Environmental and Experimental Botany 44 2000 49 – 58
Fungicides cytotoxicity expressed in male gametophyte development in Brassica campestris after in vitro application
of converted field doses
Milan Pavlı´k
a,
, Olga M. Jandurova´
b
a
Department of Natural Products, Institute of Organic Chemistry and Biochemistry, Academy of Sciences of Czech Republic, Flemingo6o na´m.
2
, CZ-
16610
Prague
6
, Czech Republic
b
Institute of Animals Production, Pratelst6i
850
, CZ-
10400
Prague
10
, Czech Republic Received 26 March 1999; received in revised form 27 March 2000; accepted 27 March 2000
Abstract
A simple method to determine the toxicity of fungicides on male gametophyte in Brassica campestris subsp. oleiferae is described. The calculation of fungicide concentration used in the test is derived from doses used in field
application. The expression of regression curves and calculation of regression equations require the logarithmic transformation of fungicide concentration. The range of the sensitivity of the method is very wide. The minimal
concentration detected as significantly different from control ranges from 1.7 to 7.0 pg of the active compound. Fungicides declared as non-toxic for plants in field tests were cytotoxic for male gametophyte development. The
synergistic action of more than one active compound resulted in higher toxicity. © 2000 Elsevier Science B.V. All rights reserved.
Keywords
:
Brassica campestris subsp. oleiferae; Carbendazim; Fungicide; Pollen germination; Toxicity; Triazole www.elsevier.comlocateenvexpbot
1. Introduction
In the instructions for the application of pesti- cides we can find the notion of protection time,
e.g. the limitation of fungicide treatment from the point of view of consumption by man or animals.
The recommendation for the treatment is given in relation to the occurrence of pathogens and to
plant development stage, when the treatment is applied. There are no data related to a possible
decrease of fertility due to lower pollen ger- minability. The degree of toxicity, according the
WHO classification Tomlin, 1994, is slightly hazardous for cyproconazole, flutriafol, flusila-
zole, propiconazole and carbendazim. The EPA classification is similar except for carbendazim,
classified
in the
IV degree.
Cyproconazole, flutriafol, and flusilazole have no mutagenic and
teratogenic effect according to the literature Tomlin, 1994. The effect of fungicides on pollen
Corresponding author. fax: + 420-2-24310177. E-mail
addresses
:
mpavlikuochb.cas.cz M.
Pavlı´k, jandurovavuzv.cz O.M. Jandurova´.
S0098-847200 - see front matter © 2000 Elsevier Science B.V. All rights reserved. PII: S 0 0 9 8 - 8 4 7 2 0 0 0 0 0 5 3 - 8
germinability and consequently on fruit-set and yield were investigated mostly on pear, apple,
raspberries Redalen, 1980; Fell et al., 1983; Mar- cucci and Filiti, 1984, as fungicides are frequently
used in orchards during flowering time. The great diversity of published results is partly due to
non-comparable levels of the presented data in vitro, in vivo on stigmas, just after treatment or
ex post by means of fruit crop, respectively. Taking the case of fruit trees as a model, a direct
effect of fungicides on fruit crop was not detected.
The study of fungicides at cellular level showed the influence of triazoles on sterol metabolism due
to inhibition of ergosterol synthesis. The effect is non-specific, in that fungicides inhibit sterol syn-
thesis in host plant as well as in fungus hyphae Fuller et al., 1990; Tomlin, 1994. The accumula-
tion of steroid precursors lanosterol after propi- conazole
treatment led
to cholesterol
and phytosterol inhibition Vanden et al., 1987. Tria-
zole fungicides decreased the activity of peroxi- dase Lebedev et al., 1989, while carbendazim
inhibited aldehyde dehydrogenase Wiegand-Rosi- nus et al., 1988. The quantitative estimation of
the phytotoxic activity of pesticides carbendazim is based on specific enzyme inhibition in photo-
synthetic active leaf discs from cotyledons of Sinapis alba Petzold et al., 1988.
Little information is available as yet concerning the effect of field applications of fungicides on
pollen development,
subsequent germination,
andor leaf morphology in any species. He and Wetzstein 1994 showed for the first time that the
application of some early season fungicides caused degeneration of developing pollen and re-
tarded growth of catkins and leaves.
Many papers have focused on testing xenobi- otics for example fungicides for germination of
pollen grains He et al., 1995. Studying the in vitro germination of pollen treated with fungicides
showed usually a decrease in pollen grain germi- nation, deformation of pollen tubes and their
bursting, but also an increase in pollen germina- tion at very low concentrations of fungicides.
Authors used a great range of concentrations sometimes without relation to actual doses ap-
plied in field. Papers focused on pollen in vitro tests used frequently 1 mg of testing pollen in 1 ml
of medium during experiments Kappler and Kristen, 1987; Strube et al., 1991. Calculation of
doses for tests in vitro from doses using in tests in vivo used results from tests in vitro. Therefore the
aim of this work is to verify calculation of dose of fungicides for tests in vitro from doses using in
field conditions and toxicity of minimum tested doses of fungicides on limited quantity of tested
pollen. The evaluation of ecotoxicity of a given dose is possible when optimal conditions for pol-
len germination of donor plants are known Jan- durova´ and Pavlı´k, 1995. If the presence of
xenobiotic compound is the only stress factor in the experiment, then any significant difference
between control optimal conditions and treat- ment should be explained as a direct reaction to
the stress factor.
2. Material and methods
