase and potential rainfall to residents living on the coast of North Jakarta and the Thousand Islands in order for them to anticipate flooding. Several parts in North Jakarta are at risk of tidal flooding as the water level at a nearby floodgate rose following hours of heavy rainfall on Wednesday afternoon, inundating at least 20 community units (RW) across the capital.The Jakarta Regional Disaster Mitigation Agency (BPBD) recorded an increase in water level at the Pasar Ikan floodgate in North Jakarta to 210 centimeters, raising the standby alert status early on Thursday.Although the water level receded later in the morning, the agency warned that there might be more heavy rainfall in several parts of Jakarta on Thursday. Topics :center_img Following heavy rainfall on Wednesday afternoon, at least 20 community units in Jakarta were flooded, according to the BPBD Data and Information Center.“Data showed that at 3 p.m., 20 community units were inundated,” center chief Insyaf told tribunnews.com on Wednesday.The affected community units were spread across 10 subdistricts in East and South Jakarta, consisting of Bangka, Kebon Baru, Duren Tiga, Rawa Jati, Batu Ampar, Cililitan, Cipinang Cempedak, Jati Padang, Pejaten Timur and Bintaro.Water levels in residential areas ranged from 10 to 90 cm deep.After the heavy rainfall, Mampang and Pulo Rivers in South Jakarta overflowed and caused flooding in some areas, including Bangka and Jati Padang. (syk)last_img read more

Continue Reading

Bulldogs Freshman Team Falls Short To Panthers

first_imgThe Batesville Freshman fell to the Jennings County Monday night 40-37.Alex Roell led the Bulldogs with 13 followed by Zach Britton with 10. Peyton Meyer (7), Gunner Olsen (5), and John Harmeyer (2) also scored in the loss.“Alex Roell had a breakout game for us tonight. He battled inside all night, and finished through contact. Our guys did a good job of feeding him in the post, and he did a good job of finding scorers as the defense collapsed on him. If we continue to get post production like that, we’re far from seeing this group’s ceiling.”  Batesville Coach Ben Siefert.After a 19 point first quarter, the Bulldogs were only able to muster up 18 points over the last 3 quarters. That stalemate proved to be the difference.“We were just unable to overcome some things not going our way in the second half. We got into foul trouble, and couldn’t find our way to the line on offense. I don’t think we stopped playing hard though, so there’s a silver lining there.”  Batesville Coach Ben Siefert.With the loss, Batesville falls to 3-3. The Bulldogs host South Dearborn Tuesday night at 6:00pm.Submitted by Batesville Coach Ben Siefert.last_img read more

Continue Reading