Elevated CO2 effect on tolerance of Eragrostis plana to glyphosate and drought stress.

Resumo

Sequenciamento genômico de capim-annoni.

O objetivo deste trabalho foi verificar o nível de ploidia, estimar o tamanho do genoma e iniciar o sequenciamento genômico da planta invasora capim-annoni.Editores técnicos: Guilherme Braga Pereira Braz, Naiara Guerra

Glyphosate efficacy, absorption and translocation for Eragrostis plana control.

Abstract: Background: Glyphosate is the most effective herbicide to control the invasive and perennial Eragrostis plana in Southern Brazil. However, one application has not been sufficient to prevent the regrowth of plants. Objective: The aim of this research was to evaluate the efficacy of glyphosate sprayed alone or mixed with fluazifop-p-butyl or flumioxazin on E. plana control and to investigate 14C-glyphosate absorption and translocation. Methods: Plants with 2-3 tillers were treated with glyphosate (700 g a.e. ha- 1), fluazifop-p-butyl (47 g a.i. ha-1), flumioxazin (100 g a.i. ha-1), glyphosate + fluazifop-p-butyl (700 g a.e. ha-1 + 47g a.i. ha-1), glyphosate + flumioxazin (700 g a.e. ha-1 +100 g a.i. ha-1). Weed control was evaluated visually for 28 d after treatment (DAT) when plants were harvested for shoot dry biomass determination. 14C-glyphosate absorption and translocation were measured at 24 and 72 h after treatment. Results: Glyphosate at 700 g a.e. ha-1 controlled E. plana plants at 2-3 tillers. The mixture with fluazifop-p-butyl or flumizin did not significantly increase the level of control (87 and 86% at 7 DAT, respectively) but increased 14C-glyphosate translocation to the roots. Conclusions: Glyphosate is effective on E. plana. However, applied with fluazifop-p-butyl could improve the control of this weed, especially when perennial plants of E. plana dominate the field, preventing their fast regrowth. Keywords: 14C-glyphosate; fluazifop-p-butyl; forage grass; invasive plant; tough lovegras

Snorkeling Strategy: Tolerance to Flooding in Rice and Potential Application for Weed Management (Review).

Abstract: Flooding is an important strategy for weed control in paddy rice fields. However, terrestrial weeds had evolved mechanisms of tolerance to flooding, resulting in new ?snorkeling? ecotypes. The aim of this review is to discuss the mechanisms of flooding tolerance in cultivated and weedy riceat different plant stages and the putative utility of this trait for weed management. Knowledge about flooding tolerance is derived primarily from crop models, mainly rice. The rice model informs us about the possible flooding tolerance mechanisms in weedy rice, Echinochloa species, and other weeds. During germination, the gene related to carbohydrate mobilization and energy intake (RAmy3D),and genes involved in metabolism maintenance under anoxia (ADH, PDC, and OsB12D1) are the most important for flooding tolerance. Flooding tolerance during emergence involved responses promoted by ethylene and induction of RAmy3D, ADH, PDC, and OsB12D1. Plant species tolerant to complete submersion also employ escape strategies or the ability to become quiescent during the submergence period. In weedy rice, the expression of PDC1, SUS3, and SUB1 genes is not directly related to flooding tolerance, contrary to what was learned in cultivated rice. Mitigation of flooding tolerance in weeds could be achieved with biotechnological approaches and genetic manipulation of flood tolerance genes through RNAi and transposons, providing a potential new tool for weed management