Use of Lilium longiflorum, cv. Ace pollen germination and tube elongation as a bioassay for the hepatocarcinogens, aflatoxins [Trumpet lily]

Although various animal tissues are used for bioassay of aflatoxins ( B1, B2, G1, G2), a rapid bioassay dependent upon a plant part's response does not exist. Both pollen germination (G) and tube elongation (TE) were enhanced in a 3.0 mM KH2PO4(K)-containing but AFB1-lacking, modified Dickinson's medium. The B1did not affect G when K was withheld but K supplementation impaired G above 15 μg/ml B1. Without K, 5-20 stimulated but 25 and 30 μg/ml B1inhibited TE which was suppressed by every B1conc tested in K-containing medium. Addition of NaH2PO4( N) instead of K to medium did not promote G. Slight G stimulation occurred at 16.6μg/ml mixed aflatoxins (MA) in medium lacking either K or N but low G inhibitions were observed with K or N. The MA at 33.3 μg/ml reduced G 2.5% in K's or N's absence and 26 or 17% in their presence. While K did not stimulate TE without MA, N did 26%. At 16.6 and 33.3 μg/ml MA, TE was reduced 19, 6, 19% and 24, 25, 31%, respectively, in control, K- and N- media. Pollen G and TE were markedly sensitive to G1. Significant inhibitions of Zea mays seed G were observed at 5.8 and 11.6 μg/ml B1but not root elongation (RE) from 0.4-11.6 μg/ml. The MA (31.5 μg/ml) administered for 72-240 hr did not influence either Arachis hypogeae seed G or RE. However, imbibing 5 cultivars each of Avena sativa (65-117 hr) and Hordeum vulgare (39-89 hr) inhibited RE 4/15-62%. Thus, except for Z. mays, pollen G and TE appear to be more B1-sensitive than seed G and RE. But, the pollen bioassay is less sensitive than both certain animal bioassays (0.025 μg/ml) and analytical methodologies (10 pg)