Effect of morphactin on stem growth in relation to auxin in precooled rooted tulip bulbs

Effect of morphactin IT 3456, an auxin transport inhibitor, on tulip stem elongation induced by indole-3-acetic acid (IAA) was investigated. Tulip stem growth induced by IAA 0.1 % in lanolin paste applied on the top internode after excision of flower bud and removal of all leaves was greatly inhibited by 0.2 % morphactin IT 3456 applied on the 4th, 3rd, 2nd and 1st internode. The inhibitory effect of the morphactin on tulips stem growth promoted by IAA was restored by additional application of IAA below the morphactin treatment place. Morphactin inhibited also the growth of all internodes induced by flower bud in the absence of leaves. These results suggest a crucial role of auxin in the control growth of all internodes in tulip stem.     

Methyl jasmonate stimulates the formation and the accumulation of anthocyanin in <Emphasis Type="Italic">Kalanchoe blossfeldiana</Emphasis>

Methyl jasmonate (JA-Me) at concentrations of 0.1, 0.5 and 1.0 % (w/w) greatly stimulated anthocyanins accumulation in shoots of young plants of Kalanchoe blossfeldiana when it was applied around the stem as a lanolin paste. Stimulatory effect of JA-Me was evidently observed as early as two days after treatment. Anthocyanins were formed in the main and lateral shoots, including petioles, both below and above portions of the treatment. When leaves were removed from the plant, almost no anthocyanin formation was observed. It should be mentioned that leaves are necessary for the anthocyanin accumulation in stems induced by JA-Me.     

Effects of Methyl Jasmonate on Anthocyanin Accumulation, Ethylene Production, and CO2 Evolution in Uncooled and Cooled Tulip Bulbs

Effects of methyl jasmonate (JA-Me) on anthocyanin accumulation, ethylene production, and CO₂ evolution in uncooled and cooled tulips (Tulipa gesneriana L. cvs. Apeldoorn and Gudoshnik) were studied. JA-Me stimulated anthocyanin accumulation in stems and leaves from uncooled and cooled bulbs of both cultivars. The highest level of anthocyanin accumulation was observed in leaves from cooled bulbs treated with 200 μL/liter JA-Me. In sprouting bulbs treated with 100 μL/liter and higher concentrations of JA-Me, the ethylene production began to increase at 3 days after treatment, being extremely greater in uncooled bulbs than in cooled ones. JA-Me also stimulated CO₂ evolution in both cultivars, depending on its concentrations. CO₂ evolution in sprouting bulbs was not affected by cooling treatment. These results suggest that anthocyanin accumulation by JA-Me in tulip leaves is not related to ethylene production stimulated by JA-Me. Received October 10, 1997; accepted November 17, 1997     

The effect of Aminooxyacetic acid on ethylene production induced by methyl jasmonate in tomatoes

Aminooxyacetic acid (AOA), an inhibitor of ACC biosynthesis, applied together with methyl jasmonate (JA-Me) to mature green and light-green tomatoes cv. Venture greatly inhibited ethylene production stimulated by JA-Me, when analyzed in ripe and overripe stages. AOA applied alone did not affect ethylene production in the same conditions of treatment and analysis. It is suggested that after JA-Me treatment of tomatoes the turnover rate of ACC is higher (JA-Me stimulates EFE activity) in comparison to control tissues, and, consequently, AOA inhibited ethylene production stimulated by methyl jasmonate.