Language：English   Publishing type：Research paper (scientific journal)   Publisher：Wiley  

Cell walls, especially secondary cell walls (SCWs), maintain cell shape and reinforce wood, but their structure and shape can be altered in response to gravity. In hardwood trees, tension wood is formed along the upper side of a bending stem and contains wood fiber cells that have a gelatinous layer (G-layer) inside the SCW. In a previous study, we generated nst/snd quadruple-knockout aspens (Populus tremula × Populus tremuloides), in which SCW formation was impaired in 99% of the wood fiber cells. In the present study, we produced nst/snd triple-knockout aspens, in which a large number of wood fibers had thinner SCWs than the wild type (WT) and some had no SCW. Because SCW layers are always formed prior to G-layer deposition, the nst/snd mutants raise interesting questions of whether the mutants can form G-layers without SCW and whether they can control their postures in response to changes in gravitational direction. The nst/snd mutants and the WT plants showed growth eccentricity and vessel frequency reduction when grown on an incline, but the triple mutants recovered their upright growth only slightly, and the quadruple mutants were unable to maintain their postures. The mutants clearly showed that the G-layers were formed in SCW-containing wood fibers but not in those lacking the SCW. Our results indicate that SCWs are essential for G-layer formation and posture control. Furthermore, each wood fiber cell may be able to recognize its cell wall developmental stage to initiate the formation of the G-layer as a response to gravistimulation.

DOI： 10.1111/tpj.15466

PubMed

Other Link： https://onlinelibrary.wiley.com/doi/full-xml/10.1111/tpj.15466

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

Key message We assessed the narrow-sense heredity and genetic gains of multiple traits obtained using the indirect selection method for progeny ofCryptomeria japonicaD. Don by artificial crossing. Using stress wave velocity and Pilodyn penetration depth as indicative parameters, wood properties could be improved in future generations ofC. japonicaplus trees and forest breeding programs will become more efficient. Context To advance generations of C. japonica D. Don breeding populations, the narrow-sense heredity and genetic gain of traits of progenies are required to assess the practical genetic performance of parental trees and improve traits. Aims We assessed the genetic gains in both growth characteristics and wood properties by indirect selection using full-sib progenies of C. japonica plus trees produced through artificial crosses. Methods In 18-year-old progenies of 549 trees, we assessed growth characteristics, dynamic modulus of elasticity, basic density, stress wave velocity, and Pilodyn penetration depth. Genetic parameters were calculated using a mixed model and the breedR package. Results The genetic correlation between growth characteristics and wood properties was low. The efficiencies of indirect selection for dynamic modulus of elasticity by stress wave velocity and for basic densities by Pilodyn penetration depth were higher than those for growth characteristics by stress wave velocity and Pilodyn penetration depth, respectively. Strong correlations were found between the parental clonal values and breeding values of parental trees predicted from progeny using stress wave velocity and Pilodyn penetration depth. Conclusion Using stress wave velocity and Pilodyn penetration depth as indicative parameters, future generations of C. japonica plus trees could produce superior wood properties. Growth characteristics and wood properties are independent; thus, both traits could be genetically improved compatibly.

DOI： 10.1007/s13595-021-01064-1

Web of Science

Other Link： https://link.springer.com/article/10.1007/s13595-021-01064-1/fulltext.html

Language：English  

Language：English   Publishing type：Research paper (scientific journal)  

Rawanbuki, a variety of Japanese butterbur (Petasites japonicus subsp. giganteus), grow naturally along the Rawan River, Hokkaido, northern Japan. Most plants reach 2–3 m in height and 10 cm in diameter in 2 months and are much larger than those grown along other rivers. We examined the hypothesis that nutrients exported from upland streams enhance the growth of the Rawanbuki. Nutrient concentrations, including nitrogen, phosphorus, and base cations, in the Rawan River were much higher than those in rivers of adjacent watersheds. High nutrient concentrations and moisture contents were found in soil along the Rawan River and a significant relationship was found between physicochemical soil conditions and aboveground biomass of butterburs. This indicates that extremely large Rawanbuki plants could be caused by these high nutrient concentrations and moisture contents in the soils. A manipulation experiment showed that fertilization simulated the growth environment along the Rawan River and enhanced the stem height and stem diameter of butterburs. This study concluded that the extremely large butterburs are caused by a large amount of nutrients exported from upland areas. These results are the first demonstration of the role of stream water nutrients in enlarging agricultural crops.

DOI： 10.1038/s41598-021-81191-x

Scopus

PubMed

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

Authorship：Lead author   Language：English  

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

Language：English  

Language：Japanese   Presentation type：Poster presentation  

Presentation type：Poster presentation  

Language：Japanese   Presentation type：Poster presentation  

Language：Japanese