Using violet laser-induced chlorophyll fluorescence emission spectra for crop yield assessment of cowpea (Vigna unguiculata (L) Walp) varieties

Abstract

The use of violet laser-induced chlorophyll fluorescence (LICF) emission spectra to monitor the growth of five varieties of cowpea in the University of Cape Coast Botanical Garden is presented. Radiation from a continuous-wave violet laser diode emitting at 396 nm through a fibre is closely incident on in vivo leaves of cowpea to excite chlorophyll fluorescence, which is detected by an integrated spectrometer with CCD readout. The chlorophyll fluorescence spectra with peaks at 683 and 731 nm were used for growth monitoring of the cowpea plants over three weeks and analysed using Gaussian spectral functions with curve fitted parameters to determine the peak positions, area under the spectral curve and the intensity ratio F683/F731. The variation in the intensity ratio of the chlorophyll bands showed sensitive changes indicating the photosynthetic activity of the cowpea varieties. A discussion of the fluorescence result as compared to conventional assessment is presented with regard to discrimination between the cowpea varieties in terms of crop yield performance.

Effects of intertidal ­microphytobenthos migration on biomass determination via laser-induced ­fluorescence

“…LIF techniques overcome this limitation and have been successfully used in the remote sensing of terrestrial plants (e.g. Subhash & Mohanan 1997, Richards et al 2003, Anderson et al 2004, phytoplankton (Barbini et al 1998) and macroalgae (Kieleck et al 2001). More recently, a laser-induced fluorescence transient (LIFT) fluorometer, which uses a fast repetition rate technique (Kolber & Falkowski 1993), has been developed to operate with relatively low excitation power with subsaturating flashes for measurement of fluorescence parameters from a distance of up to 50 m (Kolber et al 2005, Pieruschka et al 2010.…”

“…Subhash & Mohanan 1997, Richards et al 2003, Anderson et al 2004, phytoplankton (Barbini et al 1998) and macroalgae (Kieleck et al 2001). The chlorophyll (chl) fluorescence spectrum of plant leaves typically includes 2 maxima, one in the red (684 to 695 nm) and one in the far-red (730 to 740 nm) region, which are primarily dependent on the concentration of chl a (see review by Buschmann 2007).…”

Application of Laser-Induced Fluorescence in Functional Studies of Photosynthetic Biofilms

“…On the contrary, LIF has been successfully used in medium-and long-range remote sensing of vegetation [27,57,58]. More recently, LIFT (laser-induced fluorescence transients) have been measured using devices able to operate at a distance reaching 50 m from the sample [34,59,60].…”

Correcting the effect of the detection angular on laser-induced chlorophyll fluorescence

“…Gu et al [25] discussed the effect of flooding and waterlogging on the fluorescence characteristics. Anderson et al [26] analyzed the performance of LIF spectra for the assessment of the crop yield of cowpea (Vigna unguiculata (L) Walp), and found that the fluorescence characteristics can be efficiently applied in analyzing the change in photosynthetic activity. In addition, Yang et al [12,19] thoroughly discussed the performance of fluorescence parameters combined with multivariate analysis in the monitoring of N stress in paddy rice.…”