Root cortical burden influences drought tolerance in maize

Jaramillo, Raúl E.; Nord, Eric A.; Chimungu, Joseph G.; Brown, Kathleen M.; Lynch, Jonathan P.

doi:10.1093/aob/mct069

Cited by 116 publications

(90 citation statements)

References 48 publications

(48 reference statements)

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“…Chimungu et al (2014) and Jaramillo et al (2013) reported that larger cells of the root cortical parenchyma reduce cellular respiration in this region, contributing to the deepening of the root system due to a lower metabolic cost, and that corn plants with lower cortex have higher drought tolerance, due to the smaller number of cell rows. Aerenchyma in corn roots may have the function of supporting a greater soil and water acquisition, since these structures decrease the metabolic cost of growing roots because of the reduced presence of cells in respiration (Zhu et al, 2010;Souza et al, 2013).…”

Section: Resultsmentioning

confidence: 99%

Corn root morphoanatomy at different development stages and yield under water stress

Souza

Magalhães

Castro

et al. 2016

Pesq. agropec. bras.

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-The objective of this work was to characterize the morphoanatomy of roots and the yield traits of two corn hybrids contrasting for drought tolerance (DKB 390, tolerant; and BRS 1030, sensitive), at different stages of development. Water deficit was imposed for ten days, in a greenhouse, at three growth stages: V5, VT, and R3. These treatments were combined to generate cumulative stress during the plant cycle, as: V5VT, V5R3, VTR3, and V5VTR3. The following were analyzed: root anatomy; proportion of aerenchyma in the cortex; metaxylem number and diameter; phloem thickness; as well as morphological characteristics, such as root length, volume, and surface area, specific root length, length of fine roots, grain yield, and ear length and diameter. Development stage affected the responses to stress: DKB 390 showed the best performance for root morphoanatomy and yield traits, under drought stress, at the reproductive stages, mainly R3, and in the treatments with cumulative stress, especially V5VTR3; whereas BRS 1030 presented higher means for the studied parameters, mainly at the V5 and VT stages, but did not show a higher grain yield under water stress. The greater tolerance of the DKB 390 hybrid to water deficit is probably linked with a memory of pre-exposure to water stress at different growth stages.Index terms: Zea mays, aerenchyma, drought, endoderm, specific root length, WinRhizo. Morfoanatomia radicular em diferentes estádios de desenvolvimento e produtividade do milho sob estresse hídricoResumo -O objetivo deste trabalho foi caracterizar a morfoanatomia radicular e os atributos de rendimento de dois híbridos de milho contrastantes quanto à seca (DKB 390, tolerante; e BRS 1030, sensível), em diferentes estádios de desenvolvimento. A deficiência hídrica foi imposta por dez dias, em casa de vegetação, em três estádios de desenvolvimento: V5, VT e R3. Esses tratamentos foram combinados para gerar estresses acumulativos durante o ciclo da planta, como: V5VT, V5R3, VTR3 e V5VTR3. Foram analisados: anatomia radicular; proporção de aerênquima no cortex; número e diâmetro de metaxilema; espessura do floema; bem como características morfológicas, como comprimento, volume e área de superfície radicular, comprimento específico das raízes, comprimento de raízes finas, rendimento de grãos, e comprimento e diâmetro da espiga. O estádio de desenvolvimento influenciou as respostas ao estresse: DKB 390 apresentou o melhor desempenho quanto à morfoanatomia radicular e aos atributos de rendimento, quando submetido a estresse hídrico, nos estádios reprodutivos, sobretudo em R3, e nos tratamentos acumulativos de estresse, principalmente no V5VTR3; enquanto BRS 1030 apresentou as maiores médias para os parâmetros estudados, principalmente nos estádios V5 e VT, mas não apresentou maior rendimento de grãos sob estresse hídrico. A maior tolerância do híbrido DKB 390 ao estresse hídrico provavelmente relaciona-se à memória de exposição prévia ao estresse hídrico em diferentes estádios de desenvolvimento.Termos para indexação...

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Section: Resultsmentioning

confidence: 99%

Corn root morphoanatomy at different development stages and yield under water stress

Souza

Magalhães

Castro

et al. 2016

Pesq. agropec. bras.

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“…Both RCS and RCA improve nutrient acquisition, driven by reduced root metabolic costs, and increase plant growth in edaphic stress (Zhu et al 2010;Postma and Lynch 2011a;Postma and Lynch 2011b;Schneider et al 2017b). However, reductions in nutrient and water transport and root respiration associated with RCS are significantly greater compared to RCA formation (Fan et al 2007;Zhu et al 2010;Postma and Lynch 2011b;Jaramillo et al 2013;Hu et al 2014;Saengwilai et al 2014;Chimungu et al 2015;Schneider et al 2017a).…”

Section: Rcs and Nutrient Remobilizationmentioning

confidence: 99%

“…Both RCS and RCA are accelerated by nutrient deficiencies (Gillespie and Deacon 1988;Drew et al 1989;Elliott et al 1993), reduce radial nutrient transport (Hu et al 2014;Schneider et al 2017a), reduce radial hydraulic conductivity (Fan et al 2007;Schneider et al 2017a), reduce metabolic costs (Zhu et al 2010;Postma and Lynch 2011b;Jaramillo et al 2013;Saengwilai et al 2014;Chimungu et al 2015), are influenced by exposure to ethylene (Lascaris and Deacon 1991b;Lenochová et al 2009;Schneider et al 2017c), and are types of PCD Jiang et al 2010;Schneider et al 2017c). Two ethylene-related genes were upregulated during both RCS and RCA formation (Rajhi et al 2011;Schneider et al 2017c).…”

Section: Rcs and Nutrient Remobilizationmentioning

confidence: 99%

“…Cortical phene states that reduce living cortical tissue reduce root respiration and nutrient content, thereby permitting greater resource allocation to other plant functions including growth and reproduction Lynch 2015). For example, the development of root cortical aerenchyma (RCA) in maize improves plant performance in environments with suboptimal nutrient and water availability (Zhu et al 2010;Postma and Lynch 2011a, b;Jaramillo et al 2013;Saengwilai et al 2014;Chimungu et al 2015), an effect which modeling studies show can be attributed to a reduction in root metabolic costs (Postma et al 2014;Dathe et al 2016). Fewer cell files or greater cell size in the root cortex of maize substantially reduces root respiration and improves soil exploration and water acquisition in conditions of suboptimal water availability (Chimungu et al 2014a(Chimungu et al , 2014b.…”

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Functional implications of root cortical senescence for soil resource capture

Schneider

Lynch

2017

Plant Soil

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Background Root phenes play a primary role in plant adaptation to edaphic stress. Understanding the functional implications of root phenotypes will enable the development of crop varieties with improved soil resource acquisition. Root cortical senescence (RCS) is a type of programmed cell death in cortical cells of several Poaceae species. Until recently there has been very little attention to the functional implications of RCS for water and nutrient capture. Scope We explore the functional implications of RCS as an adaptive trait for water and nutrient acquisition. The present review summarizes evidence from our own studies and other published work, and provides novel insights into the fitness landscape of RCS. Progress has recently been achieved in understanding the development and physiological implications of RCS. We propose that RCS is a useful trait for water and nutrient acquisition, particularly in edaphic stress conditions. Conclusions Further research is needed to understand the utility and tradeoffs of RCS in the context of specific environments, management practices, and phenotypic backgrounds. The utility of RCS for improved plant performance under edaphic stress merits investigation in the field. RCS may be a useful breeding target for improved soil resource capture in several major crop species including wheat, barley, and triticale.

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“…Under drought, maize genotypes with high RCA formation had greater root length, deeper rooting, better leaf water status, and 8 times greater yield than closely related genotypes with low RCA (Zhu et al, 2010a). Effects of RCA on root respiration were more pronounced for largediameter roots compared with small-diameter roots (Jaramillo et al, 2013). Results from the functionalstructural plant model SimRoot showed that RCA formation could be an adaptive response to deficiency of N, P, and potassium by decreasing the metabolic cost of soil exploration.…”

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confidence: 94%

Root Cortical Aerenchyma Enhances Nitrogen Acquisition from Low-Nitrogen Soils in Maize

et al. 2014

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ORCID ID: 0000-0002-7265-9790 (J.P.L.).Suboptimal nitrogen (N) availability is a primary constraint for crop production in developing nations, while in rich nations, intensive N fertilization carries substantial environmental and economic costs. Therefore, understanding root phenes that enhance N acquisition is of considerable importance. Structural-functional modeling predicts that root cortical aerenchyma (RCA) could improve N acquisition in maize (Zea mays). We evaluated the utility of RCA for N acquisition by physiological comparison of maize recombinant inbred lines contrasting in RCA grown under suboptimal and adequate N availability in greenhouse mesocosms and in the field in the United States and South Africa. N stress increased RCA formation by 200% in mesocosms and by 90% to 100% in the field. RCA formation substantially reduced root respiration and root N content. Under low-N conditions, RCA formation increased rooting depth by 15% to 31%, increased leaf N content by 28% to 81%, increased leaf chlorophyll content by 22%, increased leaf CO 2 assimilation by 22%, increased vegetative biomass by 31% to 66%, and increased grain yield by 58%. Our results are consistent with the hypothesis that RCA improves plant growth under N-limiting conditions by decreasing root metabolic costs, thereby enhancing soil exploration and N acquisition in deep soil strata. Although potential fitness tradeoffs of RCA formation are poorly understood, increased RCA formation appears be a promising breeding target for enhancing crop N acquisition.

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Root cortical burden influences drought tolerance in maize

Abstract: The results are consistent with the hypothesis that LCA is a driver of root metabolic costs and may therefore have adaptive significance for water acquisition in drying soil.

Cited by 116 publications

References 48 publications

Corn root morphoanatomy at different development stages and yield under water stress

Corn root morphoanatomy at different development stages and yield under water stress

Functional implications of root cortical senescence for soil resource capture

Root Cortical Aerenchyma Enhances Nitrogen Acquisition from Low-Nitrogen Soils in Maize

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