Where Does The Daffodil Flower’s “Trumpet” Come From?
An answer to this question can be found in a 2013 report published in The Plant Journal (please see Ref. 1 below). The full text of this article is now available online (thanks to the Wiley Online Library), and I’ve read it (so that you don’t have to). Here’s my take on this story:
Maybe we should we should start by taking a closer look at the flower of the daffodil.
Starting from the outside working in, the six petals are actually “tepals”, which are a kind of developmental combination of sepals and petals.
Next up is the famous trumpet-shaped part of the daffodil flower called the corona (“crown”) that is the main subject of this blog post.
The central part of the daffodil flower consists of the six stamens that encircle the carpel (gynoecium). In the photo above, you can barely see the anthers (produce pollen) of the stamens, and also you can only see the top of the carpel called the stigma (receives pollen).
When And How Is A Daffodil Flower Made?
You maybe surprised to find out that a miniature version of the daffodil flower actually develops not in the spring just before it blooms, but at the end of the previous growth season. Thus, a floral bud is fully formed, and over-winters, within the dormant bulb.
This means that plant scientists investigating daffodil flower formation (see Ref. 1 below) have to dissect out flower buds from the developing bulbs. Whew! (Thank goodness for grad students: nearly the ultimate in cheap labor. Ultimate = undergrads!)
Anyway, as a result of such efforts, Waters, et al. (Ref. 1 below) discovered that the daffodil corona forms relatively late in the flower-development program.
As described in a previous post, the flower-development program can be described like a play with several acts.
In the first act, the plant genetically shifts from a vegetative state to a flowering state.
In the second stage, which I call “arranging the chairs”, the spatial arrangement of the flower is determined.
In the third act, which I call “seating the guests”, the different flower parts (in this case, tepals, stamens and carpel) are seated in their appropriate “chairs”.
In daffodils (and perhaps other species within the Amaryllis plant family that have trumpet-shaped flowers) there apparently is an additional fourth act.
In this final act of daffodil flower development, new “chairs” are provided and arranged in a circle between the rings of the tepals and the stamens. These “late” guests are then seated.
The question was: to which of the four basic flower parts (sepals, petals, stamens, carpels) are these “late” guests most related? Turns out they are genetically related to stamens.
But, of course, an obvious question is: How does the daffodil make something that looks like petals by starting with the genetic “blueprints” for stamens?
The honest answer is we simply don’t know at the present time. It should be mentioned, however, that some of the results of Ref. 1 show that there is a late burst of coronal growth in the spring, so a great deal of elaboration of the “stamen” program is happening to result in a petal-like structure. This and other evidence suggest that petal-like structures “…can be produced by different genetic pathways even within the same flower.” (from Ref 1 below)
Why Do Daffodils Have Trumpet-Shaped Flowers?
Most explanations from botanists involve attracting pollinators. But who pollinates domesticated daffodils? Mostly likely, it’s people!
Most of the showy daffodils that we see in the spring in parks and around homes and businesses are a product of plant breeding, i.e., artificial selection, not natural selection. (You can read more about this here.)
That is, such daffodil flowers are a product of what has looked good to humans (daffodil breeders especially), not insects. Indeed, most of the domesticated daffodils that we see in the spring may not be especially attractive to bees, and thus the daffodils may not even be pollinated (unless the bees are desperate).
What about the origin and evolution of trumpet-shaped flowers (before humans got involved)?
No one can be absolutely certain of an answer, but the long narrow corona of the genus Narcissus may have evolved to accommodate pollination by bees over butterflies or moths, which can’t easily enter the tall narrow corona to access the pollen. (from Ref. 2 below)
If all of the above was a bit much, it might help to listen to a brief (4 min) audio clip about the daffodil’s mysterious trumpet courtesy of The Science Show on Australian Broadcasting Corporation’s RadioNational.
OK, if you’ve listened to this audio clip, then you’ve heard that the “trumpet” or “corona” of the daffodil flower is probably not an extension of the petals, as previously thought, but is a distinct organ – sharing genetic identity with stamens.
If you haven’t listened (and even if you have), you can read brief summaries of Ref. 1 (below) here and here.
1. Waters, M. T., A. M. M. Tiley, E. M. Kramer, A. W. Meerow, J. A. Langdale, and R. W. Scotland (2013) “The corona of the daffodil Narcissus bulbocodium shares stamen-like identity and is distinct from the orthodox floral whorls.” The Plant Journal, Vol. 74, pp. 615-625. (Full Text)
2. Graham, S. W. and S. C. H. Barrett (2004) “Phylogenetic reconstruction of the evolution of styler polymorphisms in Narcissus (Amaryllidaceae).” American Journal of Botany, Vol. 91, pp. 1007–1021. (PDF)
Question: Doesn’t the scientific study of flower development ruin people’s appreciation of the aesthetic beauty of flowers?
Answer: Here’s the best answer to this question that I know of, provided by Nobel Laureate (Physics, 1965) Prof. Richard Feynman:
We’re back for Round 2 of the iPhone vs. plant rematch: Which is more intelligent, an iPhone 6 or a plant?
If you missed Rematch, Round 1, here it is. (I think the iPhone 6 clearly took the first round.)
By the way, this contest mainly has to do with the question of which is better at sensing its environment, an iPhone 6 or a plant?
As previously mentioned, intelligence is often defined as an entity’s ability to adapt to a new environment or to changes in the current environment. So, here we’re using complexity and versatility of environmental sensing as a measure of relative intelligence.
They’ve Got The Touch
This second round has to do with “touch ID”.
This is not “touch” as it relates to feeling or stimulation, but “touch” as it relates to identity.
Thus, we’re NOT talking about “touch-sensitive” plants, for instance, such as the Venus flytrap or Mimosa.
Instead, we’re talking about surface-to-surface contact as a means for specific identification. (Think fingerprints, for example.)
Such “touch ID” is useful for security reasons, such as for determining friend versus foe. In a biological context, it’s also a way to determine self from non-self at the cellular level, especially in regard to innate immunity.
I think that most people would expect that plants would possess much more complex and versatile environmental surface-to-surface sensors for recognizing “friend” versus “foe”, or self from non-self, than a smartphone, even the iPhone 6.
But let’s take a look at what the iPhone 6 can do in this regard before we award Round 2 of this rematch to the plants.
iPhone Fingerprint Recognition
The iPhone 6 Touch ID is a security technology that this smartphone uses to identify a unique individual via fingerprint recognition.
“Touch ID is Apple’s biometric fingerprint authentication technology. A capacitive ring activates the scanner on contact which then takes a high-resolution picture of your fingerprint. That fingerprint is then converted into a mathematical formula, encrypted, and carried over a hardware channel to a secure enclave on the Apple A7 chipset. If the fingerprint is recognized, a “yes” token is released. If it’s not, a “no” token is released.” (from: imore.com)
Briefly put, the iPhone “Touch ID” works by first taking a picture of a finger’s surface and then comparing it to previously-taken pictures of the owner’s (“self”) fingerprints. So, in reality, it’s just comparing two-dimensional digital images. There’s no actual mechanical surface-to-surface contact involved in unlocking the iPhone, such as with a key in a lock.
The “lock and key” analogy does, however, apply for how “touch ID” works in plants, albeit at the molecular level rather than at the mechanical level. And it’s most likely to occur in 3-D rather than in 2-D.
But – you may indeed be wondering – why would plants need something like “touch ID”?
Self/Non-Self Perception In Plants
This is a big old complex subject, with many facets, so I don’t want to wade in too deep here. Let me just briefly tell you about four examples of why “touch ID” is very important in the life of plants.
1. Self-Incompatibility – About one half of all flowering plant species are “self-infertile” (a.k.a., “self-incompatible”), that is, the flowers of such plants are able to distinguish between self and non-self pollen (hint: proteins on the pollen surface may play a role), and they reject their own pollen.
2. Disease Resistance – In a previous post, I asked the question Do plants have an immune system?. Briefly, the answer is yes, plants have a rudimentary immune system, but it’s much less complex compared to the mammalian immune system, for instance.
One of the things that plant and animal immune system’s have in common, however, is that they have cellular receptors that can detect foreign substances occurring only in microorganisms and that, when activated, trigger defensive reactions.
3. Symbiosis – I think most plant scientists would agree that plants were able to colonize the land thanks to symbiotic partnerships with certain soil-dwelling fungi, which we call mycorrhizae. And many plants are able to thrive in nitrogen-poor soils thanks to nitrogen fixation resulting from a symbiosis with specific soil bacteria.
But in order to form such symbiotic partnerships with such “friendly” microorganisms, plants must first turn off their defensive responses. That is, they need to be able to distinguish between “friend” and “foe” when it comes to bacteria and fungi.
4. Kin Recognition – “Several lines of experimental evidence suggest that roots have ways to discriminate non-related roots, kin, and—importantly—that they can sense self/non-self roots to avoid intra-plant competition.” (from Ref 2. below)
These are four examples of different sorts of “touch ID” in plants. From this, I think it’s clear that plants are much, much more sophisticated than an iPhone 6 at answering the question: “Who Are You?*
Bottom Line: The winner, and still champ, at environmental sensing and response is the plant. Thus, plants are more intelligent than even the iPhone 6. (But don’t stop trying Apple.)
*Look for more information about HOW plants answer the question “Who Are You?” in future posts.
1. Sanabria, N. M., J.-C. Huang and I. A. Dubery (2010) “Self/nonself perception in plants in innate immunity and defense.” Self Nonself, Vol. 1, pp. 40-54. (Full Text)
2. Depuydt, S. (2014) “Arguments for and against self and non-self root recognition in plants.” Frontiers in Plant Science, Vol. 5, p.614. (Full Text)
Intelligence is often defined as an entity’s ability to adapt to a new environment or to changes in the current environment.
“Intelligence is not a term commonly used when plants are discussed. However, I believe that this is an omission based not on a true assessment of the ability of plants to compute complex aspects of their environment, but solely a reflection of a sessile lifestyle.” (from Ref. 1 below)
If the new iPhone is better at sensing its environment than a typical plant, then does it follow that the iPhone 6 is more “intelligent” than the average plant?
So, of course, the critical question: Is the iPhone 6 better than plants at environmental sensing?
According to the Apple website, the new iPhone 6 has the following sensors:
Apple added a barometric (atmospheric) pressure sensor to provide the iPhone 6 with relative altitude data to help the device more rapidly acquire a GPS lock by delivering altitude coordinates to the required latitude and longitude GPS equation (see here for example). The iPhone 6 barometer may also be useful for weather forecasting (see here, for example), with some caveats.
The iPhone 6 uses a Bosch BMP280 absolute barometric pressure sensor. This type of electronic pressure sensor uses a force collector (such a diaphragm or piston) to measure strain (or deflection) due to applied force (pressure) over an area. (Specifically, the iPhone 6 pressure sensor is a piezoresistive pressure sensor.)
How accurate is the iPhone barometer? “…absolute accuracy of +-1 hPa and relative accuracy for pressure changes of +-.1 hPa (normal sea level pressure is roughly 1013 hPa). To give you a better idea of the accuracy of this barometer, the average decrease in pressure with height near sea level is 1 hPa per 8 meters (26 ft).” (from Cliff Mass Weather Blog)
So, the iPhone 6 atmospheric pressure sensor is highly accurate and responds to pressure changes nearly instantaneously.
Do plants have environmental sensors comparable to the iPhone’s ability to sense changes in barometric pressure?
Despite the existence of the so-called “barometer bush” (Leucophyllum frutescens), I could find no credible evidence that plants have the ability to sense changes in barometric pressure.
The first places on plants I might look, however, are the stomatal guard cells. This is because they are known to be sensitive to, and respond to, changes in the relative humidity (which may be the “secret” behind the “barometer bush”.)
This is not to say that plants don’t respond to significant changes in barometric pressure. They do (see Ref. 2 below, and literature cited therein). Many of these responses are most likely related to changes in atmospheric CO2 and O2partial pressures such as occur with plants growing at high altitudes versus sea level, for example. (This is somewhat analogous to how your body adapts to breathing in the mountains at high altitudes.)
Atmospheric pressure also may affect the rate of transpiration in plants as well as levels of the gaseous plant hormone ethylene (see Ref. 3 below, for example).
Bottom Line: It looks like the iPhone 6 wins this round because it has the ability to sense subtle changes in atmospheric pressure, and plants apparently do not possess such sensitive barometers.
Next-Time: The match continues with round two – Touch ID.
1. Trewavas, A. (2003) “Aspects of Plant Intelligence” Annals of Botany, Vol. 92, pp. 1-20. (Full Text)
2. Paul, A.-L., et al. (2004) “Hypobaric Biology: Arabidopsis Gene Expression at Low Atmospheric Pressure.” Plant Physiology, Vol. 134, pp. 215-223. (Full Text)
3. He, C., et al. (2003) “Effect of hypobaric conditions on ethylene evolution and growth of lettuce and wheat.” Journal of Plant Physiology, Vol. 160, pp. 1341–1350. (Abstract)
A recently published report has pounded another nail in the biofuels coffin.
This report, published by the World Resources Institute provides evidence that governments have made a mistake by supporting the large-scale conversion of plants into fuel.
“Turning plant matter into liquid fuel or electricity is so inefficient that the approach is unlikely ever to supply a substantial fraction of global energy demand, the report found. It added that continuing to pursue this strategy — which has already led to billions of dollars of investment — is likely to use up vast tracts of fertile land that could be devoted to helping feed the world’s growing population.” (from Ref. 1 below)
I’ve always been a skeptic of industrial-scale cultivation of plants for bioenergy (see here, for example.)
Please Note: This does NOT mean I’m against recycling used vegetable oil to make biodiesel, for example, or the conversion of waste biomass into ethanol.
But is spending tens of millions of dollars on biofuels-related plant research to facilitate the conversion of natural grasslands, and even croplands, to grow plants to be harvested and then be chemically converted into fuel for cars, jets and ships a misguided policy?
After reading this report you may indeed think so.
To read a summary of this report – or to download a free copy of the report itself (PDF) – please click on the link in Ref. 2 below.
The month of December 2014 featured some amazing discoveries in plant-related science.
From a new way to look at plant genomes and plant cells to “shape-shifting” plants to surprising info regarding organic farms and, yes, even Christmas trees.
Prepare to be (at least mildly) astonished.
“A groundbreaking paper from a team of Florida State University biologists could lead to a better understanding of how plants could adapt to and survive environmental swings such as droughts or floods.” See a surprising new way of looking at DNA at: Maize analysis yields whole new world of genetic science.
“…changing conditions can prompt immediate shifts in organisms’ physical traits — or what researchers call phenotypic plasticity, which allows for different looking organisms without changing their genetic code.“ Learn how this may help save some plants in the future at: Shape-shifting may help some species cope with climate change.
“…deep thinking on how the eukaryotic cell came to be is astonishingly scant. Now, however, a bold new idea of how the eukaryotic cell and, by extension, all complex life came to be is giving scientists an opportunity to re-examine some of biology’s key dogma.“ Read about this new way of thinking at: New theory suggests alternate path led to rise of the eukaryotic cell.
“Each Christmas, families gather around evergreens, real or fake, to celebrate the season. But what holiday revellers may not realise is just how incredible these spruce, fir and pines can be.“ Discover some Xmas tree “secrets” at: Five things you didn’t know about Christmas trees.
And for your final “dessert” from 2014: Filamentous Fungal Freeways
Hope you enjoyed this sampling of 2014 plant news “treats”.
“Plants grow in environments where the availability of light fluctuates quickly and drastically, for example from the shade of clouds passing overhead or of leaves on overhanging trees blowing in the wind. Plants thus have to rapidly adjust photosynthesis to maximize energy capture while preventing excess energy from causing damage. So how do plants prevent these changes in light intensity from affecting their ability to harvest the energy they need to survive?“ Discover a possible answer to this question at: Switching on a dime: how plants function in shade and light.
Fungi live in darkness. Since they don’t do photosynthesis, they don’t require light. But they also live in a kind of “darkness” in another way. Because they are often hard to see, most people don’t notice them, except for maybe the mushrooms at the grocery store. In this way, they’re sort of “dark” (unknown) to most people, including many scientists. Recently, “…A light has been shone on the world of fungi through a global study that reveals the staggering and previously unknown diversity of species.“ Explore this new world at: The secret world of fungi revealed.
Next-Time: For our last taste of 2014…a few surprises.
“Though modern medicine seems the epitome of all that severs our society from the past, it still draws on the same ancient processes of cognition that have always served to keep people alive — and that make us uniquely human.“ Read about how a physician found that identifying wild mushrooms is like diagnosing human diseases at: Learning From Fungi: Of Medicine and Mushrooms.
“Plant breeders have long identified and cultivated disease-resistant varieties. A research team at the University of California, Riverside has now revealed a new molecular mechanism for resistance and susceptibility to a common fungus that causes wilt in susceptible tomato plants.“ Find out how researchers identified a new process that explains why tomatoes are susceptible to a disease-causing fungus at: To Wilt or Not to Wilt.
Menu #9: From Caffeine To An Asteroid (Plus “Dessert”)
The plant news “smorgasbord” of September 2014 provided quite a variety “dishes”.
It was difficult to choose only five, but I did manage to include a video “dessert”.
“Caffeine is the most widely consumed psychoactive substance in the world.” A recent study, published last September, “…sheds light on how plants evolved to make caffeine as a way to control the behavior of animals — and, indirectly, us.” Read this fascinating article at: How Caffeine Evolved to Help Plants Survive and Help People Wake Up.
Almost everyone is familiar with the smell of a freshly-mowed lawn. “The smell of cut grass in recent years has been identified as the plant’s way of signaling distress, but new research says the aroma also summons beneficial insects to the rescue.” You probably will never think of a mowed lawn in the same way after you read: Mown grass smell sends SOS for help in resisting insect attacks.
Leaf surfaces are wonderful microbial habitats (for example, please see here). Research published last fall “…demonstrates for the first time that host plants from different plant families and with different ecological strategies possess very different microbial communities on their leaves,…“ Learn more at: Research finds each tree species has a bacterial identity.
The giant asteroid that most believe resulted in the demise of the dinosaurs also must have affected terrestrial plant communities. Unlike the dinosaurs, plants are still here. Find out how plants survived this cataclysm at: A Plant’s Guide to Surviving the Chicxulub Impact.
Plant-related news did not take a vacation in August 2014.
There were certainly plenty of stories to choose from for our eighth nibble at last year’s “leftovers”.
So tuck in for some toothsome treats.
Most seed-preservation endeavors have followed pretty much a “one-size-fits-all” approach for collecting and saving seeds. “A new study, however, has found that more careful tailoring of seed collections to specific species and situations is critical to preserving plant diversity.” Find out what’s new about saving seeds at: Saving Seeds the Right Way Can Save the World’s Plants.
“How does a complete plant with stems, leafs and flowers develop from a tiny clump of seemingly identical cells?” See how a research team combined math and genetics to discover a piece of the puzzle regarding: How plants grow and develop.
According to a paper published last August, planet Earth was a pretty boring place before flowering plants came along. Flowers may indeed have transformed land-based ecosystems. See how at: Flowering plants revolutionized life on Earth.
One of the main objections people have to GMO crop plants is that they contain foreign DNA from totally different organisms, even fungi and bacteria. But what if GMO crops are the result of relatively minor changes in the plant’s own genome? Will this change everything regarding the public acceptance of GMOs? Learn more at: Coming soon: Genetically edited fruit?
Next-Time: Caffeine and asteroids and their effects on plants…and more.
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