RESUMEN
MAIN CONCLUSION: Consequences of air pollutants on physiology, biology, yield and quality in the crops are evident. Crop and soil management can play significant roles in attenuating the impacts of air pollutants. With rapid urbanization and industrialization, air pollution has emerged as a serious threat to quality crop production. Assessing the effect of the elevated level of pollutants on the performance of the crops is crucial. Compared to the soil and water pollutants, the air pollutants spread more rapidly to the extensive area. This paper has reviewed and highlighted the major findings of the previous research works on the morphological, physiological and biochemical changes in some important crops and fruits exposed to the increasing levels of air pollutants. The crop, soil and environmental factors governing the effect of air pollutants have been discussed. The majority of the observations suggest that the air pollutants alter the physiology and biochemical in the plants, i.e., while some pollutants are beneficial to the growth and yields and modify physiological and morphological processes, most of them appeared to be detrimental to the crop yields and their quality. A better understanding of the mechanisms of the uptake of air pollutants and crop responses is quite important for devising the measures â at both policy and program levels â to minimize their possible negative impacts on crops. Further research directions in this field have also been presented.
Asunto(s)
Contaminantes Atmosféricos , Contaminación del Aire , Contaminación del Aire/efectos adversos , Productos Agrícolas , SueloRESUMEN
The isolation of lignin containing micro- and nanofibrillated cellulose (L-MNFC) requires a multistep process. In this study, beech wood was pre-treated by steam explosion (SE), refined or pre-treated by 3 SE and grinded until gel formation. A conventional cooking in an autoclave (SC) was applied in order to get a control sample. The effect of bleaching of a SE pulp was also studied. The chemical composition of the pulps was assessed as well as fiber morphology to compare the effect of the different processes. Quality index and energy consumption during the production process were studied. Results showed that SE can replace SC for the production of pulps with higher lignin content: 8-12% wt. and 3% wt., respectively. Gels contain micro and nanofibrillated cellulose and residual fibers with a dispersion of lignin nanoparticles and some nanocrystals. Optimization of the ultrafine grinding step was required to minimize the energy consumption.