scholarly journals Seedling traits predict drought-induced mortality linked to diversity loss

2019 ◽  
Vol 116 (12) ◽  
pp. 5576-5581 ◽  
Author(s):  
Susan Harrison ◽  
Marina LaForgia
Keyword(s):  
Plant Traits ◽  
Life Stage ◽  
Root Traits ◽  
Adaptive Plasticity ◽  
Adult Plant ◽  
Seedling Mortality ◽  
Correlated Traits ◽  
Seedling Traits ◽  
Seedling Roots ◽  
Native Diversity

Trait-based approaches are increasingly used to predict ecological consequences of climate change, yet seldom have solid links been established between plant traits and observed climate-driven community changes. Most analyses have focused on aboveground adult plant traits, but in warming and drying climates, root traits may be critical, and seedlings may be the vulnerable stage. Relationships of seedling and root traits to more commonly measured traits and ecological outcomes are poorly known. In an annual grassland where winter drought-induced seedling mortality is driving a long-term decline in native diversity, using a field experiment during the exceptionally dry winter of 2017–2018, we found that seedling mortality was higher and growth of seedlings and adults were lower in unwatered than watered sites. Mortality of unwatered seedlings was higher in species with shorter seedling roots, and also in species with the correlated traits of small seeds, high seedling specific leaf area (SLA), and tall seedlings. Adult traits varied along an axis from short-stature, high SLA and foliar N, and early flowering to the opposite values, and were only weakly correlated with seedling traits and seedling mortality. No evidence was found for adaptive plasticity, such as longer roots or lower SLA in unwatered plants. Among these species, constitutive variation in seedling root length explained most of the variation in survival of a highly vulnerable life stage under winter drought. Selective loss of species with high adult SLA, observed in this community and others under drought stress, may be the byproduct of other correlated traits.

The ecological relationships and demography of restricted ironstone endemic plant species: implications for conservation

2011 ◽  
Vol 59 (7) ◽  
pp. 692 ◽  
Author(s):  
Colin J. Yates ◽  
Neil Gibson ◽  
Neil E. Pettit ◽  
Rebecca Dillon ◽  
Russell Palmer
Keyword(s):  
Mediterranean Climate ◽  
Life Stage ◽  
Low Frequency ◽  
Plant Establishment ◽  
Endemic Plant ◽  
Seedling Mortality ◽  
Winter Rainfall ◽  
Easy Method ◽  
Ecological Relationships ◽  
Endemic Plant Species

We investigated the ecological relationships, reproductive biology and demography of four shrub taxa restricted to ironstone ranges in south-western Australia, to assess the feasibility of post-mining reintroductions. We found that three taxa were restricted to narrow fissures in massive ironstone and the fourth was restricted to fissures and skeletal soils over ironstone. In all taxa, adult plants were the most abundant life stage in populations and produced seeds annually. Newly emerged seedlings were observed in low numbers each winter of three census years, with the highest rates occurring when winter rainfall was above average in the semiarid Mediterranean climate. Mortality was highest and most variable for <1-year-old seedlings (50–93%), 1-year-old seedlings (17–67%), juveniles (21–54%) and vegetative adults (6–50%), and was lowest and least variable for the reproductive adults (2–7%). The restriction of three of our study taxa to narrow fissures excludes the option of using seedlings in reintroductions. Using seeds, although possible, will be both an inefficient and a high-risk strategy for at least three of the four taxa studied. This is because of the low frequency of years when winter rainfall is sufficient to stimulate high rates of seed germination, coupled with the consistently high rates of seedling mortality in most years, and no easy method for determining which rock fissures will be suitable for plant establishment. The more widespread taxa showed reproductive and demographic characteristics similar to those of the taxa restricted to the narrow fissures, indicating that establishment of many species will be difficult in this environment.

scholarly journals Shoot–Root Interplay Mediates Defoliation-Induced Plant Legacy Effect

2021 ◽  
Vol 12 ◽  
Author(s):  
Xiliang Li ◽  
Zhen Zhang ◽  
Fenghui Guo ◽  
Junjie Duan ◽  
Juan Sun
Keyword(s):  
Plant Traits ◽  
Perennial Grass ◽  
Root Traits ◽  
Leymus Chinensis ◽  
Shoot Biomass ◽  
Grassland Species ◽  
Legacy Effect ◽  
Trait Plasticity ◽  
Grassland Plants ◽  
Defoliation Treatment

Shoot defoliation by grazers or mowing can affect root traits of grassland species, which may subsequently affect its aboveground traits and ecosystem functioning (e.g., aboveground primary production). However, experimental evidence for such reciprocal feedback between shoots and roots is limited. We grew the perennial grass Leymus chinensis–common across the eastern Eurasian steppe–as model species in a controlled-hydroponics experiment, and then removed half of its shoots, half of its roots, or a combination of both. We measured a range of plant aboveground and belowground traits (e.g., phenotypic characteristics, photosynthetic traits, root architecture) in response to the shoot and/or root removal treatments. We found the regenerated biomass was less than the lost biomass under both shoot defoliation and root severance, generating a under-compensatory growth. Root biomass was reduced by 60.11% in the defoliation treatment, while root severance indirectly reduced shoot biomass by 40.49%, indicating a feedback loop between shoot and root growth. This defoliation-induced shoot–root feedback was mediated by the disproportionate response and allometry of plant traits. Further, the effect of shoot defoliation and root severance on trait plasticity of L. chinensis was sub-additive. That is, the combined effects of the two treatments were less than the sum of their independent effects, resulting in a buffering effect on the existing negative influences on plant persistence by increased photosynthesis. Our results highlight the key role of trait plasticity in driving shoot–root reciprocal feedbacks and growth persistence in grassland plants, especially perennial species. This knowledge adds to earlier findings of legacy effects and can be used to determine the resilience of grasslands.

scholarly journals Has agricultural intensification impacted maize root traits and rhizosphere interactions related to organic N acquisition?

AoB Plants ◽  
2020 ◽  
Vol 12 (4) ◽  
Author(s):  
Jennifer E Schmidt ◽  
Amisha Poret-Peterson ◽  
Carolyn J Lowry ◽  
Amélie C M Gaudin
Keyword(s):  
Nutrient Cycling ◽  
Agricultural Intensification ◽  
Extracellular Enzymes ◽  
Plant Traits ◽  
Root Traits ◽  
N Fertilization ◽  
N Cycling ◽  
Organic N ◽  
Microbe Interactions ◽  
Rhizosphere Processes

Abstract Plant–microbe interactions in the rhizosphere influence rates of organic matter mineralization and nutrient cycling that are critical to sustainable agricultural productivity. Agricultural intensification, particularly the introduction of synthetic fertilizer in the USA, altered the abundance and dominant forms of nitrogen (N), a critical plant nutrient, potentially imposing selection pressure on plant traits and plant–microbe interactions regulating N cycling and acquisition. We hypothesized that maize adaptation to synthetic N fertilization altered root functional traits and rhizosphere microbial nutrient cycling, reducing maize ability to acquire N from organic sources. Six maize genotypes released pre-fertilizer (1936, 1939, 1942) or post-fertilizer (1984, 1994, 2015) were grown in rhizoboxes containing patches of 15N-labelled clover/vetch residue. Multivariate approaches did not identify architectural traits that strongly and consistently predicted rhizosphere processes, though metrics of root morphological plasticity were linked to carbon- and N-cycling enzyme activities. Root traits, potential activities of extracellular enzymes (BG, LAP, NAG, urease), abundances of N-cycling genes (amoA, narG, nirK, nirS, nosZ) and uptake of organic N did not differ between eras of release despite substantial variation among genotypes and replicates. Thus, agricultural intensification does not appear to have impaired N cycling and acquisition from organic sources by modern maize and its rhizobiome. Improved mechanistic understanding of rhizosphere processes and their response to selective pressures will contribute greatly to rhizosphere engineering for sustainable agriculture.

scholarly journals Seed and seedling traits affecting critical life stage transitions and recruitment outcomes in dryland grasses

2014 ◽  
Vol 52 (1) ◽  
pp. 199-209 ◽  
Author(s):  
Julie E. Larson ◽  
Roger L. Sheley ◽  
Stuart P. Hardegree ◽  
Paul S. Doescher ◽  
Jeremy J. James
Keyword(s):  
Life Stage ◽  
Seedling Traits

Prevalence, pathogenicity and cultivar resistance of Fusarium and Rhizoctonia species causing soybean root rot

2013 ◽  
Vol 93 (2) ◽  
pp. 221-236 ◽  
Author(s):  
J. X. Zhang ◽  
A. G. Xue ◽  
E. R. Cober ◽  
M. J. Morrison ◽  
H. J. Zhang ◽  
...  
Keyword(s):  
Plant Height ◽  
Root Rot ◽  
Seedling Emergence ◽  
Dry Weight ◽  
Field Resistance ◽  
Adult Plant ◽  
Cultivar Resistance ◽  
Soybean Root ◽  
Root Dry Weight ◽  
Seedling Roots

Zhang, J. X., Xue, A. G., Cober, E. R., Morrison, M. J., Zhang, H. J., Zhang, S. Z. and Gregorich, E. 2013. Prevalence, pathogenicity and cultivar resistance of Fusarium and Rhizoctonia species causing soybean root rot. Can. J. Plant Sci. 93: 221–236. Root rot complex, caused by Fusarium and Rhizoctonia species, is a major soybean disease in Canada. We isolated nine Fusarium and Rhizoctonia species including F. oxysporum (Fo), F. graminearum (Fg), F. solani (Fs), F. avenaceum (Fa), F. tricinctum (Ft), F. sporotrichioides (Fsp), F. equiseti (Fe), F. poae (Fp), and R. solani (Rs) from soybean roots in eastern Ontario, Canada. The isolation results indicated that Fo was the most prevalent species while Fa, Fsp, and Fp were the least frequent species in the soybean rhizosphere. Numbers of Fo, Fs, Fg, and Rs isolates recovered from adult plant roots were significantly greater than those from seedling roots (P<0.01). The Rs, Fg and Fsp isolates were significantly more abundant in the no-till field than in the tilled field (P<0.01). Based on the greenhouse assays, Rs, Fg, and Fa were the most pathogenic species, while Fe and Fsp were the least pathogenic to soybean. The field resistance evaluation, based on the root rot severity, identified 21, 17, 30, and 3 out of 70 cultivars among the most tolerant to Fg, Fo, Fs, and Rs, respectively. A few of the cultivars showed partial resistance to multiple species, based on root rot severity and reduction in their seedling emergence, plant height, and root dry weight, but no cultivar was found to partially resist all four species. There was no correlation (P>0.05) between root rot severity and the reduction in seedling emergence, plant height, or root dry weight.

scholarly journals Speed breeding: a powerful tool to accelerate crop research and breeding

2017 ◽  
Author(s):  
Amy Watson ◽  
Sreya Ghosh ◽  
Matthew J. Williams ◽  
William S. Cuddy ◽  
James Simmonds ◽  
...  
Keyword(s):  
Plant Traits ◽  
Crop Improvement ◽  
Adult Plant ◽  
Crop Breeding ◽  
Improvement Rate ◽  
Global Food Security ◽  
Generation Times ◽  
Improvement Programs ◽  
Supplemental Lighting ◽  
Rapid Generation

The growing human population and a changing environment have raised significant concern for global food security, with the current improvement rate of several important crops inadequate to meet future demand [1]. This slow improvement rate is attributed partly to the long generation times of crop plants. Here we present a method called ‘speed breeding’, which greatly shortens generation time and accelerates breeding and research programs. Speed breeding can be used to achieve up to 6 generations per year for spring wheat (Triticum aestivum), durum wheat (T. durum), barley (Hordeum vulgare), chickpea (Cicer arietinum), and pea (Pisum sativum) and 4 generations for canola (Brassica napus), instead of 2-3 under normal glasshouse conditions. We demonstrate that speed breeding in fully-enclosed controlled-environment growth chambers can accelerate plant development for research purposes, including phenotyping of adult plant traits, mutant studies, and transformation. The use of supplemental lighting in a glasshouse environment allows rapid generation cycling through single seed descent and potential for adaptation to larger-scale crop improvement programs. Cost-saving through LED supplemental lighting is also outlined. We envisage great potential for integrating speed breeding with other modern crop breeding technologies, including high-throughput genotyping, genome editing, and genomic selection, accelerating the rate of crop improvement.

scholarly journals Unravelling the Role of Rhizosphere Microbiome and Root Traits in Organic Phosphorus Mobilization for Sustainable Phosphorus Fertilization. A Review

Agronomy ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 2267
Author(s):  
Issifou Amadou ◽  
David Houben ◽  
Michel-Pierre Faucon
Keyword(s):  
Plant Traits ◽  
Organic Phosphorus ◽  
Cropping Systems ◽  
Root Traits ◽  
Soil Microbiome ◽  
Phosphorus Fertilization ◽  
P Availability ◽  
Organic Input ◽  
Rhizosphere Microbiome ◽  
P Fertilizer

Moving toward more sustainable sources for managing phosphorus (P) nutrition in agroecosystems, organic phosphorus (Po) derived from organic inputs and soil is increasingly considered to complement mineral P fertilizer. However, the dynamics of P added by organic input in soil-plant systems is still poorly understood and there is currently no clear information on how the Po composition of these amendments determines P availability through interactions with the soil microbiome and root traits. Here, we review the main mechanisms of rhizosphere microbiome and root traits governing the dynamics of organic input/soil-derived Po pools in the soil-plant system. We discuss the extent to which the major forms of Po derived from organic input/soil can be used by plants and how this could be improved to provide efficient utilization of organic inputs as potential P sources. We provide new insights into how a better understanding of the interactions between Po forms, root traits, and rhizosphere microbiomes can help better manage P fertilization, and discuss recent advances in the mobilization and recovery of Po from organic inputs. We then develop proposed strategies in agroecology that could be used to improve Po utilization, specifically by better linking plant traits and Po forms, and developing new cropping systems allowing more efficient Po recycling.

scholarly journals Adaptive plasticity in plant traits increases time to hydraulic failure under drought in a foundation tree

2020 ◽  
Author(s):  
A Challis ◽  
CJ Blackman ◽  
CW Ahrens ◽  
BE Medlyn ◽  
PD Rymer ◽  
...  
Keyword(s):  
Climate Change ◽  
Drought Tolerance ◽  
Water Deficit ◽  
Plant Traits ◽  
Stomatal Closure ◽  
Adaptive Plasticity ◽  
List Type ◽  
Environment Interaction ◽  
Forest Trees ◽  
Hydraulic Failure

SummaryThe viability of forest trees, in response to climate change-associated drought, will depend on their capacity to survive through genetic adaptation and phenotypic plasticity in drought tolerance traits. Genotypes with enhanced plasticity for drought tolerance (adaptive plasticity) will have a greater ability to persist and delay the onset of hydraulic failure.Corymbia calophylla populations from two contrasting climate-origins (warm-dry and cool-wet) were grown under well-watered and chronic soil water deficit treatments in large containers. Hydraulic and allometric traits were measured and then trees were dried-down to critical levels of drought stress.Significant plasticity was detected in the warm-dry population in response to water-deficit, with adjustments in drought tolerance traits that resulted in longer dry-down times from stomatal closure to 88% loss of stem hydraulic conductance (time to hydraulic failure, THF). Plasticity was limited in the cool-wet population, indicating a significant genotype-by-environment interaction in THF.Our findings contribute information on intraspecific variation in key drought tolerance traits and THF. It highlights the need to quantify adaptive capacity in populations of forest trees facing climate change-type drought to improve predictions of forest die-back. Corymbia calophylla may benefit from assisted gene migration by introducing adaptive warm-dry populations into vulnerable cool-wet population regions.

scholarly journals Assessing Root System Architecture of Wheat Seedlings Using A High-Throughput Root Phenotyping System

2019 ◽  
Author(s):  
E. Adeleke ◽  
R. Millas ◽  
W. McNeal ◽  
J Faris ◽  
A. Taheri
Keyword(s):  
Root System ◽  
System Architecture ◽  
Root Traits ◽  
Wheat Seedling ◽  
Root System Architecture ◽  
Rapid Screening ◽  
Wheat Seedlings ◽  
Ploidy Levels ◽  
Seedling Traits ◽  
Root Phenotyping

AbstractBackground and aimsRoot system architecture is a vital part of the plant that has been shown to vary between species and within species based on response to genotypic and/or environmental influences. The root traits of wheat seedlings is critical for the establishment and evidently linked to plant height and seed yield. However, plant breeders have not efficiently developed the role of RSA in wheat selection due to the difficulty of studying root traits.MethodsWe set up a root phenotyping platform to characterize RSA in 34 wheat accessions. The phenotyping pipeline consists of the germination paper-based moisture replacement system, image capture units, and root-image processing software. The 34 accessions from two different wheat ploidy levels (hexaploids and tetraploids), were characterized in ten replicates. A total of 19 root traits were quantified from the root architecture generated.ResultsThis pipeline allowed for rapid screening of 340 wheat seedlings within 10days. Also, at least one line from each ploidy (6x and 4x) showed significant differences (P < 0.05) in measured traits except in mean seminal count. Our result also showed strong correlation (0.8) between total root length, maximum depth and convex hull area.ConclusionsThis phenotyping pipeline has the advantage and capacity to increase screening potential at early stages of plant development leading to characterization of wheat seedling traits that can be further examined using QTL analysis in populations generated from the examined accessions.

scholarly journals Wheat Resistances to Fusarium Root Rot and Head Blight Are Both Associated with Deoxynivalenol- and Jasmonate-Related Gene Expression

2018 ◽  
Vol 108 (5) ◽  
pp. 602-616 ◽  
Author(s):  
Qing Wang ◽  
Beiqi Shao ◽  
Fayaz Imamrasul Shaikh ◽  
Wolfgang Friedt ◽  
Sven Gottwald
Keyword(s):  
Gene Expression ◽  
Root Rot ◽  
Defense Mechanisms ◽  
Defense Responses ◽  
Pathogen Resistance ◽  
Adult Plant ◽  
Head Blight ◽  
Fusarium Root Rot ◽  
Age Related ◽  
Seedling Roots

Fusarium graminearum is a major pathogen of wheat causing Fusarium head blight (FHB). Its ability to colonize wheat via seedling root infection has been reported recently. Our previous study on Fusarium root rot (FRR) has disclosed histological characteristics of pathogenesis and pathogen defense that mirror processes of spike infection. Therefore, it would be interesting to understand whether genes relevant for FHB resistance are induced in roots. The concept of similar-acting defense mechanisms provides a basis for research at broad Fusarium resistance in crop plants. However, molecular defense responses involved in FRR as well as their relation to spike resistance are unknown. To test the hypothesis of a conserved defense response, a candidate gene expression study was conducted to test the activity of selected prominent FHB defense-related genes in seedling roots, adult plant roots, spikes, and shoots. FRR was examined at seedling and adult plant stages to assess age-related pattern of disease and pathogen resistance. This study offers first evidence for a significant genetic overlap in root and spike defense responses, both in local and distant tissues. The results point to plant development-specific rather than organ-specific determinants of resistance, and suggest roots as an interesting model for studies on wheat−Fusarium interactions.

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