An integrating sphere for the rapid nondestructive estimation of whole-plant chlorophyll content

1983 ◽  
Vol 61 (12) ◽  
pp. 3072-3079 ◽  
Author(s):  
F. D. H. Macdowall
Keyword(s):  
Chlorophyll Content ◽  
Scattered Light ◽  
Red Light ◽  
Quadratic Equation ◽  
Coefficient Of Determination ◽  
Integrating Sphere ◽  
Selective Absorption ◽  
Chlorophyll Contents ◽  
Whole Plant ◽  
Before And After

The chlorophyll contents of seedlings of several plant species were estimated from the voltages emitted by a photocell before and after the insertion of the shoot systems into a 61-cm integrating sphere. Red light of 675-nm wavelength was projected into the sphere for selective absorption by chlorophyll, as shown by an absorption spectrum, and the readout was calibrated against total extracted chlorophyll. The species and thus the morphology of the plant were of no significant consequence. The absorbance by chlorophyll in plants obeyed Beer's law up to a content of about 60 mg chlorophyll; however, over a wider range the calibration curve for absorbance, like that for absorptance, was best fitted by a quadratic equation which gave a coefficient of determination of 98% and a standard error of estimate for chlorophyll of 2 mg. A band width of 4 mg chlorophyll was obtained between the 95% confidence limits for chlorophyll as a function of absorbance of plants that contained less than 20 mg chlorophyll. A similar 4-mg confidence belt for chlorophyll on absorptance applied through the range of about 5 to 45 mg chlorophyll in plants. A usable linear relation was obtained between chlorophyll content and the ratio of the scattered light not absorbed at 750 nm to that at 675 nm.

scholarly journals Whole-plant Response of Six Poinsettia Cultivars to Three Fertilizer and Two Irrigation Regimes

1996 ◽  
Vol 121 (1) ◽  
pp. 69-76 ◽  
Author(s):  
Ursula Schuch ◽  
Richard A. Redak ◽  
James Bethke
Keyword(s):  
Leaf Area ◽  
Chlorophyll Content ◽  
Dry Weight ◽  
Shoot Biomass ◽  
Vegetative Development ◽  
Chlorophyll Contents ◽  
Shoot Dry Weight ◽  
Irrigation Regimes ◽  
Whole Plant ◽  
Leaf N

Six cultivars of poinsettia (Euphorbia pulcherrima Wind.), `Angelika White', `Celebrate 2', `Freedom Red', `Lilo Red', `Red Sails', and `Supjibi Red' were grown for 9 weeks during vegetative development under three constant-feed fertilizer treatments, 80,160, or 240 mg N/liter and two irrigation regimes, well-watered (high irrigation) or water deficient (low irrigation). Plants fertilized with 80 or 240 mg N/liter were 10% to 18% shorter, while those fertilized with 160 mg N/liter were 25 % shorter with low versus high irrigation. Leaf area and leaf dry weight increased linearly in response to increasing fertilizer concentrations. Low irrigation reduced leaf area, leaf, stem, and shoot dry weight 3670 to 41%. Cultivars responded similarly to irrigation and fertilizer treatments in all components of shoot biomass production and no interactions between the main effects and cultivars occurred. Stomatal conductance and transpiration decreased with increasing fertilizer rates or sometimes with low irrigation. Highest chlorophyll contents occurred in leaves of `Lilo Red' and `Freedom Red'. Leaves of plants fertilized with 80 mg N/liter were deficient in leaf N and had 40 % to 49 % lower leaf chlorophyll content compared to plants fertilized with 160 or 240 mg N/liter. Irrigation had no effect on leaf N or chlorophyll content. At the end of the experiment leaves of `Supjibi Red' and `Angelika White' contained higher concentrations of soluble proteins than the other four cultivars.

THE RELATIONSHIP BETWEEN CHLOROPHYLL CONTENT AND RATE OF PHOTOSYNTHESIS IN SOYBEANS

1977 ◽  
Vol 57 (1) ◽  
pp. 1-5 ◽  
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.

scholarly journals Scaling Effects on Chlorophyll Content Estimations with RGB Camera Mounted on a UAV Platform Using Machine-Learning Methods

Sensors ◽  
2020 ◽  
Vol 20 (18) ◽  
pp. 5130 ◽  
Author(s):  
Yahui Guo ◽  
Guodong Yin ◽  
Hongyong Sun ◽  
Hanxi Wang ◽  
Shouzhi Chen ◽  
...  
Keyword(s):  
Machine Learning ◽  
Chlorophyll Content ◽  
Scale Effects ◽  
Coefficient Of Determination ◽  
Support Vector ◽  
Flight Altitude ◽  
Chlorophyll Contents ◽  
Leaf Chlorophyll ◽  
Quantitative Remote Sensing ◽  
Rgb Images

Timely monitoring and precise estimation of the leaf chlorophyll contents of maize are crucial for agricultural practices. The scale effects are very important as the calculated vegetation index (VI) were crucial for the quantitative remote sensing. In this study, the scale effects were investigated by analyzing the linear relationships between VI calculated from red–green–blue (RGB) images from unmanned aerial vehicles (UAV) and ground leaf chlorophyll contents of maize measured using SPAD-502. The scale impacts were assessed by applying different flight altitudes and the highest coefficient of determination (R2) can reach 0.85. We found that the VI from images acquired from flight altitude of 50 m was better to estimate the leaf chlorophyll contents using the DJI UAV platform with this specific camera (5472 × 3648 pixels). Moreover, three machine-learning (ML) methods including backpropagation neural network (BP), support vector machine (SVM), and random forest (RF) were applied for the grid-based chlorophyll content estimation based on the common VI. The average values of the root mean square error (RMSE) of chlorophyll content estimations using ML methods were 3.85, 3.11, and 2.90 for BP, SVM, and RF, respectively. Similarly, the mean absolute error (MAE) were 2.947, 2.460, and 2.389, for BP, SVM, and RF, respectively. Thus, the ML methods had relative high precision in chlorophyll content estimations using VI; in particular, the RF performed better than BP and SVM. Our findings suggest that the integrated ML methods with RGB images of this camera acquired at a flight altitude of 50 m (spatial resolution 0.018 m) can be perfectly applied for estimations of leaf chlorophyll content in agriculture.

scholarly journals The Preferences of Different Cultivars of Lettuce Seedlings (Lactuca sativa L.) for the Spectral Composition of Light

Agronomy ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1211
Author(s):  
Barbara Frąszczak ◽  
Monika Kula-Maximenko
Keyword(s):  
Chlorophyll Content ◽  
Blue Light ◽  
White Light ◽  
Leaf Shape ◽  
Red Light ◽  
Spectral Composition ◽  
Fresh Weight ◽  
Light Spectrum ◽  
Dark Green ◽  
Relative Chlorophyll Content

The spectrum of light significantly influences the growth of plants cultivated in closed systems. Five lettuce cultivars with different leaf colours were grown under white light (W, 170 μmol m−2 s−1) and under white light with the addition of red (W + R) or blue light (W + B) (230 μmol m−2 s−1). The plants were grown until they reached the seedling phase (30 days). Each cultivar reacted differently to the light spectrum applied. The red-leaved cultivar exhibited the strongest plasticity in response to the spectrum. The blue light stimulated the growth of the leaf surface in all the plants. The red light negatively influenced the length of leaves in the cultivars, but it positively affected their number in red and dark-green lettuce. It also increased the relative chlorophyll content and fresh weight gain in the cultivars containing anthocyanins. When the cultivars were grown under white light, they had longer leaves and higher value of the leaf shape index. The light-green cultivars had a greater fresh weight. Both the addition of blue and red light significantly increased the relative chlorophyll content in the dark-green cultivar. The spectrum enhanced with blue light had positive influence on most of the parameters under analysis in butter lettuce cultivars. These cultivars were also characterised by the highest absorbance of blue light.

Parameter Optimization for Vibration Flow Field of Polystyrene Melts via RBF Neural Networks Combined with SALS

2012 ◽  
Vol 602-604 ◽  
pp. 757-761
Author(s):  
Guang Ming Xian ◽  
Jing Ping Qu ◽  
Bi Qing Zeng
Keyword(s):  
Light Intensity ◽  
Flow Field ◽  
Polymer Melts ◽  
Scattered Light ◽  
Projection Area ◽  
Rbf Neural Networks ◽  
Maximum Light ◽  
Before And After ◽  
Small Angle Light Scattering ◽  
Slit Die

This work aims at developing an accurate measurement of characterization flow field of polymer melts by small-angle light scattering (SALS). In this article we propose a new method, based on radial basis function neural network (RBFNN) for predicting the optimum vibration field parameters. A laser light passes through polymer melts in the visual slit die. The results reported in this study were obtained with polystyrene (PS) with rotation speed at 20 rpm. In order to capture the scattered light, a polarizer and an analyzer are placed before and after the polymer melts. RBFNN inputs consist of frequency and amplitude, which are used as input parameters to predict the maximum light intensity projection area. RBFNN predicts that the optimum value of frequency, amplitude are 15.86 Hz and 0.20mm, respectively. And the maximum light intensity projection area is predicted to be 9260 pixels.

scholarly journals Phytotoxic Activity of Parthenium Against Wheat and Canola Differ With Plant Parts and Bioassays Techniques

2016 ◽  
Vol 34 (1) ◽  
pp. 11-24 ◽  
Author(s):  
A. KHALIQ ◽  
F ASLAM ◽  
A MATLOOB ◽  
A JAVAID ◽  
A TANVEER ◽  
...  
Keyword(s):  
Seedling Growth ◽  
Filter Paper ◽  
Leaf Extracts ◽  
Invasive Weed ◽  
Test Species ◽  
Chlorophyll Contents ◽  
Phenolic Contents ◽  
Plant Parts ◽  
Phytotoxic Activity ◽  
Whole Plant

Phytotoxic effects of invasive weed Parthenium hysterophorus were studied by using whole plant, leaf and root aqueous extracts at 0, 2.5, 5.0, 7.5 and 10% (w/v) concentrations against germination and early seedling growth of wheat and canola. Studies were carried out both in Petri plates with filter paper as substratum placed in controlled conditions and soil-filled plastic pots placed in open environments. Pronounced variation was noted for phytotoxic activity of different plant parts of parthenium, aqueous extract concentrations, test species, and bioassay techniques. Aqueous parthenium extracts either inhibited or delayed the germination and suppressed seedling growth of test species over control. For both test species, all the germination attributes were suppressed to a greater extent in Petri plates than in plastic pots. Leaf extracts were more suppressive to germination of test species than whole plant and root extracts. Increasing extract concentration beyond 2.5% caused significant reduction in seedling dry biomass of both test species. Aqueous parthenium extract diminished chlorophyll contents of wheat and canola by 32-63% and 29 69%, respectively. Nevertheless, an increase of 9-172% and 22-60% in phenolic contents of wheat and canola was recorded. Canola appeared to be more susceptible than wheat at all extract concentrations. Present study concluded that bioassays conducted under controlled condition using filter paper as substratum may be misleading due to over estimation of allelopathic response and variation in potential of receiver and donor species. Furthermore, it implies that threshold concentrations of allelochemicals for test species in Petri plates are rarely reached under field conditions.

scholarly journals Effects of 1-MCP on External Postharvest Qualities and Shelf Life of ‘Maha Chanok’ Mango Fruit

2015 ◽  
Vol 8 (1) ◽  
pp. 68
Author(s):  
B. Chutichudet ◽  
Prasit Chutichudet ◽  
Usana Trainoak
Keyword(s):  
Chlorophyll Content ◽  
Fruit Weight ◽  
Storage Life ◽  
Fruit Firmness ◽  
Mango Fruit ◽  
Chlorophyll Contents ◽  
Randomized Design ◽  
Fruit Decay ◽  
Completely Randomized Design ◽  
And Storage

<p>‘Maha Chanok’<strong> </strong>mango is an economic fruit crop widely cultivated commercially throughout Thailand. By nature, mango fruit has a rather limited storage life after harvest. 1-methylcyclopropene (1-MCP) has been accepted as a commercial substance to improve several fruit qualities. The objective of this research was to study the effects of 1-MCP on the external postharvest qualities and storage life on the ‘Maha Chanok’ mango fruit. The experiment was laid out in a Completely Randomized Design with three replicates, ten fruits per replicate. Mango fruit was fumigated with 1-MCP at three concentrations (1000, 1250, or 1500 nl l<sup>-1</sup>) and three fumigation periods (12, 18, or 24 h), compared with the control fruit. After treating, all treatments were stored under ambient temperature (27 °C, 80%R.H.). The following determinations were made every two days for assessment of fruit weight loss, firmness, chlorophyll content, decay incidence, and storage life. The results showed that fruit treated with 1500 nl l<sup>-1</sup><strong> </strong>1-MCP for 24 h had the maximal fruit firmness. For chlorophyll content, the results showed that fruit-treated with 1500 nl l<sup>-1</sup><strong> </strong>1-MCP for 12 h could effectively retain the highest chlorophyll contents. Furthermore, both the lowest fruit decay and the longest storage life of 12 days were achieved from the fruit treated with 1000 nl l<sup>-1</sup><strong> </strong>1-MCP for 12 h.</p>

scholarly journals Evaluation of Automated Enforcement Program in Amman

2018 ◽  
Author(s):  
Hana Naghawi ◽  
Bushra Al Qatawneh ◽  
Rabab Al Louzi
Keyword(s):  
Traffic Safety ◽  
Questionnaire Survey ◽  
Positive Impact ◽  
Red Light ◽  
Crash Frequency ◽  
Red Light Running ◽  
Red Light Cameras ◽  
Percent Confidence Level ◽  
Before And After ◽  
Traffic Violations

This study aims, in a first attempt, to evaluate the effectiveness of using the Automated Enforcement Program (AEP) to improve traffic safety in Amman, Jordan. The evaluation of the program on crashes and violations was examined based on a “before-and-after” study using the paired t-test at 95 percent confidence level. Twenty one locations including signalized intersections monitored by red light cameras and arterial roads monitored by excessive speed cameras were selected. Nine locations were used to study the effectiveness of the program on violations, and twelve locations were used to determine the effectiveness of the program on frequency and severity of crashes. Data on number and severity of crashes were taken from Jordan Traffic Institution. Among the general findings, it was found that the AEP was generally associated with positive impact on crashes. Crash frequency was significantly reduced by up to 63%. Crash severities were reduced by up to 62.5%. Also, traffic violations were significantly reduced by up to 66%.  Finally, drivers’ opinion and attitude on the program was also analyzed using a questionnaire survey. The questionnaire survey revealed that 35.5% of drivers are unaware of AEP in Amman, 63.9% of drivers don’t know the camera locations, most drivers knew about excessive speed and red light running penalties, most drivers reduce their speed at camera locations, 44.4% of drivers think that the program satisfies its objective in improving traffic safety and 52% of drivers encourage increasing the number of camera devices in Amman.

scholarly journals ALLELOPATHIC INFLUENCE OF TRIANTHIMA PORTULACASTRUM L. ON GROWTH AND DEVELOPMENTAL RESPONSES OF SESAME (SESAMUM INDICUM L.)

2017 ◽  
Vol 4 (2) ◽  
pp. 183-186
Author(s):  
Prabhakaran J ◽  
Kavitha D
Keyword(s):  
Block Design ◽  
Dry Weight ◽  
Germination Percentage ◽  
Sesamum Indicum ◽  
Negative Effects ◽  
Chlorophyll Contents ◽  
Whole Plant ◽  
Low Concentrations ◽  
Seedling Length ◽  
Developmental Responses

An experiment was conducted in order to determine the allelopathic effects of the aqueous extract of Trianthima portulacastrum L.on the seed germination, seedling growth and chlorophyll content ofsesame (Sesamum indicum L.). Greenhouse experiment was carried out as RCBD (Randomized complete block design)with four replications. Treatments included 0, 1, 2, 3 and 4% (W/W) residues of whole plant of T.portulacastrum with normal field soil. Results showed that the low concentrations of T.portulacastrum had no significant effect on the germination percentage, seedling length, dry weight, total chlorophyll contents at lower concentration(1%) of weed residues. However, treatments with higher concentrations had negative effects on germination, growth and seedling dry weight of sesame.

Sign in / Sign up

Export Citation Format

Share Document