Nitrogen allocation regulates the relationship between maximum carboxylation rate and chlorophyll content along the vertical gradient of subtropical forest canopy

Establishment of disease in oil palm seedlings through artificial inoculation of Ganoderma are widely used for studies of various aspects of plant pathology, including epidemiology, etiology, disease resistance, host-parasite interaction and disease control. The estimation of chlorophyll content in the infected seedlings possibly could provide a good indicator for degree of disease or infection, and changes during pathogenesis. Thus, the objective of this study was to evaluate the relationship between disease severity index (DSI) and chlorophyll content in Ganoderma infected oil palm seedlings. Three-month-old oil palm seedlings were infected with Ganoderma inoculum on rubber wood block (RWB), where 44 isolates of Ganoderma were tested. Disease severity index (DSI) and chlorophyll content using a single-photon avalanche diode (SPAD) meter were recorded at 4 weeks interval for a period of 24 weeks after inoculation (WAI). Pearson's correlation analysis and regression analysis were performed to evaluate the relationship between the variables. It was found that the relationship between DSI and SPAD chlorophyll value was inversely proportional (R = -0.92) in a linear trend (R2 = 0.85). Furthermore, the increasing trend of the DSI across the weeks were fitted in a quadratic model (R2 = 0.99). In contrast, the SPAD chlorophyll value declined in a linear trend (R2 = 0.98). The SPAD chlorophyll value could be considered as a better alternative over the DSI as the SPAD chlorophyll value was strongly related to DSI, as well as able to detect physiological changes in the infected oil palm seedlings at the early stages of pathogenesis. J Bangladesh Agril Univ 17(3): 355–358, 2019

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The Optical Measurement of Lapse Rate *

Bulletin of the American Meteorological Society ◽

10.1175/1520-0477-31.2.51 ◽

1950 ◽

Vol 31 (2) ◽

pp. 51-55 ◽

Cited By ~ 18

Author(s):

Robert G. Fleagle

Keyword(s):

Optical Measurement ◽

Vertical Gradient ◽

Lapse Rate ◽

Speed Of Light ◽

Indirect Methods ◽

Reliable Determination ◽

Air Density ◽

Lapse Rates ◽

The Relationship

The need for reliable determination of the temperature of the air very near the ground and the difficulties inherent in measurement of this quantity by the ordinary indirect methods are pointed out. It is suggested that the dependence of the speed of light on air density provides a convenient method for the determination of the temperature near the ground by direct measurement of the lapse rate, and evidence is given from other papers to show that this is feasible where the vertical gradient of humidity is not great. The relationship between apparent elevation and lapse rates of temperature and vapor pressure is derived, and the relationship is illustrated by the results of computations.

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Fluxes of nitrogen oxides above a subtropical forest canopy in China

The Science of The Total Environment ◽

10.1016/j.scitotenv.2020.136993 ◽

2020 ◽

Vol 715 ◽

pp. 136993

Author(s):

Piaopiao Ke ◽

Qian Yu ◽

Yao Luo ◽

Ronghua Kang ◽

Lei Duan

Keyword(s):

Nitrogen Oxides ◽

Forest Canopy ◽

Subtropical Forest

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THE RELATIONSHIP BETWEEN CHLOROPHYLL CONTENT AND RATE OF PHOTOSYNTHESIS IN SOYBEANS

Canadian Journal of Plant Science ◽

10.4141/cjps77-001 ◽

1977 ◽

Vol 57 (1) ◽

pp. 1-5 ◽

Cited By ~ 55

Author(s):

B. R. BUTTERY ◽

R. I. BUZZELL

Keyword(s):

Linear Regression ◽

Chlorophyll Content ◽

Photosynthetic Rate ◽

Regression Line ◽

Quadratic Equation ◽

Chlorophyll Contents ◽

Rate Of Photosynthesis ◽

Highly Correlated ◽

The Relationship ◽

Selection Of

Photosynthetic rate of soybeans (on a leaf area basis, PA) estimated from the incorporation of 14CO2 under field conditions was highly correlated with chlorophyll content of the side leaflets of the same leaves. Among a collection of 48 cultivars, the linear regression of PA on chlorophyll content accounted for 44% of the variation, whereas with a selection of genotypes with various mutant chlorophyll genes, the regression accounted for 81%. When the data for the two tests were re-calculated relative to the check cv. Altona, a quadratic equation between PA and chlorophyll accounted for nearly 90% of the variation. When photosynthetic rate was expressed on a unit chlorophyll basis (Pc), no significant differences among lines were established in the cultivar test. In the mutants test, significant differences in Pc were established with higher values of Pc associated with lower chlorophyll contents; a linear regression accounted for 45% of the variation. Transformation of the data from both experiments relative to Altona allowed the fitting of a common regression line (quadratic) which accounted for 63% of the variation. We suggest that initial screening of progenies in a breeding program for high photosynthetic rate could be done by measuring chlorophyll content.

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Chlorophyll as an indicator of green tea quality

Acta Veterinaria Brno ◽

10.2754/avb201483s10s103 ◽

2014 ◽

Vol 83 (10) ◽

pp. S103-S109 ◽

Cited By ~ 5

Author(s):

Martina Ošťádalová ◽

Bohuslava Tremlová ◽

Jana Pokorná ◽

Martin Král

Keyword(s):

Chlorophyll Content ◽

Green Tea ◽

Storage Time ◽

Chlorophyll Concentration ◽

Storage Period ◽

Storage Conditions ◽

Qualitative Variable ◽

Chlorophyll Contents ◽

Tea Quality ◽

The Relationship

The objective of this work was to study the changes in chlorophyll contents in green teas stored under different conditions and to suggest the most suitable way and length of green tea storage. A secondary aim was to evaluate the possibility of using the chlorophyll content as an indicator of tea freshness. Samples for analysis were obtained from a range of tea-growing regions. Chlorophyll contents were measured using UV-vis spectrophotometry. Chlorophyll absorbance was measured at 642.5 and 660 nm. Prior to storage, chlorophyll concentration in teas ranged from 1.12 to 1.89 mg per 1 g of tea, which corresponded to data given by other authors. Storage was found to lead to a decline in chlorophyll concentration. From the 6th month of storage onwards, a significant decrease (P < 0.05) was observed in all samples, irrespective of storage conditions. Based on the findings of this study, original and metal packaging can be considered the most chlorophyll-friendly. On the other hand, glass and paper packaging stored in direct daylight were found to have the strongest impact on chlorophyll concentration. Overall, it can be concluded that the storage time can have a strong influence on oolong green tea colour as an important qualitative variable. Thus, the shelf-life of tea should be shorter than the 12 months claimed by most manufacturers. Once the relationship between changes in chlorophyll concentration and length of the storage period had been established, the chlorophyll content was suggested as an indicator of the storage time (freshness) of a tea substance.

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The Prediction of Chlorophyll Content in African Leaves (Vernonia amygdalina Del.) Using Flatbed Scanner and Optimised Artificial Neural Network

Pertanika Journal of Science and Technology ◽

10.47836/pjst.29.4.15 ◽

2021 ◽

Vol 29 (4) ◽

Author(s):

Retno Damayanti ◽

Nurul Rachma ◽

Dimas Firmanda Al Riza ◽

Yusuf Hendrawan

Keyword(s):

Chlorophyll Content ◽

Selection Process ◽

Ann Model ◽

Vernonia Amygdalina ◽

Flatbed Scanner ◽

Filter Methods ◽

Texture Parameters ◽

Hidden Layer ◽

The Relationship ◽

Non Destructive

African leaves (Vernonia amygdalina Del.) is a nutrient-rich plant that has been widely used as a herbal plant. African leaves contain chlorophyll which identify compounds produced by a plant, such as flavonoids and phenols. Chlorophyll testing can be carried out non-destructively by using the SPAD 502 chlorophyll meter. However, it is quite expensive, so that another non-destructive method is developed, namely digital image analysis. Relationships between chlorophyll content and leaf image colour indices in the RGB, HSV, HSL, and Lab* space are examined. The objectives of this study are 1) to analyse the relationship between texture parameters of red, green, blue, grey, hue, saturation(HSL), lightness (HSL), saturation( HSV), value(HSV), L*, a*, and b* against the chlorophyll content in African leaves using a flatbed scanner (HP DeskJet 2130 Series); and 2) built a model to predict chlorophyll content in African leaves using optimised ANN through a feature selection process by using several filter methods. The best ANN topologies are 10-30-40-1 (10 input nodes, 40 nodes in hidden layer 1, 30 nodes in hidden layer 2, and 1 output node) with a trainlm on the learning function, tansig on the hidden layer, and purelin on the output layer. The selected topology produces MSE training of 0.0007 with R training 0.9981 and the lowest validation MSE of 0.012 with R validation of 0.967. With these results, it can be concluded that the ANN model can be potentially used as a model for predicting chlorophyll content in African leaves.

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DETERMINATION OF THE VERTICAL GRADIENT OF GRAVITY FROM GRAVITY ANOMALIES

Interexpo GEO-Siberia ◽

10.33764/2618-981x-2021-6-116-124 ◽

2021 ◽

Vol 6 ◽

pp. 116-124

Author(s):

Ivan A. Inzhevatov

Keyword(s):

Field Data ◽

Gravity Anomalies ◽

Vertical Gradient ◽

Indirect Methods ◽

Gravimetric Measurements ◽

Urgent Task ◽

Physical Fields ◽

The Relationship ◽

Vertical Gradient Of Gravity

In connection with the need to use the vertical gradient in the processing of the results of gravimetric measurements and their interpretation when solving problems of geology, geophysics, geodesy, geodynamics and navigation, in addition to the urgent problems of improvement, socalled indirect methods of measuring the vertical gradient, there is an equally urgent task of developing methods for determining the vertical gradient of gravity, using dependencies between different physical fields. The article presents the development and study of a method for determining the vertical gradient from gravity anomalies using the relationship between gravity anomalies and altitude based on field data obtained in the area of the Tashtagol field on Mount Boulanger in 2019 and 2020.

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Y A-T-Il Une Relation Entre Teneur En Chlorophylle Et Accumulation De La Proline Chez Les Céréales À Paille Sous Déficit Hydrique?

European Scientific Journal ESJ ◽

10.19044/esj.2018.v14n15p234 ◽

2018 ◽

Vol 14 (15) ◽

pp. 234

Author(s):

Merabta Sarra ◽

Zerafa Chafia ◽

Benlaribi Mostefa

Keyword(s):

Chlorophyll Content ◽

Triticum Aestivum L ◽

Hordeum Vulgare L ◽

Test Conditions ◽

Triticum Durum Desf ◽

The Moment ◽

Déficit Hydrique ◽

The Relationship ◽

Very High ◽

Barley Genotypes

This paper focuses on the relationship between two genotypes of durum wheat (Triticum durum Desf.): Gamgoum Rekham (GGR) and Haurani; two genotypes of common wheat (Triticum aestivum L.): Florence aurore 8193 (FA) and Mexipak; and two genotypes of barley (Hordeum vulgare L.): Manel and Saïda 183. These genotypes were subjected to a water deficit during a period of twenty days at the heading stage. The proline content and the chlorophyll content are determined on the standard leaves both on the control and on the sample subjected to water stress after twenty days and after one and two weeks, following the return of watering. Despite the fact that these varieties are cultivated under the same conditions on the Algerian highlands, their reactions to the test conditions are very different. As a matter of fact, GGR and FA recorded very high levels of proline at the end of the stress. This, however, was at the moment when the two barley genotypes presented relatively low values for the two studied parameters. After the return of watering, the proline contents at the various genotypes returned gradually to those of the controls. The GGR genotype recovers more quickly than the others. As for the chlorophyll content, it evolves, unevenly, in the course of the test, showing no evolutionary indication in relation to the proline.

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Effects of Crop Leaf Angle on LAI-Sensitive Narrow-Band Vegetation Indices Derived from Imaging Spectroscopy

Applied Sciences ◽

10.3390/app8091435 ◽

2018 ◽

Vol 8 (9) ◽

pp. 1435 ◽

Cited By ~ 5

Author(s):

Xiaochen Zou ◽

Iina Haikarainen ◽

Iikka Haikarainen ◽

Pirjo Mäkelä ◽

Matti Mõttus ◽

...

Keyword(s):

Chlorophyll Content ◽

Vegetation Index ◽

Normalized Difference Vegetation Index ◽

Vegetation Indices ◽

Imaging Spectroscopy ◽

Leaf Angle ◽

Field Crops ◽

Leaf Chlorophyll ◽

Simple Ratio ◽

The Relationship

Leaf area index (LAI) is an important biophysical variable for understanding the radiation use efficiency of field crops and their potential yield. On a large scale, LAI can be estimated with the help of imaging spectroscopy. However, recent studies have revealed that the leaf angle greatly affects the spectral reflectance of the canopy and hence imaging spectroscopy data. To investigate the effects of the leaf angle on LAI-sensitive narrowband vegetation indices, we used both empirical measurements from field crops and model-simulated data generated by the PROSAIL canopy reflectance model. We found the relationship between vegetation indices and LAI to be notably affected, especially when the leaf mean tilt angle (MTA) exceeded 70 degrees. Of the indices used in the study, the modified soil-adjusted vegetation index (MSAVI) was most strongly affected by leaf angles, while the blue normalized difference vegetation index (BNDVI), the green normalized difference vegetation index (GNDVI), the modified simple ratio using the wavelength of 705 nm (MSR705), the normalized difference vegetation index (NDVI), and the soil-adjusted vegetation index (SAVI) were only affected for sparse canopies (LAI < 3) and MTA exceeding 60°. Generally, the effect of MTA on the vegetation indices increased as a function of decreasing LAI. The leaf chlorophyll content did not affect the relationship between BNDVI, MSAVI, NDVI, and LAI, while the green atmospherically resistant index (GARI), GNDVI, and MSR705 were the most strongly affected indices. While the relationship between SR and LAI was somewhat affected by both MTA and the leaf chlorophyll content, the simple ratio (SR) displayed only slight saturation with LAI, regardless of MTA and the chlorophyll content. The best index found in the study for LAI estimation was BNDVI, although it performed robustly only for LAI > 3 and showed considerable nonlinearity. Thus, none of the studied indices were well suited for across-species LAI estimation: information on the leaf angle would be required for remote LAI measurement, especially at low LAI values. Nevertheless, narrowband indices can be used to monitor the LAI of crops with a constant leaf angle distribution.

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