Dear Saeid

can you please clarify your question?  By the way I am interested in your works on plant essential oils. Very interesting

best wishes

ravi

some latex has proper characters. for example  Ficus sp. has protease. some Ferula spp. have traditional uses. 

Many species of plants produce latex, as stated In the Wikipedia article on latex, below.  

"Latex is produced by 20,000 species from over 40 families occurring in multiple lineages in both dicotyledonous and monocotyledonous types of plant. It is also found in conifers and pteridophytes. 14% of tropical plant species create latex, as opposed to 6% of temperate plant species.[5] Several members of the fungal kingdom also produce latex upon injury, such as Lactarius deliciosus and other milk-caps. This suggests it is the product of convergent evolution and has been selected for on many separate occasions.[1]"

http://en.m.wikipedia.org/wiki/Latex_(rubber)

The three most common products made from latex are rubber, chewing gum, and opium.  Since all three have been used for millenia by many cultures, they legitimately fall under the definition of "traditional use".  

Thanks, do you know ecological rule of latex?

Dear Saeid

In addition to opium poppy, rubber and chewing gum mentioned by Wise Young, I would like to add Calotropis gigantea/procera  (white and purple flowered types), many of Euphorbia species yield latex that have traditional uses. Some of the Nerium species also yield latex, however the species may be poisonous therefore, have to be handled with care.

The blood red latex of sangre de drago (Croton lechleri) continues to be used in traditional healing in South America. A proanthocyanidin derivative of the latex recently became the first botanical drug (Fulyzaq) allowed for prescription in the U.S. As for an ecological role, when the smooth outer bark is cut, the latex that exudes from the tree serves to seal and protect the wound. In Peru, indigenous peoples use the latex for the same purpose of healing skin wounds.

Latex is a plant defense utilized by 1,000 of plants around the globe.  The Latex has multiple uses for humans, but for the plant they are often known as plant venom.  When exposed to air such as when a snail or insect cuts a leaf....the oxygen level coming in contact with the latex makes the chemical change to become poisonous to the herbivore such as an insect or snail or slug or other animals.  Guayule is one such plant extract latex/rubber used by Aztec's to make rubber bottom sandals, a tea to fight bacteria such as TB.  The history of rubber is a fascinating story.  Ford first used Guayule out of Northern Mexico to make his rubber tires. They later made use of the  Rubber tree in the Amazon.  Once they started mono culture practices growing close together they experienced plant diseases and eventually moved the Rubber Tree plantations to Malaysia.  When the Second World War broke out....Japan had cornered the Rubber Tree plantations and the US had to go back to Gauyule and the Russians used Russian Dandelions for make Rubber Tires and Rubber Tracks (Tanks and Carriers).      

We have done a fantastic M.Sc thesis with my M.Sc special paper students entitled Laticiferous taxa with their economic important with special emphasis on toxicity.