Physiological and Genetic Bases of the Circadian Clock in Plants and Their Relationship with Herbicides Efficacy

Abstract

-In order to adapt to daily environmental changes, especially in relation to light availability, many organisms, such as plants, developed a vital mechanism that controls time-dependent biological events: the circadian clock. The circadian clock is responsible for predicting the changes that occur in the period of approximately 24 hours, preparing the plants for the following phases of the cycle. Some of these adaptations can influence the response of weeds to the herbicide application. Thus, the objectives of this review are to describe the physiological and genetic mechanisms of the circadian clock in plants, as well as to demonstrate the relationship of this phenomenon with the effectiveness of herbicides for weed control. Relationships are described between the circadian clock and the time of application of herbicides, leaf angle and herbicide interception, as well as photosynthetic activity in response to the circadian clock and herbicide efficiency. Further, it is discussed the role of phytochrome B (phyB) in the sensitivity of plants to glyphosate herbicide. The greater understanding of the circadian clock in plants is essential to achieve greater efficiency of herbicides and hence greater control of weeds and higher crop yields.Keywords: time of herbicide application, weeds, photoreceptors, phytochromes. RESUMO -Para se adaptarem às variações ambientais diárias

Influence of time of day on dicamba and glyphosate efficacy

“…Sicklepod responded to glyphosate applications most significantly between day and night timings using Tukey-Kramer HSD (α = 0.05) for means comparison (Table 2). Diurnal nyctinastic leaf movement during hours of darkness probably resulted in less interception of the applied herbicide (Kraatz and Anderson 1980), as has been noted by others (Dalazen and Merotto 2016;Norsworthy et al 1999). Dicamba application showed a smaller effect based on TOD.…”

Weed control of glufosinate, oxyfluorfen, and paraquat as affected by the application time of day

“…For this reason, although its applicability is difficult, there is a recommendation to apply all types of herbicides at night-time, leading to an improvement in herbicide efficacy and/or a reduction in non-target effects (Mohr et al, 2007). On the other hand, leaf orientation at night-time (leaf angle > -90 o ) distinctly differs from those at day-time (leaf angle < 0 o ) due to the so-called foliar nyctinasty (Norsworthy et al, 1999;Sellers et al, 2003;Mohr et al, 2007;Dalazen and Merotto Jr, 2016), affecting spray retention on leaf surfaces and, subsequently, herbicide efficacy. Therefore, this background was the second reason why our experiment was conducted only at the time of sunrise and sunset.…”

Investigation into interactions of environmental and application time effects on 2,4-D and dicamba-induced phytotoxicity and hydrogen peroxide formation

“…However, these conditions are, by no means, uniform across seasons. Reduced herbicide efficacy has been reported with applications made at dawn and/or dusk (Dalazen and Merotto 2016;Johnston et al 2018;Prasad et al 1967;Sellers et al 2003;Stewart et al 2009). Unfortunately, dawn and dusk are times when cropping operations apply herbicides in order to cover large amounts of acreage in a timely manner and/or to reduce drift potential and decrease evaporation of spray droplets before herbicide can penetrate leaf tissues (Johnston et al 2018).…”