Effect of Phosphorus Deficiency on Reflectance and Chlorophyll Fluorescence of Cotyledons of Oilseed Rape (Brassica napus L.)

Abstract

The spectroscopic changes in reflectance and fluorescence caused by phosphorus (P) starvation in Brassica napus L. young plants were evaluated. P deficiency produced an important decrease in reflectance values between 500 and 650 nm for both intact leaves and cotyledons. Furthermore, cotyledons under P deficiency showed a Chl-F ratio in the red/far-red region (F red /F far-red ) lower than that of non-stressed plants (1.91 and 2.89 respectively). As minimal differences in F red /F far-red were detected in leaves, P deficiencies may be better perceived by measuring changes in Chl-F emission in cotyledons than in leaves. Stressed cotyledons also showed different emission spectra in the blue green (maxima at 470 and 560 nm) from those of non-stressed cotyledons. The results are explained in terms of higher anthocyanin and chlorophyll contents and of damage to photosystem II. We evaluate that measuring variations in fluorescence and reflectance data may be useful to detect early damages induced by P stress.

Integrating Solar Induced Fluorescence and the Photochemical Reflectance Index for Estimating Gross Primary Production in a Cornfield

“…These findings suggest a future approach to significantly improve the performance of current LUE models, by combining these two optical signals. NPQ and chlorophyll fluorescence emission are considered as direct indicators of photosynthetic activities and physiological stress when plants are under sub-optimal environmental conditions [28,53,59,80,[90][91][92][93] such as low water availability [81,[93][94][95], unfavorable temperatures [96,97], nutrients [98][99][100][101], and salinity [102,103]. Consequently, many studies have utilized the spectral indices, PRI and SIF retrievals, as indicators of stress and down-regulation of LUE and GPP [29,50,51,65,82,92,[104][105][106][107].…”

Physiological differences in Rhododendron calophytum seedlings regenerated in mineral soil or on fallen dead wood of different decaying stages

“…The probable reason is that the leaf N concentration, the most important influencing factor of the pigment concentration, did not vary statistically significantly among the seedlings. A low leaf P concentration either increases, decreases or has no effect on the concentration of chlorophyll in leaf tissue (Wallin et al 2002;Lin et al 2009;Yaryura et al 2009). Furthermore, the difference in water availability between different substrates may not be large enough to cause significant differences in the pigment concentration or it may be counteracted by the effect of available P.…”

Spectral Response of Citrus and Their Application to Nutrient and Water Constraints Diagnosis

“…Although N is considered the most important nutrient to monitor in crops, other element de fi ciencies as phosphorous can lead to lower shoot and root growth and eventually to a decrease in yield (Milton et al 1991 ;Osborne et al 2004 ) . The biggest spectral differences due to leaf P concentration have been found in the 500-650 nm and near-infrared regions (Milton et al 1991 ;Osborne et al 2002 ;Yaryura et al 2009 ) . Phosphate-de fi cient leaves have less inorganic phosphorous in the tissue water, lower photosynthetic and stomatal conductance rates, and higher number of small cells per unit area (Jacob and Lawlor 1991 ) .…”

“…The limited photosynthetic rate and the decrease of stomatal conductance are symptoms that are more affected by water or nitrogen stress. Changes in the green-red region can be due to a decrease of the pigment pool due to severe stress (Yaryura et al 2009 ) .…”