Spectral Properties of Light Conducted in Stems of Woody Plants Show Marked Seasonal Differences Suggesting a Close Relationship With Photomorphogenesis

Sun, Qiang; Yoda, Kiyotsugu; Suzuki, Hitoshi

doi:10.1163/22941932-90000352

Cited by 5 publications

(7 citation statements)

References 23 publications

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“…Among these, the fibres and vessels die upon maturation. As indicated previously (Sun et al, 2003(Sun et al, , 2004, the light conducted by fibres and vessels is not restricted to the light conductors only, but in fact leaks out to the surrounding living tissues during axial conduction. This has been verified in recent investigations of the spectral properties of specific tissues and cells, and even specific parts of a tissue or cell, by means of a fine light-guide detector (Q Sun and H Suzuki, unpublished data).…”

Section: Functional Significance Of the Internal Light Environment Ofmentioning

confidence: 78%

“…These findings also identify certain differences between the structural components involved in light conduction in herbaceous and woody species. In woody species (Sun et al, 2003(Sun et al, , 2004, vascular tissue (consisting mainly of secondary xylem and secondary phloem) comprises the majority of the stem and root structure, and the vessels, fibres, and tracheids were the only efficient axial Fig. 6.…”

Section: Differences In Internal Stem and Root Light Conduction Betwementioning

confidence: 99%

“…In the roots, any direct relations between them and the external light environment above-ground have yet to be investigated. In previous studies on the optical properties of the stems and roots of woody plants, it became clear that light can not only enter the interior of a woody stem but it is also conducted towards the roots along the axis (Sun et al, 2003(Sun et al, , 2004. Certain elements of vascular tissue (fibres, tracheids, and vessels) are involved in axial light conduction, and the living tissues in the xylem and phloem of stems and roots are bathed in an internal light environment, comprised mostly of far-red light, which is probably correlated with the photomorphogenic processes in the stems and roots of woody plants.…”

Section: Introductionmentioning

confidence: 99%

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Internal axial light conduction in the stems and roots of herbaceous plants

Sun¹

2004

Journal of Experimental Botany

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In order to reveal any roles played by stems and roots of herbaceous plants in responding to the surrounding light environment, the optical properties of the stem and root tissues of 18 herbaceous species were investigated. It was found that light was able to penetrate through to the interior of the stem and was then conducted towards the roots. Light conduction was carried out within the internodes and across the nodes of the stem, and then in the roots from the tap root to lateral roots. Light conduction in both the stem and root occurred in the vascular tissue, usually with fibres and vessels serving as the most efficient axial light conductors. The pith and cortex in many cases were also involved in axial light conduction. Investigation of the spectral properties of the conducted light made it clear that only the spectral region between 710 nm and 940 nm (i.e. far-red and near infra-red light) was the most efficiently conducted in both the stem and the root. It was also found that there were light gradients in the axial direction of the stem or root, and the light intensity generally exhibited a linear attenuation in accord with the distance of conduction. These results revealed that tissues of the stem and root are bathed in an internal light environment enriched in far-red light, which may be involved in phytochrome-mediated metabolic activities. Thus, it appears that light signals from above-ground directly contribute to the regulation of the growth and development of underground roots via an internal light-conducting system from the stem to the roots.

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Section: Functional Significance Of the Internal Light Environment Ofmentioning

confidence: 78%

Section: Differences In Internal Stem and Root Light Conduction Betwementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Internal axial light conduction in the stems and roots of herbaceous plants

Sun¹

2004

Journal of Experimental Botany

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“…Our results show that the peaks and shoulders of transmittance were found in the ranges of 870-900 nm and 930-950 nm, and at around 1100 nm. Sun et al (2004) investigated longitudinal light-transmittances of shorter NIR (<950 nm) in the fresh wood of 6 conifer species (Ginkgo biloba, Metasequoia glyptostroboides, Abies firma, Cryptomeria japonica, Chamaecyparis obtusa and Pinus densiflora). They found three peaks in the wavelength ranges of 730-740 nm, 820-830 nm and 918-925 nm, respectively.…”

Section: Discussionmentioning

confidence: 99%

“…Tsuchikawa and Tsutsumi (1996) indicated that light with a wavelength of 1100 nm had high transmittance in the wood of Picea sitchensis. The longitudinal light-transmitting properties of shorter NIR (<950 nm) have been investigated in the fresh branches and roots of some wood species (Sun et al 2003(Sun et al , 2004. However, there had been no comprehensive study investigating the transmittance of shorter NIR in wood, by species, using xylarium-authorized wood samples.…”

Section: Introductionmentioning

confidence: 99%

Longitudinal transmittance of visible and near-infrared light in the wood of 21 conifer species

Abe

Kurata

Watanabe

et al. 2022

IAWA J.

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Summary Light transmittance and reflectance were measured in 21 conifer species using a spectrophotometer equipped with an integrating sphere and light within a wavelength range of 500–1200 nm, to clarify the variety of longitudinal light transmitting properties among wood species. Transmittance values varied not only among different species but also between the sapwood and heartwood within certain species. Transmittance intensity increased from about 600–700 nm and showed peaks or shoulders in the ranges of 870–900 nm and 930–950 nm, and at around 1100 nm in all samples. The spectra tended to show similar patterns for 2 species within the same genus (Chamaecyparis, Abies, Picea, Pinus, Pseudotsuga and Tsuga). Light transmittance differed between the sapwood and the heartwood in several species, and, patterns of the difference differed among the different genera. Peaks at around 1100 nm were observed in both the sapwood and heartwood of all samples. Maximum conductivities of light at these peaks were relatively lower in wood species with helical thickenings (genera Pseudotsuga, Torreya and Taxus). Based on these results, it can be seen that the anatomical characteristics of wood influence the transmittance of light. The density of wood and secondary metabolites occurring in heartwood are also thought to influence the transmittance of light.

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Morphological and transcriptomic responses/acclimations of erect‐type submerged macrophyteHydrilla verticillataboth at low‐light exposure and light recovery phases

Guo,

Gao,

Song

et al. 2023

Ecology and Evolution

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Light intensity is a determinant for submerged macrophytes. Little is known about their molecular responses to low‐light exposure, despite more informative and responsive than morphological traits. For erect‐type submerged macrophytes, the stem is more crucial relative to the leaf in acclimation to low‐light stress, but receives less attention. We determined morphological and stem transcriptomic responses/acclimations of Hydrilla verticillata to extremely and mildly low light (7.2 and 36 μmol photons m−2 s−1, respectively), that is, EL and ML, with the radiation intensity of 180 μmol photons m−2 s−1 as the control. Low‐light exposure continued for 9 days, followed by a 7‐day recovery phase (180 μmol photons m−2 s−1). At the exposure phase, the low‐light treatments, in particular the EL, decreased the relative growth ratio, but induced greater height and longer stem internode distance and epidermal cell. Such responses/acclimations continued into the recovery phase, despite more or less changes in the magnitude. Transcriptome showed that the photosynthetic system was inhibited at the exposure phase, but the macrophyte adjusted hormone synthesis relating to cell division and elongation. Moreover, the EL activated cell stress responses such as DNA repair. Following light recovery, the macrophyte exhibited a strong‐light response, although energy metabolism enhanced. Especially, the EL enriched the pathways relating to anthocyanin synthesis at such phase, indicating an activation of photoprotective mechanism. Our findings suggest that negative influences of low light occur at both low‐light exposure and recovery phases, but submerged macrophytes would acclimate to light environments. Transcriptome can show molecular basis of plant responses/acclimations, including but not limited to morphology. This study establishes a bridge connecting morphological and molecular responses/acclimations.

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Spectral Properties of Light Conducted in Stems of Woody Plants Show Marked Seasonal Differences Suggesting a Close Relationship With Photomorphogenesis

Cited by 5 publications

References 23 publications

Internal axial light conduction in the stems and roots of herbaceous plants

Internal axial light conduction in the stems and roots of herbaceous plants

Longitudinal transmittance of visible and near-infrared light in the wood of 21 conifer species

Morphological and transcriptomic responses/acclimations of erect‐type submerged macrophyteHydrilla verticillataboth at low‐light exposure and light recovery phases

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