Tolerance of Plants to Toxicity Induced by Micronutrients

Micronutrient elements such as zinc, boron copper, iron, manganese, molybdenum, and chlorine are frequently responsible by the regulatory activity of the cell organelles, being nutrients that are absorbed and found in lower concentrations in plant tissues, they also contribute to supply the nutritional exigency of the plant. Study with Zea mays plants exposed to Zn toxicity + Si presented significant increases in stomatal conductance, net photosynthetic rate, transpiration rate, and water use efficiency, respectively, in comparison with treatment only with Zn. In relation to chlorophylls a, b and total and carotenoids presented non-significant increases, when compared to plants exposed to Zn toxicity. This study revealed the positive contribution of the Si on gas exchange and reduction of the negative effects provoked on chlorophylls and carotenoids in maize plants under Zn toxicity. Other results described that prolonged exposure to excessive Cu resulted in serious toxic effects on the rice seedlings. In contrast, Tre pretreatment has been shown to be beneficial in alleviating Cu toxicity, which was mainly attributed to the ability of Tre to restrict Cu uptake and accumulation to maintain Cu homeostasis, and to induce production of antioxidant and Gly enzymes to alleviate excessive Cu-triggered oxidative stress. Stress caused by the excessive supply of micronutrients to plants frequently promotes repercussions on oxidant system, inducing the overproduction of reactive oxygen species. The oxidative damage is a situation characterized by the large ROS accumulation and insufficient detoxification promoted by antioxidant enzymes, such as catalase and glutathione peroxidase. Different mechanisms have been proposed to explain the tolerance of plants to toxicity induced by micronutrients, as uses of other elements and substances, in which it can positively act with specific transporters, metal ion homeostasis and compartmentalization of micronutrients into the vacuole

Boron Supply and Water Deficit Consequences in Young Paricá (Schizolobium parahyba var. amazonicum) Plants

Boron (B) is a very important nutrient required by forest plants; when supplied in adequate amounts, plants can ameliorate the negative effects of abiotic stresses. The objective of this study was to (i) investigate gas exchange, (ii) measure oxidant and antioxidant compounds, and (iii) respond how B supply acts on tolerance mechanism to water deficit in young Schizolobium parahyba plants. The experiment employed a factorial that was entirely randomised, with two boron levels (25 and 250 µmol L-1, simulating conditions of sufficient B and high B, respectively) and two water conditions (control and water deficit). Water deficit induced negative modifications on net photosynthetic rate, stomatal conductance and water use efficiency, while B high promoted intensification of the effects on stomatal conductance and water use efficiency. Hydrogen peroxide and electrolyte leakage of both tissues suffered non-significant increases after B high and when applied water deficit. Ascorbate levels presented increases after water deficit and B high to leaf and root. Our results suggested that the tolerance mechanism to water deficit in young Schizolobium parahyba plants is coupled to increases in total glutathione and ascorbate aiming to control the overproduction of hydrogen peroxide and alleviates the negative consequences on electrolyte leakage and gas exchange. In relation to B supply, this study proved that sufficient level promoted better responses under control and water deficit conditions

Vivenciando a dor: a experiência de crianças e adolescentes em cuidados paliativos

El estudio tuvo como objetivo conocer la experiencia de niños y adolescentes en cuidados paliativos en el manejo diario del dolor. La investigación cualitativa fue realizada con entrevistas semi-estructuradas con seis niños entre siete y 17 años. La teoría del Desarrollo cognitivo de Piaget fue utilizada como Marco teórico y la Historia Oral como Referencial Metodológico. Cuatro temas fueron encontrados: describiendo el dolor; buscando una vida más próxima de la normalidad, a pesar del dolor y la enfermedad; utilizando varias alternativas para el control del dolor y viviendo la autoimagen perjudicada. A pesar del dolor ser un agente limitante en la vida de los niños y adolescentes, verificamos que enfrentaban el dolor diariamente y, que así mismo, tenían vida además del dolor y la enfermedad. Adicionamos, aun, la importancia de los enfermeros comprender que el eficaz manejo del dolor es esencial para una vida mas próxima de la normalidad, reduciendo su sufrimiento.A qualitative study was conducted with semi-structured interviews with the aim of understanding the experience of children and adolescents under palliative care when managing pain daily and how they describe the intensity, quality and location of pain. We used Piaget’s theory of cognitive development as a theoretical framework and oral history as a methodological framework. We found four themes: describing pain; seeking a life closer to normality, despite pain and disease; using a variety of alternatives for pain control; and living with damaged physical appearance. Although pain is a limiting factor in the lives of children and adolescents, we found that they faced their daily pain and still had a life beyond pain and illness. In addition, we highlight the relevance of nurses’ understanding that effective management of pain in children is essential for a normal life and less suffering.Objetivo Conhecer como as crianças e adolescentes em cuidados paliativos manejam a dor em seu cotidiano e como a descrevem em intensidade e qualidade. Método Pesquisa qualitativa realizada com entrevistas semiestruturadas com seis crianças entre 6 e 17 anos. A teoria do desenvolvimento cognitivo de Piaget foi utilizada como marco teórico e a história oral como referencial metodológico. Resultados Foram encontrados quatro temas: Descrevendo a dor; Buscando uma vida mais próxima da normalidade, apesar da dor e da doença; Utilizando várias alternativas para o controle da dor; e Vivenciando a autoimagem prejudicada. Conclusão Apesar de a dor ser um agente limitante na vida de crianças e adolescentes, constatamos que enfrentavam a dor diariamente e, mesmo assim, tinham vida além da dor e da doença. Acrescentamos, ainda, a importância de os enfermeiros compreenderem que o manejo eficaz da dor é essencial para uma vida mais próxima da normalidade, reduzindo seu sofrimento.


Effect of phosphite supply in nutrient solution on yield, phosphorus nutrition and enzymatic behavior in common bean (Phaseolus vulgaris L.) plants

Abstract Aim of this study was to (i) understand the phosphite action used as P source on growth and grain yield, (ii) measure P concentration and accumulation in shoot and root, and (iii) evaluate enzymatic behaviour in common bean (Phaseolus vulgaris L.) plants grown in nutrient solution under phosphate starvation. Experimental design was completely randomised with 7 levels of phosphite (0, 16, 32, 64, 128, 256 and 512 µM) and 2 levels of phosphate (80 and 800 µM, corresponding to phosphate-starved plants and phosphatesufficient plants, respectively) in nutrient solution. Common bean plants were evaluated at 2 different growth stages: flowering and mature grain stages. For plants harvested at the mature grain stage, two more treatments (additional treatments) were added: -P = no P supply in nutrient solution; and +Phi = all the P (800 µM) from nutrient solution was supplied only as Phi. This study revealed that growth and grain yield in plants grown under phosphate starvation presented negative repercussions on these parameters, in which treatments with 64, 128, 256 and 512 µM of phosphite resulted in no-filled grains. Concentration and accumulation of P in shoot and root of phosphate-starved plants was increased with increasing phosphite levels in nutrient solution, but this additional P concentration did not convert into grain yield. The phosphite application in phosphate-starved plants promoted a decrease in acid phosphatase (EC 3.1.3.4.1) activity, while catalase (EC 1.11.1.6) activity was increased up to 32 µM of phosphite and was reduced at higher levels of phosphite