Genotypic differences in phosphorus acquisition efficiency and root performance of cotton (Gossypium hirsutum) under low-phosphorus stress

Low availability of phosphorus (P) is a major constraint to production of cotton (Gossypium hirsutum L.). The extent to which genotypic variation in root traits exists or contributes to P-acquisition efficiency (PAE) in cotton is unknown. To assess genetic variation in PAE, the biomass and P-acquisition characteristics of 32 cotton genotypes were evaluated in a hydroponic experiment. Significant genotypic variation in biomass and P content was detected among the cotton genotypes in two seasons. We then conducted a 2-year pot experiment to compare P-efficiency traits between three P-efficient and two P-inefficient genotypes under P-deficient and P-sufficient conditions (0 and 75 mg P2O5 kg–1 soil, respectively). We detected significant differences in biomass accumulation and allocation, P accumulation and allocation, root traits and PAE among the five cotton genotypes under P-sufficient and P-deficient conditions. Compared with P-inefficient genotypes, P-efficient genotypes had longer surface fine roots, and greater total root surface area, total root length, surface root length, and P concentration (partitioning index) in bolls. Root morphology, especially surface fine root length and middle root length, played an important role in P uptake under P-deficient conditions.

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Targeting Low-Phytate Soybean Genotypes Without Compromising Desirable Phosphorus-Acquisition Traits

Frontiers in Genetics ◽

10.3389/fgene.2020.574547 ◽

2020 ◽

Vol 11 ◽

Author(s):

Mireadili Kuerban ◽

Wenfeng Jiao ◽

Jiayin Pang ◽

Jingying Jing ◽

Li-Juan Qiu ◽

...

Keyword(s):

Genotypic Variation ◽

Root Traits ◽

Dry Weight ◽

Root Surface ◽

Root Surface Area ◽

Soil P ◽

P Acquisition ◽

P Concentration ◽

Soybean Genotypes ◽

Food And Feed

Phytate-phosphorus (P) in food and feed is not efficiently utilized by humans and non-ruminant livestock, potentially contributing to high losses of P to the environment. Crops with high P-acquisition efficiency can access soil P effectively. It remains elusive whether crop genotypes with high P-acquisition efficiency can also have low seed phytate concentrations. A core collection of 256 soybean [Glycine max (L.) Merr.] genotypes from China with diverse genetic background were grown in the same environment and seeds were sampled to screen for seed phytate-P concentration. Some of these genotypes were also grown in a low-P soil in the glasshouse to measure root morphological and physiological traits related to P acquisition. Large genotypic variation was found in seed phytate-P concentration (0.69–5.49 mg P g–1 dry weight), total root length, root surface area, rhizosheath carboxylates, and acid phosphatase activity in rhizosheath soil. Geographically, seed phytate-P concentration was the highest for the genotypes from Hainan Province, whereas it was the lowest for the genotypes from Inner Mongolia. Seed phytate-P concentration showed no correlation with any desirable root traits associated with enhanced P acquisition. Two genotypes (Siliyuan and Diliuhuangdou-2) with both low phytate concentrations and highly desirable P-acquisition traits were identified. This is the first study to show that some soybean genotypes have extremely low seed phytate concentrations, combined with important root traits for efficient P acquisition, offering material for breeding genotypes with low seed phytate-P concentrations.

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Novel approaches to improving growth of pasture legumes at low phosphorus levels

Proceedings of the New Zealand Grassland Association ◽

10.33584/jnzg.2014.76.2952 ◽

2014 ◽

Vol 76 ◽

pp. 197-202

Author(s):

S.N. Nichols ◽

J.R. Crush

Keyword(s):

White Clover ◽

Root Length ◽

Specific Root Length ◽

Root Traits ◽

Dry Weight ◽

Root Weight ◽

Soil P ◽

P Acquisition ◽

Shoot Dry Weight ◽

Use Efficiency

Abstract Strategies to reduce the economic and environmental costs of phosphate (P) fertiliser use in mixed pastures through plant breeding are focussed on inefficiencies in the legume component. One approach is breeding within white clover for root systems with improved P acquisition properties. Selection for root length per unit root weight (specific root length, SRL) showed that higher SRL plants could retain more biomass in the above ground fraction with decreasing soil P, whereas plants with lower SRL diverted more biomass to roots. Back cross 1 (BC1) generation interspecific hybrids between white clover and a wild relative, Trifolium uniflorum L., may possess additional root traits influencing P acquisition. In glasshouse experiments, some T. repens × T. uniflorum hybrids, back-crossed to white clover, also exhibited higher shoot dry weight than their white clover cultivar parents at low nutrient supply levels and low to intermediate soil Olsen P. This, combined with low internal P concentrations, suggests some BC1 hybrids may be more tolerant of low soil P than white clover. Differences in both P acquisition ability and internal P use efficiency may contribute to the observed yield differences. There are good prospects for delivery of new-generation clover cultivars with improved phosphate use efficiency to New Zealand farmers. Keywords: phosphorus, white clover, Trifolium uniflorum, interspecific

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Lateral Root Traits of Taxodium Hybrid ‘Zhongshanshan 406’ in Response to Drought Stress

HortScience ◽

10.21273/hortsci12387-17 ◽

2018 ◽

Vol 53 (4) ◽

pp. 547-551

Author(s):

Qin Shi ◽

Yunlong Yin ◽

Zhiquan Wang ◽

Wencai Fan ◽

Jinbo Guo ◽

...

Keyword(s):

Drought Stress ◽

Surface Area ◽

Root Length ◽

Lateral Root ◽

Plant Root ◽

Lateral Roots ◽

Specific Root Length ◽

Root Traits ◽

Root Tip ◽

Root Surface Area

Roots are vital organs for resource uptake. However, the knowledge regarding the extent by which responses in roots influence plant resistance is still poorly known. In this study, we examined the morphological and physiological responses of lateral roots of Taxodium hybrid ‘Zhongshanshan 406’ (Taxodium mucronatum♀ and Taxodium distichum♂, T. 406) to 8 (DS-8) and 12 days (DS-12) drought. Control plants (CK-8 and CK-12) were well-watered throughout the experiment. Results indicated that drought resulted in significantly decreased root length, surface area, volume, and biomass and a relatively high death rate of roots (>2 mm). Specific root length (SRL) and specific root surface area (SRA) of drought-stressed T. 406 plants were reduced to enhance resource uptake. Meanwhile, root relative water content (RWC) of T. 406 plants in CK-12 treatment was 5.81 times of those in DS-12 treatment. Under drought stress and root superoxide dismutase and ascorbic acid (ASA) activities, proline and hydrogen peroxide (H2O2) contents consistently increased to benefit the elimination of O2−. At the ultrastructural level, the organelle structure of T. 406 plant root tip was visibly damaged because of dehydration. The nucleus swelled and then exhibited uncommon features of disorganization and disruption. In short, our results provided substantial information about lateral root traits of T. 406 plants in response to drought stress, which is crucial to improve the drought resistance of Taxodium hybrid in the future breeding.

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Fine Root Length of Maize Decreases in Response to Elevated CO2 Levels in Soil

Applied Sciences ◽

10.3390/app10030968 ◽

2020 ◽

Vol 10 (3) ◽

pp. 968

Author(s):

Yaojie Han ◽

Xueyan Zhang ◽

Xin Ma

Keyword(s):

Root Morphology ◽

Root Length ◽

Fine Root ◽

Plant Root ◽

Control Treatment ◽

Root Surface Area ◽

Co2 Leakage ◽

Coarse Roots ◽

Fine Root Length ◽

The Impact

To assess the environmental risks of carbon capture and storage (CCS) due to underground CO2 leakage, many studies have examined the impact on plant growth; however, the effect of leaked CO2 on root morphology remains poorly understood. This study simulated the effects of CO2 leakage from CCS on maize (Zea mays L.) root systems through pot experiments—one control treatment (no added CO2) and two elevated soil CO2 treatments (1000 g m−2 d−1 and 2000 g m−2 d−1). Compared with the control, root length, root surface area, and root volume were reduced by 44.73%, 34.14%, and 19.16%, respectively, in response to CO2 treatments with a flux of 2000 g m−2 d−1. Meanwhile, the fine root length in CO2 treatments with a flux of 1000 g m−2 d−1 and 2000 g m−2 d−1 were reduced by 29.44% and 45.88%, respectively, whereas no obvious difference in regard to coarse roots was found. Understanding changes in plant root morphology in this experiment, especially the decrease in the fine root length, are essential for explaining plant responses to CO2 leakage from CCS.

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Integrating GWAS and Gene Expression Analysis Identifies Candidate Genes for Root Morphology Traits in Maize at the Seedling Stage

Genes ◽

10.3390/genes10100773 ◽

2019 ◽

Vol 10 (10) ◽

pp. 773 ◽

Cited By ~ 1

Author(s):

Wang ◽

Wei ◽

Li ◽

Wang ◽

Ge ◽

...

Keyword(s):

Root System ◽

Candidate Genes ◽

Root Development ◽

Root Length ◽

Root Traits ◽

Root Surface ◽

Root Surface Area ◽

Phenotypic Variance ◽

Potential Candidate ◽

Short Root

Root system plays an essential role in water and nutrient acquisition in plants. Understanding the genetic basis of root development will be beneficial for breeding new cultivars with efficient root system to enhance resource use efficiency in maize. Here, the natural variation of 13 root and 3 shoot traits was evaluated in 297 maize inbred lines and genome-wide association mapping was conducted to identify SNPs associated with target traits. All measured traits exhibited 2.02- to 21.36-fold variations. A total of 34 quantitative trait loci (QTLs) were detected for 13 traits, and each individual QTL explained 5.7% to 15.9% of the phenotypic variance. Three pleiotropic QTLs involving five root traits were identified; SNP_2_104416607 was associated with lateral root length (LRL), root surface area (RA), root length between 0 and 0.5mm in diameter (RL005), and total root length (TRL); SNP_2_184016997 was associated with RV and RA, and SNP_4_168917747 was associated with LRL, RA and TRL. The expression levels of candidate genes in root QTLs were evaluated by RNA-seq among three long-root lines and three short-root lines. A total of five genes that showed differential expression between the long- and short-root lines were identified as promising candidate genes for the target traits. These QTLs and the potential candidate genes are important source data to understand root development and genetic improvement of root traits in maize.

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Covariation in root traits of Leymus chinensis in response to grazing in steppe rangeland

The Rangeland Journal ◽

10.1071/rj18099 ◽

2019 ◽

Vol 41 (4) ◽

pp. 313

Author(s):

Wei Xiaoting ◽

Zhong Mengying ◽

Liu Yuehua ◽

Wu Ruixin ◽

Shao Xinqing

Keyword(s):

Root Length ◽

Topological Structure ◽

Grazing Intensity ◽

Root Traits ◽

Root Surface ◽

Leymus Chinensis ◽

Root Surface Area ◽

Total Root Length ◽

Grazing Season ◽

Heavy Grazing

Root traits are closely related to nutrient absorption and resource competition and can even influence plant recovery and community succession. Grazing can influence root traits directly through trampling and foraging, or indirectly by changing soil characteristics. In the present study, a grazing experiment that involved combinations of grazing season (from June to September) and intensity (rest, moderate and heavy) was conducted in steppe rangeland, Inner Mongolia, China to investigate how the root traits of Leymus chinensis respond to different grazing regimes in the case of aboveground miniaturisation after long-term overgrazing. Root traits such as root length, root surface area, specific root length, root tissue density, root links (unbranched parts of a root connecting either a tip and a branching point or two branching points) and root topological structure were scanned and analysed using Win-RHIZO image analysis software. The results showed that the size of L. chinensis plants was reduced in response to overgrazing, typically by a smaller plant height, total root length, root surface area, root volume, number of tips and number of links. However, root diameter and link length, branching angle and topological structure (herringbone or dichotomous) were unaffected by grazing. Most root traits showed strong correlations under moderate grazing intensity, but not under heavy grazing, indicating that grazing changed the relationships among root traits. Relationships between plant height and root traits (total root length and number of links) shifted from positive to negative as grazing intensity increased, and the trade-off between aboveground and belowground traits was an important adaptive strategy of L. chinensis under heavy grazing. Decreasing grazing intensity in the late grazing season could benefit plant recovery, and a rest in the early grazing season would mitigate root and shoot damage.

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Phenotypic Diversity for Root Traits and Identification of Superior Germplasm for Root Breeding in Watermelon

HortScience ◽

10.21273/hortsci15093-20 ◽

2020 ◽

Vol 55 (8) ◽

pp. 1272-1279

Author(s):

Dennis N. Katuuramu ◽

W. Patrick Wechter ◽

Marcellus L. Washington ◽

Matthew Horry ◽

Matthew A. Cutulle ◽

...

Keyword(s):

Root System ◽

Surface Area ◽

Root Length ◽

Root Traits ◽

Root Surface ◽

Root Diameter ◽

Root Surface Area ◽

Total Root Length ◽

Root Volume ◽

Diverse Range

Root traits are an important component for productive plant performance. Roots offer immediate absorptive surfaces for water and nutrient acquisition and are thus critical to crop growth and response to biotic and abiotic stresses. In addition, roots can provide the first line of defense against soilborne pathogens. Watermelon crop performance is often challenged by inclement weather and environmental factors. A resilient root system can support the watermelon crop’s performance across a diverse range of production conditions. In this study, 335 four-day-old watermelon (Citrullus spp.) seedlings were evaluated for total root length, average root diameter, total root surface area, and total root volume. Total root length varied from 8.78 to 181 cm (20.6-fold variation), total surface area varied from 2 to 35.5 cm2, and average root diameter and total root volume had an 8- and 29.5-fold variation, respectively. Genotypes PI 195927 (Citrullus colocynthis) and PI 674448 (Citrullus amarus) had the largest total root length values. Accessions PI 674448 and PI 494817 (C. amarus) had the largest total root surface area means. Watermelon cultivars (Citrullus lanatus) had a relatively smaller root system and significantly fewer fibrous roots when compared with the roots of the other Citrullus spp. Positive genetic correlations were identified among total root length, total root surface area, and total root volume. This genetic information will be useful in future breeding efforts to select for multiple root architecture traits in watermelon. Germplasm identified in this study that exhibit superior root traits can be used as parental choices to improve watermelon for root traits.

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Linking root traits to superior phosphorus uptake and utilisation efficiency in three Fabales in the Core Cape Subregion, South Africa

Functional Plant Biology ◽

10.1071/fp17209 ◽

2018 ◽

Vol 45 (7) ◽

pp. 760 ◽

Cited By ~ 3

Author(s):

Dunja MacAlister ◽

A. Muthama Muasya ◽

Samson B. M. Chimphango

Keyword(s):

Root Length ◽

Phosphorus Uptake ◽

Specific Root Length ◽

Root Traits ◽

Biomass Accumulation ◽

P Uptake ◽

N Availability ◽

P Acquisition ◽

Plant P Uptake ◽

Polygala Myrtifolia

In the low-P soil of the fynbos biome, plants have evolved several morphological and physiological P acquisition and use mechanisms, leading to variable uptake and use efficiencies. We expected that plants grown in low-P soils would exhibit greater P acquisition traits and hypothesised that Aspalathus linearis (Burm. f.) R. Dahlgren, a cluster-root-forming species adapted to drier and infertile soils, would be the most efficient at P acquisition compared with other species. Three fynbos Fabales species were studied: A. linearis and Podalyria calyptrata (Retz.) Willd, both legumes, and Polygala myrtifolia L., a nonlegume. A potted experiment was conducted where the species were grown in two soil types with high P (41.18 mg kg–1) and low P (9.79 mg kg–1). At harvest, biomass accumulation, foliar nutrients and P acquisition mechanisms were assessed. Polygala myrtifolia developed a root system with greater specific root length, root hair width and an average root diameter that exuded a greater amount of citrate and, contrary to the hypothesis, exhibited greater whole-plant P uptake efficiency. However, P. calyptrata had higher P use efficiency, influenced by N availability through N2 fixation. Specific root length, root length and root : shoot ratio were promising morphological traits for efficient foraging of P, whereas acid phosphatase exudation was the best physiological trait for solubilisation of P.

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ROOTING OF Inga edulis Mart. (LEGUMINOSAE-MIMOSOIDEAE) MINI-CUTTINGS

FLORESTA ◽

10.5380/rf.v50i1.61297 ◽

2019 ◽

Vol 50 (1) ◽

pp. 1091

Author(s):

Marciana Christo Berude ◽

Emanuel França Araújo ◽

Bruna Tomaz Sant'Ana ◽

Rodrigo Sobreira Alexandre ◽

Elzimar De Oliveira Gonçalves

Keyword(s):

Surface Area ◽

Root Length ◽

Dry Matter ◽

Weighted Average ◽

Specific Root Length ◽

Root Surface ◽

Root Surface Area ◽

Root Volume ◽

Inga Edulis ◽

Fine Root Length

Seeds of the species Inga edulis are recalcitrant and lose viability quickly, which restricts seedling production at only a certain time of the year. Thus, this study aimed to analyze the potential of mini-cutting and the influence of different indole-3-butyric acid (IBA) concentrations on the vegetative propagation of Inga edulis. The vegetative material was collected from juvenile plants from a clonal mini-garden. The experiment was carried out in a completely randomized design, with five replications and each experimental unit with eight cuttings. Treatments consisted of different IBA concentrations (0, 1000, 2000, 4000, and 8000 mg kg−1). The percentage of live and rooted mini-cuttings, number of roots emitted from the base, longest root length, total number of roots, fine root length, total root length, root surface area, weighted average root diameter, root volume, shoot dry matter, root dry matter, total dry matter, specific root length, specific root surface area, and root density were analyzed after 45 days in a greenhouse. All Inga edulis mini-cuttings survived, and rooting was over 85%. IBA concentrations had no significant effect on most of the analyzed variables. However, exogenous auxin concentration between 2000 and 4636.96 mg kg−1 provided mini-cuttings with a higher number of roots, surface area, and root volume. Rooting of juvenile Inga edulis mini-cuttings may occur without the use of IBA.

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Characterization of Root System Architecture Traits in Diverse Soybean Genotypes Using a Semi-Hydroponic System

Plants ◽

10.3390/plants10122781 ◽

2021 ◽

Vol 10 (12) ◽

pp. 2781

Author(s):

Shuo Liu ◽

Naheeda Begum ◽

Tingting An ◽

Tuanjie Zhao ◽

Bingcheng Xu ◽

...

Keyword(s):

Root Length ◽

Eastern China ◽

Genotypic Variation ◽

Root Traits ◽

Growth Stages ◽

Root Mass ◽

Total Root Length ◽

Shoot Height ◽

Hydroponic System ◽

Soybean Genotypes

Phenotypic variation and correlations among root traits form the basis for selecting and breeding soybean varieties with efficient access to water and nutrients and better adaptation to abiotic stresses. Therefore, it is important to develop a simple and consistent system to study root traits in soybean. In this study, we adopted the semi-hydroponic system to investigate the variability in root morphological traits of 171 soybean genotypes popularized in the Yangtze and Huaihe River regions, eastern China. Highly diverse phenotypes were observed: shoot height (18.7–86.7 cm per plant with a median of 52.3 cm); total root length (208–1663 cm per plant with a median of 885 cm); and root mass (dry weight) (19.4–251 mg per plant with a median of 124 mg). Both total root length and root mass exhibited significant positive correlation with shoot mass (p ≤ 0.05), indicating their relationship with plant growth and adaptation strategies. The nine selected traits contributed to one of the two principal components (eigenvalues > 1), accounting for 78.9% of the total genotypic variation. Agglomerative hierarchical clustering analysis separated the 171 genotypes into five major groups based on these root traits. Three selected genotypes with contrasting root systems were validated in soil-filled rhizoboxes (1.5 m deep) until maturity. Consistent ranking of the genotypes in some important root traits at various growth stages between the two experiments indicates the reliability of the semi-hydroponic system in phenotyping root trait variability at the early growth stage in soybean germplasms.

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