EFFECT OF PROPAQUIZAFOP TREATMENT ON PIGMENTS CONTENT AND GROWTH OF SWEET MAIZE SEEDLINGS
Background. We examined the response of sweet maize seedlings (Zea mays var. saccharata L., cv. Złota Karłowa), as a non-target plant, to various doses of propaquizafop ((R)-2-[4-[(6-chloro-2-quinoxalinyl)oxy] phenoxy]-propionic acid 2-[[(1-methylethylidene)amino]oxy]ethyl ester) applied to the root zone or on shoots.
Material and methods. The herbicide at concentrations of 0.56; 5.63 or 56.3 μM was used in a study on seedlings grown in hydroponic cultures in controlled light and temperature conditions. In the experiment the roots of maize seedlings were exposed to propaquizafop for 7 days. Also, seedling shoots were exposed by their immersing for 30 seconds in the investigated propaquizafop concentrations. We assessed the impact of propaquizafop on the seedlings elongation of primary roots and shoots. The content of anthocyanins in epicotyls and photosynthetic pigments (chlorophyll a, chlorophyll b, total carotenoids) in leaves were also measured.
Results. A weaker effect on shoot growth was found when the roots of sweet maize seedlings were exposed to propaquizafop than was the case in the application of the herbicide to shoot. Application of the herbicide to the root zone also had little effect on the levels of chlorophylls and carotenoids, or on the ratios between them, in the leaves. The presumed responsibility for this effect is a weak uptake of the herbicide by the roots and / or its transport to the leaves of the maize seedlings.
Conclusion. Propaquizafop has a smaller effect on sweet maize seedlings when applied to the root zone than it has after foliar exposition. A decline of anthocyanin content under the influence of low doses of propaquizafop suggests that it has a greater effect on the metabolism of phenylpropanoids than other inhibitors of acetyl coenzyme A carboxylase have.