Plant Root
Online ISSN : 1881-6754
ISSN-L : 1881-6754
Current issue
Displaying 1-4 of 4 articles from this issue
Published on March 15, 2024
  • Nethone Samba, Satoru Tsukagoshi, Akimasa Nakano
    2024 Volume 18 Pages 1-9
    Published: 2024
    Released on J-STAGE: March 15, 2024
    JOURNAL FREE ACCESS

    The influence of training methods on the yields of cucumber (Cucumis sativus) was investigated in the aspects of root characteristics. The experiment was conducted in the new Nutrient Film Technique hydroponics system specially developed for cucumber production (Mitsubishi Chemical Aqua Solutions, Co., Ltd., Tokyo, Japan).The lowering training (LT) and the pinching training (PT) were used to manage the cucumber plant’s canopy during the growth cycle. At the end of the experiment, the xylem sap bleeding rate, the root biomass, the remaining aerial biomass and the main stem diameter were measured. In addition, individual fresh and dry weights of matured leaves at the lower, middle and upper parts of the plant’s canopy were measured during the growth period. The recorded fruits yield was used for a correlation test with the xylem sap bleeding rate. The results indicated that the sap bleeding rate, root dry weight and root dry and fresh weights ratio were significantly higher in LT treatment. Similarly, the remaining aerial biomass fresh weight was significantly greater in the same treatment. On the other hand, individual leaf fresh and dry weights and the main stem diameter were significantly greater in the PT treatment, at the middle and upper parts of the plant’s canopy. These results were explained by the fact that in the PT treatment, more carbohydrates produced by plants were apparently used to re-establish the pinched shoots at the expense of root production. Moreover, after pinching the lateral shoots, biomass production was improved due to the penetration of sunlight in the plant’s canopy. Considering the relationships between root traits and plant productivity, the LT method is suitable for a long-term cultivation due to its faster sap bleeding rate, which is necessary to stimulate root physiological activity and promote plant biomass production.

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Published on July 10, 2024
  • Phoura Y, Ryo Ohtomo, Akihiko Kamoshita
    2024 Volume 18 Pages 10-21
    Published: 2024
    Released on J-STAGE: July 10, 2024
    JOURNAL FREE ACCESS

    Knowledge of biodiversity of soil microorganisms, including arbuscular mycorrhizal fungal (AMF) species, is limited in agroecological contexts. We investigated the effects of the popular inoculant Dr. Kinkon R10 on AMF communities in rice and pearl millet in upland and lowland fields under different water regimes by using a metagenomic approach. Numbers of operational taxonomic units (OTUs) were much lower in lowland than in upland. In upland, alpha diversity was lowest in rice but highest in pearl millet under the nonirrigated treatment (W0); OTUs of Claroideoglomus showed the greatest differences in abundance. Three OTUs of Claroideoglomus tended to have higher abundance in pearl millet under W0, whereas that of two OTUs (Acaulospora, Diversispora) increased under the well-irrigated treatment (W100). In lowland, alpha diversity was higher under the flooded condition than alternate wetting and drying, with greater abundance of Acaulospora, Ambispora, and Scutellospora. Overall, inoculation with R10 did not change the alpha and beta diversity of AMF communities. In upland, eight OTUs showed greater abundance in pearl millet than in rice, including one OTU present in the R10 inoculant. In upland, the shallow soil layer (0-10 cm) had greater abundance of Claroideoglomus, Paraglomus, and Acaulospora, with a higher diversity index, whereas the deep layer (20-30 cm) had greater abundance of Rhizophagus and Scutellospora. This study highlighted abundance of Acaulospora in higher water regimes in both upland and lowland and of Claroideoglomus for pearl millet in lower water regimes in upland.

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Published on September 26, 2024
  • Vivek Deshmukh, Akihiko Kamoshita, Nelson Amézquita, Natalia Espinosa, ...
    2024 Volume 18 Pages 22-34
    Published: 2024
    Released on J-STAGE: September 26, 2024
    JOURNAL FREE ACCESS

    Investigating effects of introgressed root-trait QTLs in field environments is a challenging task. Seven rice BC3F4 lines with at least one of six QTLs for root vertical distribution (DRO1, DRO2, DRO3, qFSR4, qRL6.1, QRO2) introgressed into a popular Colombian variety, FEDEARROZ 60, were evaluated for changes in root traits together with a BC3F4 line lacking root QTLs and the parent FEDEARROZ 60. A flooded experiment with deep-flooded and shallow-flooded treatments and an aerobic experiment using a raised-bed system were repeated in two seasons in Central Colombia. In the flooded experiment, ST604_302, containing DRO2, showed the highest root weight and root weight proportion in the 20–30-cm soil layer. The average root weight and proportion of roots at the 10–20-cm soil depth and average root weight at the 20–30-cm depth were significantly greater for the lines containing DRO2 than for those without. In the aerobic experiment, the four lines with DRO2 had higher deep-root ratios than the other genotypes. In the aerobic experiment, a higher deep-root ratio did not lead to greater root weight at either depth examined; the root weight parameters showed genotype × season interaction, and genotype had no significant effect on root weight. In the flooded experiment, the four DRO2-introgressed lines showed higher root length density below 10-cm depth than other lines in the deep-flooded treatment but not in the shallow-flooded treatment. These results showed limited but positive changes in deep-root growth in field environments through root-QTL introgression, and revealed interactions with water management and season.

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Published on December 16, 2024
  • Shunichi Yano, Teruya Takushima, Tatsuhiro Ezawa, Yusaku Sugimura, Aki ...
    2024 Volume 18 Pages 35-47
    Published: 2024
    Released on J-STAGE: December 16, 2024
    JOURNAL FREE ACCESS
    Supplementary material

    Soybean (Glycine max L.) can establish a symbiotic relationship with rhizobia. However, little is known about the host plant genes that correlate with the nitrogen fixation activity of symbiotic rhizobia. In this study, we investigated soybean genes that correlate with bacterial symbiotic nitrogen fixation in two experiments. In the first experiment, soybean seeds were inoculated with two strains of soybean rhizobia exhibiting different nitrogen fixation activities and were grown in the field until the R1 stage. Subsequently, the roots and nodules were subjected to RNA-seq analysis to identify the expression of soybean genes related to bacterial nitrogen fixation. In the second experiment, to confirm host gene expressions dependent on bacterial nitrogen fixation activity, nod+/fixnif gene) mutants and the wild type were inoculated into soybean, and gene expressions were evaluated by qRT-PCR. GmNRT2.5, a high-affinity nitrate transporter gene, was correlated with nitrogen fixation activity. qPCR analysis of roots and nodules inoculated with a nod+/fix mutant revealed that GmNRT2.5 on chromosome 8 (Glyma.08G284000: GmNRT2.5 Chr8) was particularly correlated with nitrogen fixation activity in the root nodule section. Based on the results, it is suggested that GmNRT2.5 Chr8 may function as a regulatory gene bridging nitrogen fixation and nitrate absorption from the soil. Therefore, GmNRT2.5 Chr8 might be a useful host gene for estimating symbiotic nitrogen fixation activity.

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