scholarly journals Ability of Modified Spectral Reflectance Indices for Estimating Growth and Photosynthetic Efficiency of Wheat under Saline Field Conditions

Agronomy ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 35 ◽  
Author(s):  
Salah El-Hendawy ◽  
Nasser Al-Suhaibani ◽  
Yaser Dewir ◽  
Salah Elsayed ◽  
Majed Alotaibi ◽  
...  
Keyword(s):  
Salt Stress ◽  
Spectral Reflectance ◽  
Photosynthetic Efficiency ◽  
Near Infrared ◽  
Field Conditions ◽  
Physiological Status ◽  
Dry Matter Content ◽  
Reflectance Indices ◽  
Non Destructive ◽  
Spectral Reflectance Indices

Hyperspectral sensing offers a quick and non-destructive alternative for assessing phenotypic parameters of plant physiological status and salt stress tolerance. This study compares the performance of published and modified spectral reflectance indices (SRIs) for estimating and predicting the growth and photosynthetic efficiency of two wheat cultivars exposed to three salinity levels (control, 6.0, and 12.0 dS m−1). Results show that individual SRIs based on visible- and near-infrared (VIS/VIS, NIR/VIS, and NIR/NIR) estimate and predict measured parameters considerably more efficiently than those based on shortwave-infrared (SWIR/VIS and SWIR/NIR), with the exception of some modified indices (the water balance index (WABI-1(1550, 482), WABI-2(1640, 482), and WABI-3(1650, 531)), normalized difference moisture index (NDMI(1660, 1742)), and dry matter content index (DMCI(1550, 2305)), which show moderate to strong relationships with measured parameters. Overall results indicate that modified SRIs can serve as rapid and non-destructive high-throughput alternative approaches for tracking growth and photosynthetic efficiency of wheat under salt stress field conditions.

Spectral Reflectance Indices as a Potential Indirect Selection Criteria for Wheat Yield under Irrigation

Crop Science ◽  
2006 ◽  
Vol 46 (2) ◽  
pp. 578-588 ◽  
Author(s):  
M. A. Babar ◽  
M. P. Reynolds ◽  
M. van Ginkel ◽  
A. R. Klatt ◽  
W. R. Raun ◽  
...  
Keyword(s):  
Spectral Reflectance ◽  
Selection Criteria ◽  
Wheat Yield ◽  
Indirect Selection ◽  
Reflectance Indices ◽  
Spectral Reflectance Indices

The Potential of Using Spectral Reflectance Indices to Estimate Yield in Wheat Grown Under Reduced Irrigation

Euphytica ◽  
2006 ◽  
Vol 150 (1-2) ◽  
pp. 155-172 ◽  
Author(s):  
M. A. Babar ◽  
M. van Ginkel ◽  
A. R. Klatt ◽  
B. Prasad ◽  
M. P. Reynolds
Keyword(s):  
Spectral Reflectance ◽  
Reflectance Indices ◽  
Spectral Reflectance Indices

Reflectance indices as nondestructive indicators of the physiological status of Ceratonia siliqua seedlings under varying moisture and temperature regimes

2012 ◽  
Vol 39 (7) ◽  
pp. 588 ◽  
Author(s):  
Júlio Osório ◽  
Maria Leonor Osório ◽  
Anabela Romano
Keyword(s):  
Water Availability ◽  
Spectral Reflectance ◽  
Water Status ◽  
Chlorophyll Concentration ◽  
Photochemical Efficiency ◽  
Principal Component ◽  
Physiological Status ◽  
Total Chlorophyll ◽  
Ceratonia Siliqua ◽  
Reflectance Indices

We investigated the use of spectral reflectance techniques to monitor the physiological responses of Ceratonia siliqua L. seedlings exposed to different levels of water availability under normal (25 : 18°C, day : night) and elevated (32 : 21°C, day : night) temperatures. Three spectral reflectance indices (photochemical reflectance index, PRI; water index, WI; red edge position, REP) were measured along with water status, chlorophyll fluorescence and chlorophyll concentration variables in the leaves of well watered, moderately stressed, severely stressed and rehydrated plants under each temperature regime. The PSII effective photochemical efficiency (φ2) and the intrinsic efficiency of open PSII centres (F′v/F′m) correlated significantly with PRI, and these three variables loaded heavily onto the same principal component of a three-factor principal component analysis solution. Water concentration (WC) and the succulence index (SI) were more strongly correlated with WI than either water potential (ΨPD) or relative water content (RWC). Accordingly, WI, WC and SI were combined in the second principal component, and ΨPD and RWC in the third. Our results provide clear evidence for interaction between water availability and temperature in the WI and the PRI response segments of the reflectance curves. Elevated temperature inhibited the recovery of WI spectral segments more than that of the PRI segments in SS plants. REP showed a strongly positive linear relationship with leaf total chlorophyll concentration across all water and temperature treatment combinations. PRI, WI and REP are therefore reliable markers that can be used to monitor φ2, WC and total chlorophyll concentration, respectively, in C. siliqua seedlings under drought and temperature stress.

Association of biomass production and canopy spectral reflectance indices in winter wheat

2009 ◽  
Vol 89 (3) ◽  
pp. 485-496 ◽  
Author(s):  
B. Prasad ◽  
M. A. Babar ◽  
B. F. Carver ◽  
W. R. Raun ◽  
A. R. Klatt
Keyword(s):  
Winter Wheat ◽  
Grain Yield ◽  
Water Content ◽  
Biomass Production ◽  
Spectral Reflectance ◽  
Water Based ◽  
Canopy Spectral Reflectance ◽  
Reflectance Indices ◽  
Canopy Water ◽  
Spectral Reflectance Indices

Increased biomass production could be an important criterion for future grain yield improvement in wheat (Triticum aestivum L.). Quick assessment of genetic variations for biomass production may become a useful tool for wheat breeders. The potential of using canopy spectral reflectance indices (SRI) to assess genetic variation for biomass production in winter wheat was evaluated. Three experiments were conducted for 2 yr (2003-2004 and 2004-2005) at Oklahoma State University, Stillwater, OK. The first experiment consisted of 25 winter wheat cultivars, and the other two experiments contained two sets of 25 F4:6 and F4:7 recombinant inbred lines from two crosses developed by breeding programs in the great plains of the United States of America. Three groups of SRI (vegetation-based, pigment-based, and water-based) were tested for their ability to assess biomass production at three growth stages (booting, heading, and grainfilling). The water index and the normalized water indices gave stronger genetic correlations (P < 0.01) and linear relationship for biomass production compared with the vegetation-based and pigment-based indices. The strong association of water-based indices with biomass was related to the canopy water content of the genotypes. Canopy water content was significantly (P < 0.05) correlated with biomass production. A strong positive association (P < 0.05) of grain yield and dry biomass was observed at the heading and grainfilling stages. Our study demonstrated the potential of using water-based SRI as a breeding tool to estimate genetic variability and identify genotypes with higher biomass production, and could eventually help to achieve higher grain yield in winter wheat. Key words: Wheat; biomass; grain yield; spectral reflectance index

scholarly journals Changes in spectral reflectance of selected Antarctic and South American lichens caused by dehydration and artificially-induced absence of secondary compounds

2016 ◽  
Vol 6 (2) ◽  
pp. 221-230 ◽  
Author(s):  
Miloš Barták ◽  
Josef Hájek ◽  
Ana Carolina Amarillo ◽  
Jana Hazdrová ◽  
Hebe Carreras
Keyword(s):  
Secondary Metabolites ◽  
Spectral Reflectance ◽  
Spectral Characteristics ◽  
Great Majority ◽  
Secondary Compounds ◽  
Hydration Status ◽  
Alpine Regions ◽  
Species Specific ◽  
Reflectance Indices ◽  
Spectral Reflectance Indices

Recently, spectral characteristics of lichens are in focus because of increasing number of spectral data applications in remote sensing of treeless polar and alpine regions. Therefore, species-specific spectral reflectance indices are measured in lichen species dominating polar ecosystems. Hydration status of the lichen thalli, as well as the presence of intrathalline secondary metabolites - which are UV-B absorbing compounds - both affects the spectral reflectance curves as well as numeric values of spectral reflectance indices. In the present paper, the reflectance spectra in 380-800 nm was measured in selected lichens to assess the effects of full hydration, and to evaluate the influence of secondary metabolites, they were wash out from lichen thalli with acetone (i.e. acetone rinsing) and then the spectra were also measured. For these experiments, Antarctic (Xanthoria elegans, Leptogium puberulum, Physconia muscigena and Rhizoplaca melanophthalma) and Argentinean lichens from mountain regions (Parmotrema conferendum and Ramalina celastri) were used. Changes in several spectral reflectance indices were evaluated and discussed in relation with hydration status and the absence of secondary metabolites. For the great majority of studied lichens, MCARI (Modified Chlorophyll Absorption in Reflectance Index) was the most effective index to reflect the changes between dry and wet state of thallus.

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