SUCROSE AND JASMONIC ACID INTERACT IN PHOTOSYNTHETIC PIGMENT METABOLISM AND DEVELOPMENT OF POTATO (SOLANUM-TUBEROSUM L. CV SANTE) GROWN IN-VITRO

Potato (Solanum tuberosum L., cv. Sante) plantlets grown from stem nod e culture on medium supplemented with 90 mM sucrose accumulated lower amounts of photosynthetic pigments per mg dry weight in comparison to those grown on 30 mM sucrose. Addition of 0.1, 1 or 10 mu M jasmonic a cid (JA) to the medium resulted in a decrease of chlorophylls and caro tenoids in the plantlets grown on either sucrose concentration. JA tre atment induced de-epoxidation of violaxanthin to antheraxanthin and ze axanthin only in those plantlets grown on a higher amount of sucrose i n which hyperhydric symptoms were observed. The synergistic effect of JA and sucrose was clearly demonstrated in the plantlets grown on 90 m M sucrose and 1 mu M JA. This was possibly due to overaccumulation of sucrose, the consequence of the most developed root system, and/or to stimulated water and solute transport by other mechanisms.