Non-destructive determination of maize leaf and canopy chlorophyll content

Abstract

SummaryThe objective of this study was to develop a rapid non-destructive technique to estimate total chlorophyll (Chl) content in a maize canopy using Chl content in a single leaf. The approach was (1) to calibrate and validate a reflectance-based nondestructive technique to estimate leaf Chl in maize; (2) to quantify the relative contribution of each leaf Chl to the total Chl in the canopy; and (3) to establish a relationship between leaf Chl content and total Chl in a maize canopy. The Red Edge Chlorophyll Index Clred edge = (RNIRIRred edge)-l based on reflectances, R, in the red edge (720-730nm) and near infrared (770-800nm) was found to be an accurate measure of maize leaf Chl. It was able to predict leaf Chl ranging from 10 to 805 mg Chl m-2 with root mean-square error less than 38 mg Chl mP2. Relationships between Chl content in each maize leaf and total canopy Chl content were established and showed that Chl in the collar leaf before silking or ear leaves explained more than 80% and 87% of the variation in total Chl in a maize canopy, respectively. Thus, non-destructive measurements of both reflectance and area of a single leaf (either collar or ear) can be used to accurately estimate total Chl content in a maize canopy.

Efficiency of chlorophyll in gross primary productivity: A proof of concept and application in crops

“…For both crops combined, the coefficient of determination of this relationship was above 0.9, the root mean square error of Chl estimation was below 0.35 g m −2 and the normalized root mean squire error was less than 13% (Ciganda et al, 2009). …”

“…The red edge chlorophyll index CI rededge = (ρ 760-780 /ρ 720-740 − 1) where ρ 760-780 and ρ 720-740 are reflectances in the NIR range of the spectrum from 760 to 780 nm and red edge range from 720 to 740 nm, respectively, was used. CIrededge has been shown to be an accurate measure of canopy Chl in contrasting vegetation canopies with different architectures and leaf structures without the need for re-parameterization Ciganda et al, 2009). Total canopy Chl (in g m −2 ) was calculated using the CI rededge following the equation:…”

Multiple drivers of seasonal change in PRI: Implications for photosynthesis 2. Stand level

“…A 99% reflectance standard (Spectralon, LabSphere, North Sutton NH, USA) was scanned before and after each leaf measurement. The reflectance was calculated as the ratio of upwelling leaf radiance to the upwelling radiance of the standard (details are in Gitelson et al, 2005, Ciganda et al, 2009.…”

“…RMSE of Chl content prediction by CI red edge was 38 mg m -2 in the range of Chl content 22-880 mg m -2 by (details in Gitelson et al, 2003Gitelson et al, , 2006Ciganda et al, 2009). The stand reflectance measurements and ground measurements were not always concurrent and, since LAI and leaf Chl content changed gradually, spline interpolations were taken between destructive LAI sampling dates for each field in each year using Matlab (V. 7.9.0.529, The MathWorks, Massachusetts, USA) (Nguy-Robertson et al, 2012).…”

Pigmentos fotossintéticos em azevém suscetível e resistente ao herbicida glyphosate

“…Diferentemente, os leitores portáteis de clorofi la utilizam princípios não destrutivos, simples e instantâneos, possibilitando estudos ontogênicos foliares das culturas (SALLA et al, 2007). Clorofi lômetros portáteis estão sendo utilizados com êxito na determinação de pigmentos fotossintéticos em diferentes espécies, como relatado por CIGANDA et al (2009), em milho, e RIGON et al (2013, na cultura do pinhão-manso.…”