The Mysterious and Puzzling World of Plants
1. Almost all life on Earth relies directly or indirectly on primary production which is the synthesis of organic compounds from atmospheric or aqueous carbon dioxide. This mainly occurs through the process of photosynthesis, which uses light as its source of energy. Primary producers in terrestrial ecoregions are mainly higher plants, while in aquatic ecoregions are predominantly algae. It is therefore good to remember that plant productivity was been and is the pre-requisite for all life (animals and people) on earth.
2. Almost all fossil energy in oil, gas, and coal originally comes from plant biomass captured through photosynthesis in ancient times. In the same way in which we burn wood to release energy that the trees capture from the sun, we burn fossil fuels to release the energy that ancient plants captured from the sun. It is therefore good to recognize that plant productivity in ancient times is the pre-requisite for today´s lifestyle: from heating to mobility and synthesis of plastics.
Chief Scientist, Crop efficiency, Gent (Belgium)
3. 90 percent of the human diet is based only on 30 major crops (plants). There are more than 80.000 species of edible plants, of which 70.000 plant species are being utilized for medicinal purposes. A well-known example is Bayer´s famous Aspirin originally extracted from the bark of willow trees.
4. Plants are rather the opposite of individuals: they are dividuals. You can chop off part of their “body” and it easily survives, even the chopped section continues to grow. A feature of plants which allows clonal propagation. Even more fascinating, most plant cells are totipotent, which enables the regeneration of the whole plant from a single cell. This aspect is used in trait research to create transgenic plants. In fact each transgenic plant is derived from a single transformed cell.
5. Due to clonal propagation plants can get very, very old. Pando is a Populus tremuloides (quaking aspen) tree or clonal colony that has been estimated to be 80,000 years old. The above-ground trunks remain connected to each other by a single massive root system. A Great Basin bristlecone pine (Pinus longaeva) is the oldest known living tree in the world. Measured by ring counts it is 5066 years old. Maybe a mammoth scratched his skin with its bark when it was some thousand years old.
6. Although capable of getting so old, trees are actually more dead than alive. An average tree consists of about 99% dead cells. The only living parts are the leaves, the root tips and the phloem1.
7. Even though plants don’t have true nervous systems, they produce electrical impulses to spread signals and react to external stimuli. In most cases, plant biologists still don’t know what those signals are and for what purpose they are being used. The notable exceptions to this mystery are plants that rely on electric signals for rapid movement, like the well-known carnivorous Venus flytrap or Mimosa pudica—a plant whose leaves fold up when brushed, to discourage herbivores.
The picture on the right shows the set up to measure the electrical impulses in Venus flytrap which do occur upon physical stimulation of the sensory hairs located within the trap. If two of such hairs are touched within a timeframe shorter than 20 seconds an action is generated leading to fast closure of the trap.
8. Some plant species do care about their “children,” or seedlings. In fact, they have mechanisms to care for their offsprings. One of them is seed retention, called serotiny. Tree species like pines or Eucalyptus keep their seeds in cones until a fire occurs. Through this mechanism they ensure that their seeds fall on ground fertilized by ash and cleared from any competitors. Serotiny also exists in adverse environments like deserts, where many cacti keep part of their ripe seeds inside their stem for a while. A recent study on a little cactus called Mammillaria hernandezii demonstrated that the retained seeds got “primed” (i.e., well-informed) to adverse conditions and as a consequence have higher fitness and survival rates compared to the seeds which were immediately released.
9. Many mushrooms we collect in forests or meadows are living in symbiosis with higher plants exchanging photosynthezised sugar (from the plant) and nitrogen and micronutrients (from the mushroom). This is why most fungi can be found next to certain trees or bushes. Among some preferred symbiotic partnerships we can mention: Boletus edulis / celp / Steinpilz next to oaks (Eichen), and Cantharellus cibarius /chanterelle/ Pfifferling, next to Pinus sylvestris (Waldkiefer). This well-known principle of beneficial interaction between certain fungi and bacteria with the plant root systems provides the rationale basis for agricultural biologicals, which constitute part of Bayer Crop Science product portfolio (Poncho/VOTIVO in the USA) and Crop Efficiency research portfolio.
10. Genome size does not really matters. Important crops differ massively in their genome size ranging from 390 (rice) to 17.000 Mega base pairs (Mbp)2 in wheat. In comparison, the size of the human genome is 3300 MBp.
1 A tissue in a vascular plant that functions primarily in transporting organic food material (e.g., sucrose) from the photosynthetic organ (leaf to all parts of the plant.
2 A unit consisting of two nucleobases bound to each other by hydrogen bonds. They form the building blocks of the DNA double helix.