[34]

Investigation of 4, 4, 4 Trifluoro-3-(indole-3-) butyric Acid Transport in Primary Roots of  Zea mays cv. Merit. G. Ku and K.H. Hasenstein, Biology Department, University of Louisiana at Lafayette 70504-2451

   4, 4, 4 Trifluoro-3-(indole-3-) butyric acid (TFIBA) is a newly synthesized plant regulator that enhances root elongation. Growth measurements on Zea mays cv. Merit showed 20 % increase in root length when roots were incubated with 100 мM TFIBA. With this experiment, we tried to elucidate if TFIBA is transported acropetally and/or basipetally and therefore may interfere with auxin transport.  Apical 5 mm segments of 2 d old primary corn roots were excised and sandwiched between an agar donor (1.5 mm3) and receiver block (1.5x5x20 mm3).  Donors containing 10, 50, 100 M TFIBA or none were applied to the cut surface or tip of the excised portion of the root tip.  After 2 and 4 hours of transport, the receiver, donor and tissue fractions were analyzed by gas chromatography and mass spectroscopy. Identification and quantification of acropetal TFIBA transport in the tissue showed that after 2 h ca. 40 % TFIBA is taken up by the roots. After 4 h, the tissue contained ca. 60 % of the initial TFIBA concentration applied to the donors. Basipetal transport resulted in only ca. 15 % of TFIBA in the tissue after 4 h. TFIBA could not be detected in receivers, which indicates that it is not transported. However, TFIBA may be metabolized within the tissue. Further research will investigate the metabolism of TFIBA and the occurrence of possible byproducts.

Supported by NASA (NAG10-0190)