Evaluation of three proposed indices for the retrieval of leaf water content from the mid-wave infrared (2–6μm) spectra

Ullah, Saleem; Skidmore, Andrew K.; Groen, T.A.; Schlerf, Martin

doi:10.1016/j.agrformet.2012.11.014

Cited by 64 publications

(27 citation statements)

References 29 publications

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“…However, in the current study, in addition to at an individual species level, the scaling relationship between leaf fresh weight and area is stronger than that between leaf dry weight and area, even at the family level; thus, the conclusion is still the same. It shows that foliar water content is fairly important in photosynthesis, contributing significantly to leaf growth and form [37,38]; thus, there is a better scaling relationship between leaf fresh weight (leaf dry weight + foliar water content) and area.…”

Section: Discussionmentioning

confidence: 99%

Leaf Fresh Weight Versus Dry Weight: Which is Better for Describing the Scaling Relationship between Leaf Biomass and Leaf Area for Broad-Leaved Plants?

Huang

Ratkowsky

Hui

et al. 2019

Forests

102

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Leaf dry mass per unit area (LMA) is considered to represent the photosynthetic capacity, which actually implies a hypothesis that foliar water mass (leaf fresh weight minus leaf dry weight) is proportional to leaf dry weight during leaf growth. However, relevant studies demonstrated that foliar water mass disproportionately increases with increasing leaf dry weight. Although scaling relationships of leaf dry weight vs. leaf area for many plants were investigated, few studies compared the scaling relationship based on leaf dry weight with that based on leaf fresh weight. In this study, we used the data of three families (Lauraceae, Oleaceae, and Poaceae, subfamily Bambusoideae) with five broad-leaved species for each family to examine whether using different measures for leaf biomass (i.e., dry weight and fresh weight) can result in different fitted results for the scaling relationship between leaf biomass and area. Reduced major axis regression was used to fit the log-transformed data of leaf biomass and area, and the bootstrap percentile method was used to test the significance of the difference between the estimate of the scaling exponent of leaf dry weight vs. area and that of leaf fresh weight vs. area. We found that there were five species across three families (Phoebe sheareri (Hemsl.) Gamble, Forsythia viridissima Lindl., Osmanthus fragrans Lour., Chimonobambusa sichuanensis (T.P. Yi) T.H. Wen, and Hibanobambusa tranquillans f. shiroshima H. Okamura) whose estimates of the scaling exponent of leaf dry weight to area and that of leaf fresh weight to area were not significantly different, whereas, for the remaining ten species, both estimates were significantly different. For the species in the same family whose leaf shape is narrow (i.e., a low ratio of leaf width to length) the estimates of two scaling exponents are prone to having a significant difference. There is also an allometric relationship between leaf dry weight and fresh weight, which means that foliar water mass disproportionately increases with increased leaf dry weight. In addition, the goodness of fit for the scaling relationship of leaf fresh weight vs. area is better than that for leaf dry weight vs. area, which suggests that leaf fresh mass might be more able to reflect the physiological functions of leaves associated with photosynthesis and respiration than leaf dry mass. The above conclusions are based on 15 broad-leaved species, although we believe that those conclusions may be potentially extended to other plants with broad and flat leaves.

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Section: Discussionmentioning

confidence: 99%

Leaf Fresh Weight Versus Dry Weight: Which is Better for Describing the Scaling Relationship between Leaf Biomass and Leaf Area for Broad-Leaved Plants?

Huang

Ratkowsky

Hui

et al. 2019

Forests

102

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“…Similar results were obtained by Peñuelas and Inoue [25] when evaluating reflectance indices associated with water and pigment contents of peanut and wheat leaves. Ullah et al [1] proposed three indices for the retrieval of leaf water content in nine different plant species and verified that spectral reflectance increased as drought conditions were intensified. The regression between plant water content (dry basis) and water index is presented in Figure 2 for Sunbright Supreme variety under progressive dehydration.…”

Section: Resultsmentioning

confidence: 99%

“…Water is a fundamental constituent of plants for maintaining leaf structure and shape, photosynthesis, and thermal regulation [1]. Chlorophylls are the most important photosynthetic pigments in plants [2].…”

Section: Introductionmentioning

confidence: 99%

Assessment of Photosynthetic Pigment and Water Contents in Intact Sunflower Plants from Spectral Indices

2017

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Under water-limited conditions, monitoring water and chlorophyll status is essential to avoid restrictions in crop growth and yield. This study was carried out to assess water and chlorophyll contents from spectral indices in sunflower plants. The hybrid Sunbright Supreme was cultivated inside a non-acclimatized greenhouse until the start of the flowering stage, and later was maintained in a growth chamber with the purpose of submitting the plants to a slow and progressive dehydration rate for 12 consecutive days. Spectral (reflectance and transmittance), leaf masses (fresh and dry), and total chlorophyll measurements were accomplished in sunflower plants. The water stress caused a reduction in the water and chlorophyll contents, resulting in linear and nonlinear decreases for the spectral indicators Water Index (WI) and Chlorophyll Content Index (CCI), respectively. The low scattering of the average values around the fitted models indicates that WI and CCI were effective in representing changes in water and chlorophyll status for sunflowers (R 2 = 0.912 and R 2 = 0.905). The benefits of using hand-held optical meters for reflectance and transmittance are that they enable rapid, accurate, and nondestructive assessments of water and chlorophyll contents in sunflower plants from radiometric indicators.

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“…Many methodologies are available for this task, some being more preferable than others, depending on research preferences. Leaf water potential associated with RDI can be determined using the method, such as pressure chamber method (Sperry et al 1996), hyperspectral indices (Yi et al 2013), normalized spectral indices and ratio spectral indices (Cheng et al 2011;Zhang et al 2012), Mid-wave Infrared Normalized Difference Water Index (Ullah et al 2013), near-infrared hyperspectral imaging (Higa et al 2013), and microfabricated thermal sensor (Atherton et al 2012), among others. We suggest that detailed experiments need to be conducted to compare which method would provide most accurate assessment of leaf water potential in response to RDI.…”

Section: Leaf Water Contentmentioning

confidence: 99%

Regulated deficit irrigation for crop production under drought stress. A review

Chai

Gan

Zhao

et al. 2015

Agron. Sustain. Dev.

401

234

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Agriculture consumes more than two thirds of the total freshwater of the planet. This issue causes substantial conflict in freshwater allocation between agriculture and other economic sectors. Regulated deficit irrigation (RDI) is key technology because it helps to improve water use efficiency. Nonetheless, there is a lack of understanding of the mechanisms with which plants respond to RDI. In particular, little is known about how RDI might increase crop production while reducing the amount of irrigation water in real-world agriculture. In this review, we found that RDI is largely implemented through three approaches: (1) growth stage-based deficit irrigation, (2) partial root-zone irrigation, and (3) subsurface dripper irrigation. Among these, partial root-zone irrigation is the most popular and effective because many field crops and some woody crops can save irrigation water up to 20 to 30 % without or with a minimal impact on crop yield. Improved water use efficiency with RDI is mainly due to the following: (1) enhanced guard cell signal transduction network that decreases transpiration water loss, (2) optimized stomatal control that improves the photosynthesis to transpiration ratio, and (3) decreased evaporative surface areas with partial root-zone irrigation that reduces soil evaporation. The mechanisms involved in the plant response to RDI-induced water stress include the morphological traits, e.g., increased root to shoot ratio and improved nutrient uptake and recovery; physiological traits, e.g., stomatal closure, decreased leaf respiration, and maintained photosynthesis; and biochemical traits, e.g., increased signaling molecules and enhanced antioxidation enzymatic activity.

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Evaluation of three proposed indices for the retrieval of leaf water content from the mid-wave infrared (2–6μm) spectra

Cited by 64 publications

References 29 publications

Leaf Fresh Weight Versus Dry Weight: Which is Better for Describing the Scaling Relationship between Leaf Biomass and Leaf Area for Broad-Leaved Plants?

Leaf Fresh Weight Versus Dry Weight: Which is Better for Describing the Scaling Relationship between Leaf Biomass and Leaf Area for Broad-Leaved Plants?

Assessment of Photosynthetic Pigment and Water Contents in Intact Sunflower Plants from Spectral Indices

Regulated deficit irrigation for crop production under drought stress. A review

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