Editor’s Comment – The importance of green plants

BEN Aldiss has drawn attention to what must be an issue that is common in so-called developed countries.

It is likely to be more prevalent in island communities, such as that of the UK, in which the countryside is particularly benign. Our most poisonous snake is the adder, and one person recently was bitten by a fox in her home –it made the news!

As the world population rises an increasing proportion of the population and families will live in tower blocks, or apartments, where the nearest “wild life” will be a canary or a window box.

However, with increasing travel and climate change exotic diseases will be more common. Parents in the UK need to inculcate their children with a fascination for wild life, but also to be aware of the current risks of Lyme disease, malaria, Weil’s disease etc.

In a majority of today’s families first the parents, themselves, need to learn.- perhaps even more importantly that milk doesn’t originate in bottles, but in a cow’s udder and that will depend on rain and green grass. It is of increasing importance that children understand the importance of wild life and in particular of plant life.

Ultimately Mankind depends for its very existence on plant life – which, in turn, depends on photosynthesis  a process by which chlorophyll in “green” plants, most algae, and cyanobacteria  convert lightenergy into carbohydratefrom carbon dioxide and water. In most cases, oxygen is released as a waste product.

Without this process our atmosphere would be depleted of oxygen and the carbon dioxide content would be extremely high. Photosynthesis is largely responsible for producing and maintaining the oxygen content of the Earth's atmosphere, and supplies all of the organic compounds and most of the energy necessary for life on Earth(Solar panels, hydro-electric and nuclear power etc. decrease this dependence).

Whereas CO₂ is abundant, fresh water, the other component required for photosynthesis is not always available. Moreover, in the absence of chlorophyll the temperature of the Earth would be extremely high- too high for higher life!

There are now known to be two processes by which photosynthesis is carried out-these are C3 and C4. The C4 mechanism was first discovered in maize and found In tropical grasses, including maize, sorghum, sugarcane and Bermuda grass. This process is more efficient than the C3, especially in hot climates.

As world temperature rises and also to accommodate the expected needs of the world’s growing population large sums are being spent in an effort to modify rice from its current C3 to C4 – some doubt this modification will be possible!

Today, the average rate of energy capture by photosynthesis globally is approximately 130 terawatts^1,2, which is about three times the current power consumption of human civilization³. Photosynthetic organisms also convert around 100–115 thousand million tonnes of carbon into biomass per year^4,5. Without this process we would have no oxygen to breath. Moreover, without photosynthesis there would be no discernible life on earth- either plant or animal.

Children (and adults) should admire green plants in wonder and thank them for enabling humans to exist.

References

1. Nealson K.H. & Conrad P.G. (1999). "Life: past, present and future". Philos. Trans. R. Soc. Lond. B, Biol. Sci. 354 (1392): 1923–39. doi:10.1098/rstb.1999.0532. PMC 1692713. PMID 10670014.

2. Steger U.; et al. (2005). Sustainable development and innovation in the energy sector. Berlin: Springer. p. 32. ISBN 3-540-23103-X. The average global rate of photosynthesis is 130 TW (1 TW = 1 terawatt = 1012 watt).

3. "World consumption of primary energy by energy type and selected country groups, 1980–2004" (XLS). Energy Information Administration. 2006. Retrieved 2007-01-20.

4. Field C.B. et al (1998). "Primary production of the biosphere: integrating terrestrial and oceanic components". Science 281 (5374): 237–40. doi:10.1126/science.281.5374.237. PMID 9657713.

5. "Photosynthesis". McGraw-Hill Encyclopedia of Science & Technology. 13. New York: McGraw-Hill. 2007. ISBN 0-07-144143-3.