We bury our dead and only ever on accident bury the living. But for some plants, burying them alive may be the very thing that saves their lives.

When Italians and other Mediterranean folk began to immigrate to North America in the early 1800s, they wanted to bring a taste of home along with them. What better way to do that than by bringing native plants to the New World? Fig trees were a travel companion of choice as they ameliorated both aesthetic and olfactory homesicknesses.

Unfortunately, fig trees are not well suited to the blustery winds or freezing temperatures of the American Northeast, so to keep these plants around, those who cared about them had to get creative. They had to bury them alive. Trees were tipped over, placed in two foot deep trenches, covered with dirt, then plywood, then a layer of insulating compost, and were left for the winter. Seems like a lot of work for just a few fruits come springtime, but this practice has been passed on through generations and is still carried on today by American fig growers.

Source

“Why Bury Fig Trees? A Curious Tradition Preserves A Taste Of Italy.” NPR. NPR, n.d. Web. 13 Jan. 2017. <http://www.npr.org/sections/thesalt/2014/12/25/371184053/why-bury-fig-trees-a-curious-tradition-preserves-a-taste-of-italy>.

Buried Alive was originally published in Botany Thoughts on Medium, where people are continuing the conversation by highlighting and responding to this story.

If you were hiking through the Andes foraging for edible fruits, you may encounter a climbing shrub covered in some familiar looking berries. If you’re from North America, you may want to call these blackberries, and you would be correct.

Blackberry is actually a common name for the genus Rubus of the Roseaceae family. There are over 375 species of blackberry distributed across Europe, North and South America, northwestern Africa, and western and central Asia.

Blackberries grow wild in many countries and are both ecologically and culturally important. Many species of caterpillar and and several species of grazing mammal rely on the plant’s leaves for sustenance. The red fox and eurasian badger consume the berries and act as agents of seed dispersal as well.

These berries have also been consumed by humans for thousands of years. Picking and eating them is a popular pastime, unfortunately human fondness of the plant and its delicious fruits have led to its development into an invasive species in regions of the world that do not have their own native blackberry species.

Source

Wikipedia. Wikimedia Foundation, n.d. Web. 11 Jan. 2017. <https://en.wikipedia.org/wiki/Blackberry?oldformat=true>.

Here a berry, there a berry was originally published in Botany Thoughts on Medium, where people are continuing the conversation by highlighting and responding to this story.

The trees have turned to gray and skeletal, perhaps they’re even covered in a fine layer of snow, so why are some of them still clinging to last summer’s leaves? What good could it do them to hang on to those dry brown clumps?

This strange winter-long leaf retention is called marcescence and it is most common in American beech, witch hazel, hornbeam, hophornbeam, and many species of oak. When autumn rolls around deciduous trees excrete enzymes that create an abscission layer between the branch and the leaf, causing the leaf to fall off. Remaining leafless throughout winter allows trees to reduce water loss and put energy toward preforming next spring’s leaves in over-wintering buds. Sometimes, leaves on low lying trees or leaves on the lower branches of large trees don’t go through the abscission process as quickly as other leaves because they are exposed to less sunlight. Then, when the cold comes, the enzymes that prompt leaf dropping are inhibited and the leaves are stuck on for the winter.

Marcescence could also be a strategic defense mechanism against winter herbivory. Crunchy brown leaves could deter hungry herbivores and keep them from eating the buds that will eventually form next spring’s leaves. The trees might also be saving their leaves as a snack for themselves. When leaves fall in autumn, they sit on the forest floor all winter, slowly decomposing under the snow. As they decay, their nutrients are released in the soil, but some of those nutrients are liable to wash away when the snow melts. By hanging onto some leaves and dropping them when warm weather comes around, trees can ensure that there will be at least some dependable nutrient source in their soil.

No matter the reason a tree keeps its leave over the winter, when spring comes around, spring bud expansion in the spring time will pop them right off. I think it’s safe to say that no one knows exactly why marcescence occurs but there are plenty of plausible, interesting ideas.

Source

Finley, Jim. “Winter Leaves That Hang On.” Center for Private Forests (Penn State University). PennState, n.d. Web. 25 Nov. 2016. <http://ecosystems.psu.edu/research/centers/private-forests/news/2012/winter-leaves-that-hang-on>.

Wintertime trees was originally published in Botany Thoughts on Medium, where people are continuing the conversation by highlighting and responding to this story.

Orchids are something like the plant version of a canary in a coal mine. When the orchids start to disappear from an area, that means there is something seriously wrong with the ecosystem. Unfortunately, disappearances or orchid populations are happening all across North America as pollinator habitat loss leads to lower pollinator populations and subsequently less successful orchid reproduction.

There are 200 orchid species native to North America and more than half of them are endangered. The Smithsonian Institute is currently leading a broad effort to collect and store seeds from every North American orchid species and the Minnesota Landscape Arboretum is joining in.

48 of the 200 native orchid species can be found in Minnesota, including the state flower, the showy lady’s slipper. David Remucal, the curator of endangered plants, and other Arboretum staff are traveling around the state in search of orchids and gathering seeds from every species they can find. Keeping these seeds in a seed bank allows for the preservation of the genetic diversity of these rare plants and could potentially provide opportunity for assisted repopulation in the future. More work has to be done to determine how long certain species’ seeds can be stored and still remain viable. To make things even more complicated, orchids can not simply be grown in soil. While most plant’s seeds contain nutrients that can be used to fuel sprouting, orchid seeds contain only the embryo, no food included. Because of this, orchids must feed on soil fungi to survive. Some species survive for years underground, and only surface to flower and reproduce.

The cryptic, picky nature of these plants makes them particularly difficult to find and even harder to grow, so who’s to know what the future looks like for North American orchids.

Source

Kraker, Dan. 2016. “Their Mission: Save Minnesota’s Rare Orchids Before It’s Too Late”. Mprnews.Org. Accessed November 3 2016. https://www.mprnews.org/story/2016/10/31/saving-minnesota-rare-orchids-mission-smithsonian.

Oh not the Orchids was originally published in Botany Thoughts on Medium, where people are continuing the conversation by highlighting and responding to this story.

Do you live in a place where you experience all four seasons in full force? I certainly do. That’s one of the reasons why Minnesota is a cool place to exist. It is also a difficult place to exist, especially if you’re a tree.

Here in the North Star State, and throughout the midwest, we have a mixture of deciduous and evergreen trees. The deciduous ones, those that drop their leaves, are the ones responsible for the characteristic fall reds and oranges, but how do they do it?

All summer long the trees, more specifically their chloroplasts, were working hard to turn sunlight into energy, but when fall rolls around, the party is over. Because of changes in day length and temperature, chlorophyll breaks down red, orange, yellow and brown take over. The brown color comes from tannins, cellular waste products that are also responsible for the brown color and bitter taste of coffee and tea. The red comes from anthocyanin pigments made from stored glucose in the leaf. It’s not entirely clear why trees put energy into synthesizing red pigments just before they drop their leaves, but some say it may have something to do with cold resistance and frost protection. Other fall colors were in the leaves all along. Yellow xanthophyll and orange carotene become visible only after the chlorophyll disappears.

As fall progresses, the wall of cells that connects a leaf to its branch, the “abscission layer”, begins to harden and block the flow of nutrients to the leaf. Give it enough time and maybe a little wind and the leaf will fall right off.

After the trees drop their leaves and winter arrives, what do they do? Well, like many biological organisms, trees contain a lot of water. When temperatures get really low, they avoid freezing with some pretty sneaky strategies. Some trees convert starch stores into sugars that dissolve in their vascular fluids which lowers the freezing point of the water inside the tree. Some trees acclimate to the cold by allowing their cell membranes to become more pliable which allows water to move out of the cells. The cells shrink to offset the pressure from the extracellular water and it is then less likely that ice crystals will form within cells and rupture them. This might almost seem like magic, but that’s probably just because we can’t see it with our own eyes.

Perhaps a microscope would make us all believers.

Sources

“A Tree Leaf Ages and Drops and Called Senescence and Abscission.” About.com Education. N.p., 23 Sept. 2015. Web. 10 Oct. 2016. <http://forestry.about.com/od/Treebiology/g/Definition-Of-Leaf-Abscission.htm>.

“Autumn Leaves: How Plants Prepare for Winter by Science Made Simple.”Autumn Leaves. N.p., n.d. Web. 10 Oct. 2016. <http://www.sciencemadesimple.com/plants-in-winter.html>.

Communications, SUNY-ESF Office of. “Why Leaves Change Color.” Why Leaves Change Color. N.p., n.d. Web. 10 Oct. 2016. <http://www.esf.edu/pubprog/brochure/leaves/leaves.htm>.

@northwoodlands. “Do Tree Stems Freeze in Winter? | Winter 2009.” Center for Northern Woodlands Education. N.p., 1 Feb. 2010. Web. 10 Oct. 2016. <http://northernwoodlands.org/articles/article/do-tree-stems-freeze-in-winter>.

Seasonal Tree Transition Magic was originally published in Botany Thoughts on Medium, where people are continuing the conversation by highlighting and responding to this story.

Does extended drought spell ‘the end’ for all plant species?

Not necessarily.

Most vascular plants are unable to survive when allowed to desiccate to an air-dried state, that is, when they are allowed to dry to the point at which no more evaporation can occur. Seeds and pollen grains can withstand this level of dryness, but even pollen grains falter in such situations. It seems almost impossible that a full grown plant would be able to survive where a pollen grain could not, but there are in fact plants that do this.

These creatures, aptly termed “resurrection plants”, are able to survive severe water loss and regain full photosynthetic function once water is reintroduced. Resurrection plants can be placed in one of two groups based on their drought tolerance strategies. One group is considered poikilochlorophyllous, meaning that the photosynthetic pigments and photosynthetic machinery within their cells breaks down or is at least somewhat degraded during drought. Other plants are considered homoiochlorophyllous, meaning that they retain the structural integrity of their machinery but there are some slight changes in the pigments. These plants bounce back much more quickly than those whose photosynthetic machinery break down entirely.

You can find resurrection plants in the Southern hemisphere, across Africa and Australia for the most part. They tend to establish themselves in areas where large amounts of rainfall are seasonal and sporadic. Many species of resurrection plant have been identified within the herbaceous angiosperms, or the non-woody flowering plants, but none have yet been discovered among the non-flowering gymnosperms and there are no known resurrection species that are able to grow past shrub size. Some studies suggest that the ability to withstand severe drought is constrained by size since all known resurrection plants do not exceed a certain height.

Source

Bartels, Dorothea. “Desiccation tolerance studied in the resurrection plant Craterostigma plantagineum.” Integrative and Comparative Biology 45.5 (2005): 696–701.

No Water? No Problem. was originally published in Botany Thoughts on Medium, where people are continuing the conversation by highlighting and responding to this story.

What’s tropical and evergreen and smells like a combination of cinnamon, cloves, ginger, and nutmeg?

Allspice! Or Pimenta dioica. You’ve probably heard of allspice before if you’re a seasoned cook (pun intended) or a foodie of any sort.

Allspice is only grown in the Western Hemisphere because it is native to South and Central American rainforest. Not too many of those wild allspice trees are still standing, but you can find some of the best cultivated ones in Jamaica as that is where the climate and soil are best for the trees.

The berries of the tree are used to make allspice spice. Throughout history they’ve been used as an embalming agent, chocolate flavoring, and even for meat curing. That’s an interesting, if not unnerving, combination of uses. The spice wasn’t brought to Europe until the discovery of the New World. Once European explorers discovered the aromatic trees, they tried to bring them home and replant them in spice producing, eastern regions of Europe, but to no avail. Allspice was popular enough, but it had a hard time competing with the pre-established spice dominance of cinnamon and pepper and with the sexy new sugar and coffee imports from the new world that were much more profitable than allspice. Nonetheless, it was quite popular in England and eventually earned the name “English Spice”.

Nowadays we use allspice in jerk meats, pickling, and mulling and it’s frequently added into ice cream, pumpkin pie, and cakes. It’s also used in cosmetics, particularly in men’s toiletries. Hm, what brand was that again…..

Source

“Allspice.” The Epicentre. N.p., n.d. Web. 30 Aug. 2016. <http://theepicentre.com/spice/allspice-2/>.

Ye Old Spice was originally published in Botany Thoughts on Medium, where people are continuing the conversation by highlighting and responding to this story.