Sustainability, certification, and regulation of biochar

Biochar has a relatively long half-life in soil and can fundamentally alter soil properties, processes, and ecosystem services. The prospect of global-scale biochar application to soils highlights the importance of a sophisticated and rigorous certification procedure. The objective of this work was to discuss the concept of integrating biochar properties with environmental and socioeconomic factors, in a sustainable biochar certification procedure that optimizes complementarity and compatibility between these factors over relevant time periods. Biochar effects and behavior should also be modelled at temporal scales similar to its expected functional lifetime in soils. Finally, when existing soil data are insufficient, soil sampling and analysis procedures need to be described as part of a biochar certification procedure.O “biochar” tem um tempo de meia-vida no solo relativamente longo e pode alterar substancialmente as propriedades, processos e funções do solo. A perspectiva da aplicação de “biochar” aos solos, em escala global, evidencia a importância de se lhe atribuir um processo de certificação sofisticado e rigoroso. O objetivo deste trabalho foi discutir o conceito da integração das propriedades do “biochar” com os fatores ambientais e socioeconômicos relevantes do local de aplicação selecionado, como parte de um procedimento de certificação sustentável que otimize a complementaridade e a compatibilidade entre esses fatores, em períodos de tempo relevantes. Os efeitos e o comportamento do “biochar” devem, também, ser modelados em escalas temporais similares às de seu tempo de vida funcional nos solos do local selecionado. Finalmente, onde os dados existentes sobre as características do solo forem insuficientes, procedimentos de amostragem e análise do solo devem ser descritos como parte do procedimento de certificação do “biochar”.publishe

Auxinic herbicides, mechanisms of action, and weed resistance: A look into recent plant science advances

Auxin governs dynamic cellular processes involved at several stages of plant growth and development. In this review, we discuss the mechanisms employed by auxin in light of recent scientific advances, with a focus on synthetic auxins as herbicides and synthetic auxin resistance mechanisms. Two auxin receptors were reported. The plasma membrane receptor ABP1 (Auxin Binding Protein 1) alters the structure and arrangement of actin filaments and microtubules, leading to plant epinasty and reducing peroxisomes and mitochondria mobility in the cell environment. The second auxin receptor is the gene transcription pathway regulated by the SCFTir/AFB ubiquitination complex, which destroys transcription repressor proteins that interrupt Auxin Response Factor (ARF) activation. As a result mRNA related with Abscisic Acid (ABA) and ethylene are transcribed, producing high quantities of theses hormones. Their associated action leads to high production of Reactive Oxygen Species (ROS), leading to tissue and plant death. Recently, another ubiquitination pathway which is described as a new auxin signaling route is the F-box protein S-Phase Kinase-Associated Protein 2A (SKP2A). It is active in cell division regulation and there is evidence that auxin herbicides can deregulate the SKP2A pathway, which leads to severe defects in plant development. In this discussion, we propose that SFCSKP2A auxin binding site alteration could be a new auxinic herbicide resistance mechanism, a concept which may contribute to the current progress in plant biology in its quest to clarify the many questions that still surround auxin herbicide mechanisms of action and the mechanisms of weed resistance