Decoupled drought responses of fine-root versus leaf acquisitive traits among six Prunus hybrids

2020 ◽  
Vol 13 (3) ◽  
pp. 304-312
Author(s):  
Shuang-Xi Zhou ◽  
Rob R Walker ◽  
Everard Edwards
Keyword(s):  
Drought Stress ◽  
Fine Root ◽  
Root Traits ◽  
Resource Conservation ◽  
Root Diameter ◽  
Root Trait ◽  
Soil Drought ◽  
Drought Response ◽  
Severe Drought ◽  
Significant Change

Abstract Aims Predicting drought consequences on forests and fruit crop plantings requires improved understanding of drought responses of both leaf and fine-root resource acquisitive traits (specific leaf area—SLA, specific root surface area—SRA and specific root length—SRL). We hypothesize their responses are coordinated towards integrated plant resource conservation under severe drought. Methods We tested the hypothesis with a greenhouse-based drought experiment on saplings of six Prunus hybrids with a priori known contrasting drought sensitivity. Saplings were subjected to either control (100% field capacity) or severe drought stress treatment (33% evapotranspiration of hybrid-specific control plants). Sample collections were carried out at 30 and at 60 days after the start of treatments, for both control and stressed saplings. Important Findings No hybrid showed concurrent significant decrease of SLA and SRA (or SRL) under severe drought. The fine-root traits of the six hybrids showed two major drought-response scenarios, in particular: (i) increased root tissue density (RTD) and decreased average root diameter without significant change of SRL and (ii) increased RTD and decreased SRL without significant change of average root diameter. Drought responses of leaf gas exchange, SRA, SRL and RTD were closely correlated along a gradient towards resource conservation from control to drought-stressed plants in all hybrids, which was orthogonal to another gradient characterized by a hybrid-dependent decrease of SLA. These findings highlight (i) the multi-dimensionality of root-trait drought responses, (ii) the decoupling between leaf economics and leaf hydraulics and (iii) the covariation of leaf and root hydraulics in terms of trait drought responses. The study contributes to identifying the origin of the multi-dimensionality of root-trait drought response at intraspecific scale, and highlights differential drought–response combinations of leaf and fine-root traits among hybrids to survive under severe soil drought stress.

scholarly journals What is the Difference between the Response of Grass Pea (Lathyrus sativus L.) to Salinity and Drought Stress?—A Physiological Study

Agronomy ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 833 ◽  
Author(s):  
Barbara Tokarz ◽  
Tomasz Wójtowicz ◽  
Wojciech Makowski ◽  
Roman J. Jędrzejczyk ◽  
Krzysztof M. Tokarz
Keyword(s):  
Drought Stress ◽  
Crop Productivity ◽  
Lathyrus Sativus ◽  
Soil Drought ◽  
Severe Drought ◽  
Chemical Stress ◽  
Plant Tolerance ◽  
Grass Pea ◽  
Physiological Level ◽  
Lathyrus Sativus L

Understanding the mechanisms of plant tolerance to osmotic and chemical stress is fundamental to maintaining high crop productivity. Soil drought often occurs in combination with physiological drought, which causes chemical stress due to high concentrations of ions. Hence, it is often assumed that the acclimatization of plants to salinity and drought follows the same mechanisms. Grass pea (Lathyrus sativus L.) is a legume plant with extraordinary tolerance to severe drought and moderate salinity. The aim of the presented study was to compare acclimatization strategies of grass pea seedlings to osmotic (PEG) and chemical (NaCl) stress on a physiological level. Concentrations of NaCl and PEG were adjusted to create an osmotic potential of a medium at the level of 0.0, −0.45 and −0.65 MPa. The seedlings on the media with PEG were much smaller than those growing in the presence of NaCl, but had a significantly higher content percentage of dry weight. Moreover, the stressors triggered different accumulation patterns of phenolic compounds, soluble and insoluble sugars, proline and β-N-oxalyl-L-α,β-diamino propionic acid, as well as peroxidase and catalase activity. Our results showed that drought stress induced a resistance mechanism consisting of growth rate limitation in favor of osmotic adjustment, while salinity stress induced primarily the mechanisms of efficient compartmentation of harmful ions in the roots and shoots. Furthermore, our results indicated that grass pea plants differed in their response to drought and salinity from the very beginning of stress occurrence.

Relationships among arbuscular mycorrhizas, root morphology and seedling growth of tropical native woody species in southern Brazil

2005 ◽  
Vol 21 (5) ◽  
pp. 529-540 ◽  
Author(s):  
Waldemar Zangaro ◽  
Fabio Rodrigo Nishidate ◽  
Flavia Regina Spago Camargo ◽  
Graziela Gorete Romagnoli ◽  
Julia Vandressen
Keyword(s):  
Root Hair ◽  
Fine Root ◽  
Root Hairs ◽  
Woody Species ◽  
Root Traits ◽  
Arbuscular Mycorrhizas ◽  
Root Diameter ◽  
Mycorrhizal Colonization ◽  
Native Woody Species ◽  
Mycorrhizal Response

The relationships between arbuscular mycorrhizal fungi and root morphological characteristics were studied under greenhouse conditions of 78 tropical native woody species and 47 seedling species collected in the field. Seedlings of native woody pioneer and early secondary species that generally exhibited fine roots with a dense cover of long root hairs showed higher mycorrhizal response and root mycorrhizal colonization than late-secondary and climax species with coarse roots with a sparse cover of short root hairs. Root-hair length and incidence decreased with the progression among the successional groups while fine-root diameter increased, both in the greenhouse and in the field. The mycorrhizal response was highly correlated to root mycorrhizal colonization in the greenhouse and in the field. These parameters were inversely correlated with the seed mass and fine-root diameter, but directly correlated with root-hair incidence, both in the greenhouse and in the field. Mycorrhizal response and root mycorrhizal colonization were also directly correlated with the root-hair length and root/shoot ratio of uninoculated plants. The seedling mycorrhizal status of the early successional woody species suggests that the root traits of these fast-growing species can be more receptive to attraction, infection and colonization by arbuscular mycorrhizas than root traits of late-successional species.

scholarly journals Trade-Offs in Phosphorus Acquisition Strategies of Five Common Tree Species in a Tropical Forest of Puerto Rico

2021 ◽  
Vol 4 ◽  
Author(s):  
Daniela Yaffar ◽  
Camille E. Defrenne ◽  
Kristine G. Cabugao ◽  
Stephanie N. Kivlin ◽  
Joanne Childs ◽  
...  
Keyword(s):  
Phosphatase Activity ◽  
Tree Species ◽  
Fine Root ◽  
Root Traits ◽  
Root Trait ◽  
Soil P ◽  
P Acquisition ◽  
Trade Offs ◽  
Acquisition Strategies ◽  
Common Tree

Tree species that are successful in tropical lowlands have different acquisition strategies to overcome soil phosphorus (P) limitations. Some of these strategies belowground include adjustments in fine-root traits, such as morphology, architecture, association with arbuscular mycorrhizal fungi, and phosphatase activity. Trade-offs among P-acquisition strategies are expected because of their respective carbon cost. However, empirical evidence remains scarce which hinders our understanding of soil P-acquisition processes in tropical forests. Here, we measured seven fine-root functional traits related to P acquisition of five common tree species in three sites of the Luquillo Experimental Forest in Puerto Rico. We then described species-specific P-acquisition strategies and explored the changes in fine-root trait expression from 6 months before to 6 months after two consecutive hurricanes, Irma and María, passed over the island. We found that variations in root trait expression were driven mainly by the large interspecific differences across the three selected sites. In addition, we revealed a trade-off between highly colonized fine roots with high phosphatase activity and fine roots that have a high degree of branching. Furthermore, the former strategy was adopted by pioneer species (Spathodea campanulata and Cecropia schreberiana), whereas the latter was adopted by non-pioneer species (mostly Dacryodes excelsa and Prestoea montana). Additionally, we found that root trait expression did not change comparing 6 months before and after the hurricanes, with the exception of root phosphatase activity. Altogether, our results suggest a combination of structural and physiological root traits for soil P acquisition in P-poor tropical soils by common tropical tree species, and show stability on most of the root trait expression after hurricane disturbances.

scholarly journals Analysis of Whole Transcriptome RNA-seq Data Reveals Many Alternative Splicing Events in Soybean Roots under Drought Stress Conditions

Genes ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1520
Author(s):  
Li Song ◽  
Zhenzhi Pan ◽  
Lin Chen ◽  
Yi Dai ◽  
Jinrong Wan ◽  
...  
Keyword(s):  
Alternative Splicing ◽  
Drought Stress ◽  
Drought Response ◽  
Severe Drought ◽  
Ontology Term ◽  
Soybean Root ◽  
A Genome ◽  
Drought Conditions ◽  
Soybean Roots ◽  
Mild Drought

Alternative splicing (AS) is a common post-transcriptional regulatory mechanism that modulates gene expression to increase proteome diversity. Increasing evidence indicates that AS plays an important role in regulating plant stress responses. However, the mechanism by which AS coordinates with transcriptional regulation to regulate drought responses in soybean remains poorly understood. In this study, we performed a genome-wide analysis of AS events in soybean (Glycine max) roots grown under various drought conditions using the high-throughput RNA-sequencing method, identifying 385, 989, 1429, and 465 AS events that were significantly differentially spliced under very mild drought stress, mild drought stress, severe drought stress, and recovery after severe drought conditions, respectively. Among them, alternative 3′ splice sites and skipped exons were the major types of AS. Overall, 2120 genes that experienced significant AS regulation were identified from these drought-treated root samples. Gene Ontology term analysis indicated that the AS regulation of binding activity has vital roles in the drought response of soybean root. Notably, the genes encoding splicing regulatory factors in the spliceosome pathway and mRNA surveillance pathway were enriched according to the Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis. Splicing regulatory factor-related genes in soybean root also responded to drought stress and were alternatively spliced under drought conditions. Taken together, our data suggest that drought-responsive AS acts as a direct or indirect mode to regulate drought response of soybean roots. With further in-depth research of the function and mechanism of AS in the process of abiotic stress, these results will provide a new strategy for enhancing stress tolerance of plants.

scholarly journals Inherent and Stress-Induced Responses of Fine Root Morphology and Anatomy in Commercial Grapevine Rootstocks with Contrasting Drought Resistance

Plants ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1121
Author(s):  
Idan Reingwirtz ◽  
Jake Uretsky ◽  
Italo F. Cuneo ◽  
Thorsten Knipfer ◽  
Clarissa Reyes ◽  
...  
Keyword(s):  
Drought Stress ◽  
Drought Resistance ◽  
Root Morphology ◽  
Root Length ◽  
Fine Root ◽  
Lateral Roots ◽  
Root Diameter ◽  
Root Tip ◽  
Soil Conditions ◽  
Plant Materials

Some grapevine rootstocks perform better than others during and after drought events, yet it is not clear how inherent and stress-induced differences in root morphology and anatomy along the length of fine roots are involved in these responses. Using a variety of growing conditions and plant materials, we observed significant differences in root diameter, specific root length (SRL) and root diameter distribution between two commonly used commercial grapevine rootstocks: Richter 110 (110R; drought resistant) and Millardet et de Grasset 101-14 (101-14Mgt; drought sensitive). The 110R consistently showed greater root diameters with smaller SRL and proportion of root length comprised of fine lateral roots. The 110R also exhibited significantly greater distance from tip to nearest lateral, longer white root length, and larger proportion of root length that is white under drought stress. Mapping of fine root cortical lacunae showed similar patterns between the rootstocks; mechanical failure of cortical cells was common in the maturation zone, limited near the root tip, and increased with drought stress for both genotypes; however, lacuna formed under wetter soil conditions in 110R. Results suggest that drought resistance in grapevine rootstocks is associated with thick, limitedly branched roots with a larger proportion of white-functional roots that tend to form lacuna under more mild water deficit, all of which likely favor continued resource acquisition at depth.

Influence of fine root traits on in situ exudation rates in four conifers from different mycorrhizal associations

2020 ◽  
Vol 40 (8) ◽  
pp. 1071-1079
Author(s):  
Maiko Akatsuki ◽  
Naoki Makita
Keyword(s):  
Root System ◽  
Root Morphology ◽  
Fine Root ◽  
Root Exudation ◽  
Specific Root Length ◽  
Root Traits ◽  
Root Diameter ◽  
Small Scale ◽  
Exudation Rate

Abstract Plant roots can exude organic compounds into the soil that are useful for plant survival because they can degrade microorganisms around the roots and enhance allelopathy against other plant invasions. We developed a method to collect carbon (C) exudation on a small scale from tree fine roots by C-free filter traps. We quantified total C through root exudation in four conifers from different microbial symbiotic groups (ectomycorrhiza (ECM) and arbuscular mycorrhiza (AM)) in a cool-temperate forest in Japan. We determined the relationship of mass-based exudation rate from three diameter classes (<0.5, 0.5–1.0, and 1.0–2.5 mm) of the intact root system with root traits such as morphological traits including root diameter, specific root length (SRL), specific root area (SRA), root tissue density (RTD) and chemical traits including root nitrogen (N) content and C/N. Across species, the mass-based root exudation rate was found to correlate with diameter, SRA, RTD, N and C/N. When comparing mycorrhizal types, there were significant relationships between the exudation and diameter, SRL, SRA, root N and C/N in ECM species; however, these were not significant in AM species. Our results show that relationships between in situ root exudation and every measured trait of morphology and chemistry were strongly driven by ECM roots and not by AM roots. These differences might explain the fact that ECM roots in this study potentially covaried by optimizing the exudation and root morphology in forest trees, while exudation in AM roots did not change with changes in root morphology. In addition, the contrasting results may be attributable to the effect of degree and position of ECM and AM colonization in fine root system. Differences in fine root exudation relationships to root morphology for the two types of mycorrhizae will help us better understand the underlying mechanisms of belowground C allocation in forest ecosystems.

Differences between root traits of early- and late-successional trees influence below-ground competition and seedling establishment

2016 ◽  
Vol 32 (4) ◽  
pp. 300-313 ◽  
Author(s):  
Waldemar Zangaro ◽  
Luis Eduardo Azevedo Marques Lescano ◽  
Enio Massao Matsuura ◽  
Artur Berbel Lirio Rondina ◽  
Marco Antonio Nogueira
Keyword(s):  
Root System ◽  
Plant Species ◽  
Seedling Establishment ◽  
Fine Root ◽  
Woody Species ◽  
Root Traits ◽  
Root Systems ◽  
Root Diameter ◽  
Grass Root ◽  
Below Ground

Abstract:The competitive influence of the root system of the exotic grass Urochloa brizantha and the widespread forb Leonotis nepetifolia on the emergence, survival and early growth of the seedlings of eight tropical heliophilous herbaceous species, six early-successional woody species and five late-successional woody species from Brazil, grown in 3500-cm3 pots and in greenhouse without light restriction were assessed. The density of fine-root systems produced by the forb and the grass in pots were 6.8 cm cm−3 soil and 48.1 cm cm−3 soil, respectively. Seedlings survival of the heliophilous herbaceous, early- and late-successional woody species were 86%, 70% and 100% in presence of the forb root system and 12%, 14% and 100% in competition with grass root system, respectively. The competitive pressure applied by the grass root system on seedling growth of the heliophilous herbaceous, early- and late-successional woody species were 2.4, 1.9 and 1.4 times greater than the forb root system. Total root length of the heliophilous herbaceous, early- and late-successional woody species grown without competitors were 13, 33 and 5 times greater than in competition with forb, and were 66, 54 and 6 times greater than in competition with grass root system, respectively. The averages of fine-root diameter of plants grown without competitors were 209 μm for the heliophilous herbaceous, 281 μm for early-successional trees and 382 μm for late-successional trees. The root system of the forb did not avoid seedling establishment of most plant species, but the grass root system hampered more the establishment of heliophilous herbaceous and early-successional woody species than the seedling establishment of late-successional woody species. The different density of root systems produced in soil by the forb and the grass, and the distinct root traits (e.g. root diameter and root tissue density) of the early- and late-successional plant species can explain the differences in the establishment of seedlings of plant species belonging to different groups of tropical succession when exposed to below-ground competition.

Do nutrients retranslocate from fine roots?

1987 ◽  
Vol 17 (8) ◽  
pp. 913-918 ◽  
Author(s):  
E. K. Sadanandan Nambiar
Keyword(s):  
Fine Roots ◽  
Fine Root ◽  
Seasonal Pattern ◽  
Root Diameter ◽  
Nutrient Concentrations ◽  
Root Production ◽  
Severe Drought ◽  
Significant Difference ◽  
Average Rainfall ◽  
Monthly Variations

The changes in nutrient and starch concentrations in live and dead roots were studied as a part of a research project concerned with the dynamics of fine root production and turnover in a Pinusradiata (D. Don) plantation. The study period of 30 months included a year of severe drought, followed by a year of more than average rainfall. Nutrient concentrations were strongly related to root diameter. Monthly variations in nutrient concentrations in fine roots were minor and showed no seasonal pattern. This was in contrast with large seasonal fluctuations in starch concentrations in roots. Prolonged drought also had only minor effects on nutrient concentrations in roots. These results and the absence of significant difference in N, P, K, and Mg concentrations between live and dead roots suggest that there is little retranslocation of nutrients from senescent roots of Pinusradiata.

scholarly journals Candidate regulators and target genes of drought stress in needles and roots of Norway spruce

2019 ◽  
Author(s):  
Julia C. Haas ◽  
Alexander Vergara ◽  
Vaughan Hurry ◽  
Nathaniel R. Street
Keyword(s):  
Drought Stress ◽  
Norway Spruce ◽  
Stress Responses ◽  
Large Scale ◽  
Target Genes ◽  
Forest Tree ◽  
Drought Response ◽  
Severe Drought ◽  
Molecular Response ◽  
Transcriptional Responses

AbstractDrought stress impacts on seedling establishment, survival and whole-plant productivity. Drought stress responses have been extensively studied at the physiological and molecular level in angiosperms, particularly in agricultural species and the model Arabidopsis thaliana, with the vast majority of work performed on aboveground tissues. Boreal forests are dominated by coniferous tree species and cover vast areas of the terrestrial surface. These areas are predicted to be particularly influenced by ongoing climate change and will be exposed to more frequent and acute drought. The associated impact at all stages of the forest tree life cycle is expected to have large-scale ecological and economic impacts. To provide a comprehensive understanding of the drought response mechanisms of Picea abies seedlings, we assayed the physiological response of needles and transcriptional responses of roots and needles after exposure to mild and severe drought. Shoots and needles showed extensive reversible plasticity for physiological measures indicative of drought response mechanisms, including stomatal conductance (gs) and shoot water potential. Root and needle transcriptional responses contrasted, with an extensive root-specific down-regulation of growth. When we compared the responses of P. abies with previously-characterised A. thaliana drought response genes, we found that the majority of the genes were conserved across lineages. However, in P. abies, transcription factors (TFs) previously identified as belonging to the ABA-dependent pathway had a more limited role and most differentially expressed genes were specific to the stress response of P. abies. These results highlight the importance of profiling both above- and below-ground tissues and provide a comprehensive framework to advance understanding of the drought response mechanism of P. abies.One sentence summaryAnalysis of the drought transcriptome of Norway spruce reveals divergent molecular response pathways in conifers.

The role of biochar in alleviating soil drought stress in urban roadside greenery

Geoderma ◽  
2021 ◽  
Vol 404 ◽  
pp. 115223
Author(s):  
You Jin Kim ◽  
Junge Hyun ◽  
Sin Yee Yoo ◽  
Gayoung Yoo
Keyword(s):  
Drought Stress ◽  
Soil Drought
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