Use of a hand‐held chlorophyll meter in winter wheat: Evaluation of different measuring positions on the leaves

Hoel, Bernt

doi:10.1080/09064719809362502

Cited by 28 publications

(26 citation statements)

References 18 publications

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“…Correlações positivas entre as duas variáveis foram observadas também por Debaeke et al (2006), independente do ano de cultivo, cultivar e ano, e por Cammarano et al (2011) em plantas no período de antese e enchimento de grãos. O acúmulo de nitrogênio na fase de antese é de grande importância para a produtividade da cultura do trigo, estando altamente correlacionado com o teor de proteína nos grãos e com a produtividade (Debaeke et al, 1996;Hoel, 1998), principalmente quando o nitrogênio é um fator determinante para o cultivo (Debaeke et al, 2006). …”

Section: Resultsunclassified

Efeito da densidade de semeadura e de reguladores vegetais sobre os caracteres morfofisiológicos da folha bandeira do trigo

Fioreze

Rodrigues

2012

Agraria

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Efeito da densidade de semeadura e de reguladores vegetais sobre os caracteres morfofisiológicos da folha bandeira do trigo RESUMO O presente trabalho teve por objetivo estudar as características morfofisiológicas da folha bandeira do trigo em densidades crescentes de semeadura sob aplicação de reguladores vegetais. O delineamento experimental utilizado foi o de blocos casualizados em esquema de parcelas subdivididas com quatro repetições. As parcelas foram constituídas por quatro densidades de semeadura (30, 50, 70 e 90 plantas m -1 ), enquanto as subparcelas foram constituídas pela aplicação de reguladores vegetais, sendo um produto comercial composto por auxina+giberelina+citocinina (Ax+GA+CK), Etil-Trinexapac e a combinação dos dois produtos, além de uma testemunha sem a aplicação. Foram determinados o acúmulo de matéria seca total e a altura de plantas, as características morfológicas, o índice SPAD e os teores de nitrogênio e pigmentos fotossintéticos da folha bandeira. O aumento da densidade de semeadura resultou em diminuição no acúmulo de matéria seca e no índice SPAD da folha bandeira. A aplicação de Etil-Trinexapac resultou em aumento no índice SPAD da folha bandeira, estando os valores mais correlacionados com os teores de nitrogênio foliar do que com os teores de clorofila, que apresentaram redução em função da aplicação do regulador. A aplicação de Ax+GA+CK não afetou o desenvolvimento da folha bandeira de plantas de trigo. Palavras-chave:Auxina, citocinina, clorofila, Etil-Trinexapac, giberelina, nitrogênio, SPAD. Effects of sowing density and plant growth regulators on the morphological and physiological characteristics of the wheat flag leaf ABSTRACTThe objective of this work was to study the morphological and physiological characteristics of the wheat flag leaf as affected by increasing sowing densities and plant growth regulators application. The experimental design was a split-plot with completely randomized blocks and four replications. Plots were consisted by four sowing densities (30, 50 70 and 90 plants m -1 ) and the split-plots by plant growth regulators: a product composed by auxin+gebberellin+cytokinin (Ax+GA+CK), Trinexapac-Ethyl e (Ax+GA+CK) + Trinexapac-Ethyl, and a control without application. Dry mass accumulation, plant height, morphological characteristics, SPAD index, nitrogen and photosynthetic pigments contents in the flag leaf were determined. The increase in the sowing density resulted in lower dry mass accumulation and SPAD index of the flag leaves. Trinexapac-Ethyl caused increase in the SPAD index, but the chlorophyll content of the flag leaf was reduced. The SPAD index values were more correlated with the nitrogen than the chlorophyll contents. Ax+GA+CK did not affect flag leaf characteristics in wheat plants.

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Section: Resultsunclassified

Efeito da densidade de semeadura e de reguladores vegetais sobre os caracteres morfofisiológicos da folha bandeira do trigo

Fioreze

Rodrigues

2012

Agraria

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“…Each leaf was clipped at the midpoint using cork borers to obtain a disk of known surface (S); this is the optimal position from which to take chlorophyll readings (Hoel, 1998). Three SPAD-502 chlorophyll meter readings were taken from each disk, at different positions, to compute a mean index value.…”

Section: Site Sampling and Measurementsmentioning

confidence: 99%

Detecting the effects of hydrocarbon pollution in the Amazon forest using hyperspectral satellite images

Arellano

Tansey

Balzter

et al. 2015

Environmental Pollution

142

110

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The global demand for fossil energy is triggering oil exploration and production projects in remote areas of the world. During the last few decades hydrocarbon production has caused pollution in the Amazon forest inflicting considerable environmental impact. Until now it is not clear how hydrocarbon pollution affects the health of the tropical forest flora. During a field campaign in polluted and pristine forest, more than 1100 leaf samples were collected and analysed for biophysical and biochemical parameters. The results revealed that tropical forests exposed to hydrocarbon pollution show reduced levels of chlorophyll content, higher levels of foliar water content and leaf structural changes. In order to map this impact over wider geographical areas, vegetation indices were applied to hyperspectral Hyperion satellite imagery. Three vegetation indices (SR, NDVI and NDVI705) were found to be the most appropriate indices to detect the effects of petroleum pollution in the Amazon forest.

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“…Use of SPAD measurements to guide in-season fertilizer N management was demonstrated to reduce N losses without loss of corn yield . SPAD meter readings are sensitive to the leaf chosen and the measurement location on the leaf (Hoel 1998) and therefore well-defined sampling protocols are required (Denuit et al 2002). Disadvantages of the SPAD meter include the need for cultivar specific critical values (Minotti et al 1994) and the requirement for considerable manual leaf sampling in order to produce reliable average values.…”

Section: Plant-based Diagnostic Testsmentioning

confidence: 99%

Opportunities for improved fertilizer nitrogen management in production of arable crops in eastern Canada: A review

Zebarth¹,

Drury²,

Tremblay³

et al. 2009

Can. J. Soil. Sci.

176

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There is increasing public pressure to reduce the environmental impacts of agricultural production. Therefore, one key challenge to producers is to manage their crop production systems in order to minimize losses of nitrogen to air or water, while achieving crop yield and quality goals. Many strategies have been developed in recent years to meet this challenge. These include: development of new tools to measure crop N status in order to refine in-season fertilizer N management, development of new soil N tests to improve prediction of soil N supply, development of new fertilizer N products with release patterns more closely matched to crop N uptake patterns, and development of site-specific N management strategies. We review the opportunities and limitations to these new strategies within different arable crop production systems under the humid and sub-humid soil moisture regimes present in eastern Canada. Future research opportunities to improve the efficiency of fertilizer N utilization include development of practical methods to predict the magnitude of soil N mineralization; refinement of decision-making processes which take into consideration the crop N status and soil properties as a basis for variable rate fertilizer N application; development of affordable controlled-release fertilizer N products with improved N release characteristics; development of practical methods for capturing and recycling nutrient-laden drainage water; development of gene expression profiling based techniques to identify crop N stress; and application of crop genomics and molecular breeding techniques to accelerate the development of new cultivars with increased N use efficiency. Key words: Soil N tests, plant N tests, nitrogen fertilizers, nitrogen cycling

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Use of a hand‐held chlorophyll meter in winter wheat: Evaluation of different measuring positions on the leaves

Cited by 28 publications

References 18 publications

Efeito da densidade de semeadura e de reguladores vegetais sobre os caracteres morfofisiológicos da folha bandeira do trigo

Efeito da densidade de semeadura e de reguladores vegetais sobre os caracteres morfofisiológicos da folha bandeira do trigo

Detecting the effects of hydrocarbon pollution in the Amazon forest using hyperspectral satellite images

Opportunities for improved fertilizer nitrogen management in production of arable crops in eastern Canada: A review

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