sodininkystė ir daržininkystė 25(4)

SODININKYSTË IR DARÞININKYSTË. SCIENTIFIC ARTICLES. 2006. 25(4).
DYNAMICS AND ROLE OF PHYTOHORMONES IN
COMMON CARAWAY AFTER FLOWERING INDUCTION
G. Samuolienë, P. Duchovskis
Summary
This study was aimed on investigation of phytohormones dynamic and role in
common caraway (Carum carvi L.) during different flowering initiation stages. The
process of common caraway flowering initiation and morphogenesis was studied in
a phytotron facility. Different level of development is needed for photo- and thermoinduction
of caraway. 9 leaves in rosette are needed to complete the juvenile
period. High-performance liquid chromatography (HPLC) with diode array detection
was used for separation and determination of gibberellic, indol-3-acetic and abscisic
acids, and zeatin. Conditions of photo and thermoperiod during flowering induction:
EXP2 – 8 hr and 4°C, EXP3 – 16 hr and 4°C, EXP4 – 8 hr and 21/16°C, EXP5 –
16 hr and 21/16°C.
Our results showed that under dark treatment both in caraway with 7 and 9
leaves in rosette did not develop at all and rotted away. The best floral development
was observed when plants were treated under low positive temperature and long day
photoperiod (EXP3). Under these conditions the GA3/IAA ratio during evocation
stages I and II was high, but it decreased twice after flower initiation. During evocation
stage II zeatin/IAA ratio was equal to 0. This could mean that the apical dominance
disappeared. Under treatment with long day photoperiod and high temperature
(EXP5) this ratio did not increase even during flower initiation. Otherwise during
this moment an antagonistic interaction between ABA and IAA occurs. This phytohormones
action could influence slower developmental processes of common caraway.
In summary, for development of common caraway thermoinduction is more
important than influence of photoinduction. The best generative development was
noticed when plants were treated under low temperature and long day photoperiod.
For common caraway floral development thermoinduction processes are more important
than photoinduction. The stabile decrease of all phytohormones synthesis till
flower differentiation and the best floral development is determined by low positive
temperatures and long day photoperiod.
Key words: caraway, evocation, flowering initiation, phytohormones.
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