SPAD index and leaf pigments in cauliflower in different water conditions and silicon fertilization

The measurement of leaf pigments using non-destructive methods can be influenced by water management conditions and the use of nutrients in cauliflower, not showing adequate correlations with chlorophyll contents. The objective of this study was to evaluate the correlation between the SPAD index and the pigment content in cauliflower leaves managed with different water conditions and the application of silicon (Si). The cultivation was carried out in a protected environment in the city of Maringá, Paraná State from October 2019 to March 2020. It was adopted a randomized block design, with treatments in a 3 x 4 factorial scheme, with three levels of water recharge (40; 70 and 100% of crop evapotranspiration (ETc)) and four doses of Si (0; 50; 100 and 150 kg ha-1), with four replications. Once plants showed developed inflorescence, the SPAD index was determined in the field and the levels of chlorophyll a, chlorophyll b, and carotenoids in the laboratory using leaves from the upper third. The correlation between water recharge and Si fertilization on the SPAD index was determined. The proportion of carotenoids in relation to total pigments was compared under different conditions. Correlation analysis was performed considering silicon fertilization, water recharge, leaf pigments, and the SPAD index. Silicon fertilization reduced the levels of carotenoids in addition to being related to chlorophyll a (100% of ETc) and chlorophyll b (70% of ETc). The correlation of the SPAD index with pigments is variable with the water condition of the crop, in a condition without water deficit, it is related to chlorophyll a and in a condition of 70% replacement of ETc, it is correlated with chlorophyll b.

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Chlorophyll a fluorescence and development of zucchini plants under nitrogen and silicon fertilization

Agronomía Colombiana ◽

10.15446/agron.colomb.v38n1.79172 ◽

2020 ◽

Vol 38 (1) ◽

pp. 45-52

Author(s):

Jackson De Mesquita Alves ◽

Alex Serafim De Lima ◽

Francisco Romário Andrade Figueiredo ◽

Toshik Iarley Da Silva ◽

Lourival Ferreira Cavalcante ◽

...

Keyword(s):

Chlorophyll A ◽

Chlorophyll A Fluorescence ◽

Block Design ◽

C3 Plants ◽

Financial Return ◽

Nitrogen Levels ◽

Randomized Block Design ◽

Silicon Fertilization ◽

Productive Potential ◽

Semi Arid Region

Zucchini (Cucurbita pepo L.) has a great economic and productive potential in the semi-arid region of Brazil, due to the wide acceptance by consumers and quick financial return. The nitrate (NO3-) assimilation process in C3 plants such as zucchini is related to photorespiration, and Si accumulated near the stomata reduces the transpiration rate, making the photosynthesis cycle more efficient. The objective of this study was to evaluate the interaction between nitrogen and silicon fertilization ongrowth, chlorophyll index, and chlorophyll a fluorescence of zucchini plants. The treatments were distributed in a split-plot scheme in a randomized block design with three replicates. The plot was arranged by silicon levels (0 and 6 g/plant) and the subplots constituted by five nitrogen levels (30, 60, 90, 120 and 150 kg ha-1). Leaf, stem and total dry masses, chlorophylla, chlorophyll b, total chlorophyll, chlorophyll a/b ratio and chlorophyll a fluorescence were evaluated. The highest dry matter productions in zucchini were obtained in treatments without Si. Si and N application together positively influences the chlorophyll a/b ratio of zucchini plants. The interaction between Si and N positively influences the maximum fluorescence, variable fluorescence and quantum yield of photosystemII of zucchini plants.

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Tomato grafting on rootstock of Jilo, Cocona and Jurubeba

Horticultura Brasileira ◽

10.1590/s0102-053620190203 ◽

2019 ◽

Vol 37 (2) ◽

pp. 138-145

Author(s):

Marcelo de A Guimarães ◽

Manuel Filipe N Garcia ◽

Jean Paulo de J Tello ◽

Hozano de S Lemos Neto ◽

Benedito P Lima Neto ◽

...

Keyword(s):

Solanum Lycopersicum ◽

Chlorophyll A ◽

Block Design ◽

Chlorophyll B ◽

Randomized Block Design ◽

Grafting Technique ◽

Solanaceae Species ◽

Graft Diameter ◽

Graft Length ◽

Adverse Environments

ABSTRACT Grafting has been considered an important tool to produce tomato in adverse environments. Therefore, the aim of this study was to develop grafting protocols for tomato on rootstocks of Jilo, Cocona and Jurubeba. The work was carried out in a randomized block design, in a factorial scheme (3x2) + 1 with three grafting methods (slant-cut grafting, cleft grafting and splice grafting), combined with two graft ages and rootstocks (depending on the species), and the control. The rootstocks for tomato (Solanum lycopersicum) cv. Santa Clara were: 1) Jilo (S. gilo) cv. Comprido Grande Rio; 2) Cocona (S. sessiliflorum) and 3) Jurubeba (S. jamaicense). The methods were individually studied and the graft length (GL); chlorophyll ‘a’ and chlorophyll ‘b’ in pre and post-grafting; graft diameter (GD), pre-grafting and tissue union of the grafted individuals through the assignment of grades were evaluated. Seven days after grafting, evaluations of grafted plants were performed. It was possible to establish a grafting protocol for all the combinations. The rootstock of Cocona provided greater vigor to ‘Santa Clara’ tomato graft. The cleft grafting technique can be indicated as the most effective for tomato grafting on the studied Solanaceae species.

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Biochemical descriptors: importance of the genetic divergence study in peppers

Horticultura Brasileira ◽

10.1590/s0102-053620190212 ◽

2019 ◽

Vol 37 (2) ◽

pp. 210-214

Author(s):

Lourismar M Araújo ◽

Leonarda G Neves ◽

Demétrio A Sousa ◽

Walmes M Zeviani ◽

Lucinéia da R Silva ◽

...

Keyword(s):

Ascorbic Acid ◽

Chlorophyll A ◽

Block Design ◽

Titratable Acidity ◽

Chlorophyll B ◽

Total Phenols ◽

Mato Grosso ◽

Randomized Block Design ◽

Capsicum Spp ◽

Biochemical Analyses

ABSTRACT The genetic diversity of pepper genotypes is usually evaluated based on morphological and molecular descriptors. However, studies using biochemical descriptors of peppers are still incipient. Thus, the objective of this study was identify biochemical descriptors of Capsicum spp. with antioxidant action, most responsive to the selection of superior genotypes, and evaluate the correlation between concentrations of the parameters using principal components analysis. The experiment was conducted in the city of Cáceres, southwest Mato Grosso, Brazil. Seventy-eight pepper accessions from the Active Germplasm Bank of UNEMAT were planted in randomized block design. The harvested fruits were immersed in liquid nitrogen for two minutes, and the following biochemical analyses were performed: titratable acidity, ascorbic acid, total phenols, flavonoids, anthocyanins, carotenoids, chlorophyll a, chlorophyll b, and antioxidant activity. Biochemical descriptors that best estimated the genetic variability of the accessions were flavonoids, total phenols, chlorophyll a, and ascorbic acid. Chlorophyll a and chlorophyll b were the compounds that showed the highest degree of correlation. Except chlorophyll a with ascorbic acid, all other vectors showed correlation ranging from moderate to strong.

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Pengaruh Ukuran Partikel dan Lama Ekstraksi terhadap Karakteristik Ekstrak Pewarna Alami Daun Pandan Wangi (Pandanus amaryllifolius R.)

JURNAL REKAYASA DAN MANAJEMEN AGROINDUSTRI ◽

10.24843/jrma.2020.v08.i02.p08 ◽

2020 ◽

Vol 8 (2) ◽

pp. 234

Author(s):

Made Hary Sayoga ◽

Ni Made Wartini ◽

Lutfi Suhendra

Keyword(s):

Particle Size ◽

Chlorophyll A ◽

Leaf Extract ◽

Block Design ◽

Extraction Process ◽

Extraction Time ◽

Chlorophyll B ◽

Total Chlorophyll ◽

Randomized Block Design ◽

Pandanus Amaryllifolius

Fragrant pandan leaves can be used as a natural coloring because they contain chlorophyll obtained through the extraction process. The purposes of this study were to determine the effect of particle size and extraction time on the characteristics of natural pandanus fragrance leaf extract and determine the best treatment of particle size and extraction time to produce natural pandanus leaf extract dye. This study used a 2 factorial factorial randomized block design. The first factor is the particle size which consists of 3 levels, namely 40, 60, 80 mesh. The second factor is the extraction time which consists of 3 levels, namely 24, 36, and 48 hours. The results showed that the treatment of particle size and extraction time affected the yield, chlorophyll a, chlorophyll b, total chlorophyll, brightness (L *), redness (a *) and yellowish level (b *). The treatment of 60 mesh particle size and 36 hour extraction time are the best treatment to produce natural pandanus fragrance extract coloring with yield characteristics of 8.81% chlorophyll a level of 23.66%, chlorophyll b level of 3.92%, total chlorophyll content of 27.57%, the brightness level (L *) 21.06, the redness level (a *) 4.92, the yellowish level (b *) 6.21. Keywords: Pandanus amaryllifolius R., chlorophyll, color, extraction

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Karakteristik Ekstrak Pewarna Alami Daun Singkong (Manihot esculenta) pada Perlakuan Jenis Pelarut dan Suhu Maserasi

JURNAL REKAYASA DAN MANAJEMEN AGROINDUSTRI ◽

10.24843/jrma.2021.v09.i01.p06 ◽

2021 ◽

Vol 9 (1) ◽

pp. 53

Author(s):

Rian Lamhot Parasian Hutabarat ◽

Ni Made Wartini ◽

Nyoman Semadi Antara

Keyword(s):

Chlorophyll A ◽

Block Design ◽

Natural Dye ◽

Chlorophyll B ◽

Total Chlorophyll ◽

Cassava Leaves ◽

Randomized Block Design ◽

Solvent Type ◽

Leaf Powder ◽

Effect On Yield

This study aims to determine the effect of type of solvent and maceration temperature on the characteristics of cassava leaves extracts as a natural dyes leaves and determine the type of solvent for cassava leaf powder and the best maceration temperature to obtain the extract of natural cassava leaves. This study used a factorial randomized block design with 2 factors, namely the type of solvent (85% ethanol, 85% acetone and mixture (85% ethanol: 85% acetone) and maceration temperature (35 ° C, 45 ° C and 55 ° C). The data obtained were analyzed with variance and if the treatment had a significant effect, then continued with the Tukey test. The results showed that the treatment interactions had a very significant effect on yield, chlorophyll b, brightness (L *), yellowish level (b *), total chlorophyll, chlorophyll a. , redness (a *), but had no significant effect on the interaction at the level of redness (a *). The treatment of 85% acetone solvent and 55 ° C maceration temperature was the best treatment to produce acetone extract of natural dye of cassava leaves with yield characteristics of 14, 04%, total chlorophyll 12.10%, chlorophyll a 4.39%, chlorophyll b 7.71%, brightness (L *) 16.46, redness (a *) 9.77 yellowish (b *) of 5.70.brightness level (L*) of 11.03, redness level (a*) of 10.29, yellowish level (b*) of 2.83. Key words: cassava leaves, dye extract, maceration temperature, natural dye, solvent type.

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Karakteristik Ekstrak Aseton Pewarna Alami Daun Singkong (Manihot Esculenta C.) pada Perlakuan Ukuran Partikel Bahan dan Lama Maserasi

Jurnal Ilmiah Teknologi Pertanian Agrotechno ◽

10.24843/jitpa.2020.v05.i02.p02 ◽

2020 ◽

Vol 5 (2) ◽

pp. 49

Author(s):

Ezra Elkana Karo Sekali ◽

Ni Made Wartini ◽

Lutfi Suhendra

Keyword(s):

Particle Size ◽

Chlorophyll A ◽

Block Design ◽

Acetone Extract ◽

Chlorophyll B ◽

Total Chlorophyll ◽

Brightness Level ◽

Cassava Leaves ◽

Randomized Block Design ◽

Two Factors

Penelitian ini bertujuan untuk mengetahui pengaruh ukuran partikel dan lama maserasi terhadap karakteristik ekstrak aseton pewarna alami daun singkong dan menentukan ukuran partikel dan lama maserasi terbaik untuk mendapatkan ekstrak aseton pewarna alami daun singkong. Penelitian ini menggunakan Rancangan Acak Kelompok Pola Faktorial dengan 2 Faktor yaitu Ukuran Partikel (40 mesh, 60 mesh, 80 mesh) dan Lama Maserasi (24 jam, 36 jam, 48 jam). Data yang diperoleh dianalisis dengan sidik ragam dan apabila perlakuan berpengaruh nyata dilanjutkan dengan uji Duncan. Hasil penelitian menunjukkan bahwa interaksi perlakuan berpengaruh sangat nyata terhadap rendemen, klorofil b, tingkat kecerahan (L*), tingkat kekuningan (b*) tetapi berpengaruh tidak nyata terhadap klorofil total, klorofil a, kemerahan (a*). Perlakuan ukuran partikel 80 mesh dan lama maserasi 36 jam merupakan perlakuan terbaik untuk menghasilkan ekstrak aseton pewarna alami daun singkong dengan karakteristik rendemen sebesar 8,08%, klorofil total sebesar 3,83%, klorofil a sebesar 2,05%, klorofil b sebesar 1,77%, tingkat kecerahan (L*) sebesar 11,03, tingkat kemerahan (a*) sebesar 10,29, tingkat kekuningan (b*) sebesar 2,83. This study aims to know the effect of particle size and maceration time on the characteristics of the natural dye acetone extract of cassava leaves and determine the best particle size and maceration time to obtain the acetone extract of natural coloring cassava leaves.This research used a randomized block design with factorial pattern with two factors namely, particle size (40 mesh, 60 mesh, 80 mesh) and maceration time (24 hours, 36 hours, 48 hours). The data obtained were analyzed by analysis of variance. If the treatment had a significant effect, it would be followed by the Duncan test. The result showed that interactions had significant effect on theextract yield, chlorophyll b levels, brightness level L*, yellowish level b*, but had no effect on total chlorophyll levels, chlorophyll a levels, redness level a*. Treatment of particle size 80 mesh and maceration time 36 hours, is the best treatment to produce aceton extract natural dyes of cassava leaves with extract yield characteristics of 8.08%,total chlorophyll levels of 3.83, chlorophyll a levels of 2.05%,chlorophyll b levels of 1.77%,brightness level (L*) of 11.03,redness level (a*) of 10.29,yellowish level (b*) of 2.83.

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The effect of drought stress and nitrogen fertilization on the active ingredient, chlorophyll A and B, and chlorophyll index of henna

Nexo Revista Científica ◽

10.5377/nexo.v33i02.10802 ◽

2020 ◽

Vol 33 (02) ◽

pp. 694-706

Author(s):

Hassan Sarhadi ◽

Jahanfar Daneshian ◽

Seyyed Alireza Valadabadi ◽

Hossein Heidary Sharafabad ◽

...

Keyword(s):

Drought Stress ◽

Chlorophyll A ◽

Active Ingredient ◽

Block Design ◽

N Fertilization ◽

Water Requirement ◽

Plant Water ◽

Chlorophyll B ◽

Chlorophyll A And B ◽

Chlorophyll Index

The response of active ingredient, chlorophyll a and b contents, and chlorophyll index of henna to different rates of N fertilization and drought stress was explored in a split-split-plot experiment based on a randomized complete block design with four replications in the research farm of Jiroft Branch, Islamic Azad University, Jiroft, Iran in the 2016-2017 growing season. In the current study, the main plot was assigned to drought stress at three levels (including irrigation to supply 100%, 75% or 50% of plant water requirement), the sub-plot was assigned to N fertilization at three rates (50, 100 or 150 kg ha-1 pure N), and the sub-sub-plot was assigned to ecotype at three levels (Bami, Bushehri, and Rudbari). The results showed that the effect of drought level was significant on active ingredient and chlorophyll index at the p < 0.01 level and on chlorophyll a, total chlorophyll, and chlorophyll a/b ratio at the p < 0.05 level. But, it could not influence chlorophyll b significantly. The effect of N fertilization was significant on most studied traits at the p< 0.01 level, but its effect was significant on the chlorophyll index at the p < 0.05 level and insignificant on dye and chlorophyll b. According to the results, it seems that the application of 100 kg ha-1 N and the irrigation to supply 75% of plant water requirement can contribute to having more fresh plants with the higher active ingredient and dye contents.

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ALTURA DE PLANTAS E DIÂMETRO DE COLMOS DE SORGO FORRAGEIRO IRRIGADO EM FUNÇÃO DE CORTES

Irriga ◽

10.15809/irriga.2020v25n2p223-233 ◽

2020 ◽

Vol 25 (2) ◽

pp. 223-233

Author(s):

Jardel Henrique Kirchner ◽

Adroaldo Dias Robaina ◽

Marcia Xavier Peiter ◽

Rogério Ricalde Torres ◽

Wellington Mezzomo ◽

...

Keyword(s):

Plant Height ◽

Block Design ◽

Rio Grande ◽

Stem Diameter ◽

Rio Grande Do Sul ◽

Pasture Production ◽

Randomized Block Design ◽

Water Conditions ◽

Cattle Herds ◽

Santa Maria

ALTURA DE PLANTAS E DIÂMETRO DE COLMOS DE SORGO FORRAGEIRO IRRIGADO EM FUNÇÃO DE CORTES JARDEL HENRIQUE KIRCHNER1; ADROALDO DIAS ROBAINA2; MARCIA XAVIER PEITER3; ROGÉRIO RICALDE TORRES4; WELLINGTON MEZZOMO5 E RICARDO BENETTI ROSSO6 1 Eng. Agrônomo, Doutor, Professor do Instituto Federal de Educação, Ciência e Tecnologia do Rio Grande do Sul, Rua Nelsi Ribas Fritsch, nº 1111, bairro Esperança, Ibirubá, RS, Brasil, CEP: 98200-000, [email protected]. 2 Eng. Agrônomo, Doutor, Professor Titular do Departamento de Engenharia Rural, UFSM, Avenida Roraima, nº 1000, bairro Camobi, Santa Maria, RS, Brasil, CEP: 97195-000, [email protected]. 3 Eng. Agrônoma, Doutora, Professora Associada do Departamento de Engenharia Rural, UFSM, Avenida Roraima, nº 1000, bairro Camobi, Santa Maria, RS, Brasil, CEP: 97195-000, [email protected]. 4 Eng. Agrônomo, Doutor, Professor do Instituto Federal de Educação, Ciência e Tecnologia do Rio Grande do Sul, Rua Eng. João Viterbo de Oliveira, nº 3061, Zona Rural, Vacaria, RS, Brasil, CEP: 95219-899, [email protected]. 5 Eng. Agrônomo, Mestre, Doutorando no Programa de Pós-Graduação em Engenharia Agrícola, UFSM, Avenida Roraima, nº 1000, bairro Camobi, Santa Maria, RS, Brasil, CEP: 97195-000, [email protected]. 6 Eng. Agrônomo, Doutor, Professor no Instituto Federal Catarinense, Rodovia SC 283 - km 17, Concórdia, SC, Brasil, CEP: 89703-720, ricardo.rosso @ifc.edu.br. 1 RESUMO A obtenção de elevadas produtividades de pastagens é essencial para a manutenção dos níveis alimentares de rebanhos bovinos. A altura de plantas e o diâmetro de colmos caracterizam-se como determinantes no sucesso produtivo da pastagem pela quantidade de massa produzida. Um dos fatores que alteram esses índices são as precipitações irregulares, tornando necessária a reposição da demanda através da irrigação. O objetivo do trabalho foi avaliar o diâmetro de colmos e a altura de plantas sob diferentes condições hídricas e cortes no sorgo forrageiro, em dois anos agrícolas no estado do Rio Grande do Sul. Foram conduzidos dois experimentos nos anos agrícolas de 2015/2016 e 2016/2017 em Santa Maria (RS), e foram avaliadas as alturas de plantas e os diâmetros de colmos em seis condições hídricas (não irrigado, 25, 50, 75, 100 e 125 % da ETo), em três períodos de cortes (50, 80 e 110 dias após a semeadura) em delineamento blocos ao acaso. Foram encontradas diferenças estatisticamente significativas para a variação da altura de plantas e também do diâmetro de colmos, tanto conforme a lâmina de irrigação, quanto na sequência de cortes. Palavras chave: pastagem irrigada, capacidade de rebrote, irrigação. KIRCHNER, J. H.; ROBAINA, A. D.; PEITER, M. X.; TORRES, R. R.; MEZZOMO, W.; ROSSO, R. B. HEIGHT OF PLANTS AND DIAMETER OF STEMS OF SORGHUM FORAGE IRRIGATED BY CUTS 2 ABSTRACT Achieving high pasture yields is essential for maintaining feed levels in cattle herds. Plant height and stem diameter are determinants of pasture production success by the amount of mass produced. One of the factors that change these rates is irregular rainfall, making it necessary to replenish demand through irrigation. The objective of this work was to evaluate stem diameter and plant height under different water conditions and forage sorghum cuts in two agricultural years in the state of Rio Grande do Sul. Two experiments were conducted in the agricultural years of 2015/2016 and 2016/2017 in Santa Maria / RS, and plant heights and stem diameters were evaluated in six water conditions (non-irrigated, 25, 50, 75, 100 and 125% of ETo), in three cutting periods (50, 80 and 110 days after sowing) in a randomized block design. Statistically significant differences were found for plant height and stem diameter variation, both according to irrigation depth and cut sequence. Keywords: irrigated pasture, regrowth capacity, irrigation.

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Allometric relationship and leaf area modeling estimation on chia by non-destructive method

Revista Brasileira de Engenharia Agrícola e Ambiental ◽

10.1590/1807-1929/agriambi.v25n5p305-311 ◽

2021 ◽

Vol 25 (5) ◽

pp. 305-311

Author(s):

Patrícia C. H. Goergen ◽

Isabel Lago ◽

Natalia T. Schwab ◽

Alexandre F. Alves ◽

Charles P. de O. Freitas ◽

...

Keyword(s):

Leaf Area ◽

Block Design ◽

Main Stem ◽

Allometric Relationship ◽

Linear Quadratic ◽

Predictive Capacity ◽

Randomized Block Design ◽

Number Of Leaves ◽

Salvia Hispanica L ◽

Non Destructive

ABSTRACT This study aimed to obtain equations to estimate leaf area from linear leaf dimensions and establish the allometric relationship between leaf area and the number of leaves on the main stem of chia (Salvia hispanica L.) at different sowing times. The experiment was conducted in the agricultural year 2016/2017 on five sowing times in Santa Maria, RS, Brazil, in a randomized block design with four repetitions. In each plot, ten random plants were marked weekly during the vegetative phase to determine the number of leaves (NL) in the main stem, and three of these for the determination of leaf area (LA). A total of 70 leaves of different sizes were used to calibrate the model. Another 106 leaves were used to test the predictive capacity of the equations by various statistical indices. The length (L) and the largest leaf width (W) were measured. Leaf collection was carried out during the cycle, in all sowing times to represent all leaf sizes. The linear, quadratic, exponential, and potential models were adjusted. The non-destructive method, through the linear dimensions of the leaf, is appropriate for estimating the leaf area in chia. The general equation LA = 0.642 (L x W) can be used to estimate the leaf area of the chia plants without loss of precision. The potential model is appropriate to characterize the allometric relationship between leaf area evolution and the number of leaves accumulated in the main stem of chia at different sowing times.

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Non-destructive measurement of chlorophyll b:a ratios and identification of photosynthetic pathways in grasses by reflectance spectroscopy

Functional Plant Biology ◽

10.1071/fp09201 ◽

2009 ◽

Vol 36 (11) ◽

pp. 857 ◽

Cited By ~ 11

Author(s):

Katharina Siebke ◽

Marilyn C. Ball

Keyword(s):

Chlorophyll A ◽

Reflectance Spectra ◽

Grass Species ◽

Chlorophyll B ◽

Hordeum Vulgare L ◽

Chlorophylls A And B ◽

Fluorescence Characteristics ◽

Destructive Measurement ◽

Non Destructive

Equations for non-destructive determination of chlorophyll b : a ratios in grasses were developed from reflectance spectra of intact leaves of barley (Hordeum vulgare L.) and two barley mutants: clorina f2, which lacks chlorophyll b and clorina f104, which has a low chlorophyll b content. These plants enabled separation of effects of chlorophyll composition on reflectance spectra due to differential light absorption by chlorophylls a and b and to measure the effects of chlorophyll b on the contribution of fluorescence emitted by chlorophyll a to the reflectance spectra. Indices developed from these data were then tested on growth chamber-grown leaves from six C3 and 17 C4 grass species (7 NAD-ME and 10 NADP-ME subtypes). We used the chlorophyll b : a ratio because the data were less skewed than the chlorophyll a : b ratio. The best index for determination of the chlorophyll b : a ratio utilised wavelengths affected by chlorophyll absorbance: [R626 – 0.5 (R603 + R647)]/[R552– R626]. The chlorophyll b : a ratio was significantly lower in the C4 than C3 grasses, but was not sufficient in itself to separate these two functional groups. However, because of differences in fluorescence characteristics, C3 and C4 species could be distinguished by an index based on wavelengths affected by chlorophyll fluorescence: [R696 to 709/R545 to 567].

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