plant science research

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Speaking of Food: A Special Issue of American Journal of Botany

“At the center of discussions about agriculture and the future of food in a changing climate are the plants that we grow for food, fiber, and fuels and the science that is required to understand, improve, and conserve them.”

That is a line from the opening paragraph of the introduction to the October 2014 issue of American Journal of Botany, Speaking of Food: Connecting Basic and Applied Plant Science. In this Special Issue, the American Journal of Botany – inspired by Elizabeth Kellogg’s 2012 presidential address to the Botanical Society of America – endeavors to demonstrate ways in which basic plant biology research can benefit the applied science of agriculture, and how this “use-inspired” research can help address the challenges of feeding a growing population in a changing climate.

speaking of food_ajb

In its 100 year history, the American Journal of Botany, has published hundreds of papers that serve to advance agricultural and horticultural sciences. However, this connection has not always been made explicit. With this special issue, they are hoping to change that by “illustrat[ing] that ‘basic’ and ‘applied’ are not two discrete categories, nor are they even extremes of a linear continuum.” “Basic” research can be used to answer questions and solve “human-centered problems,” and “applied” research can “illuminate general biological principles.” When both approaches to scientific inquiry come together, everyone benefits.

I originally chose to study horticulture because I was interested in growing food in a sustainable and responsible manner. During my studies, I gained a greater interest in the broader field of horticulture as well as an interest in botany. After receiving a degree in horticultural and crop sciences, I decided to pursue a Master’s Degree. I wanted to study green roof technology, an applied science that incorporated my interests in both horticulture and sustainability. The school that I ended up going to did not have a horticulture program, so I enrolled in a biological sciences program. It was there, while doing applied science research on green roofs and taking mostly botany related science courses, that I deepened my love for science and began to see how basic science had applications, not just in horticulture and agriculture, but in all aspects of life.

That explains my great interest in this recent issue of American Journal of Botany, and why I was so excited when I heard about it. Using science to understand and address the challenges that we face today (challenges that, many of which, are a result of human activity) is intriguing to me. Based on my interest in horticulture, food production, and sustainability, establishing and advancing science-based sustainable agriculture is incredibly important to me. And so I have decided that, over the next several posts, I will provide reviews of each of the 17 articles in AJB’s Special Issue. Each post will offer a brief overview of one or more articles, outlining the basic premises and findings of each study. If your interest is peaked, and I hope it will be, you can go on to read more about each of the studies. The Introduction to this issue gives an excellent overview of the articles, so I won’t include that here. I’ll just dive right in. If you feel inclined, read ahead, otherwise stay tuned and I will preview you it all for you over the next several weeks.

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Palm Oil Production and Its Threat to Biodiversity

Improvements in cultivated varieties of oil palms could have devastating ecological effects. This is according to an article published in a recent issue of Science. Doom doesn’t have to be the story though, if – as the authors suggest – governments and conservation organizations take proper action to safeguard vulnerable land.

Palm oil is a versatile vegetable oil derived from the fruits of oil palms. It has myriad culinary uses and is also used in the manufacturing of cosmetics and the production of biofuel. Oil palms have high yields, easily outyielding other major oil crops like soybean, rapeseed, and sunflower. Oil palms are grown in the tropics in developing countries where land and labor are inexpensive. As human population grows, demand for palm oil increases. To meet the demand, tropical forests are converted into agricultural land. The majority of palm oil production occurs in Southeast Asian countries like Indonesia and Malaysia. However, palm oil production is expected to increase in African and Latin American countries as new varieties better suited for these particular environments become available.

oil world graph

Genome sequencing of oil palm may allow plant breeders to develop varieties that are disease resistant, drought tolerant, and able to grow in salinized soils. Already making its debut, though, is a new variety of oil palm that is boasting yields from 4 tons to as much as 10 tons per hectare. Higher yielding varieties could be the solution to preventing more tropical forests from being converted into oil palm plantations. Or could they lead to more growth? Intrigued by the development of improved varieties of oil palms and other tropical crops, the authors of this study developed computer models in order to determine what this might mean for the future.

African Oil Palm (Elaeis guineensis) is the species of oil palm most commonly grown for palm oil production.

African Oil Palm (Elaeis guineensis) is the species of oil palm most commonly grown in palm oil production (photo credit: www.eol.org)

The results of simulations suggested two possible outcomes: one potentially positive and the other largely negative. On the positive side, “an assumed 56% increase in oil palm yield per tree in Malaysia and Indonesia” could result in ” around 400,000 hectares of agricultural land…taken out of production in Brazil, India, and Canada.” This is because less land will be needed to meet the demand, and the increased availability and resulting lower price of palm oil will outcompete other oil crops (like rapeseed, which is one of Canada’s main agricultural crops). However, the author’s seem to assume that agricultural land taken out of production will be restored back into natural lands. I find this argument hard to accept. Anecdotal evidence suggests that if farmers are no longer making a profit from a particular crop, they will choose to either grow something more profitable or sell their land to developers. A concerted effort would have to be made to capture this land and ensure that it remain uncultivated and undeveloped. Also, as the author’s point out, restoring land in Canada is very different from restoring or protecting tropical land. Loss of biodiversity is a much greater risk in areas where the level of biodiversity per hectare is high.

On the negative side, higher yields can encourage increased production. Tropical forest conversion may accelerate if farmers see an opportunity for growth. Additionally, improved varieties may increase palm oil production in African and Latin American countries, resulting again in more land conversion and deforestation. This effect may also become the story, not just for oil palms, but for cacao, eucalyptus, coffee, and other tropical crops as varietal improvements are achieved.

Oil Palm Friuits (photo credit: www.eol.org)

Oil Palm Friuits (photo credit: www.eol.org)

In light of this predicted consequence, the authors of this study recommend that governments, working together with conservation organizations and industry associations, regulate the conversion of agricultural lands and ensure that certain areas are specifically set aside for conservation. This means that “models of the drivers of environmental change” must be developed that “incorporate feedbacks at a range of scales” so that measures can be put into place to address “the unintended negative consequences of technical advances.”

More information on sustainable palm oil production can be found here.

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Trees Are Good For Your Lungs

Trees help reduce air pollution. They do this primarily by pulling gases (like ozone, sulfur dioxide, and nitrogen dioxide) into their leaves and then diffusing them and/or chemically altering them so that they are no longer a direct threat to humans. They also intercept particulate matter, trapping it on the surfaces of their leaves until the wind comes along and blows it away or the rain comes around and washes it into the soil. Trees are filters in this sense, reducing the health threats of our polluted air.

But didn’t I just report on the contribution of urban trees to air pollution via their production of volatile organic compounds? Yes I did. And that remains a possibility; however, according to a study recently published in the journal, Environmental Pollution, the presence of trees is a great benefit to human health despite potential risks. More research is necessary of course, but the consensus so far is that having trees around is a net positive.

Alnus glutinosa, European Alder (photo credit: wikimedia commons)

Alnus glutinosa, European Alder (photo credit: wikimedia commons)

There have been many studies on the relationship between trees and air quality, but little is known about the extent to which human health impacts are avoided and the related money that is saved as a result of air pollution mitigation by trees and forests. With the aid of computer simulations, researchers at US Forest Service and The Davey Institute used 2010 Census data, tree cover maps from the 2001 National Land Cover Database, US EPA’s BenMAP program, and other data to seek answers to these questions. Their analyses – focused at the county level – involved the 48 contiguous United States.

According to their study, trees and forests removed around 17.4 million tons of air pollution in 2010, which resulted in a health care savings of $6.8 billion. 850 human deaths were avoided, and incidences of acute respiratory symptoms were reduced by 670,000. Ozone and nitrogen dioxide experienced the greatest decrease, while the removal of ozone and particulate matter resulted in the greatest health value. Air pollution removal was greater in rural areas compared to urban areas simply because there is more rural area in the US than urban area; however, the removal of air pollution was found to be more valuable in urban areas due to differences in population density. Resulting health benefits and savings are quite dramatic considering that air pollution removal by trees was only found to improve air quality by about 1%.

There were many things left out in this study though, and the researchers acknowledge this. First of all – as stated earlier – trees have the potential to contribute to air pollution. They emit volatile organic compounds which can result in ozone formation, they can reduce wind speeds which concentrates pollutants, and they produce pollen which is a direct contribution to air quality and a major health issue for those with serious allergies.  But trees reduce air pollution in indirect ways as well. For example, by shading buildings, trees can reduce energy demands which results in decreased power plant emissions and a reduction in air pollution.

Quercus sp., Oak Tree (photo credit: wikimedia commons)

Quercus sp., Oak Tree (photo credit: wikimedia commons)

Trees can also be negatively affected by air pollution. When particulate matter collects on leaf surfaces, photosynthesis is compromised, limiting a tree’s ability to take gaseous air pollution into its leaves. Urban trees are stressed in additional ways. For example, trees growing near sidewalks, driveways, and roadways deal with serious soil compaction and are often not receiving optimal amounts of water, which can limit their ability to mitigate air pollution. Thus, environmental factors should be considered when determining the relationship between trees and air quality.

This study was conducted at the county level. The researchers acknowledge that more precise predictions could be obtained if analyses were conducted at a finer scale. “Local-scale design of trees and forests can affect local-scale pollutant concentrations.” So, the number of trees, their concentration and configuration, the length of the growing season, the percentage of evergreen trees vs. deciduous trees, etc. all play a role in the extent of air pollution reduction.

While limitations to the study abound, the researchers assert that this initial analysis gives “a first-order approximation of the magnitude of pollution removal by trees and their effect on human health.” Future studies will provide more accurate approximations, but for now I think it is safe to say that trees are good for our health and worthwhile things to have around.

Boise National Forest

Boise National Forest

This study focused mainly on health issues of the respiratory variety. The positive psychological benefits of plants have been observed in separate studies, and our also worthy of our consideration when determining the health benefits of trees and forests.

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Feeding the World with Microbes

Back in the mid 1900’s, after the tragic days of the Dust Bowl in North America, new agricultural techniques and technologies were developed and distributed in the name of food security. These developments included higher yielding plant varieties, synthetic fertilizers and pesticides, and advancements in irrigation and other management practices. This period in time was termed the Green Revolution, and it truly was a remarkable time. Agricultural advancements that came out of this period have helped us feed the world and stave of starvation for millions of people. Today, issues of hunger and starvation are political problems, not necessarily agricultural ones. However, the human population continues to grow, and today’s 7 billion people is projected to reach up to 10 billion (or more) in the coming decades. The world’s best farmland is either already in use, degraded, or being used for other things. This means that we must find a way to feed a growing population with the diminishing farmland that is available. We may be producing enough food now (despite the distribution problem), but will we be able to produce enough in the future? The hunt for the Green Revolution 2.0 is on.

“According to the [UN’s Food and Agriculture Organization], most of the growth in production…has to come from increasing yields from crops. Selective breeding doesn’t seem to be offering the types of dramatic yield increases seen in the past. Meanwhile, genetic engineering has yet to lead to any significant increase in yields. Now, many scientists are saying that we’ve been looking at the wrong set of genes.”

These are the words of Cynthia Graber, author of an article that appeared last month on PBS Online’s NOVANext entitled, “The Next Green Revolution May Rely on Microbes.” In it she explores the argument that increasing future yields will depend on better understanding the soil’s microbial community and its complex interaction with the plant community. The big question: if microbes can be artificially bred – the same way virtually all agricultural plants have been – might they help us increase food production?

Microbial life in the soil is incredibly diverse. In one teaspoon of soil, there can be millions of individual microbes including bacteria, fungi, protozoa, algae, and nematodes. Our current understanding of soil life is extremely limited, akin to our understanding of outer space and the depths of the oceans. That is because, as stated in Graber’s article, “perhaps 1% of all soil microbes can be grown in a petri dish, the conventional model for such research.” This limits our ability to study soil microbes and their interactions with other living things. We do, however, acknowledge that the interactions between the roots of plants and soil microbes is incredibly important.

Fruiting Body of an Ectomycorrhizal Fungus (photo credit: eol.org)

Fruiting Body of an Ectomycorrhizal Fungus (photo credit: eol.org)

One major player in these interactions is a group of fungi called mycorrhizae. “Mycorrhizal fungi cannot survive without plants, and most plants cannot thrive without mycorrhizal fungi.” It is a symbiotic relationship, in which the fungi offer plants greater access to water and nutrients, and plants feed sugars derived from photosynthesis to fungi. Recent advancements in genetics have allowed researchers to better analyze the genes in microbes like mychorrizal fungi and determine the functions of them. Through selective breeding, microbes can be produced that will offer even greater benefits to plants, thereby increasing yields. For example, some microbes help plants tolerate heat and drought. Isolating the genes that give microbes these abilities, and then breeding these genes into other microbes might allow for a wider palette of plants to receive this kind of assistance.

In researching this article, Graber followed a Swiss researcher to Colombia where he was testing lines of mychorrhizal fungi on cassava. The fungi were specifically selected to increase a plant’s access to phosphorous. This is one of many experiments that are now under way or in the works looking at specially bred microbes in agricultural production. It’s an exciting new movement, and rather than spoil too much more of Graber’s article, I implore you to read it for yourself. Share any comments you may have in the comment section below, and expect more posts about plant and microbe interactions in the future.

Cynthia Graber appeared at the beginning of a recent episode of Inquiring Minds podcast to talk about her article. I recommend listening to that as well.

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Hundreds of Japanese Plants Threatened with Extinction

Life has existed on earth for at least 3.5 billion years, and during that time there have been five mass extinctions. Currently, we are in the middle of a sixth one. The major difference between the current extinction event and others is that this one is largely human caused, which is pretty upsetting. However, knowing that detail has its upside: if humans are the drivers of this phenomenon, we can also be the ones to put on the brakes.

Biologists have spent the last several decades tracking the current mass extinction, endeavoring to come up with a list of species that have the greatest risks of extinction, as well as lists of species that are at less of a risk, etc. The problem is that factors leading up to extinctions are diverse, and available data for making predictions is lacking, especially temporal data. Recognizing this information gap, researchers in Japan set out to better determine the extinction risk of Japanese flora. Using data from surveys done by lay botanists in 1994-95 and 2003-04, they were able to calculate a trend which indicated that, under current circumstances, between 370 and 561 plant species in Japan will go extinct within the next 100 years.

photo credit: wikimedia commons

photo credit: wikimedia commons

The methods for this study, as described in the findings which appeared last month in PLOS ONE, involved dividing Japan into 3574 sections measuring around 100 square kilometers each and covering about 80% of the country. More than 500 lay botanists tallied the numbers of species that were found in each section during the two time periods. 1735 taxa were recorded, and out of those, 1618 were considered quantifiable and used in the analysis.

Japan is home to a recorded 7087 vascular plant taxa. Historically, the extinction rate of plant taxa in Japan has been around 0.01% per year. According to this study, over the next 100 years the extinction rate will rise to between 0.05 and 0.08% per year. Researchers are organizing a third census in the near future in order to monitor the actual extinction rate and better determine the accuracy of this prediction.

Data collected in these censuses was also used to evaluate the effectiveness of protected areas and determine the need for improvements and expansions. Natural parks cover 14.3% of Japan, but only about half of that area is regulated for biodiversity conservation. The researchers found that protected areas do help to reduce the risk of extinctions, but that their effectiveness is far from optimum and that even expanding protected areas to cover at least 17% of the nation (a target set at the recent Convention on Biological Diversity) would not effectively gaurd threatened plant species from extinction.

In their conclusion, the researchers advise not only to expand protected areas but to improve the “conservation effectiveness” of them, and “to improve the effectiveness of them, we need to know the types of pressures causing population decline in the areas.” They go on to list a few of these pressures, including land development and recreational overuse, and suggest that management schemes should be developed to focus on specific pressures.

Japanese Primrose, Primula japonica (photo credit: eol.org)

Japanese Primrose, Primula japonica (photo credit: eol.org)

One thing I found very interesting and encouraging about this study was the recruitment of lay botanists in collecting data. As stated in the findings, “Monitoring data collected by the public can play an essential role in assessing biodiversity.” I am excited by the growing citizen science movement and hope to see it continue to expand as more and more people become interested in science and eager to add to this body of knowledge. In fact, I consider the term “awkward botany” to be synonymous with citizen, lay, and amateur botany. That is precisely why I chose it as the title for my blog. So, in short, expect more posts involving citizen science in the future.

You can read more about this study on John Platt’s blog Extinction Countdown at Scientific American.

 

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Urban Trees: Unlikely Polluters

Trees are central features in urban environments, and their benefits are numerous and well documented. They give off oxygen and sequester carbon, provide food for urban wildlife, help slow storm water runoff, and provide shade which not only keeps us cool in the hot sun but can help increase the energy efficiency of surrounding buildings. And even if they weren’t doing all these things and more, the aesthetic value they add to our concrete jungles alone is worth having them around. So it is a little disconcerting to learn that the trees we benefit so much from may actually be doing us harm by way of increasing levels of air pollution.

It sounds unlikely, but according to researchers at the Institute for Advanced Sustainability Studies in Postdam, Germany, urban trees can contribute to increased levels of tropospheric ozone, a key component of smog. This occurs when trees emit volatile organic compounds (VOCs), special gasses that are meant to attract pollinators, repel insects, and warn nearby trees of ensuing insect herbivory. These biogenic VOCs react with sunlight and nitrogen oxides (another key component of smog and a result of burning fossil fuels) and form ozone. Ozone in high concentrations is particularly harmful to the lungs, aggravating asthma, increasing susceptibility to lung infections, and damaging the lining of the lungs.

Fortunately, according to the study, certain trees contribute significantly less to ozone production than other trees.  Poplars, oaks, and willows, for example, tend to be high emitters of VOCs, whereas birches and lindens emit much less. Planting low VOC emitters in dense urban areas and keeping high VOC emitters scattered throughout the city instead of planted in large groups will help reduce this phenomenon. A recent article at Scientific American points out that cities that are sunnier and warmer have more to worry about than cloudy and cool cities since sunlight and high temperatures speed up the ozone producing reaction.

Despite this unfortunate discovery, trees still have an important role in cities. Apart from placing and planting the proper trees, our focus should be on finding ways to reduce our fossil fuel emissions which remain the major culprit of our polluted air.

River birch (Betula nigra) - Birches were found to low emitters of volatile organic compounds compared to other common urban trees

River birch (Betula nigra) – Birches were found to be low emitters of volatile organic compounds compared to other common urban trees (photo credit: wikimedia commons)

 

 

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Moss Reanimated After 1,500 Years in Permafrost

Some plants die hard. At least that seems to be the lesson learned after moss retrieved from deep within the frozen ground of Antarctica was found to still have life left in it. Following in the footsteps of the discovery by a separate research team of moss revived after spending 4oo years beneath glacial ice, researchers from the British Antarctic Survey and the University of Reading set out to determine the viability of the innards of a moss bank encased in permafrost.

Mosses are ancient plants, predecessors to the more recently evolved (at least on a geological timescale) vascular plants. They produce no flowers or seeds and have no roots. Their leaves carry out photosynthesis – just like other plants – but they also absorb water and nutrients. There are about 12,000 species of mosses found in a wide range of habitats. Because they lack a vascular system, mosses require a damp environment (or at least one that is seasonally damp). While commonly seen growing in shady locations, there are some moss species that thrive in full sun, such as those growing on rocks in alpine environments. Mosses are the dominant vegetation in the polar regions where they can form thick moss banks in which an actively growing layer is underlain with moss that has slowly become incorporated into the permafrost.

SAMSUNG

The researchers in this study, which was published in the latest issue of Current Biology, took a core sample of a moss bank on Signy Island, Antarctica. The moss bank consisted of a single species – Chorisodontium aciphyllum. The sample core went 138 centimeters (4.5 feet) deep, and  radio carbon dating of material taken from near the bottom of the core gave it an age of between 1533-1697 years old. The core was cut into several sections and then exposed to temperature and light conditions similar to the moss’s native environment. New growth occurred in many of the sections, but the most impressive finding was that after only 22 days, growth was noted in the 121-138 cm section, demonstrating that even after being frozen for more than 1500 years the moss was still alive. It was simply in a cryptobiotic state – a state in which all metabolic processes pause due to adverse environmental conditions.

signy research stationSigny Research Station on Signy Island (photo credit: Wikimedia Commons)

Certain microbial life has been known to survive in a cryptobiotic state for tens of thousands of years, however this is the first time that a multicellular organism has been found to survive in such a state for longer than a few decades. So is their a moss species out there that has been surviving frozen conditions for even longer? It’s quite possible. And from an ecological standpoint, suspended animation is essential in order for polar mosses to survive periodic ice ages. Perhaps that’s why they have developed this remarkable trait.

Read more about this study here and here.

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Wise Management of Invaded Plant Communities

Late last year the journal Nature published an article by Katherine Suding called “A Leak in the Loop,” which discussed the findings from long-term observations of an invaded plant community in Hawai’i. (A report authored by the researchers can be found in the same issue of Nature.) Once introduced, exotic species can become invasive by modifying their surroundings in such a way that ensures their survival and spread. Examples include modifications to fire and disturbance regimes, nutrient cycles, hydrology, and soil microbe communities. This self-reinforcement strategy is called a positive feedback loop. However, positive feedback loops are not eternally stable and can at some point be interrupted by negative feedback. In the case of invasive species, these “leaks in the loop” can result in population declines  and opportunities for restoration.

Back in the 1960’s, woodlands in Hawai’i Volcanoes National Park that were traditionally dominated by Metrosideros polymorpha, a flowering evergreen tree in the myrtle family (Myrtaceae), were invaded by a perennial grass from Africa commonly known as molasses grass (Melinis minutiflora). Molasses grass was successful because its presence increased the frequency and size of fires which reduced populations of native plant species without negatively affecting itself. Additionally, accelerated nitrogen cycling rates resulted due to the presence of the exotic grass, which benefited the invader. But now things have changed.

Returning to these sites 50 years later, researches have discovered that nitrogen cycling rates have returned to pre-invasion levels. Since molasses grass requires high levels of nitrogen, it is now on the decline. What exactly caused this reduction in nitrogen availability is unclear. It could be because winter rains flush nitrogen from the soil, making it unavailable when the grass begins to actively grow again in the spring. Several years of reduced growth resulting from reduced nitrogen availability diminishes the grass’s initial contribution to accelerated nitrogen cycling, hence a breakdown in the positive feedback loop.

With the invader on the decline, the woodlands should be able to restore themselves. Ideally, anyway. Instead what the researchers observed is that another invader, Morella faya – a nitrogen fixing evergreen shrub from Europe, is moving in. Acacia koa, a native nitrogen fixing tree, is the ideal candidate for restoring these woodlands, however its seeds are heavy and don’t spread easily. Seeds of M. faya are bird-dispersed, and so they find their way into these sites first. In order to restore these sites and avoid further invasions, land managers must recognize when and where molasses grass is declining and start planting Acacia koa trees in large numbers, getting them established before M. faya arrives.

acacia koa

Acacia koa (photo credit: eol.org)

This research is important for anyone in the business of managing invaded plant communities. As Suding concludes in her article, “this new perspective will inform where and when we might best intervene in systems to capitalize on their changing dynamics.” Millions of dollars are spent each year in an attempt to reduce and ultimately eradicate invasive plant species. Long-term studies of invaded plant communities can help us recognize when the best times to employ restoration strategies might be. When we find a leak in the loop, we should take advantage of it, otherwise we may just be wasting resources.

Related Post:

Invasivore: One Who Consumes Invasive Species

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Article: The Intelligent Plant

The New Yorker’s last issue in 2013 included an article by Michael Pollan called “The Intelligent Plant” in which Pollan explores some of the latest research revealing the ability of plants to sense their environment in ways that are analogous to seeing, hearing, and smelling. In the article Pollan dialogs back and forth between plant scientists who call this line of research “plant neurobiology” and plant scientists who seem to abhor that term. As the article progresses, you learn that the arguments between the two groups are not necessarily about the science itself but about vocabulary. Can plants learn the way we understand the term, to learn? Can we really say that plants are intelligent or conscious? Aren’t those traits reserved for organisms with brains? And regarding brains, plants don’t have them, so why plant neurobiology? Neuroscience is the study of nervous systems, so plant neurobiology must be a misnomer, right?

Well, despite the arguments over language, the research is pretty compelling. Plants are proving to be more aware of their surroundings and their actions seem to be more calculated than we originally assumed. They are not simply sessile organisms being acted upon, but they are doing some acting – lots of it, in fact. It is a remarkable field of study (whether you choose to refer to it as plant neurobiology or something else), and it will be exciting to see where it takes us.

Pollan’s article is worth a read if you can find the time (be warned, it’s lengthy), and it’s getting some coverage. Pollan recently appeared on Science Friday with Ira Flatow where he talked about his experience researching the article. And Pollan, of course, isn’t the only one talking about this stuff, Wired featured an article about it last month as well.

Check out this video associated with Pollan’s article (narrated by Pollan) of bean plants that appear to be deliberately reaching out to grab onto a pole.

sensitive plant

sensitive plant – Mimosa pudica

photo credit: Wikimedia Commons

Related Posts

– Book Review: What a Plant Knows

– Documentary: What Plants Talk About