The palm oil tree’s fruit (or the origin of evil)

Mis en avant

To understand where palm oil comes from, here is a little note on plant anatomy.  
Let us begin with the plant itself. This palm tree, called Elaeis guineensis, comes from Africa. It grows in hot and humid zones that are especially found in the tropics. It has an average height of 20 meters (65 feet) and consists of a type of trunk, called stipe, with big, robust, spiny leaves at the end. The male and female flowers are small and cream-coloured. They are produced in big clusters (called inflorescences in scientific jargon) at the base of the leaves and are far from pretty: you really wouldn’t want to add them to a bouquet…

 
 If you look closely at Elaeis guineensis, you will find that the male flowers are separated from the female flowers yet are on the same plant. This is particularly important as both sexes are usually found on the same flower in most plants, or, in some cases, the male flowers, located on a completely different plant, are fully isolated from the female flowers…

Whatever the situation, for all flowering plants, the rest of the story happens more or less like it would for humans, apart from a few details… The Gentleman’s pollen grain will be dropped by the wind or animals onto the Lady’s pistil, and will produce a long rigid tube that will penetrate it (yep…) to reach the ovule and deposit its sperm. Forget the image of a tadpole or of a little moving tail: the sperm here has the aspect of a little sphere. Once this magical fusion has occurred, a little plant embryo will develop. The female flower will then change its appearance…  
Its ovary will grow into a fruit and, inside it, food reserves will be produced to form the nut around the embryo. These stocks will ensure the survival of the little seedling when it germinates, once the fruit frees itself from the parent plant. In the case of the palm oil tree, the seed containing the embryo is white. Each seed is solidly enclosed within a fleshy fruit with a yellow orange colour. And this is exactly what will be collected and ground in order to extract the palm’s fat.
  
The reason why the food industry is so seduced by this little ball of fat is simple: its lipid content (the fat molecules) can reach half of its weight! That makes palm oil the first source of vegetable oil in the world, for all cultures (source: USDA). Translation: Noriane Simon
Lire la suite
Non classé | Mots-clefs :

The cultivated tomato’s clock ticks slower than its ancestor’s

What? Tomatoes have clocks? Despite the fact that it doesn’t have hands, there is indeed a clock within each cell of tomato plants. However surprising this may seem, you can find one in most living beings, including humans! This clock is actually molecular, and usually has a 24 hour rhythm. It is also known under the name of the circadian clock, as circa diem means “nearly a day” in Latin. Just like our familiar mechanical clocks, which give the time in an autonomous fashion, the circadian clock is the guardian of time that enables the synchronisation of internal rhythms, such as the sleep/wake cycle in humans or night/day cycle in plants.

Another phenomenon regulated by the plant clock is leaf oscillation. Leaves actually beat like birds’ wings! But this movement is so slow that it is impossible to see it with the naked eye. This phenomenon is very useful for researchers because it is regular, and so allows them to know how long the circadian clock needs before completing a full cycle.


Researchers have compared leaf oscillation within several varieties of cultivated tomatoes (Solanum lycopersicon) and their wild ancestor (Solanum pimpinellifolium). This ancestor produces small fruit with little flesh, and its domestication first started in South America during the pre-Columbian era. Tomatoes were then dispersed throughout the world as the form we are all familiar with.





Whereas the wild ancestor’s leaves oscillate with roughly a 24-hour rhythm, those of the cultivated varieties are a lot slower. They go up and down with an average period of 27 hours. After looking at what was going on within the plants, researchers proved that the EID1 gene, which plays a known role in the clock mechanism, underwent change in cultivated tomatoes. It’s like if one of the little cogs of a mechanical clock had been modified, thus affecting the time needed for the clock hands to complete a full turn. So, without knowing it, humans have selected for tomato varieties with slower clocks. Although we already knew that artificially modifying circadian rhythms in the lab affects plant size and yield, this is the first time that a molecular change was identified in the clock during the process of plant domestication. Now we just need to figure out what the use of a slower clock in cultivated tomatoes actually is… Reference: Muller et al., Nature Genetics (2015)
Translation: Noriane Simon
Lire la suite
Non classé | Mots-clefs :