Índice SPAD em função de diferentes horários e posições no folíolo da batata sob fertilização nitrogenada

Silva, Marcelo Cleón de Castro; Coelho, Fabrício Silva; Braun, Heder; Fontes, Paulo Cézar Rezende

doi:10.1590/s1806-66902011000400020

Cited by 17 publications

(16 citation statements)

References 11 publications

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“…This is consistent with the findings of Silva et al (2011b), who showed that drought stress is typically characterized by a loss of chlorophyll, associated with a progressive decline in the photosynthetic capacity of plants. This behavior can be explained by the more prominent effect caused by drought on this variable, coupled with the likely ability that an adequate water supply has in mitigating the potential adverse effects that salinity alone could exert on total chlorophyll content.…”

Section: As the Water Supply Becomes Limiting Transpiration Decreasesupporting

confidence: 93%

Physiological Responses of Dwarf Coconut Plants Under Water Deficit in Salt-Affected Soils

et al. 2017

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-The objective of this study was to characterize the physiological acclimation responses of young plants of the dwarf coconut cultivar ‗Jiqui Green' associated with tolerance to conditions of multiple abiotic stresses (drought and soil salinity), acting either independently or in combination. The study was conducted under controlled conditions and evaluated the following parameters: leaf gas exchange, quantum yield of chlorophyll a fluorescence, and relative contents of total chlorophyll (SPAD index). The experiment was conducted under a randomized block experimental design, in a split plot arrangement. In the plots, plants were exposed to different levels of water stress, by imposing potential crop evapotranspiration replacement levels equivalent to 100%, 80%, 60%, 40%, and 20%, whereas in subplots, plants were exposed to different levels of soil salinity (1.72, 6.25, 25.80, and 40.70 dS m -1 ). Physiological mechanisms were effectively limited when water deficit and salinity acted separately and/or together. Compared with soil salinity, water stress was more effective in reducing the measured physiological parameters. The magnitudes of the responses of plants to water supply and salinity depended on the intensity of stress and evaluation period. The physiological acclimation responses of plants were mainly related to stomatal regulation. The coconut tree has a number of physiological adjustment mechanisms that give the species partial tolerance to drought stress and/or salt, thereby enabling it to revegetate salinated areas, provided that its water requirements are at least partially met.Keywords: Cocos nucifera L.. Water and salt stress. Physiology. RESPOSTAS FISIOLÓGICAS DE PLANTAS DE COQUEIRO ANÃO SOB DEFICIÊNCIA HÍDRICA, EM SOLOS AFETADOS POR SAISResumo -Objetivou-se, com este trabalho, caracterizar as repostas fisiológicas aclimatativas de plantas jovens de coqueiro Anão, cultivar -Verde do Jiqui‖, associadas com a sua tolerância às condições de múltiplos estresses abióticos (deficiência hídrica e salinidade do solo), atuando isolados e/ou combinados. O estudo foi realizado sob condições controladas e avaliaram-se: as trocas gasosas foliares, o rendimento quântico da fluorescência da clorofila a e os teores relativos de clorofila total (índice Spad). O experimento foi conduzido sob delineamento estatístico de blocos casualizados, no arranjo de parcelas subdivididas, sendo as parcelas constituídas por diferentes níveis de deficiência hídrica, mediante a imposição de cinco distintos percentuais de reposição das perdas de água por evapotranspiração potencial da cultura (100; 80; 60; 40 e 20%) e as subparcelas constituídas pelos crescentes níveis de salinidade do solo (1,72; 6,25; 25,80 e 40,70 dS m -1 ). Os mecanismos fisiológicos são efetivamente limitados quando a deficiência hídrica e a salinidade atuam isoladamente e/ou em conjunto. Os efeitos do estresse hídrico se mostram mais efetivos nos comprometimentos dos parâmetros fisiológicos, em detrimento à salinidade do solo. As magnitudes da...

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Section: As the Water Supply Becomes Limiting Transpiration Decreasesupporting

confidence: 93%

Physiological Responses of Dwarf Coconut Plants Under Water Deficit in Salt-Affected Soils

et al. 2017

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“…O nitrogênio participa de diversos compostos considerados indispensáveis para o crescimento e desenvolvimento das plantas, destacando-se as proteínas e as clorofilas (TAIZ;ZEIGER, 2009). Segundo Bredemeier e Mundstock (2000), a quantidade absorvida varia durante o ciclo de desenvolvimento da planta em função da quantidade de raízes e da taxa de absorção por unidade de peso de raiz.…”

Section: Introductionunclassified

Crescimento inicial e teor nutricional do maracujazeiro amarelo submetido à adubação com diferentes fontes nitrogenadas

Santos¹,

Lopes²,

Freitas³

et al. 2011

Rev. Bras. Frutic.

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O trabalho teve como objetivo avaliar a influência de diferentes fontes nitrogenadas sobre o crescimento inicial e o teor de nutrientes em folhas do maracujazeiro-amarelo. Para isto, foi instalado um experimento em DBC (delineamento em blocos casualizados), com quatro repetições em fatorial 4X5, sendo quatro fontes de nitrogênio (esterco bovino, esterco bovino + sulfato de amônio, esterco bovino + nitrato de amônio e esterco bovino + ureia) e cinco épocas de coleta de plantas (66; 82; 98; 111 e 127 dias após a semeadura). As plantas foram conduzidas em vasos de 30 dm³ e em condições de casa de vegetação. Com os resultados obtidos, foi possível concluir que o tratamento contendo apenas esterco bovino apresentou menor número de folhas por planta, menor área foliar, menor massa seca da parte aérea, menores valores de índice SPAD e os menores teores de N e Mg, quando comparado com os demais tratamentos. Para massa seca de raiz, as plantas submetidas ao tratamento com apenas esterco bovino apresentaram resultados superiores.

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“…The plants fertilized with phonolite + chicken manure and KCl presented higher SPAD index values when compared with those receiving the other K sources. The SPAD index is related to chlorophyll content in the plant or leaf green intensity, thus expressing nitrogen nutritional status at a specific stage of the crop cycle (Silva et al, 2011). When comparing SPAD meters results with N content and accumulation in the sandy soil (Table 3), it can be observed that the sources phonolite + chicken manure and KCl also presented higher nutrient accumulation.…”

Section: Resultsmentioning

confidence: 99%

Alternative sources of potassium for maize cultivation

et al. 2019

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Brazil is the largest importer of potassium (K) fertilizers in the world, importing about 95% of all the potassium consumed by its agriculture. Thus, new sources and technologies to increase K availability have been studied. This study aimed to evaluate the agronomic viability of the use of calcined glauconite and phonolite blended and granulated with two organic materials on maize growth in pots, using two soils of contrasting texture in a controlled environment. Were evaluated eight sources of potassium: phonolite; phonolite + poultry manure; phonolite + cattle manure; calcined glauconite; calcined glauconite + poultry manure; calcined glauconite + cattle manure; negative control (no K); and positive control (K - KCl), and two soils of contrasting texture. The experiment was carried out for 38 d. The following parameters were analyzed: plant height, stem diameter, shoot dry mass, leaf number, leaf contents of nitrogen (N), K and phosphorus (P), and the SPAD chlorophyll meter. In the sandy soil, the source consisting of phonolite + chicken manure was similar to KCl application regarding plant height, stem diameter and shoot dry mass. As for the clayey soil, when both rocks were blended with the organic wastes, they were similar to KCl for shoot dry mass. The use of pure granulated rocks, calcined glauconite and phonolite without blending with the organic residues is not efficient to provide available K to maize plants.

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Índice SPAD em função de diferentes horários e posições no folíolo da batata sob fertilização nitrogenada

Cited by 17 publications

References 11 publications

Physiological Responses of Dwarf Coconut Plants Under Water Deficit in Salt-Affected Soils

Physiological Responses of Dwarf Coconut Plants Under Water Deficit in Salt-Affected Soils

Crescimento inicial e teor nutricional do maracujazeiro amarelo submetido à adubação com diferentes fontes nitrogenadas

Alternative sources of potassium for maize cultivation

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