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. 2017 Apr 1;68(8):2027-2036.
doi: 10.1093/jxb/erw472.

Root xylem plasticity to improve water use and yield in water-stressed soybean

Silvas J Prince  1 , Mackensie Murphy  1 , Raymond N Mutava  1 , Lorellin A Durnell  1 , Babu Valliyodan  1 , J Grover Shannon  1 , Henry T Nguyen  1
Affiliations

Root xylem plasticity to improve water use and yield in water-stressed soybean

Silvas J Prince et al. J Exp Bot. .

Abstract

We tested the hypothesis that increasing the number of metaxylem vessels would enhance the efficiency of water uptake in soybean (Glycine max) and decrease the yield gap in water-limited environments. A panel of 41 soybean accessions was evaluated in greenhouse, rainout shelter, and rain-fed field environments. The metaxylem number influenced the internal capture of CO2 and improved stomatal conductance, enhancing water uptake/use in soybeans exposed to stress during the reproductive stage. We determined that other root anatomical features, such as cortex cell area and the percentage of stele that comprised cortical cells, also affected seed yield under similar growth parameters. Seed yield was also impacted by pod retention rates under drought stress (24-80 pods/plant). We surmise that effective biomass allocation, that is, the transport of available photosynthates to floral structures at late reproductive growth stages (R6-R7), enables yield protection under drought stress. A mesocosm study of contrasting lines for yield under drought stress and root anatomical features revealed that increases in metaxylem number as an adaptation to drought in the high-yielding lines improved root hydraulic conductivity, which reduced the metabolic cost of exploring water in deeper soil strata and enhanced water transport. This allowed the maintenance of shoot physiological processes under water-limited conditions.

Keywords: Drought stress; nested association mapping; pod harvest index; pod retention; root anatomy; soybean (Glycine max); yield protection under drought..

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Figures

Fig. 1.
Fig. 1.
Root anatomical analysis of soybean LG05-4317 using Rootscan software with various root anatomical features shown. A: aerenchyma; CCFN: cortical cell file number; P: phloem; MX: metaxylem.
Fig. 2.
Fig. 2.
Natural genetic variation of root anatomical features observed in 41 soybean lines of the soybean NAM panel. Scale bar = 100 μm.
Fig. 3.
Fig. 3.
Reductions observed during FT1 for variations in (A) pod number, (B) stomatal conductance, and (C) leaf area in NAM lines selected in this study.
Fig. 4.
Fig. 4.
Regression analysis to show association between seedling metaxylem number and seed yield in NAM soybean lines screened in FT1.
Fig. 5.
Fig. 5.
Variation in root anatomical response observed in metaxylem and cortex cell area among HYS and LYS lines under irrigated and drought conditions. Scale barS: HYS-1 Drought (1564 μm) and Control (715 μm); HYS-2 Drought (1001 μm) and Control (715 μm); HYS-3 Drought (1001 μm) and Control (715 μm); LYS-1 to 3 Drought (715 μm) and Control (1001 μm).
See this image and copyright information in PMC

References

    1. Abdel-Haleem H, Lee G, Boerma HR. 2011. Identification of QTL for increased fibrous roots in soybean. Theoretical Applied Genetics 122, 935–946. - PubMed
    1. Anderson JE, Kantar MB, Kono TY, et al. 2014. A roadmap for functional structural variants in the soybean genome. G3 (Bethseda) 4, 1307–1318. - PMC - PubMed
    1. Bengough AG, McKenzie BM, Hallett PD, Valentine TA. 2011. Root elongation, water stress, and mechanical impedance: a review of limiting stresses and beneficial root tip traits. Journal of Experimental Botany 62, 59–68. - PubMed
    1. Blum A. 1996. Crop responses to drought and the interpretation of adaptation. Plant Growth Regulation 20, 135–148.
    1. Brensha W, Kantartzi SK, Meksem K, Grier RL, Barakat A, Lightfoot DA, Kassem MA. 2012. Genetic analysis of root and shoot traits in the ‘Essex’ by ‘Forrest’ recombinant inbred line population of soybean. Journal of Plant Genome Science 1, 1–9.

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