Saturday, April 28, 2012

Hula skirts

Cordyline fruiticosa (Cabbage Palm)
The leaves of the Cabbage Palm (known as La'i in Hawaiian and Lauti in Samoan) are used to make Hawaiian hula skirts and the Tongan sisi dance dress. In Hawaiian lore, the plant has great spiritual power and even today is considered a good luck charm.  The leaves are so strong that they can sewn together and ridden in lava sledding (a traditional Hawaiian sport that's a cross between surfing and snow sledding)!

The strength of the leaves comes from the cellulose fibers, which are found in all leaves, but are especially thick in cabbage palm leaves. Chemically, cellulose, one of nature's strongest natural materials, is very similar to starch, one of the stickiest. Both are made of the sugar glucose, but with a slight difference. In starch the the glucose is arranged such that there's room for lots of water to surround it, which leads to its sticky nature. In cellulose the glucose is arranged such that long strings of the sugar bind to each other and exclude all water. This leads to a compact, highly stable, and very strong structure that per weight, is stronger than steel.

Tuesday, April 24, 2012

The giant misshapen phallus flower

Fractal Broccoli
Amorphophallus titanum
Amorphophallus titanum, which loosely translates as "the giant misshapen phallus", produces the world's largest flower. The flower can be over 10 feet tall at its apex. Both in its native Sumatra, and under cultivation in botanical gardens world wide, the Amorphophallus flowers only rarely, which might be good since this huge bloom also gives off a huge smell. Its odor is similar to that of a decomposing animal, which attracts the insects that help in its pollination.

Sunday, April 22, 2012

Methuselah, the 2000 year old date

The Methuselah date palm, 2012
Kibbutz Keturah, Israel
The date palm has been a source of food, medicine, shelter and shade for thousands of years. While the exact date trees grown in the bibical period are long extinct, in 2005, a 2000-year-old date seed recovered from Masada in the Judean dessert was successfully germinated. Genetic analyses have shown that this tree is distinct from all known date palms, and scientists want to see if the ancient tree has any unique medicinal properties no longer found in today's date palm varieties.

Unfortunately, Methuselah, true to its name, appears to be male, so we won't get any ancient fruit. Date palms are dioecious, meaning that there are separate male trees which make pollen, and female trees which make ovules which lead to fruit and seeds after fertilization with pollen from the male. But through careful genetic breeding, Methuselah can be used to pollinate modern species, and some of these offspring will be female. These hybrids can then be recrossed with Methuselah's pollen, to yield a new generation that's mainly the ancient date.

Wednesday, April 18, 2012

The danger in monoculture spuds

Solanum tuberosum 001
Solanum tuberosum (potato)
Potatoes were first cultivated almost 10,000 years ago in the Peruvian Andes. The Spanish introduced the potato to Europe in the 15th century, and by 1845, 1/3 of the fields in Ireland were planted with a single strain of potatoes. That same year the crops were devastated by potato blight, a disease caused by a pathogenic fungus. By 1855, Ireland's population shrunk by 25% with 2,000,000 people dying of hunger or emigrating.

This disaster highlighted the danger of using only a very small number of different crop varieties (monoculture). Blight never devastated South America where hundreds of potato varieties are grown, with each variety being both resistant to (and sensitive to) different strains of pathogens.

Reliance on single strains of crops is a danger in modern times also. Educated uses of genes from wild strains is essential for ensuring food security. For example, research funded by the Gates Foundation is looking to utilize genes from wild wheat to combat rust, a fungal disease that's devastating cultivated wheat crops in Africa.

Sunday, April 15, 2012

Food for silk

Morus alba fruits
Morus alba (Mulberry)
The mulberry tree produces a tasty berry, but not because of this did the mulberry tree change history. Leaves of the mulberry tree are the sole food of the silkworm. 1400 silkworms eat 50 pounds of mulberry leaves to make just one pound of silk. The Chinese closely guarded the secret of silk production and so had a monopoly in supplying the great demand for silk by the Egyptians, Romans, Persians and other cultures. Trade of silk, and other wares, along the Silk Road from China through the Middle East and to Europe helped lay the foundations for the modern world.

Tuesday, April 10, 2012

Living flypaper

File:Pinguicula ne1.JPG
Pinguicula gigantea (Flypaper plant)

The flypaper plant, a native of Mexico, is literally like a living flypaper. Its leaves excrete a sticky compound which traps and immobilizes small insects. Once trapped by this carnivorous plant, the unfortunate insects are digested and absorbed by the leaves, providing the plant with needed nutrition.

Friday, April 6, 2012

Is Marijuana Kosher for Passover?

In the spirit of the Passover Holiday, I couldn't resist commenting on this. High Times, which since 1974 has been spreading the gospel of legalizing pot, has run an article asking the obvious question, can a person get high on Passover and still be religious?

This may not be as absurd as it seems, as the question on what is kosher for Passover, and what isn't, is taken very seriously in some circles, and can even lead to familial conflict. For example, when I was a kid, rice was verboten as it is for all Ashkenazi Jews. This is NOT because rice is a leavened product. Indeed the Talmud clearly states that rice should be eaten at seder to commemorate sacrifices at the temple. But a few hundred years ago European rabbi's decided that rice COULD be contaminated with wheat, and this should not be eaten during Passover. This prohibition was expanded to include other grains and legumes. The overall effect on the Ashkenazi digestive system is best left not discussed. Sephardi Jews though never adopted this extreme position, and as such their seders contain rice and a variety of foods I could only dream about. So i was totally shocked to find out that my wife's family eats rice on passover! not that Shira is Sepphardic, but her family had years ago adopted the customs of one of the uncles by marriage. It didn't take long until I also became a convert.

Which then leads us to the question of marijuana. Now under no condition should this be construe as a call for illegal activity! But IF one were to partake in any illegal activity, is it still kosher (for Passover that is)?

The article concludes that marijuana would fall under the classification of legumes, which means that, as always, the Sephardim get to have all the fun.

Wednesday, April 4, 2012

And the people of Israel called the bread "manna"

The Book of Exodus gives several descriptions of the food provided by God for the Jews as they meandered through the dessert. Manna is described as fine,white flakes that melt in the sun, and taste like wafers made with honey. Like all fresh food, manna came with a "best used by..." date, which in this case was "best used by tomorrow". If collected and stored, manna became infested with worms and rotted (yech!).

So can we define the botanical basis of manna? This is a slippery slope where scientists try to merge their craft with religion, but this hasn't deterred a number of hypotheses. Manna has been claimed to have come from tamarisk trees, which excrete a sweet, melt-able resin; insect honeydoo (bug poo in other words) which is actually edible; lichens, mushrooms or even locusts.

Regardless of what it was, manna was not a food of choice. Back in Egypt, the Children of Israel would not had subsisted on bug poo or lichens. But as they were obviously suffering from problems of food security, God provided the Israelites with daily rations of manna. The manna provided basic subsistence, but not much variety. Manna could be compared to corn meal provided by the USA to Africa - its not the food that they'd choose, but given the alternatives, it did provide nutrition!

Happy Passover!

Sunday, April 1, 2012

Screaming plants mean no more fairways?


Scientists have discovered that grass blades scream when cut with a lawnmower.

Well scream may be a bit of an exaggeration, at least by human standards. While human ears can only hear sounds up to about 16,000 Hz, scientists have now measured vocalizations of 85,326 Hz emanating from grass blades cut by a power lawn mower. Admittedly, these sounds are at very low levels, 3.1415 x 10-9 decibels, which is probably why they had not been detected earlier.

The first reports of plant communication began to surface close to 40 years ago (see New York Times editorial, "When Trees Talk"), but until now, phyto-communication was limited to volatile chemical and the sense of smell.

Cross-section through a grass leaf. The dermal cells are found
on the top and bottom, the phloem in the bottom part of the
vascular bundles, the xylem in the upper part of the vascular
bundles, and the paranchymal tissues fill in most of the space
between the upper and lower epidermis.  
Now, using a highly advanced nano-level sound detector, scientists at Whoville University recorded the screams coming from the grass immediately as the lawnmower's blades cut specifically through the phloem and dermal cells of the leaf, but not when the xylem or paranchymal cells were disrupted. Prof. Horton, who headed the research program, hypothesizes that these "screams" imply that humans have inflicted immeasurable suffering on grass, and likely also other plant species. This has led him to form a new NGO called Scientists for the Ethical Treatment of Grass, which is working for a ban of all lawn mowers. When asked how this would affect his golf game, Prof. Horton replied that in any event, he usually plays out of the rough.

Example of experimental setup. The nano-level sound detector
was embedded within the blades to allow simultaneous
detection of any noise emission as the blades were cut.  
Horton's current research is in developing a smaller version of his sound detector which can be embedded within a tooth cap so as to record any similar screams from fresh vegetables as they are macerated in the mouth.

In all fairness it should be noted that these results have been contested by Prof. Wickersham from Nool University. Wickersham and his colleague Kang Aroo claim that such faint vocalizations are theoretically impossible, and that the work from Who U. is just a figment of the researchers' imaginations. When asked for a comment, Prof. Horton said, "A sound is a sound no matter how small".

For more information on plant communication, be sure to get your copy of WHAT A PLANT KNOWS.