Ros Gleadow’s presentation with the tittle “A multiscale analysis of resource allocation in cyanogenic plants in response to drought and elevated CO2” probably one the most interesting topic presented in APGC seminar this time. I think many participants agree with this as also mentioned by Malcolm J. Hawkesford in the final discussion. Gleadow started her presentation with the fact that cyanogenesis, a phenomenon where organism contains toxic HCN that can poison and kill predator who eat them or parts of their body, is a widespread phenomena, can be found from bacteria, insects to higher plants.
In their work, Gleadow et al. compared cyanogenic crops white clover (Trifolium repens), wheat (Sorghum bicolour) (or bicolor ?), and cassava (Manihot esculenta) with cyanogenic and non-cyanogenic Eucalyptus. Gleadow et al. found that in elevated CO2 -grownC3 crop plants there was a significant increase in the concentration of cyanogenic glycosides on a per mass basis in the leaves. From her presentation I noted that cyanide in leaves increased in highest emision scenario. Although there was no change in cyanogenic glycoside in cassava’s tubers, it was surpising when they found that there was a highly decrease in biomass in cassava.
According to Gleadow, cassava is a staple food for more than 750 million people in the world, especially those who live in sub-sahara desert of Africa. There has been Konzo epidemic in the area due to this HCN contained in cassaava, which paralyzed childrens. The increased of HCN concentration in the leaves of cassava when exposed to elevated CO2 is alarming to many Indonesians who like to eat cassava leaves for salad (lalab), especially the sundanese and padang tribes. We also have to prepare when the size of cassava tubers in the future will be much smaller and much lighter in weight than today’s cassava due to the increase of CO2 emission to the atmosphere.