Effects of jasmonic acid, silver nitrate and L-AOPP on the distribution of free and conjugated polyamines in roots and shoots of Solanum tuberosum in vitro.

摘要

Single-leaved potato cuttings were cultured on medium with 50μmol/litre of silver nitrate (inhibitor of ethylene action) or L-alpha-aminooxy-beta-phenylpropionic acid (AOPP, inhibitor of the phenylpropanoid pathway) or 2 or 20μmol jasmonic acid/litre. The silver treatment inhibited tuberization, increased leaf size, elongation and greening of roots and reduced shoot height and hairiness of shoots and roots. Except for tuberization, jasmonic acid induced morphological changes opposite to those ofinhibition of ethylene action. Jasmonic acid-induced shoot and root thickening was due to increased cell division. AOPP promoted shoot and root growth and reduced root hair formation and tuberization. In roots, the profile of free polyamines (PAs) in controls was putrescine (PUT) > spermidine (SPD) > spermine (SPM). PUT accounted for about 90% of conjugated PAs. Jasmonic acid, alone and with the inhibitors, greatly increased conjugated SPD and SPM relative to conjugated PUT: conjugated SPD + SPM rose from about 10% to 50-80%. Silver and/or AOPP had little effect on the relative proportions of conjugated PAs. The relative abundance of free PAs in roots was not influenced fundamentally by jasmonic acid, silver, AOPP or any combination of these. In contrast to roots, SPD dominated the free and SPM the conjugated PAs in shoots. Nevertheless, effects of jasmonic acid and AOPP on conjugated PAs (increase and decrease, respectively, in particular of SPD and SPM) were similar to those in roots. However, silver caused a contrasting response: levels of free PUT increased to make it most abundant. Conjugated SPD and SPM increased up to 10-fold. As AOPP partly counteracted this effect, conjugation is apparently dependent on newly synthesized phenolic acids. Theresults provide a strong indication that both ethylene and phenylalanine ammonia-lyase are involved in the effect of jasmonic acid on PA levels in plant tissues.