Marian Saniewski

Auxin control of tulip stalk elongation in vitro

Abstract Stalk explants isolated from uncolled and cooled tulip bulbs cultivar ‘Oxford’ were cultured on Murashige—Skoog medium supplemented with 10 mg l−1 IAA. Explants were cultured in normal (basal end down) or inverted (basal end up) positions. Distinct stalk growth of explants isolated from uncooled and cooled bulbs was observed when they were cultured in the inverted position, in the presence of IAA in the medium. In other cases, elongation of stalk explants was slight. Thus, only basipetal transport of LAA is responsible for the induction of tulip stalk growth.

BIOLOGICAL ACTIVITY OF GUMS INDUCED IN TULIP (TULIPA GESNERIANA L.) BY FUSARIUM OXYSPORUM F. SP. TULIPAE, ETHYLENE AND JASMONATES

It is well known that Fusarium oxysporum f. sp. tulipae (Fot), ethylene and jasmonates have a promoting effect on gum induction and its accumulation in tulip (Tulipa gesneriana L.) bulbs. The induction and production of gums are suggested to be regulated by a signal network of jasmonates and ethylene, especially by cross-talk between them. Tulip gums consist of glucuronoarabinoxylan with an average molecular weight of approximately 700 kDa. In this review some biological activity of tulip gums is presented. It is believed that gums have a function in limiting the spread of fungal and bacterial pathogens and insects by isolating the infected tissues. It was found that the addition of tulip gums at a concentration of 5 mg•cm3 to Czapek-Dox-Agar, Malt-Extract-Agar and Potato-Dextrose-Agar greatly stimulated mycelium growth of Fusarium oxysporum f. sp. tulipae and sporulation of the pathogen. Addition of tulip gums to the Czapek-Dox-Broth caused that the pathogen secreted the polysaccharide gum degrading enzymes. In further studies it was found that tulip gums induced by Fusarium oxysporum f. sp. tulipae, ethylene or jasmonates elicited red coloured secondary metabolite(s) in mycelium of the pathogen. The effect of homogenate of different tulip organs (scales, leaves, stem, pistils and roots), applied alone and simultaneously with tulip gums, on red pigment formation by mycelium of F. oxysporum f. sp. tulipae was investigated. It is interesting that a homogenate of tulip scales and pistils almost totally inhibited the formation of the red coloured pigment induced by tulip gums in the mycelium of Fot. It is possible that the polysaccharide of tulip gums, which is glucuronoarabinoxylan, may act as an elicitor that regulates some physiological and biochemical processes connected or responsible for mycelium growth of the Fusarium oxysporum f. sp. tulipae and induction of secondary metabolites by mycelium of the pathogen.

The effect of methyi jasmonate on ethylene production, ACC oxidase activity and carbon dioxide evolution in the yellowish-tangerine tomato fruits (Lycopersicon esculentum Mill.)

The yellowish-tangerine tomato (cv. Bursztyn) in the green, light yellow and yellow stages of ripening were treated with 0.1% and 1.0% of methyl jasmonate (JA-Me) in lanolin paste and kept for several days and then they were evaluated for production of ethylene, ACC oxidase activity and CO 2 evolution. Production of endogenous ethylene in mature green fruits was low and increased during ripening. JA-Me stimulated ethylene production and ACC oxidase activity in all investigated stages of fruit ripening. Slices excised from mature green fruits produced highest amount of carbon dioxide as compared to more advanced stages of ripening. JA-Me in O,1 % and 1,0% concentrations increased significantly CO 2 evolution in green fruits, while in light yellow and yellow fruits only higher concentration of JA-Me stimulated carbon dioxide production.

Flavonoids in white and yellow perianths and yellow anthers of tulips (Tulipa gesneriana L.)

The content of flavonoids in white and yellow perianths and yellow anthers of a few tulip cultivars were determined at the stage of full flowering. To analyses of flavonols a HPLC method was used. In anthers (yellow) of all analyzed cultivars (Oscar, Pax, Profesor Woycicki, Biala Dama, White Virgin, Calypso, Diana) high content of quercetin (2,35 - 6,01 mg·g -1 F.W.), kaempferol (1,09 - 9,47 mg·g -1 F.W.) and apigenin (1,34 - 8,24 mg·g -1 F.W.) was found. In analyzed white perianth of cvs. Oscar and White Virgin also high content of quercetin (1,3 - 1,80 mg·g -1 F.W.) and kaempferol (1,90 mg·g -1 F.W.) was documented and only traces of apigenin was found. In the yellow perianth of cv. Profesor Woycicki the level of quercetin and kaempferol was much lower than in perianth of cvs. Oscar and White Virgin, and apigenin was absent. Thus, yellow anthers and white and yellow perianth of tulip cultivars are a rich source of flavonols.

Fatty acid and sterol contents during methyl jasmonate-induced leaf abscission in Kalanchoe blossfeldiana

It was found previously that methyl jasmonate (JA-Me) induced leaf abscission in Kalanchoe blossfeldiana . In present studies it was showed that JA-Me did not affect or only slightly affected the content of free and bound fatty acids in petioles and blades. s-Sitosterol, campesterol and s-amyrin were identified in petioles and blades of K. blossfeldiana ; JA-Me decreased the content of campesterol in petioles and increased the content of s-sitosterol in blades. In blades of plants treated with JA-Me disappearance of olean-12-one was indicated but appearance of 2H-cyclopropa[a]-naphthalen-2-one,l, la, 4, 5, 6, 7, 7a, 7b-octahydro-l, 1, 7, 7a-tetramethyl (aristolone) was documented. The significance of these findings in leaf abscission induced by methyl jasmonate in K. blossfeldiana is discussed.