Growing Black Chickpeas

I met a fascinating plant on the farm this week - the black chickpea.  I'm accustomed to seeing tan chickpeas in the grocery store, but it turns out that chickpea skins come in the same variety of colors as human skins - light tan through yellow to red, dark brown and black.  Maybe it's because I am reading the Hunger Games trilogy (probably shouldn't have admitted that), but these plants sound like something that would be found in the arena - useful and dangerous at the same time.  You'll have to see if you agree with me - check it out:

Chickpea (Cicer arietinum) flower.

Chickpeas (Cicer arietinum) have miniature pea flowers, with the typical pea's asymmetrical petals.  The flowers each contain a tiny, elongate ovary that will elongate into a pod with seeds once the flower is pollinated.  Each pod contains one to three seeds, many fewer than English peas.  Chickpeas, regular peas and beans are all in the same plant family - the fabulous Fabaceae, or legume family.

Green chickpea pods.

The leaves and youngest green pods of chickpeas can be eaten raw.  The enlarged but green pods can be cooked like regular peas.  The mature pods turn brown and contain dry seeds. These seeds are usually eaten cooked.  The black chick peas do not turn black until they are mature and dry, and they retain their black color even after they are cooked.  Regardless of skin color, all chick peas are the same on the inside - tan. 

Chickpea pods and leaves with acid secretion making the plant glisten.

The really strange thing about chickpeas is that their leaves and pods secrete a liquid that contains a dangerous soup of acids (Katniss would know that!).  When you brush against these plants, they feel moist.  If you have any scratches on your skin, you will notice that the secretion burns painfully.  If you go blackberry picking one day then chickpea harvesting the next, you will be uncomfortable!  I imagine if you picked them all day, you might have some skin erosion.  On large farms, chick peas are harvested by machine, so don't worry too much about fingerless chickpea harvesters.  The acid is very useful to the plant.  If you were a disease organism or an insect looking to eat a garbanzo bean plant, you would definitely change your mind when you were burned by the malic, oxalic and hydrochloric acids on the plant.

Besides deterring pests, the garbanzo bean secretion does another important job.  It works just like sweat and keeps the plant cool!  The plants secrete their sweat later in their lifespan when their seeds are mature, and presumably when the growing season is edging toward summer heat.  The sweat keeps their leaves and pods cooler than non-sweating leaves when the temperature is high.  As what happens when we sweat, the plants lose water.  They are at risk of dehydrating if there is not enough soil moisture for them to absorb.  Also, moist things tend to rot or become infected as a general rule, so the acid is necessary to protect the moist plants from rotting.

Nearly dry chickpea pod.

The acid secretion on chickpea plants is both useful and harmful to people.  It tastes good, since acids taste sour.  In fact, one of chickpea's acids is malic acid, which provides the tartness in apples.  The acid secretion can be collected by draping a thin cloth over the leaves, letting it sit all night until dew forms, then wringing out the cloth.  It can be used to make a unique lemonade-type drink.  The harmful part comes from oxalic acid.  Oxalic acid interferes with the absorption of calcium and some other minerals from food, and it can aggravate kidney stones.  Oxalic acid is also found in spinach, and that's why spinach and chickpea leaves should not be eaten every single day, though moderate consumption is harmless.. 

Black Kabuli chickpea.

Above is a black garbanzo bean (chickpea) freshly picked.

So what's the verdict?  Would chickpeas make a great Hunger Games plant?  Edible but covered in burning acid - perfect!

Salty Language

Chicago is beautiful all dressed up in snow, but after a couple of days, the look becomes pretty dingy.  The snow pushed aside by plows reveals its underside, gross from the street dirt.  The snert (snow + dirt) then melts into brown slush pools that look solid but give way when you step on them.  Dogs also decorate the snow as they are wont to do in our neighborhood.  Then there's the salt grime, white or a rainbow of colors, depending on what variety is used.

A salted bike path by the Navy Pier.

It's remarkable how much salt is applied on this city when it snows or ices.  The streets and sidewalks are quickly covered in the stuff.  It does indeed lower the freezing point of water to about 0 degrees Fahrenheit, enabling the snow and ice to melt and run off the sidewalk, so it's a useful substance when it's not extremely cold.  I can't help but wonder what happens to all that salt as it is washed off the sidewalks and down into the drains or soil. 

Salt has bounced off the sidewalk onto the soil above this tree's roots.

Even though life is thought to have originated in the ocean, where there is plenty of salt, life on land has adapted to a low-salt environment.  Land plants are very vulnerable to excess salt because their cells shrivel and break when exposed to salt water.  Try watering a houseplant with very salty water.  It will die.  If the houseplant is a flimsy, soft one, it will wilt and shrivel in a matter of hours.  The tree in the picture above is going to be very stressed in the spring when rain washes the salt down to its roots.  I imagine the city has to replace many trees and use salt-tolerant varieties as much as possible.  It is not uncommon to see screens erected around street-facing gardens to keep the salt out.

The salt that doesn't seep into the soil washes down into the storm drains.  Some storm drains probably go straight to Lake Michigan, but most go to a sewage treatment plant, thank goodness.  Urban storm runoff contains not just rainwater and salt, but everything that drips off the underside of cars, dog waste, pollution particulates that have settled out of the air, and countless cigarette butts.  It contains more toxic compounds than regular flushed sewage. 

Salt isn't usually removed during sewage treatment, and it is released back into the environment with the cleaned sewage water, usually into a river or lake.  The salt then raises the salinity of the river, increasing mortality for aquatic life.

Road salt is the same chemical as what you sprinkle on your eggs in the morning at breakfast: sodium chloride.  It is a necessary compound, and without any salt we would die.  For us here in North America though, too much salt is usually the problem for humans as well as urban soils and river life.  Salt causes problems in our bodies the same way it does for fish downstream from winter stormwater runoff.  It's essentially a water-balance issue.  Have you noticed how thirsty you get after eating a very high-salt food like Fritos or a cheeseburger or almost any meal at a chain restaurant?  That thirst is a symptom of salt imbalance.  The salt has dehydrated our cells just like it does for plants, and our bodies become thirsty, causing us to drink more water to dilute the salt and unshrivel our cells before they break.  The excess salt and water in our bodies causes swelling and a 1-3 pound increase in body weight (also known as water weight), until our kidneys can filter out the whole mess. 

People who eat a high-salt diet long-term maintain that swelling and high kidney workload for years.  It can, depending on one's genetics and other lifestyle factors, contribute to chronic high blood pressure and eventual strokes or cardiovascular problems.  The tiny capillaries in the body can be degraded from constantly having an elevated amount of fluid in them, which disrupts function in the extremities of the body, the brain, the kidneys, the heart, the eyes, and everywhere else capillaries are essential to body function (which is, really, everywhere).  Fortunately, salt is usually only found in such high quantities in processed food and restaurant food, so if you cook for yourself most of the time and just salt your food at the table, you should be OK.

Very large quantities of salt are toxic in the short term, also known as acutely toxic.  Salt toxicity by oral ingestion has been tested on mice (thankfully not on humans).  A dose of 4g of salt per 1 kg of mouse will kill 50% of mice within one day of ingestion (those numbers are called the LD50, or lethal dose for 50%).  If that number is applicable to humans, let's figure out what it means.  A typical 150 pound person weighs about 68 kg.  4g times 68 kg equals 272 g.  So 272 grams of salt gives a person 50/50 odds of survival.  272 grams is about 15 tablespoons.  Ick.  Hypernatremia (salt toxicity) symptoms of thirst, irritiability, weakness and dizzyness kick in way before coma and death, so the problem can be remedied before it gets too bad.  Hypernatremia in humans is actually more commonly caused by removing water instead of adding salt, and we refer to it as dehydration.

Bacteria and other microbes are killed by excess salt the same way our cells are.  The salt causes their cells to shrivel.  Humans have taken advantage of this trait and used salt to prevent microbes from surviving on some foods and spoiling them.  Beef jerky, for example, is "cured" with lots of salt.  You can demonstrate this phenomenon by taking a piece of beef jerky and a piece of raw steak and leaving both out on the counter in your kitchen for a week.  Be sure to check on them daily to notice any smells or discoloration.  Or flies.

Now back to snow.  Seattle has decided it doesn't want to deal with salt pollution problems, and they handle snow clearing in a different way.  Seattle plows the snow with a rubber-coated plow, leaving some snow in a hard-pack on the streets.  Then they sprinkle sand on top of that.  The surface becomes less slippery, and the sand helps cars grip.  The streets are passable for front-wheel drive vehicles and all-wheel-drive vehicles, but they are tricky for rear-wheel-drive cars, such as the police use (oops).  Even though this solution has a slight logistical cost for getting around in winter, it really cuts down on the costs of environmental damage to Puget Sound.  Salt run-off harms fishing and tourism industries in the sound by reducing aquatic life, and it also slows natural nutrient cycling by killing bacteria, so the sound doesn't stay clean.  Seattle-ites would rather have a clean Puget Sound and drive a little slower in the winter.

Nightshades: Deadly and Delicious

This week on the farm, I harvested tomatoes, specifically orange cherry tomatoes.  We are just tipping over the edge of the top of the tomato waterfall on the farm.  Soon we'll be picking bucket after delicious bucket in a rush to keep up.

The orange cherry tomato fruits look remarkably like the fruits of one of our most poisonous local weeds, the horse nettle.  I can attest, from eating several tomatoes as I harvested, that the cherry tomatoes are delicious and non-toxic.  Here are pictures of both fruits:

Orange Cherry Tomatoes, picture source.

Horse Nettle Berries, picture source.

These two plants are actually close relatives on the evolutionary tree.  They are both in the plant family called the Nightshades, or more scientifically, the Solanaceae.  They don't belong to the same genus, (Lycopersicon esculentum for tomatoes, and Solanum carolinense for the horse nettle), but they have a surprising number of traits in common.  All members of the Solanaceae have flowers with 4-5 petals, alternate leaves, radially symmetrical flowers, and fruits that are technically berries or capsules. Both of our featured plants today have flowers with 5 petals that radiate our like little stars.  Tomato flower petals are usually yellow, whereas horse nettle flowers are light purple, but otherwise the flowers are nearly identical.  They both have fruits that are berries, meaning they are produced from one ovary and have a fleshy interior.  (As you might suspect, the botanical term berry is different than the grocery store term.  Strawberries and raspberries are not berries, watermelons and bananas are.  Don't worry about it.)  Cherry tomato and horse nettle berries are virtually identical inside and out, at least upon visual inspection.  Our two plants also have similar leaves and similar overall growth forms.

Tomato flowers, source.

Horse nettle flowers, source.

These two plants reenact the history of the Solanaceae as it affects humans - the question of whether a nightshade will nourish or kill.  The Solanaceae has no doubt been responsible for many of both outcomes.  It is a major plant family, with many species of major importance to humans.  The list of nourishing nightshades is impressive: tomatoes, garden peppers and hot peppers, potatoes, eggplants, tomatillo and more.  The poisonous nightshades include tobacco, potato (the greed parts), Jimson weed, belladonna (also called deadly nightshade), and mandrake. 

Considerable prejudice against the Solanaceae built up in Europe, as most native nightshades are highly toxic.  Our edible nightshades originated mostly in the New World.  As tempting as it is to think of tomatoes as Italian and potatoes as Irish, these plants were imports to Europe after they were 'discovered' by European explorers.  At first, Europeans were hesitant to eat the imported nightshades, but soon they incorporated them seamlessly into their cuisine.  Remnants of nightshade phobia exist today, with some people avoiding them altogether.  It is possible to be allergic to nightshades, which makes navigation of modern American cuisine very difficult - no French fries, no tomatoes, no hot sauce!

Toxic nightshades have a rainbow of alkaloids.  Mandrakes and Jimson weed are grimly hallucinogenic in smaller doses and toxic in larger doses.  Tobacco is addictive and stimulant, and the number one killer in the United States.  Belladonna is likely the most acutely toxic plant of the Western Hemisphere, with only a few of the sweet-tasting berries necessary to kill a person.  It has been used to make poison-tipped arrows.  The alkaloids in these poisonous plants can be useful to medicine.  For example, atropine, discovered in belladonna, is used to make the substance that dilates eyes in eye exams, to speed up the heart, and to counteract some pesticide poisonings.