This finding, carried by the latest issue of the Japanese journal, Plant Cell Physiology, will enable the design of experiments aimed at enhancing vegetable species in the interest of humanity.

Researchers at the Institute have shown that, in the presence of saccharose (a substance produced in leaves to be subsequently distributed around the plant), the cells of the reserve organs - such as roots, tubers, seeds or fruits - "swallow up" nutrients in order to metabolise and store them. These "swallowed-up" substances are incorporated into micro-vesicles that end up pouring their contents into an internal compartment of a vegetable cell known as the vacuola. Once inside the vacuola, the substances or nutrients are broken up, stored and metabolised.

Two processes of captation

This discovery breaks with a fundamental dogma in basic plant science holding that all substances penetrate the interior of the cell through the participation of specific transporters present in the plasma membranes - a model implying that, if hundreds of substances enter vegetable cells and each substance has its specific transporter, or even if one transporter can recognise 3 or 4 different substances, an infinity of such transporters would be required.

The conclusion of this research is that, while not discarding the existence of specific transporters in plasma membranes, their number and relevance is considerably inferior to what has been believed to date. In the absence of saccharose, nutrients can penetrate the cell by means of transporters, but the amount entering through this mechanism is less than that incorporated via endocitosis.

Thus, the experiments carried out showed the existence of processes independent of nutrient captation: a saccharose penetration process independent of "endocitosis" and another d
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Contact: Garazi Andonegi
garazi@elhuyar.com
34-943-363-040
Elhuyar Fundazioa
6-May-2005