greenseedling » Strange But True

A Social Life for Plants

Sneha — Tue, 15 Nov 2011 13:59:04 +0000

We generally think of plants as being forms of life that lack feelings and social interaction, but this may not be completely true! It has been found that plants are capable of exhibiting complex social behavior such as altruism towards related individuals but aggression towards strangers. In other words, plants may act differently, depending on who their neighbors are.

There seem to be two competing processes that are in play here. On one hand, studies have shown “altruism towards relatives” where siblings perform best in proximity to each other. Other studies have shown that a group of less-related plants growing together can outperform a group of siblings growing together. Studying these two processes together may address some important questions in understanding this complex behavior.

There are great challenges in deciphering the social interactions of plants because they can’t be interpreted as easily as interactions between animals. The author suggests that researchers tend to only look at the output and fitness of the plant when looking at competition, rather than also understand how specific traits affect output and fitness.

Discussion Question: How can these questions of social interactions between plants be used in the fields of agriculture and plant communities?

News Article: http://www.sciencedaily.com/releases/2011/11/111109115816.htm
Journal Article: http://rspb.royalsocietypublishing.org/content/early/2011/11/03/rspb.2011.1995

Image Source: http://en.wikipedia.org/wiki/File:Iris_sanguinea_2007-05-13_361.jpg

Punishment: A Powerful Tool

Sneha — Mon, 31 Oct 2011 11:30:48 +0000

There are many examples of beneficial relationships between two different species. One species helps another in return for a favor, much like how we humans interact with each other. What happens, however, when one party does not hold up their end of the deal? Humans retaliate to take revenge in sometimes malicious ways. Plants, apparently, do the same.

Through their research on the relationship between wasps and fig plants, researchers from the Smithsonian Tropical Research Institute have found that figs punish wasps that fail to pollinate the plant, and this punishment may be critical to maintain the 80-million-year-old arrangement. Figs punish a “cheater” wasp by dropping the unpollinated fruit that houses the wasp’s developing young offspring.
This prevents wasps from harvesting the benefits of using the fig as a nest without reciprocating the favor by pollinating the fig. To study this relationship, either pollen-free or pollen-carrying wasps were introduced into a mesh bag that contained an unpollinated fig. It was found that often, trees dropped unpollinated figs before the young wasps could mature because the wasps, trapped in the bag, could not pollinate the figs.

Interestingly, it was observed that less cheating was observed in plants where the sanctions or punishment was stronger. This is similar to what we observe in our world – people are less likely to commit crimes when the punishments are harsher.

Discussion Question: How do you think a relationship like this came about 80 million years ago? Do you think that time has changed this relationship? If so, how?

News Source: http://www.sciencedaily.com/releases/2010/01/100114143513.htm
Press Release:http://www.stri.si.edu/english/about_stri/media/press_releases/PDFs/STRI-PR10_Edited_Fig-Wasp_release3_2.pdf

Image source: Marcos Guerra – http://www.sciencedaily.com/releases/2010/01/100114143513.htm

The Sexual Deception of Orchids

Sneha — Mon, 10 Oct 2011 15:52:44 +0000

Orchids inhabit six continents and nearly every habitat on Earth – a surprising accomplishment and evidence of amazing adaptive capabilities. What, you may ask, is the secret to their prowess? Reproductive success, according to Michael Pollan in an introduction to a new book by Christian Ziegler called Deceptive Beauties: The World of Wild Orchids. One species of orchids, found in remote areas of the Mediterranean mountains, are tricking credulous bees in order to increase their reproductive fitness.

With a strategy termed “sexual deception,” these orchids seduce male bees with the appearance, scent, and even sensation of a female bee’s reproductive organs. The plant’s lower lip, or labellum, actually has fake fur and small folded wing structures that appear to be a female bee with her head buried in the flower’s sepals. Thus, the male bee is tricked into picking up the plant’s pollen while thinking that he is actually producing his own offspring. The pollen sticks to his back with a glue-like substance, so when the bee flies off upon realizing he has been tricked he takes the pollen with him.

The benefits of this reproductive deception are many. Because inbreeding decreases fitness, mixing of genes with those of distant beings increases genetic variety and therefore increases fitness. Furthermore, each orchid looks slightly different to prevent bees from learning not to fall for the same flower again.

These orchids’ reproductive strategy is amazing, involving imitation and deception of the world’s animals. Currently, researchers are trying to understand how this strategy came to be.

Discussion Question: Because the bees don’t actually gain anything from their relationship with these flowers, why do you think natural selection weeded out these bees that waste time mating with a fake female bee rather than a real one?

News Article: http://www.guardian.co.uk/science/2011/oct/09/orchid-sex-botany-ziegler-pollan?CMP=twt_fd
Book Source: http://www.guardianbookshop.co.uk/BerteShopWeb/viewProduct.do?ISBN=9780226982977 or http://www.amazon.com/Deceptive-Beauties-World-Wild-Orchids/dp/0226982971/ref=sr_1_1?ie=UTF8&qid=1318261741&sr=8-1

Image: Christian Ziegler/Minden Pictures

Nature’s Magical Sweetener – Transforming Sour into Sweet

Sneha — Thu, 06 Oct 2011 14:30:43 +0000

Say goodbye to artificial sweeteners and sour foods! New research has revealed the secret to creating the perfect taste of sweetness by understanding the science behind a certain “miracle fruit” that has the power to turn a sour taste into a sweet one.

This fruit was first discovered in tropical areas of West Africa in 1725, when a European explorer noted that locals would eat the red fruit before meals. In 2008, the berries made waves in the news when a New York Times article described their use in “flavor-tripping parties” where guests would chew a berry and then eat sour foods. Now, the mechanics are finally being understood.

The berry has been found to contain a protein called miraculin. Miraculin binds to receptors on taste buds that sense sweet flavors, and its power is amplified in the presence of acids from sour foods. The stronger the binding of the compound, the sweeter the taste we experience. In acidic conditions, miraculin’s molecular structure changes to enhance binding strength to one million times stronger than artificial sweetener and 100 million times stronger than sugar.

Researchers discovered how the berry works by studying the interactions between miraculin and cells that were designed to express the mouse or human versions of the sweetness receptor, however the mouse receptors did not respond to miraculin. Then, they looked for differences between the human and mouse receptors to isolate the part of the human receptor that produces the effect of sweetness. Interestingly, this crucial part of the receptor doesn’t bind other artificial sweeteners. Because most common foods are at least slightly acidic, the scope of miraculin’s utility is enormous.

Discussion question: What ways can you think of to expand the use of miraculin? How do you think researchers will go about attempting to produce the protein in a lab setting?

News article: http://www.livescience.com/16230-miracle-fruit-taste-sweet-sour.html
Journal article: http://www.pnas.org/content/early/2011/09/16/1016644108.full.pdf+html
Image: Keiko Abe

New Plant Species Discovered in Brazil –A Plant that Buries its Seeds

Sneha — Thu, 29 Sep 2011 13:36:19 +0000

Bahia, Brazil – located in the rural northeastern part of the country – holds one of the highest levels of biodiversity in the world. There, around two years ago, handyman José Carlos Mendes Santos found a miniscule plant – one inch in height and with white and pink flowers.

Though Santos took the plant home because it looked interesting, he would soon realize the plant also had very unique behavior. Santos observed that after the fruit developed on the plant, the branches would bend down and leave the fruits on the ground, sometimes even burying them in the top layer of moss and soil. This behavior seemed to ensure that the deposited seeds would end up very close to the mother, allowing for optimal growth in the next rainy season.

While observing the plant’s nature, Santos also made attempts to identify it via the Internet by posting pictures of the plant on Flickr and contacting various experts from around the world.

The plant’s family (strychnine or Loganiaceae) and genus (Spigelia) were identified, but one Brazilian botanist suggested that the plant might be a new species. The plant’s behavior is called geocarpy, and is thought to be an adaptation for survival in harsh conditions. Thus, the new species was named Spigelia genuflexa.

This discovery brings to light the vast gaps in knowledge that we as humans possess, though we think we have already found and described most phenomena in the plant world. It also shows the way that amateur and professional scientists can work together in order to bring about new knowledge that benefits us all.

News Article: http://www.sciencedaily.com/releases/2011/09/110914115842.htm

Journal Article: http://www.pensoft.net/journals

Image: (Credit: Alex Popovkin, via Flickr / licensed under the Creative Commons Attribution license (CC BY 2.0))

E. Coli and Salmonella Can Live Inside Plants

Seorin — Mon, 12 Sep 2011 13:31:09 +0000

Washing your fruits and vegetables prior to consumption may not be sufficient to rid produce of pathogenic bacteria. According to a new study conducted at Purdue University, bacteria such as E. coli and Salmonella can exist inside, as well as outside, the plant.

E. coli and Salmonella have been household terms in recent years: outbreaks involving both have resulted in public concern and recalls of produce, including spinach, peanuts and peanut-derived products such as peanut butter. Vegetables, fruits, and nuts are all susceptible to carrying harmful bacteria.

Seeds can become exposed to the bacteria through contaminated soil or water. Once the seed has been contaminated, the bacteria can thrive within the growing plant and pervade the plant’s tissues. According to the researchers, all major tissues of plants can harbor bacteria. The bacteria within a plant can be found mostly in the apoplast. Thus, in order to ensure a plant exposed to the pathogenic bacteria is safe for consumption, the plant should be washed to remove bacteria on the external surfaces of the plant and cooked at a temperature high enough to kill any bacteria living within the plant.

Discussion Question: What challenges might the researchers have faced in determining whether bacteria had actually been living inside the plant, rather than only on the external surfaces?

News Article: http://www.sciencedaily.com/releases/2011/08/110815152049.htm
Journal Articles: http://www.ingentaconnect.com/content

Image Source: http://en.wikipedia.org/wiki/File:EscherichiaColi_NIAID.jpg

How Rapid Chromosome Duplication Help Some Plants Thrive Under Stress

Seorin — Mon, 05 Sep 2011 13:48:56 +0000

For some plants, stress can actually help, rather than hurt, their chances of survival. By observing the effects of herbivorous stressors on Arbidopsis thaliana, a type of mustard plant, researchers at the University of Illinois have found a positive correlation between adverse conditions such as herbivory and plant’s growth and reproduction.

At the start of its life, each mustard plant inherits five chromosomes from each parent for a total of ten chromosomes. Through a process known as endoreduplication, the cells of the plant can create new copies of their chromosomes without going through mitosis. After multiple rounds of endoreduplication, the researchers found some cells contained as many as 320 chromosomes.

The researchers cultivated and examined two different types of mustard plants—Columbia and Landsberg erecta. They mimicked herbivory in the laboratory by clipping the plants and then observed the plants’ responses to the stress of being “eaten” or grazed.

Columbia responded by accelerating endoreduplication. As a result, Columbia that were clipped grew larger and even yielded as much as three times more seeds than those that were not clipped.

Landsberg, on the other hand, did not respond to the simulated grazing with accelerated endoreduplication. The clipped Landsberg plants thus fared worse than those that were unclipped.

Discussion Question: Why might some plants not have evolved the ability to undergo endoreduplication? Under what conditions might the lack of endoreduplication be advantageous?

News Article: http://www.sciencedaily.com/releases/2011/08/110801094715.htm
Journal Article:http://www.esajournals.org/doi/abs/10.1890/10-2269.1

Image Source: http://en.wikipedia.org/wiki/File:White-tailed_deer_(Odocoileus_virginianus)_grazing_-_20050809.jpg

African Rodent Uses Poisonous Plant Toxin to Ward Off Predators

Seorin — Mon, 29 Aug 2011 20:12:49 +0000

In East Africa, people have long employed the toxins of the Acokanthera schimperi tree to make poison arrows, which are particularly useful in hunting elephants. Researchers have now discovered that a small African rodent that typically weighs no more than two pounds has also learned to use the Acokanthera tree’s toxins to its benefit: to ward off predators by punishing those that attempt an attack with illness or even death. While the other rare mammals that have evolved poisonous methods of defense produce their own toxins (e.g., the duck-billed platypus and the solenodon), the African crested rat is the first and only placental mammal known to make itself lethal to predators by exploiting the toxins of a plant.

The rat achieves its toxicity by chewing the bark of the Acokanthera tree, thereby obtaining the poisonous substance, ouabain, from the tree. The rat then applies a slaver—the mixture of saliva and ouabain—into the absorbent fur of its flanks by grooming itself. When examined under a microscope, the rat’s lateral-line hairs appear uniquely suited to holding the slaver, as the contour of each strand is lined with vacuoles that facilitate absorption. As the vacuoles remain open, any contact with hairs saturated with slaver would result in exposure to the poison. Dogs that bite the toxic rat may lose coordination, froth at the mouth, collapse, and ultimately even die as the poison causes the heart to fail. Amazingly, the rat, however, appears to suffer no ill effects from chewing the poisonous bark.

Discussion Question: What evolutionary adaptations might the African crested rat have developed to prevent it from becoming ill while chewing the bark of the Acokanthera tree?

News Article: http://www.wcs.org/press/press-releases/african-crested-rat.aspx
Journal Article: http://rspb.royalsocietypublishing.org/content/

Image Source: http://commons.wikimedia.org/wiki/File:Acokanthera_oblongifolia_03.jpg

Dish-Shaped Leaves Help to Attract Bats

Seorin — Mon, 01 Aug 2011 14:55:29 +0000

Due to their limited mobility, plants often depend on the assistance of pollinators. Attractively colored flowers and sweet fragrances are some common evolutionary adaptations through which plants increase their likelihood of attracting pollinators such as insects and birds.

We now have evidence that some plants may have, through evolution, changed the morphology of their leaves to attract pollinators that navigate via echolocation. According to researchers at the University of Bristol and the University of Erlangen and Ulm, Marcgravia evenia, a Cuban rainforest plant, has developed dish-shaped leaves, which reflect the sonar of bats more efficiently than flat leaves.

The researchers tested the effects of leaf shape by employing bats to locate hidden nectar under three distinct conditions: (1) nectar hidden with no leaf, (2) nectar hidden with an ordinary leaf, and (3) nectar hidden with a dish-shaped leaf. The bats took roughly the same amount of time to find nectar with no leaf as they took to find nectar with an ordinary leaf. However, the bats took only half that time to find the nectar hidden by a dish-shaped leaf.

Through the evolution of dish-shaped leaves, bats benefit by finding food more efficiently, and the plants benefit by attracting the pollinators they need to successfully reproduce.

Discussion Question: In what ways might a dish-shaped leaf disadvantage the plant?

News Article: http://www.sciencedaily.com/releases/2011/07/110728144717.htm, http://www.nytimes.com/2011/08/02/science/02obbat.html, http://news.sciencemag.org/sciencenow/2011/07/how-to-invite-bats-for-dinner.html
Journal Article: http://www.sciencemag.org/content/333/6042/631

Image Source: http://commons.wikimedia.org/wiki/File:Cloud_forest_Ecuador.jpg

A Plant’s Future Survival Depends in Part on Its Past

Seorin — Wed, 20 Jul 2011 14:41:17 +0000

Memory may not be a function of the brain alone. A rudimentary memory appears to exist even in the absence of a central nervous system.

In a new study conducted at the University of Toronto Scarborough (UTSC), researchers found that poplar clones, though genetically identical, can handle stress in their environment in entirely different ways. The disparity in survival strategies lies in each plant’s history, which the plant seems to “remember” on some level.

Poplars were selected for the study because their clones can be easily produced. By removing stems and branches from existing poplars and replanting them, researchers can cultivate new, genetically identical versions of the original trees.

When subjected to drought, poplars clones from trees that had originated in environments with little water employed different genes to respond to the stress than did their genetically identical counterparts that had originated in environments with sufficient water. Their different responses indicate that each plant’s history and place of origin can play a significant role in its ability to thrive under adverse conditions, the so-called “nursery effect.”

Discussion Question: In what ways are the poplar’s “memories” similar to human memories? In what ways are they different? Since plants don’t have a central nervous system, how do you think the poplar “memories” are stored?

News Article: http://www.sciencedaily.com/releases/2011/07/110711164557.htm
Journal Article: http://www.pnas.org/content/early/2011/07/05/1103341108

Image Source: http://en.wikipedia.org/wiki/File:Populus_nigra-bekes.jpg