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Determination of Seed Soundness in Conifers Cryptomeria japonica and Chamaecyparis obtusa Using Narrow-Multiband Spectral Imaging in the Short-Wavelength Infrared Range.

Matsuda O, Hara M, Tobita H, Yazaki K, Nakagawa T, Shimizu K, Uemura A, Utsugi H - PLoS ONE (2015)

Bottom Line: Regeneration of planted forests of Cryptomeria japonica (sugi) and Chamaecyparis obtuse (hinoki) is the pressing importance to the forest administration in Japan.Based on these observations, a reflectance index SQI, abbreviated for seed quality index, was formulated using reflectance at three narrow SWIR wavebands so that it represents the extent of the depression.Thus, the methods described are readily applicable toward low-cost seedling production in combination with single seed sowing technology.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, Faculty of Sciences, Kyushu University, Fukuoka, Japan.

ABSTRACT
Regeneration of planted forests of Cryptomeria japonica (sugi) and Chamaecyparis obtuse (hinoki) is the pressing importance to the forest administration in Japan. Low seed germination rate of these species, however, has hampered low-cost production of their seedlings for reforestation. The primary cause of the low germinability has been attributed to highly frequent formation of anatomically unsound seeds, which are indistinguishable from sound germinable seeds by visible observation and other common criteria such as size and weight. To establish a method for sound seed selection in these species, hyperspectral imaging technique was used to identify a wavelength range where reflectance spectra differ clearly between sound and unsound seeds. In sound seeds of both species, reflectance in a narrow waveband centered at 1,730 nm, corresponding to a lipid absorption band in the short-wavelength infrared (SWIR) range, was greatly depressed relative to that in adjacent wavebands on either side. Such depression was absent or less prominent in unsound seeds. Based on these observations, a reflectance index SQI, abbreviated for seed quality index, was formulated using reflectance at three narrow SWIR wavebands so that it represents the extent of the depression. SQI calculated from seed area-averaged reflectance spectra and spatial distribution patterns of pixelwise SQI within each seed area were both proven as reliable criteria for sound seed selection. Enrichment of sound seeds was accompanied by an increase in germination rate of the seed lot. Thus, the methods described are readily applicable toward low-cost seedling production in combination with single seed sowing technology.

No MeSH data available.


Related in: MedlinePlus

Spectroscopic features of sound and unsound seeds of Cryptomeria japonica (sugi) and Chamaecyparis obtusa (hinoki).
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pone.0128358.g004: Spectroscopic features of sound and unsound seeds of Cryptomeria japonica (sugi) and Chamaecyparis obtusa (hinoki).

Mentions: Although outer appearance of sound and unsound seeds in sugi and hinoki was indistinguishable by visible observation (Fig 3A), what is certain is that chemical composition inside should be more or less different. Given the infrared (IR) absorption is sensitive to chemical composition and structure, and the seed coat may have some permeability to IR light, it was expected whether anatomical soundness of individual seeds can be evaluated from their IR spectroscopic features. To test this hypothesis, the two seed lots for each tree species were, in fact, subjected to hyperspectral imaging in wavelength ranges from VIS to NIR and from NIR to SWIR prior to RGB imaging followed by a cutting test. Average reflectance spectra of the area corresponding to each individual seed were extracted from hyperspectral images using the software, SeedSpecAnalyzer (Fig 1A), which is provided as S1 File (see S1 Text for methods of operation). This software allows to highlight all pixels with reflectance spectra similar to those from a pre-assigned reference area (e.g., seed area) based on either method of cross correlation matching or spectral angle mapper, and then to auto-detect all closed areas of interest to calculate their corresponding reflectance spectra. Fig 4 shows representative spectra from 10 individual seeds each for the three different groups and for tree species. In the VIS/NIR range, no characteristic difference was observed in reflectance spectra among the three seed groups. In contrast, a conspicuous feature specific to sound seeds of both sugi and hinoki was identified in the SWIR spectral range; the reflectance in a narrow waveband centered at 1,730 nm was greatly depressed relative to that in adjacent wavebands on either side, representing “m-shaped” spectra (Fig 4A and 4B), compared to “n-shaped” (Fig 4C to 4F) that was common to both unsound seed groups.


Determination of Seed Soundness in Conifers Cryptomeria japonica and Chamaecyparis obtusa Using Narrow-Multiband Spectral Imaging in the Short-Wavelength Infrared Range.

Matsuda O, Hara M, Tobita H, Yazaki K, Nakagawa T, Shimizu K, Uemura A, Utsugi H - PLoS ONE (2015)

Spectroscopic features of sound and unsound seeds of Cryptomeria japonica (sugi) and Chamaecyparis obtusa (hinoki).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4470962&req=5

pone.0128358.g004: Spectroscopic features of sound and unsound seeds of Cryptomeria japonica (sugi) and Chamaecyparis obtusa (hinoki).
Mentions: Although outer appearance of sound and unsound seeds in sugi and hinoki was indistinguishable by visible observation (Fig 3A), what is certain is that chemical composition inside should be more or less different. Given the infrared (IR) absorption is sensitive to chemical composition and structure, and the seed coat may have some permeability to IR light, it was expected whether anatomical soundness of individual seeds can be evaluated from their IR spectroscopic features. To test this hypothesis, the two seed lots for each tree species were, in fact, subjected to hyperspectral imaging in wavelength ranges from VIS to NIR and from NIR to SWIR prior to RGB imaging followed by a cutting test. Average reflectance spectra of the area corresponding to each individual seed were extracted from hyperspectral images using the software, SeedSpecAnalyzer (Fig 1A), which is provided as S1 File (see S1 Text for methods of operation). This software allows to highlight all pixels with reflectance spectra similar to those from a pre-assigned reference area (e.g., seed area) based on either method of cross correlation matching or spectral angle mapper, and then to auto-detect all closed areas of interest to calculate their corresponding reflectance spectra. Fig 4 shows representative spectra from 10 individual seeds each for the three different groups and for tree species. In the VIS/NIR range, no characteristic difference was observed in reflectance spectra among the three seed groups. In contrast, a conspicuous feature specific to sound seeds of both sugi and hinoki was identified in the SWIR spectral range; the reflectance in a narrow waveband centered at 1,730 nm was greatly depressed relative to that in adjacent wavebands on either side, representing “m-shaped” spectra (Fig 4A and 4B), compared to “n-shaped” (Fig 4C to 4F) that was common to both unsound seed groups.

Bottom Line: Regeneration of planted forests of Cryptomeria japonica (sugi) and Chamaecyparis obtuse (hinoki) is the pressing importance to the forest administration in Japan.Based on these observations, a reflectance index SQI, abbreviated for seed quality index, was formulated using reflectance at three narrow SWIR wavebands so that it represents the extent of the depression.Thus, the methods described are readily applicable toward low-cost seedling production in combination with single seed sowing technology.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, Faculty of Sciences, Kyushu University, Fukuoka, Japan.

ABSTRACT
Regeneration of planted forests of Cryptomeria japonica (sugi) and Chamaecyparis obtuse (hinoki) is the pressing importance to the forest administration in Japan. Low seed germination rate of these species, however, has hampered low-cost production of their seedlings for reforestation. The primary cause of the low germinability has been attributed to highly frequent formation of anatomically unsound seeds, which are indistinguishable from sound germinable seeds by visible observation and other common criteria such as size and weight. To establish a method for sound seed selection in these species, hyperspectral imaging technique was used to identify a wavelength range where reflectance spectra differ clearly between sound and unsound seeds. In sound seeds of both species, reflectance in a narrow waveband centered at 1,730 nm, corresponding to a lipid absorption band in the short-wavelength infrared (SWIR) range, was greatly depressed relative to that in adjacent wavebands on either side. Such depression was absent or less prominent in unsound seeds. Based on these observations, a reflectance index SQI, abbreviated for seed quality index, was formulated using reflectance at three narrow SWIR wavebands so that it represents the extent of the depression. SQI calculated from seed area-averaged reflectance spectra and spatial distribution patterns of pixelwise SQI within each seed area were both proven as reliable criteria for sound seed selection. Enrichment of sound seeds was accompanied by an increase in germination rate of the seed lot. Thus, the methods described are readily applicable toward low-cost seedling production in combination with single seed sowing technology.

No MeSH data available.


Related in: MedlinePlus