Elaiosome Information – Why Do Seeds Have Elaiosomes

Elaiosome Information – Why Do Seeds Have Elaiosomes

By: Mary Ellen Ellis

How seeds disperse and germinate to create new plants isfascinating. One important role is given to a seed structure known as theelaiosome. This fleshy appendage to a seed is related to and is crucial forimproving the odds of germination and successful development into a matureplant.

What is an Elaiosome?

An elaiosome is a small structure attached to a seed. Itconsists of dead cells and a lot of lipids, or fats. In fact, the prefix “elaio”means oil. These small structures may have other nutrients as well, includingproteins, vitamins, and starch. Although it is not quite accurate, some peoplecall seed elaiosomes arils.

Why Do Seeds Have Elaiosomes?

The main elaiosome function in seeds is to aid dispersal.For a seed to have the best chance of germinating, sprouting, and survivinginto a mature plant, it needs to travel a good distance from the mother plant.Ants are great at dispersing seeds, and the elaiosome serves to entice them.

The fancy term for seed dispersal by ants is myrmecochory.Seeds get ants to move them away from the mother plant by offering up thefatty, nutritious elaiosome. Ants drag the seed off to the colony where theyfeed on the elaiosome. The seed is then ditched in the communal trash heapwhere it can germinate and sprout.

There may be some other functions of the elaiosome beyondthis main one. For instance, researchers have found that some seeds will onlygerminate once the elaiosome has been removed, so it may serve to inducedormancy. Most seeds, though, actually germinate more quickly with theirelaiosomes intact. This may indicate that it helps seeds take in water andhydrate in order to begin germinating.

With this elaiosome information in hand, you can now enjoyyour garden even more. Try putting down some seeds with elaiosomes near antsand watch nature at work. They’ll quickly pick up and disperse those seeds.

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Elaiosome-bearing plants from the Iberian Peninsula and the Balearic Islands

The importance of many mutualistic interactions is poorly understood because information on their frequency and distribution at wide spatial scales is lacking. One such interaction is that between ants and plants bearing diaspores equipped with elaiosomes, which function as a reward for ants in exchange for dispersion. Our aim was to estimate the number of taxa having elaiosome-bearing diaspores in the Ibero-Balearic territory and its relationship to several factors. We estimated that at least 572 species and subspecies, almost one-third endemic, are present, which corresponds to ca. 5.1% of European angiosperms and 9% of Iberian ones. Because this number of elaiosome-bearing taxa is much higher than those given so far for the Northern Hemisphere, the Ibero-Balearic territory should be considered an important center of myrmecochory, with myrmecochorous species richness significantly positively correlated with ruggedness, latitude, and longitude. In contrast to other myrmecochorous territories (Australia and Cape Province), where numerous trees and shrubs develop on acid substrates, most myrmecochores in the Ibero-Balearic area are perennial herbs occupying basic substrates. Such perennial herbs are more frequent in the Eurosiberian floristic region, whereas annuals abound in the Mediterranean region. The enumerated taxa mainly inhabit forests, scrubs, and anthropized sites. Among them, 56.5% carry the elaiosome on seeds (especially strophiole and caruncle types). In 36.7%, the elaiosome is borne on indehiscent fruits, such as achenes in Asteraceae, where they are found either at the base of the style or the basal hilum, and at the base of nutlets (Boraginaceae and Lamiaceae).

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Abstract

Morphological and chemical attributes of diaspores in myrmecochorous plants have been shown to affect seed dispersal by ants, but the relative importance of these attributes in determining seed attractiveness and dispersal success is poorly understood. We explored whether differences in diaspore morphology, elaiosome fatty acids, or elaiosome phytochemical profiles explain the differential attractiveness of five species in the genus Trillium to eastern North American forest ants. Species were ranked from least to most attractive based on empirically‐derived seed dispersal probabilities in our study system, and we compared diaspore traits to test our hypotheses that more attractive species will have larger diaspores, greater concentrations of elaiosome fatty acids, and distinct elaiosome phytochemistry compared to the less attractive species. Diaspore length, width, mass, and elaiosome length were significantly greater in the more attractive species. Using gas chromatography–mass spectrometry, we found significantly higher concentrations of oleic, linoleic, hexadecenoic, stearic, palmitoleic, and total fatty acids in elaiosomes of the more attractive species. Multivariate assessments revealed that elaiosome phytochemical profiles, identified through liquid chromatography–mass spectrometry, were more homogeneous for the more attractive species. Random forest classification models (RFCM) identified several elaiosome phytochemicals that differed significantly among species. Random forest regression models revealed that some of the compounds identified by RFCM, including methylhistidine (α‐amino acid) and d‐glucarate (carbohydrate), were positively related to seed dispersal probabilities, while others, including salicylate (salicylic acid) and citrulline (L‐α‐amino acid), were negatively related. These results supported our hypotheses that the more attractive species of Trillium—which are geographically widespread compared to their less attractive, endemic congeners—are characterized by larger diaspores, greater concentrations of fatty acids, and distinct elaiosome phytochemistry. Further advances in our understanding of seed dispersal effectiveness in myrmecochorous systems will benefit from a portrayal of dispersal unit chemical and physical traits, and their combined responses to selection pressures.


Related articles

  1. ^ Gorb, E. and Gorb, S. (2003). Seed Dispersal by Ants in a Deciduous Ecosystem. Kluwer Academic Publishers, Dordrecht, the Netherlands.
  2. ^ ab Lengyel, S. et al. (2010). "Convergent evolution of seed dispersal by ants, and phylogeny and biogeography in flowering plants: a global survey". Perspectives in Plant Ecology, Evolution and Systematics12 (1): 43–55. doi:10.1016/j.ppees.2009.08.001 . http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B7GVV-4XH56DC-2&_user=10&_coverDate=02%2F20%2F2010&_rdoc=5&_fmt=high&_orig=browse&_srch=doc-info%28%23toc%2320440%232010%23999879998%231682143%23FLA%23display%23Volume%29&_cdi=20440&_sort=d&_docanchor=&_ct=7&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=ef9e1d6284ebf67bd61de6f764045736 .

What Is An Elaiosome: Learn About Elaiosome Function In Seeds - garden

This resource was created by Joanne Vogel and Kate Reilly.

Forgotten Flowers: Spring Ephemerals
Each week, we will highlight a spring ephemeral by posting an information sheet, photos, guiding questions, and enrichment activities designed for formal and informal educators, as well as life-long learners.

Week 2: Bloodroot
Perhaps the most fleeting of all the woodland ephemerals is bloodroot (Sanguinaria canadensis). It’s a curious name as the flowers are brilliant white with a ring of lemon yellow stamens. There’s nothing bloody about them until the stems or roots of these delicate beauties are bruised or damaged. Then they secrete bright red-colored sap, hence the common name.

Bloodroot pops up out of the woodland floor almost like magic. The budded stalk and plant’s single leaf emerge together, looking ever so much like a white lollipop on a stick enveloped in a crinkly green velvet wrapper. When the bud is ready to open, the stalk pushes the bud up above the leaf so when the petals unfurl, they are still protected by the leafy envelope. The 7 to 12 white petals are so fragile that they only last a few days before they are gone.

Native Americans looked for the emergence of bloodroot. The “blood” was used as a natural red natural dye to color baskets, blankets, clothing, and even as body paint! Bloodroot was also used medicinally for a multitude of ailments. Because they “bled” like humans when injured, this ephemeral was used to treat wounds, ulcers, skin cancers, and any diseases involving bleeding. The European colonists learned of its properties from the Native Americans and continued to use bloodroot as strong medicine. However, the plant can be very dangerous as it contains toxic compounds that may have done the patients more harm than good.

Bloodroot flowers entice early spring insects with their showy flowers and fluffy anthers full of pollen at a time when not much is in bloom. But since they have no nectar, they resort to trickery to get bees and other insects to provide pollination services. As the insect flies from flower to flower searching in vain for the sweet reward, the bloodroot gets pollinated. Even though there’s no nectar, the insects do come away covered with protein-rich pollen, essential food for native bee larva.

Under cold spring conditions, bloodroot may bloom before the pollinators are active. It is not uncommon for bloodroot to self-pollinate and go to seed without pollinators. However other insects then help to spread the seeds. In a process called Myrmecochory, ants help disperse the seeds of bloodroot and other spring ephemerals. The seeds have a fleshy package of fats and other nutrients called the elaiosome. The ants bring the seeds back to their nest, eat the elaiosomes, and leave the seeds intact. Bloodroot germinates readily from seeds moved around by ants and large colonies can form when left undisturbed.

Want to grow Bloodroot in your garden? Buy them from reputable Native plant nurseries and never collect them from the wild! The Native Plant Society of New Jersey is a great resource to help you find where to buy them or to get more information.

Guiding Questions and Enrichment

1. How does bloodroot get its common name?
Answer: Because when the stem or root is bruised or cut, it exudes a red sap that reminds us of blood.

2. The flowers of bloodroot are truly fleeting. How long do the blossoms last?
Answer: They only last a few days.

3. How many leaves does bloodroot emerge with wrapped around its stem?
Answer: Just one.

4. Native Americans had important uses for bloodroot plants. Name two.
Answer: As a red dye for cloth, baskets, body paint, and as strong medicine.

5. Because the plants seem to “bleed”, Native Americans and the European colonists thought they would be useful for treating disease. What kind of ailments?
Answer: Any disease involving wounds, blood, and bodily fluids.

6. How does bloodroot trick pollinators to provide pollination services?
Answer: They have big showy flowers at a time when not much is blooming, which attracts the insects to visit and look for nectar they spread pollen in the process.

7. Even though there’s no nectar, pollinators do benefit from the visit by coming away with what?
Answer: Protein-rich pollen to feed insect larva.

8. Bloodroot readily forms seeds. What insect helps to spread the seed?
Answer: Ants.

9. What special structure do bloodroot and other spring ephemerals seeds possess?
Answer: Nutrient-rich elaiosomes.

10. What is the seed dispersal by ants called?
Answer: Myrmecochory.

Duke Farms Connection

We can still find some bloodroot popping up in the Meditation Garden and lowland woodlands of Duke Farms. Efforts are underway to help all our native beauties return to their native habitats.

Family Activities to Do at Home

To learn more about the life cycle of ants and the essential work that they do, the following books and resources are included for family fun. As a gentle reminder, those interested in the aspect of ant farms should be reminded that ants are important to our natural environment and should be left outside.

Ant Cities – Let’s Read and Find Out Books by Arthur Dorros This book explores what certain types of ants do inside an anthill, showing the tunnels and rooms that are constructed.
To hear the book read aloud, click here.

For those interested in the book written in Spanish: Aprende y Descubre La Ciencia Ciudades de hormigas ¿Te preguntaste alguna vez adónde van las hormigas cuando desaparecen por el hoyo de su hormiguero? Es muy posible que debajo de ese montículo de tierra existan miles de túneles y cientos de habitaciones. ¡Lee este libro y aprende a crear tu propia granja de hormigas!

Are You an Ant? – Backyard Books by Judy Allen and Illustrated by Tudor Humphries Backyard Books: Are You an Ant? by Judy Allen with illustrations by Tudor Humphries will give children who love to track ants an inside look at the everyday life of this fascinating insect, as they explore the similarities and differences for themselves.
To hear the book read aloud, click here.

Egg Carton Ants Using Recycled Materials

This activity is a popular fan favorite for any learner. You can make an ant craft out of an egg carton using 3 cups to demonstrate the head, thorax, and abdomen. Although you can use pipe cleaners for the 6 legs and 2 antennae, try looking for sticks or other recycled materials. Don’t forget the eyes!

There are many other craft tutorials available. Do a search to find ideas.

Bloodroot Additional Resources

Connection to Standards:
There are many ways to integrate the information about bloodroot and ants into your lessons from a multidisciplinary standpoint.Here are just a few examples:
• NJ Learning Standards -Social Studieso 6.1.4.D.1 Determine the impact of European colonization on Native American populations, including the Leni Lenape of NJo Research native plants and how they were used by people throughout time.• Next Generation Science Standardso K-LS1-1 Use observations to describe patterns of what plants and animals need to survive.o 3-LS4 -3 Construct and argument with evidence that in a particular habitat some organisms can survive well, some survive less well, some cannot survive at all.o Can bloodroot flourish in a different environment? Why or Why not?• NJ Learning Standards - English Language Arts/ Literacyo W.K.7 Participate in shared research and writing projects.o Students may contribute to a book designed with illustrations they make themselves.• NJ Learning Standards – Mathematicso K-MD.A.2 Directly compare two objects with measurable attributes. More and less than.o Compare bloodroot to another ephemeral. Compare ants to another insect. Or compare which populations of each have smaller/larger numbers.

For more ways to modify the lesson on a PK and higher level, please contact Kate Reilly, Manager of Education at [email protected]

Connection to Standards:

There are many ways to integrate the information about bloodroot and ants into your lessons from a multidisciplinary standpoint.

Here are just a few examples:

NJ Learning Standards - Social Studies

  • 6.1.4.D.1 Determine the impact of European colonization on Native American populations, including the Leni Lenape of NJ
  • Research native plants and how they were used by people throughout time.

Next Generation Science Standards

  • K-LS1-1 Use observations to describe patterns of what plants and animals need to survive.
  • 3-LS4 -3 Construct and argument with evidence that in a particular habitat some organisms can survive well, some survive less well, some cannot survive at all. Can bloodroot flourish in a different environment? Why or Why not?

NJ Learning Standards - English Language Arts/ Literacy

  • W.K.7 Participate in shared research and writing projects. Students may contribute to a book designed with illustrations they make themselves.

NJ Learning Standards – Mathematics

  • K-MD.A.2 Directly compare two objects with measurable attributes. More and less than. Compare bloodroot to another ephemeral. Compare ants to another insect. Or compare which populations of each have smaller/larger numbers.

For more ways to modify the lesson on a PK and higher level, please contact Kate Reilly, Manager of Education at [email protected]

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Watch the video: Endangered Dudleys lousewart plant: seeds dispersed by ants