Estimating leaf SPAD values of freeze-damaged winter wheat using continuous wavelet analysis

Wang, Hui‐Fang; Huo, Zhiguo; Zhou, Guangsheng; Liao, Qinhong; Feng, Haikuan; Li, Wu

doi:10.1016/j.plaphy.2015.10.032

Cited by 54 publications

(39 citation statements)

References 35 publications

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“…The same symptom was also found in kiwifruit cultivar Tomuri (Caboni et al 2003). SPAD value had a direct linear relationship to the content of leaf chlorophyll, and was also an indicator of nitrogen content and grain yield in some crops (Martinez et al 2015;Xiong et al 2015;Wang et al 2016). However, in this experiment, SPAD values were relatively stable or slightly increased in new leaves of Acva-1 and Acva-2, but significantly decreased in Acva-3 and ZM-2 under high salt stress, suggesting the diversity responses in kiwifruit genotypes even though they belonged to the same species.…”

Section: Discussionsupporting

confidence: 63%

Growth and physiological responses of four kiwifruit genotypes to salt stress and resistance evaluation

Zhong

Chen

et al. 2019

Journal of Integrative Agriculture

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In this study, four genotypes (Acva-1, Acva-2, Acva-3 and ZM-2) of Actinidia germplasm resources were grown in different salt concentrations (0, 0.4, 0.8 and 1.2 g L-1 NaCl). The growth, physiological and biochemical indicators were measured, and a graded scale was developed as the salt damage index (SDI) according to different damage symptoms in leaves. The results showed SDI increased gradually, and average number and length of new shoot decreased significantly. Three antioxidant enzymes (superoxide dismutase, peroxidase and catalase) and two osmotic adjustment substances (soluble sugar and proline) showed different changes in old and new leaves of four genotypes. SPAD values exhibited a decreased trend in the whole except in the new leaf of Acva-2. Malonaldehyde contents increased and root activity decreased with the increasing salt concentrations. Principal component analysis was used to assess the salt tolerance, and the results showed Acva-3, from Actinidia valvata Dunn., had the strongest tolerance to salt, and could be a potential resistant resource to the salt-tolerance dedicated rootstock breeding of kiwifruit.

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Section: Discussionsupporting

confidence: 63%

Growth and physiological responses of four kiwifruit genotypes to salt stress and resistance evaluation

Zhong

Chen

et al. 2019

Journal of Integrative Agriculture

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“…Previous studies [9, 19, 27, 28] reported that the sensitive bands always appeared in the region where there was a large correlation coefficient or the correlation coefficient rapidly shifting. These spectral regions are always deemed to contain much more variable information.…”

Section: Methodsmentioning

confidence: 99%

“…They further recommended that the SPAD readings could be made as a nitrogen status indicator [26, 27]. Wang et al [28] reported that the SPAD value could be estimated with a high coefficient of determination (R 2 = 0.7444, RMSE = 7.359) by using the method of continuous wavelet transformation.…”

Section: Introductionmentioning

confidence: 99%

Extraction of Sensitive Bands for Monitoring the Winter Wheat (Triticum aestivum) Growth Status and Yields Based on the Spectral Reflectance

et al. 2017

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To extract the sensitive bands for estimating the winter wheat growth status and yields, field experiments were conducted. The crop variables including aboveground biomass (AGB), soil and plant analyzer development (SPAD) value, yield, and canopy spectra were determined. Statistical methods of correlation analysis, partial least squares (PLS), and stepwise multiple linear regression (SMLR) were used to extract sensitive bands and estimate the crop variables with calibration set. The predictive model based on the selected bands was tested with validation set. The results showed that the crop variables were significantly correlated with spectral reflectance. The major spectral regions were selected with the B-coefficient and variable importance on projection (VIP) parameter derived from the PLS analysis. The calibrated SMLR model based on the selected wavelengths demonstrated an excellent performance as the R2, TC, and RMSE were 0.634, 0.055, and 843.392 for yield; 0.671, 0.017, and 1.798 for SPAD; and 0.760, 0.081, and 1.164 for AGB. These models also performed accurately and robustly by using the field validation data set. It indicated that these wavelengths retained in models were important. The determined wavelengths for yield, SPAD, and AGB were 350, 410, 730, 1015, 1185 and 1245 nm; 355, 400, 515, 705, 935, 1090, and 1365 nm; and 470, 570, 895, 1170, 1285, and 1355 nm, respectively. This study illustrated that it was feasible to predict the crop variables by using the multivariate method. The step-by-step procedure to select the significant bands and optimize the prediction model of crop variables may serve as a valuable approach. The findings of this study may provide a theoretical and practical reference for rapidly and accurately monitoring the crop growth status and predicting the yield of winter wheat.

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“…Many studies have shown that the Soil and Plant Analyses Development (SPAD) value can accurately represent, and can be used instead of, the content of chlorophyll [49,50]. Immediately after we measured the spectral signals of the leaves, we took SPAD readings with a Chlorophyll Meter SPAD-502 Plus (Konika-Minolta, Inc., Tokyo, Japan) (that gave relative values of between 0 and 100).…”

Section: Measurement Of the Leaf Chlorophyll Contentmentioning

confidence: 99%

Hyperspectral Estimation of the Chlorophyll Content in Short-Term and Long-Term Restorations of Mangrove in Quanzhou Bay Estuary, China

Dou

Cui

et al. 2018

Sustainability

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The chlorophyll content can indicate the general health of vegetation, and can be estimated from hyperspectral data. The aim of this study is to estimate the chlorophyll content of mangroves at different stages of restoration in a coastal wetland in Quanzhou, China, using proximal hyperspectral remote sensing techniques. We determine the hyperspectral reflectance of leaves from two mangrove species, Kandelia candel and Aegiceras corniculatum, from short-term and long-term restoration areas with a portable spectroradiometer. We also measure the leaf chlorophyll content (SPAD value). We use partial-least-squares stepwise regression to determine the relationships between the spectral reflectance and the chlorophyll content of the leaves, and establish two models, a full-wave-band spectrum model and a red-edge position regression model, to estimate the chlorophyll content of the mangroves. The coefficients of determination for the red-edge position model and the full-wave-band model exceed 0.72 and 0.82, respectively. The inverted chlorophyll contents are estimated more accurately for the long-term restoration mangroves than for the short-term restoration mangroves. Our results indicate that hyperspectral data can be used to estimate the chlorophyll content of mangroves at different stages of restoration, and could possibly be adapted to estimate biochemical constituents in leaves.2 of 15 expected to reach 70,000 hm 2 by 2020 [4]. The chlorophyll content is an indicator of vegetation stress and can be used as a basis for estimating other biochemical parameters [5] and should be measured when monitoring, restoring and managing coastal wetland ecosystems. As such, it would therefore be useful if there were methods that resource managers could use to monitor the chlorophyll content of mangroves from hyperspectral data [6][7][8][9].Mangroves adapt to high-salt habitats using a range of physiological, biochemical, and morphological mechanisms. It is generally accepted that mangroves fall into two types, namely salt-secreting species with salt glands and salt-excluding species without salt glands [10,11]. Aegiceras plants have salt glands that secrete Na and Cl through their leaves to maintain the salt balance while Kandelia plants are known as salt-rejecting mangrove species that isolate the matrix from salt water mainly through high negative pressure in the xylem [12,13]. The mechanisms used by mangroves are unique within the plant kingdom, and the two different survival modes of mangroves have led to some differences between the leaves of the two mangrove species. The growth and physiological metabolism of mangroves are distinctive during different stages of restoration [14,15]. To date, hyperspectral data have not been used to compare the growth of these two mangrove species at different stages of restoration; instead, remote sensing has been used frequently to classify mangrove species and estimate biomass [16][17][18][19][20]. For example, Jia et al. mapped the Maipu mangrove species using hyperspectral data from the...

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Estimating leaf SPAD values of freeze-damaged winter wheat using continuous wavelet analysis

Cited by 54 publications

References 35 publications

Growth and physiological responses of four kiwifruit genotypes to salt stress and resistance evaluation

Growth and physiological responses of four kiwifruit genotypes to salt stress and resistance evaluation

Extraction of Sensitive Bands for Monitoring the Winter Wheat (Triticum aestivum) Growth Status and Yields Based on the Spectral Reflectance

Hyperspectral Estimation of the Chlorophyll Content in Short-Term and Long-Term Restorations of Mangrove in Quanzhou Bay Estuary, China

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