Aspectos fisiológicos e extração de sódio e nutrientes por Atriplex nummularia em resposta à adubação nitrogenada e fosfatada

• Autor(a) principal: Cunha, Jailson Cavalcante
• Data de Publicação: 2013
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/1667
• topic: Halófitas; Fosforo; Fitorremediação; Halophytes; Phosphorus; Phytoremediation; CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::CIENCIA DO SOLO

The salt affected soils have increased in recent years. The proportion of these areas may continue to increase as a result of inadequate management and climate change. Recovery alternatives should be established and continually improved their techniques. Phytoremediation has been promoting itself as a viable and promising technique. In this sense, Atriplex nummularia is one of the main halophytes with potential for phytoextraction. Three approaches were taken to evaluate plant and soil. The three approaches were based on experimental design consisting of a 2x5 factorial arrangement , corresponding to two levels of phosphorus (0 and 134 mg dm-3) and five nitrogen rates (0, 20, 40, 60 and 80 mg dm-3), arranged in a randomized block design with four replications. Seedlings were transplanted at 60 days of age and monitored under low water availability in the soil (-70 kPa) for 80 days. In the first approach, with the aim of evaluating the physiological behavior during the capture of light energy in the photosynthesis, there were measures of chlorophyll a fluorescence with a FluorPen FP 100 (Photon Systems Instruments) in dark adapted leaves with saturating pulse light 3,000 μmol m-2 s-1. We analyzed data from the JIP-test and the kinetics of the transient phases between O and J normalized curve, and additionally, the calculated kinetic difference (ΔWOJ) to observe the formation of the K-band. There were K-band formation in cultured with phosphate fertilizer plants, indicating the inactivation of oxygen evolution by ATP synthesis excessively complex, blocking the flow of protons and electrons for photosystem II. The K- band indicates an imbalance in the photosynthetic process, reflecting the negative effect of excess P in plants atriplex. In the second approach, to evaluate the stomatal conductance (gs), water potential, activity of enzymes of oxidative stress and soluble proteins, measurements were taken of stomatal conductance at different times of day. Database of plant water potential were collected at maximum leaf turgor, using a Scholander chamber. Leaves were collected for determination of osmotic potential, activity of catalase, ascorbate peroxidase and soluble proteins. In the period from 21 to 22 h, the gs was higher in the presence of P. The gs measured every hour of the day from 6 to 22 h was lower at the highest dose of N. This indicates that N is more effective in reducing stomatal conductance, favoring tolerance to water deficit. In the third approach, aimed to evaluate the dry matter production, the extraction capacity of the sodium and nutrient uptake by halophyte. For this, plants were harvested for quantification and the determination of production levels of Na and nutrients in leaves, stems and roots. We determined the levels of Na in phases soluble and exchangeable, dosing it with a flame photometer. Decreased Na in the saturated soil paste extract and exchange complex with the increase of N in the soil. The N supply enhances the extraction of Na and other nutrients by Atriplex nummularia, may be a viable technique to be added to the management plan for the recovery of salt affected soils by phytoremediation process.