Near the Columbian border is the Rio Canande Reserve, a lowland rain forest where more than 

 6m of rain falls per year and where the average temperature is 25-30C. This area lies within a 

 region where timber extraction is active. This reserve was formed originally to protect the Great 

 Green Macaw but like the other reserves the list of wildlife species is long, varied and includes 

 many endemic and threatened species. Staff at the reserve have had workshops to help and train 

 local community members in forest conservation management. 



The habitat loss globally for tropical rain forests is more than 10 million hectares per year. The 

 remaining forest has large areas of degraded land. Ronton gave the example of the Brazilian Rain 

 Forest which today has only 7% of the area that was found there in 1900. Reasons for the loss of 

 this territory are the conversion to pasture by local populations, selective logging locally done, 

 large-scale logging which also requires the transport infrastructure to be built into remaining areas, 

 and lowland and large-scale agriculture, currently fuelled by the demand for soya and biofuels. 

 Institutional or government action to control emissions through setting a market value for standing 

 forests, water resources and biodiversity would help in protecting these areas. The biggest single 

 effect would be as a result of adoption of the Kyoto Agreement. At present not one of these is 

 forthcoming. - 



More information on the World Land Trust and the reserves can be found at: 

 http://www.worldlandtrust.org/ 



7 Febryary - Presidential Address - Photosynthesis 

 Professor Chris Bucke 



The speaker used simple Power Point slides and analogue materials to illustrate the talk. The latter 

 included some plants, a safety match, bubble solution and a plastic box full of green hosepipe. He 

 began by describing the importance of biological membranes and listed materials that plants need 

 from the environment to complete the complex series of processes by which carbon dioxide is 

 "fixed", first into chemical compounds with 3 carbon atoms, eventually into glucose, with 6 carbon 

 atoms. To achieve this, the newly fixed carbon compounds have to be "reduced" chemically which 

 means adding hydrogen atoms to them via the compound NADPH (Nicotinamide adenine 

 dinucleotide phosphate). This process requires large amounts of energy in the form of ATP 

 (Adenosine triphosphate). To produce NADPH and ATP, quantities of positively charged hydrogen 

 ions (protons) and negatively charged electrons have to be released from water molecules and, 

 initially, kept separate from each other. Solar energy activates chlorophyll located in two "photosys- 

 tems" in the chloroplast: the first removes electrons from a complex enzyme containing 

 manganese ions that binds them as soon as they are released from the water and boosts their 

 energy level. They then pass through a series of chemicals, first cytochromes, then quinones, then 

 plastocyanin to the second photosystem where they are given another boost of energy and pass 

 through a compound called ferredoxin which passes them to NADP which gains a negative charge 

 which is neutralised by a hydrogen ion. All the electron-carrying materials are located in the very 

 complex membranes of "thylakoids": passage of electrons through the quinones carries hydrogen 

 ions from the outside of the thylakoid membrane to the inside. ATP is made from ADP (Adenosine 

 diphosphate) and phosphate, using the energy released as the hydrogen ions pass out of the 

 thylakoids. Much more ATP is needed than NADPH, hence the need for two photosystems: when 

 no more NADPH is needed the activated electrons are passed back to the quinone pool, allowing 

 more ATP to be made. 



Finally, the speaker pointed out that plants have to deal with circumstances where there is too 

 much energy and not enough water and/or carbon dioxide. Then the wasteful process "photores- 

 piration" occurs, the key enzyme RUBISCO (Ribulose-1 ,5-bisphosphate carboxylase oxygenase) 

 "fixing " oxygen instead of carbon dioxide. He described strategies that some plants use to store 

 carbon dioxide and carry on making new sugar in circumstances where the water supply has run 

 low. They incorporate carbon dioxide into malic acid and hence are named "C-4" plants. 



The talk was followed by quite spirited discussion. 



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