Effect of Temperature on Phytotoxicity and Root Uptake of Several Herbicides

Abstract

The phytotoxicity of 3-(3,4-dichlorophenyl)-1-methoxy-1-methylurea (linuron) to corn (Zea maysL.) and soybean (Glycine max(L.) Merr.) seedlings and 2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine (atrazine) to soybean seedlings increased with increasing temperature from 20 to 30 C. The phytotoxicity of α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine (trifluralin) did not change significantly between 20 and 30 C. Corn and soybean plants grown at 30 C translocated more14C from14C-atrazine and soybeans more14C from14C-linuron to the shoots during the 4-hr root uptake treatment period than plants grown at 20 C. There was less accumulation of14C from14C-atrazine in soybean roots and14C-linuron and14C-trifluralin in the roots of corn and soybean plants grown at 30 C compared to those grown at 20 C. Comparison of data at 30 C and 20 C during the 4-hr root uptake treatment period showed enhanced root to shoot movement of14C from14C-atrazine in corn and from14C-linuron in soybean at the higher uptake treatment temperature indicating a possible relationship between increased herbicide transport to the shoot at high temperature and increased phytotoxicity.

Variable tolerance of some crop species to atrazine in various soils

“…Differences in the tolerance of plant species to atrazine have been ascribed to variation in the rates of absorption and translocation of the herbicide (Vostral, Buchholtz & Kust, 1970), dissimilarity in metabolic degradation rates (Penner, 1971), and discrepancies in the ability of atrazine molecules to inhibit photosynthetic electron transport (Fuerst & Norman, 1991).…”

Physiological effects of temperature on turfgrass tolerance to amicarbazone

“…Merr.) roots increased as temperature increased from 20 to 25 °C . Similarly, oat ( Avena sativa L.) and cotton ( Gossypium hirsutum L.) leaf tissues accumulated more than twice the concentration of simazine when plants were grown at 37 °C rather than at 26 °C .…”

“…Greater herbicide absorption and translocation detected at high temperature could strengthen herbicidal effects in meristematic regions, resulting in greater phytotoxicity on grasses. Greater phytotoxicity of atrazine and simazine at higher temperatures on account of increased herbicide uptake was reported . 14 C‐atrazine uptake by soybean ( Glycine max L.…”

“…Merr.) roots increased as temperature increased from 20 to 25 ∘ C. 48 Similarly, oat (Avena sativa L.) and cotton (Gossypium hirsutum L.) leaf tissues accumulated more than twice the concentration of simazine when plants were grown at 37 ∘ C rather than at 26 ∘ C. 45 In other herbicides, Koren and Ashton 46 noted that root absorption of 14 C-pyrazone in sugar beet (Beta vulgaris L.) at 35 ∘ C was twofold higher than at 18.3 ∘ C after 360 min of herbicide treatment. It was also noted that translocation of 14 C-pyrazone into sugar beet shoots was faster at 35 ∘ C than at 18.3 ∘ C.…”

Effect of temperature on absorption and translocation of simetryn in rice cultivars.

“…An increase in temperature has been reported to enhance phytotoxicity of sime-tryn1,2,8,15,18) simazine21), atrazine10,19,22,23), propazine3), and turbutryn3,4,5); it may stimulate the acceleration of absorption and translocation of these herbicides in the phytotoxic process3, 19,21,23). KOBAYASHI et al 9) demonstrated similar growth retardation by simetryn in pot experiments under a temperature as high as that observed in fields (32C), and found that the rate of absorption by rice roots doubled as compared with that at 27C.…”