Effects of N fertilization on the relationship between photosynthetic light use efficiency and photochemical reflectance index of wetland vegetation

2010 ◽  
Author(s):  
Qian Cheng ◽  
Xiuju Wu
2004 ◽  
Vol 31 (3) ◽  
pp. 255 ◽  
Author(s):  
Jianmin Guo ◽  
Craig M. Trotter

Recent studies have shown that the photochemical reflectance index (PRI), derived from narrow waveband reflectance at 531 and 570 nm, can be used as a remote measure of photosynthetic light-use efficiency (LUE). However, uncertainty remains as to the consistency of the relationship between PRI and LUE across species. In this study we examined the relationship between the PRI and various photosynthetic parameters for a group of species with varying photosynthetic capacity. At constant irradiance, for the species group as a whole, the PRI was well correlated with LUE (r2=0.58) and with several other photosynthetic parameters, but best correlated with the ratio of carotenoids to chlorophylls contents (Caro / Chl). Despite the interspecific trends observed, determination of light response functions for the PRI in relation to photosynthetic parameters revealed that species-specific relationships were clearly stronger. For example, r2>0.90 for species-level PRI / LUE relationships. Also, the species-specific light-response data show that the magnitude of the PRI can be related to the magnitude of the saturated irradiance and the rate of CO2 uptake. As demonstrated here, a light response function provides a simple yet precise approach for characterising the relationship between the PRI and photosynthetic parameters, which should assist with improved evaluation of the usefulness of the PRI as a generalised measure of LUE.


2018 ◽  
Vol 45 (3) ◽  
pp. 278 ◽  
Author(s):  
Firmansyah Aznur ◽  
Suwarto , ◽  
Dan Heni Purnamawati

Light use efficiency (LUE) determines biomass production based on interception energy during photosynthesis. The product of photosynthesis is allocated to the plants organs based on the partitioning of carbohydrates. The LUE and carbohydrate partitioning are two important parameters in crop modelling. The research was conducted at Cikabayan experimental station of IPB, Bogor from July to November 2015. The experiment was designed according to a randomize block design with five replications. The fertilizer treatments rate were 0%, 50%, 100%, 150%, and 200% of reference N fertilization of 120 kg ha-1.  The  value  of  light use efficiency and the partition coefficient of sorghum were not affected by N fertilization. The value of light use efficiency is 1.41 g MJ-1. The carbohydrates partitioning was developed based on plant growth stage. The partition from the planting to the emergence stage (0 ≤ s ≤ 0.25) was 0.81 x s/0.25 root, 0 stem, 0.19 x s/0.25 leaves, and 0 panicle. The partition from the emergence to the maximum vegetative stage (0.25 &lt; s ≤ 0.5) was 0.81-(0.59 x s/0.5) root, 0.14 x s/0.5  stem, 0.19 + (0.45 x s/0.5) leaves, and 0 panicle. The partition from the maximum vegetative stage to the flowering stage (0.5 &lt; s ≤ 0.75) was 0.22 - (0.09 x s/0.75) root, 0.14 + (0.39 x s/0.75) stem, 0.64 - (0.46 x s/0.75) leaves, and 0.16 x s/0.75 panicle. The partition from flowering to the harvest stage (0.75 &lt; s ≤ 1) was 0.13 - (0.13 x s) root, 0.53 - (0.52 x s) stem, 0.18-(0.18 x s) leaves, and 0.16 + (0.84 x s) panicle.<br /><br />Keywords: crop modelling, light use efficiency, N fertilizer, partitioning carbohydrates<br /><br />


2015 ◽  
Vol 7 (12) ◽  
pp. 16938-16962 ◽  
Author(s):  
Qian Zhang ◽  
Weimin Ju ◽  
Jing Chen ◽  
Huimin Wang ◽  
Fengting Yang ◽  
...  

2018 ◽  
Vol 10 (8) ◽  
pp. 1202 ◽  
Author(s):  
Daniel Kováč ◽  
Petra Veselovská ◽  
Karel Klem ◽  
Kristýna Večeřová ◽  
Alexander Ač ◽  
...  

Hyperspectral reflectance is becoming more frequently used for measuring the functions and productivity of ecosystems. The purpose of this study was to re-evaluate the potential of the photochemical reflectance index (PRI) for evaluating physiological status of plants. This is needed because the reasons for variation in PRI and its relationships to physiological traits remain poorly understood. We examined the relationships between PRI and photosynthetic parameters in evergreen Norway spruce and deciduous European beech grown in controlled conditions during several consecutive periods of 10–12 days between which the irradiance and air temperature were changed stepwise. These regime changes induced significant changes in foliar biochemistry and physiology. The responses of PRI corresponded particularly to alterations in the actual quantum yield of photosystem II photochemistry (ΦPSII). Acclimation responses of both species led to loss of PRI sensitivity to light use efficiency (LUE). The procedure of measuring PRI at multiple irradiance-temperature conditions has been designed also for testing accuracy of ΔPRI in estimating LUE. A correction mechanism of subtracting daily measured PRI from early morning PRI has been performed to account for differences in photosynthetic pigments between irradiance-temperature regimes. Introducing ΔPRI, which provided a better estimate of non-photochemical quenching (NPQ) compared to PRI, also improved the accuracy of LUE estimation. Furthermore, ΔPRI was able to detect the effect of drought, which is poorly observable from PRI.


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