Root Traits Research Articles

Combination of Lolium perenne L. and Festuca arundinacea Schreb. improve yields under low phosphorus availability

AbstractPhosphorus (P) is one of the main nutrients for all plants, including grasses. However, sources of P fertilizer are not renewable, are not evenly distributed and overfertilization can lead to serious environmental degradation. Smart combinations of grasses may be able to more efficiently take up P from soils through complementarity. In a two-year field mesocosm experiment, we compared the performance of Lolium perenne L. and Festuca arundinacea Schreb. in monocultures and in combination, as well as a mixture of both species with a tetraploid variety of Lolium perenne L and Phleum pratense L. Plants were grown in an unfertilized low P soil and in P fertilized soil for two growing seasons. We measured biomass production, root traits, nutrient uptake, microbial biomass and enzymatic activities. In the unfertilized plots the combination of Lolium perenne and Festuca arundinacea generated the highest cumulative yields (25,951 ± 4059 kg ha−1), relative total yield (> 1) and P nutrition index (0.79). We related this to the complementarity found in root traits and lower intraspecific competition of Festuca arundinacea and Lolium perenne diploid. Festuca arundinacea produced higher root biomass than Lolium perenne diploid at deeper soil layers (98 vs. 44 g m−2; p < 0.05). On the other hand, Lolium perenne diploid had significantly finer roots than Festuca arundinacea both at topsoil and bottom layers (0.19 vs. 0.22 mm and 0.19 vs. 0.23 mm at top and bottom layers respectively). The 4 species combination did not result in higher yields. Our results show that, in low P soils, combinations of grass species with contrasting root traits could lead to significantly higher yields than monocultures.

Influence of GA3 (gibberellic acid) and Ca(calcium) on root trait variation and osmotic potential of linseed (Linum usitatissimum L.) under chloride-dominated salinity

Linseed (Linum usitatissimum) is a versatile crop cultivated for its seeds, which are valuable source of ω-3 fatty acids. It adversely affected by soil salinity, as high salt levels can hinder their growth and reduce yields. To assess the potential for mitigating the adverse effects of high salinity concentrations, enhancing the resilience of three genotypes (Shekhar, Sheela, and Kartika) of linseed plants, this research aimed to find out the impact of Gibberellic acid (GA3) and Calcium (Ca) on various aspects of root morphology, osmotic potential of linseed, under varying levels of Cl- dominated salinity. The study employed three salinity levels (0, 5, and 10 dSm-1) and exogenous application of 10−6 M GA3 and/or 10 mg CaCl2 kg-1 in potted plants.The findings indicated that increasing salinity stress significantly (p≤0.05) affected root parameters, including total surface area(43.45%), average diameter(42.06%), total projected area(44.45%), length per volume (66.23%), root length, total root volume (73.23%), tips, forks,fine roots, and osmotic potential(66.67%). Correlations among linseed genotypes were observed between various root morphology and osmotic potential parameters. The application of GA3 and Ca effectively ameliorated the impact of salinity stress at its highest level (10 dSm-1), resulting in increased root parameters while decreasing the osmotic potential (Ψs). Both GA3 and Ca treatments significantly influenced root architecture and maintained optimal osmotic potential. The chloride-dominated salinity exerted inhibitory effects on all three genotypes’ (Shekhar, Sheela, and Kartika) root growth parameters while applying GA3 and Ca successfully mitigated these effects, enhancing root growth.

The effect of spraying with marine algae extract and adding Humax on growth traits of the roots of two varieties of pomegranate seed-lings

The study was conducted for the period from 20/3 to 20/9/2023 to study the Effect of spraying marine algae extract and adding Humax on the growth traits of the roots of two varieties of pomegranate seedlings. The experiment was implemented relying on the completely randomized block design (RCBD) as a factorial experiment of three factors: the first was pomegranate varieties (Wonderful and Slimi), the second was marine algae extract with three concentrations (0, 1.5, and 3 ml L-1), and the third was Humax with three concentrations (0, 0.25, and 0.50 g L-1), comprising three replicates of each. On September 20 2023 measurements were taken and the results were analyzed according to the statistical design used, and the averages were compared according to the selection of the least significant difference and at the level of probability 0.05, and the most important results reached: The variety Wonderful was significantly superior to the Slimi variety in most root traits studied except the root diameter trait. The treatment of the marine algae extract at a concentration of 3ml L-1 showed significant superiority for all root traits studied, The Humax treatment at a concentration of 0.50 g L-1 showed significant superiority for all the root traits studied. The binary interaction between the varieties and the marine algae extract significantly affected all studied traits, as the variety Wonderful, when treated with 3ml L-1 increased in most root traits, while cultivar Slimi recoded highest average in the root diameter. The binary interaction between the varieties and Humax was significantly effective; when treating the variety Wonderful with 0.50 g L-1 of Humax increased all root traits significantly. The binary interaction between marine algae extract and Humax significantly affected all root traits. Treating seedlings with 3ml L-1 of marine algae extract and 0.50g L-1 of Humax.

Phenotypic variability in the US upland cotton core set for root traits and water use efficiency at the late reproductive stage

AbstractTo incorporate root traits that improve water use efficiency (WUE) in cotton (Gossypium hirsutum L.) variety development, harnessing the genetic variability for root traits is essential. The objectives of this study were to characterize the US upland cotton core set for root traits and WUE and determine the traits associated with WUE. The core set includes 23 of the 381 accessions of the cotton diversity panel and represents 74% of the allelic diversity in US upland cotton. Plants were grown in polyvinyl chloride columns (125‐cm height, 15‐cm diameter) in a greenhouse in 2021–2022 and 2022–2023. Half of the columns contained a synthetic hardpan (1 cm thickness, 300 PSI penetration resistance) at a depth of 25 cm. Plants were harvested when >50% of the population opened bolls. Based on 16 root‐ and shoot‐traits, water use, and WUE, Deltapine 14, Station Miller, and Southland M1 were the best performers, and Toole, Paymaster HS200, Western Stormproof, CD3HCABCUH‐1‐89, and PD 2164 were the poor performers irrespective of the presence or absence of hardpan stress to root growth. The WUE of the core set genotypes was positively correlated with very fine root (diameter <0.25 mm) length, surface area, and volume and total root weight (correlation coefficient ≥0.45). These traits serve as beneficial root traits for developing new varieties with enhanced WUE. The identified genotypes and traits will be valuable for developing the next generation of water‐use‐efficient cotton varieties with a broad genetic base through advanced breeding techniques involving genomic tools and genetic diversity.

Trichoderma guizhouense NJAU4742 augments morphophysiological responses, nutrient availability and photosynthetic efficacy of ornamental Ilex verticillata.

Winterberry holly (Ilex verticillata [L.] A. Gray), a deciduous shrub producing glossy bright red berries, is a valuable ornamental and medicinal plant with good market prospects. However, the growth and development of I. verticillata are significantly affected by various stresses, and environmentally hazardous agrochemicals are often used to mitigate them. Trichoderma spp., ubiquitous soil-borne eco-friendly plant growth-promoting fungi, are potent biostimulants and biofertilizers and viable alternatives to agrochemicals for healthy and sustainable agriculture. In this study, the temporal efficacy of different dosages of the filamentous fungus Trichoderma guizhouense NJAU4742 in promoting morphophysiological responses of I. verticillata and the physicochemical properties and enzymatic activities of the substrate were investigated. Different concentrations of the strain T. guizhouense NJAU4742 spore suspension (C [0%], T1 [5%, v/m], T2 [10%, v/m] and T3 [15%, v/m]) were injected in the substrate contained in a pot in which 1-year-old I. verticillata was planted for temporal treatment (15, 45 and 75 days) under open-air conditions. The beneficial effects of T2 and/or T3 treatment for a long duration (75 days) were evident on the different root, aerial and photosynthetic traits; total contents of nitrogen (N), phosphorus (P) and potassium (K) in different tissues and the physicochemical properties of the substrate and its enzymatic activities (urease and invertase). Overall, the study revealed the potency of strain T. guizhouense NJAU4742 as a sustainable solution to improve the growth and development and ornamental value of I. verticillata.

Implications of cell wall immunocytochemical profiles on the structural and functional traits of root and stem galls induced by Eriosoma lanigerum on Malus domestica.

Alterations in cell wall composition imply in new structural and functional traits in gall developmental sites, even when the inducer is a sucking exophytophagous insect with strict feeding sites as the aphid associated to Malus domestica Borkh. This host plant is an economically important, fruit-bearing species, susceptible to gall induction by the sucking aphid Eriosoma lanigerum Hausmann, 1802. Herein, the immunocytochemical detection of arabinogalactan-proteins (AGPs), pectins, and hemicelluloses using monoclonal antibodies was performed in samples of non-galled roots and stems, and of root and stem galls on M. domestica. The dynamics of these cell wall components was discussed under the structural and functional traits of the galls proximal, median, and distal regions, according to the proximity of E. lanigerum colony feeding site. In the proximal region, the epitopes of AGPs and homogalacturonans (HGs) are related to cell growth and divisions, which result in the overproduction of parenchyma cells both in root and stem galls. In the proximal and median regions, the co-occurrence of HGs and arabinans in the cell walls of parenchyma and secondary tissues favors the nutrient flow and water-holding capacity, while the xylogalacturonans and hemicelluloses may function as additional carbohydrate resources to E. lanigerum. The immunocytochemical profile of the cell walls support the feeding activity of E. lanigerum mainly in the gall proximal region. The similarity of the cell wall components of the gall distal region and the non-galled portions, both in roots and stems, relates to the decrease of the cecidogenetic field the more distant the E. lanigerum colony is.

Effects of natural and chemical rooting stimulants on some root traits of two varieties of pomegranate (Punica granatum L.) cuttings

The experiment ran from the middle of February until the start of November 2023 under the plant canopy of the Department of Horticulture and Landscape, College of Agriculture, University of Kerbala. The study employed a Randomized Complete Block Design (R.C.B.D.) as a factorial experiment, with two pomegranate varieties (Yamani and Bashkan) as the first factor and various combinations of natural and chemical rootings as the second factor. These included extracts of moringa leaves (M0, M1) and licorice roots (L0, L1) at concentrations of 0 and 15 g L-1 each, as well as indole butyric acid at a concentration of 0 and 10 mg L-1 (B0, B1). The majority of the root features of the resultant seedlings demonstrated that, overall, the Bashkan variety outperformed the Yamani variety; however, this superiority varied when combined with other rooting combinations. Between the rooting stimulant combinations utilized in the study, the cuttings' dipping results differed. When it came to the quantity, size, and fresh and dry weight of the root system, indole butyric acid in combination with B1M0L0 performed better. It resulted in 250.000 root seedlings-1, 2.270 cm3, 20,680 g, and 6,650 g, respectively. In contrast, the B0M0L1 licorice root treatment demonstrated superior root length, reaching 38,100 cm. Both the percentage of rooting and the average root diameter were the largest in the combination including both extracts, B0M1L1, reaching 5.170% and 1.603 mm, respectively. Given that natural extracts have outperformed chemical radicals in the majority of the rooting qualities under study—such as licorice root extract and moringa leaf extract—it is possible to conclude from the aforementioned results on their suitability for usage as an alternative.

Identification of Novel QTL for Seedling Root Architectural Traits in the D Genome of Natural and Resynthetic Allohexaploid Wheat

Root architectural traits at the seedling stage have been demonstrated to be crucial for the efficient uptake of nutrients and drought tolerance in wheat. To dissect the genetic basis of these traits from the D genome, 182 recombinant inbred lines (RILs) derived from the common wheat TAA10 crossed with resynthesized allohexaploid wheat XX329 possessed similar AABB genomes were used for QTL mapping of five root traits in hydroponic-cultured seedlings, including lateral root number (LRN), seminal root number (SRN), root hair length (RHL), root diameter (RD), and total root volume (TRV). A total of seven QTLs were identified for the five root traits, with six possible novel QTLs for LRN, RHL, RD and TRV, accounting for 4.98–12.17% of phenotypic variation. One QTL (QLrn.qau-5D.2), controlling lateral root number, was fine mapped an approximate 5.0-Mb interval harboring 80 annotated genes, including five auxin-related genes. We further validated that QLrn.qau-5D.2 in NILTAA10 significantly enhanced yield-related traits, such as plant height, spike length, spike compactness, tiller number per plant and grain yield per plant, as comparison with NILXX329. Collectively, these results provide vital insights for fine-mapping QTLs associated with LRN, SRN, RHL, RD and TRV and facilitate the root morphologic designs for enhancing yield performance.

Variation in root traits and phenotypic plasticity between native and introduced populations of the invasive plant Chromolaena odorata

Understanding intraspecific trait variations, particularly for invasive species that occupy large geographic areas with different resource conditions, can enhance our understanding of plant responses to changes in environmental resources. However, most related studies have focused on aboveground traits, while variations in root traits and responses to changes in resources during biological invasion have not been clarified. To fill this knowledge gap, we compared the root traits of Chromolaena odorata from 10 introduced populations in Southeast Asia and 12 native populations in North and Central America under different soil nutrients. The introduced populations of the invader exhibited greater resource-acquisitive root traits, characterized by reduced fine root diameter but increased proportions of absorbing root length and specific root length, compared to the native populations. Although nutrient addition significantly affected root traits, the introduced populations showed greater phenotypic plasticity in four traits (root / shoot ratio, specific root length, absorbing root length proportion, and branching intensity) than the native populations. Different root trait syndromes were observed between the introduced and native populations. These results indicate that after introduction, C. odorata may shift towards a more soil resource-acquisitive strategy and thus respond more positively to increased soils nutrients, thereby showing better performance in high-resource environments. This study provides a better understanding of how species respond to environment changes and reveals the factors underlying exotic plant invasion success.

Effects of the seedling tray overlapping for seed emergence mode on emergence characteristics and growth of rice seedlings.

Seedling mode plays a crucial role in the rice production process, as it significantly affects the growth and development of seedlings. Among the various seedling modes, the seedling tray overlapping for seed emergence mode (STOSE mode) has been demonstrated to be effective in enhancing seedling quality. However, the impact of this mode on the germination and growth of seeds with varying plumpness remains uncertain. To investigate the effect of the STOSE mode on seedling emergence characteristics, growth uniformity, and nutrient uptake of seeds with varying plumpness levels, we conducted a study using super early rice Zhongzao 39 (ZZ39) as the test material. The seeds were categorized into three groups: plumped, mixed, and unplumped. The results indicated that the STOSE mode significantly improved the seedling rate for all types of seeds in comparison to the seedling tray nonoverlapping for seed emergence mode (TSR mode). Notably, the unplumped seeds exhibited the most pronounced enhancement effect. The soluble sugar content of the seeds increased significantly after 2 days of sowing under the STOSE mode, whereas the starch content exhibited a significant decrease. Furthermore, the STOSE mode outperformed the TSR mode in several aspects including seedling growth uniformity, aboveground dry matter mass, root traits, and nutrient uptake. Overall, the STOSE mode not only promoted the germination and growth of plumped and mixed seeds but also had a more pronounced impact on unplumped seeds.

Genome-Wide Association Studies of Three-Dimensional (3D) Cassava Root Crowns and Agronomic Traits Using Partially Inbred Populations

Cassava (Manihot esculenta Crantz) is a key industrial crop in Southeast Asia and a staple for food security in Africa, owing to its resilience and efficiency in starch production. This study aims to unravel the genetic determinants of specific cassava root crown traits, utilizing 3D modeling for yield-related attributes and root crown morphology. Phenotypic analysis of 130 partially inbred lines and their six parental lines from Thai commercial varieties revealed a range of root traits within populations showcasing robust correlations among various traits, particularly root size parameters and root weight. Genotyping-by-sequencing yielded a total of 29,361 SNP markers identified within the nuclear genome of cassava and shared across all genotypes. Genome-Wide Association Studies (GWAS) of these 136 genotypes identified 23 significant SNPs for six out of 11 root crown traits, including 3D root angle, 3D surface area, root number, 3D crown diameter, root weight, and 3D volume. We found one shared significant SNP between 3D crown diameter and root weight, and another shared SNP between root weight and 3D volume. Two closely linked SNPs were identified for 3D volume, root weight, and 3D surface area. Linkage disequilibrium (LD) analysis for each pair of SNP markers indicated the linkage decay point at approximately 60 kb. Based on LD decay and available transcriptome data, candidate gene identification highlighted 29 genes associated with five traits, providing an understanding of the genetic basis of cassava root crown traits. Our findings offer novel insights into cassava storage root traits as well as data for marker development and candidate gene identification.

Elucidating the genomic regions through genome-wide association study (GWAS) for root traits in cowpea (Vigna unguiculata (L) Walp) mini-core collection

Enhancing the root traits through selection and breeding efforts can significantly improve the acquisition of soil resources, consequently boosting crop production in marginal environments. Cowpea is one of the important legume crops in arid and semi-arid regions, grown mostly in marginal environments under drought conditions. The roots play a crucial role in plant's ability to survive and adapt under such water stressed conditions. The understanding of cowpea genetic architecture related to root system architecture (RSA) remains limited due to difficulties in accurately measuring root traits. In the present study, a set 110 diverse mini-core collection of cowpea from IITA, Nigeria was evaluated for thirteen (13) different root-shoot traits under controlled conditions in the green house. Significant variation was recorded for all the root traits in the mini-core set. Most promising genotype for most of the root traits, viz., root volume, dry root weight, root biomass density and tap root diameter were identified. The correlation analysis revealed significant positive association (p < 0.001) of root weight with shoot weight (0.85), root volume (r = 0.61), and tap root diameter (0.56). In the principal component analysis (PCA), first three principal components explained the variance of 64.31%, with PC1 contributing 44.43%, PC2 10% and PC3 9.88%. All the root-shoot traits contribute positive variation to PC1especially dry root weight and dry shoot weight that had high component loading and in PC2 root shoot ratio had high loading. The root-shoot trait data was used with 6,574 good quality SNP data for discovery of genes/QTLs/marker-trait associations for root traits. The analysis of results of genome wide association study (GWAS) led to the identification of 52 unique SNPs associated significantly (p < 10−4) with thirteen root-shoot traits. Highest number of SNPs was found associated with root weight and chromosome 5 was identified as SNP hotspot for harboring majority of significant SNPs. We further delve candidate genes within 50 kb around the identified SNP that led to the identification of several important candidate genes underlying genomic regions responsible for root-shoot traits in cowpea. The promising cowpea genotypes for root traits and promising MTAs/candidate genes will prove useful in cowpea improvement programs including improvement of drought tolerance in cowpea.

Optimizing the evaluation of root system architectural traits in Brassica napus

A semi-hydroponic system was developed to assess canola ( Brassica napus L.) root architectural traits. Four cultivars were grown under controlled conditions in germination paper rolls immersed in half-strength Hoagland’s solution. Eight parameters, including total root length, total root surface area, average root diameter, tip number, total primary root length, total lateral root length, total tertiary root length, and basal link length, were analyzed using the WinRHIZO software after 7, 14, and 21 days. The results suggested that 14 days in the semi-hydroponic system were optimal for accurate root trait assessment, as clear differences were observed while maintaining ease of handling and scanning.

Soil microbial community contributes more to plant-soil feedback and plant-plant interactions than root traits under warming and drought

Soil microbial community contributes more to plant-soil feedback and plant-plant interactions than root traits under warming and drought

Effects of root traits on soil detachment capacity driven by farmland abandonment

Vegetation restoration significantly affected root traits during farmland abandonment, thereby considerably altering the soil detachment process. However, few studies have investigated the effects of root traits on soil detachment capacity under different ages of farmland abandonment. To examine the effects of root trait changes caused by vegetation restoration on soil detachment capacity by overland flow (Dc) and soil resistance to erosion under different ages of farmland abandonment, flow scouring tests under five shear stress levels (2.80–12.95 Pa) were conducted on 125 undisturbed soil samples collected using an indoor variable slope flume. The results showed that, compared to slope farmland, the root traits of abandoned farmland (5, 12, 24, and 36 years) increased considerably, and the Dc and erodibility decreased by 51.3–93.9 % and 61.8–94.1 %, respectively. The critical shear stress of abandoned farmland gradually increased with the age of farmland abandonment, but remained less than that of slope farmland. Among hydraulic parameters, stream power was the optimal index for predicting Dc, while among root morphological traits, root surface area density (RSAD) was the best indicator for predicting Dc. The median soil particle size (D50) and cohesion are important factors that affect soil detachment. According to the Water Erosion Prediction Project (WEPP) model, Dc can be predicted using the RSAD and soil cohesion (R2 = 0.95, NSE = 0.95). In addition, a new model was established to estimate the soil detachment capacity based on D50 (R2 = 0.97, NSE = 0.97). In the present study, the performance of the model was improved compared with that of previous studies.

Synergistic Effects of Crop Aboveground Growth and Root Traits Guarantee Stable Yield of Strip Relay Intercropping Maize

In order to reveal the yield-increasing mechanism of relay intercropping (RI) maize with different varieties from the perspective of plant growth, source sink relationship, and root growth, a two-factor randomized block design trial was designed, which includes different maize varieties (Rongyu1210 (RY1210), Zhongyu 3 (ZY3)) and plant pattern (RI, Sole cropping (SC)). The leaf area index (LAI), dry matter accumulation and distribution, root dry weight (RDW), root length (RL), root surface area (RSA), root volume (RV), and maize yield were determined. LAI of RI RY1210 was significantly higher than that of the SC RY1210 at the filling stage and maturity stage. The dry matter accumulation of RI RY1210 ear was significantly higher than that of SC RY1210 and RI ZY3, and the RDW of RY1210 was significantly higher than that of ZY3. The ratio of RDW of RI RY1210 was higher than that of RI ZY3 in the 20–40 and 40–60 cm soil layers, respectively. The RDW, RL, RV, and RSA of RI RY1210 were significantly lower than that of sole RY1210 by 25.43%, 10.75%, 30.79%, and 23.73%, respectively, but higher than that of RI ZY3 by 143.98%, 278.29%, 54.40%, and 29.57%, respectively. The average yield of RI RY1210 was 8782.71 kg ha−1, with no significant difference compared to SC, which was mainly attributed to a larger ear dry matter accumulation, higher LAI in later growth stages, larger RDW, and the ratio of roots in deeper soil layers. This study will be useful and helpful to farmers for how to select and plant high-yielding maize varieties in strip relay intercropping.

How revegetation reinforces soil at early stage of restoration: A 6‐year field study in southwest China

AbstractBackground and aimsRestoring vegetation on hillslopes has been found to increase soil strength, thereby reducing the risk of soil erosion and shallow landslides. However, limited information is available on the temporal changes in root biomechanical traits and increased soil shear strength related to vegetation growth following restoration with different species.MethodsIn 2012, Symplocos setchuensis, Buxus megistophylla, and Cynodon dactylon were replanted in a forest gap in Jinyun Mountain, Beibei District, China, and studied over a 6‐year period. We measured root traits (root tensile strength, Young's modulus, cellulose content, and root density) and soil traits (cohesion and internal friction angle) at two soil depths (0–20 and 20–40 cm) for undisturbed and reconstituted samples.ResultsS. setchuensis was found to have the highest tensile strength and resistance to failure for root diameters &lt;2 mm. With elapsed time, tensile strength and cellulose content decreased. Cohesion and root mechanical reinforcement of topsoil generally increased with time (+10% per year). Root chemical and mechanical effects contributed approximately 50% to soil reinforcement. C. dactylon had the fastest growth rate and reinforced the topsoil soil rapidly, whereas S. setchuensis exhibited a consistent increase in soil reinforcement during the study period and provided more deep roots that could reinforce subsoil.ConclusionChemical and mechanical effects almost equally contributed to soil reinforcement. Although the relative contributions varied for different species, the variation in each contribution sheds new light on the sustainable use of vegetation for mitigating shallow landslides in mountainous areas.

Variation and Correlation among Fine Root Traits of Desert Plants in Arid Areas of Northwest China

Variation and Correlation among Fine Root Traits of Desert Plants in Arid Areas of Northwest China

Coordination of pinna, petiole, and root anatomical traits in 24 tropical-subtropical fern species.

Ferns are primitive vascular plants with diverse morphologies and structures. Plant anatomical traits and their linkages can reflect adaptation to the environment; however, these remain are still poorly understood in ferns. The main objective of this study was to explore whether there was structural coordination among and within organs in fern species. We measured 16 hydraulically related anatomical traits of pinnae, petioles, and roots of 24 representative fern species from the tropical and subtropical forest understory and analyzed trait correlation networks. In addition, we examined phylogenetic signals for the anatomical traits and analyzed co-evolutionary relationships. These results indicated that stomatal density and all petiole anatomical traits exhibited significant phylogenetic signals. Evolutionary correlations were observed between the tracheid diameter and wall thickness of the petiole and between the water transport capacity of the petiole and stomatal density. Conversely, anatomical traits of roots (e.g., root diameter) showed no phylogenetic signals and were not significantly correlated with those of the pinnae and petioles, indicating a lack of structural coordination between the below- and above-ground organs. Unlike angiosperms, vein density is unrelated to stomatal density or pinna thickness in ferns. As root diameter decreased, the cortex-to-stele diameter ratio decreased significantly (enhanced water absorption) in angiosperms but remained unchanged in ferns. These differences lead to different responses of ferns to climate change and improve our knowledge of the water adaptation strategies of ferns.

Trade-offs between root-secreted acid phosphatase and root morphology traits, and their contribution to phosphorus acquisition in Brassica napus.

Oilseed rape (Brassica napus) is one of the most important oil crops in the world and shows sensitivity to low phosphorus (P) availability. In many soils, organic P (Po) is the main component of the soil P pool. Po must be mineralised to Pi through phosphatases, and then taken up by plants. However, the relationship between root-secreted acid phosphatases (APase) and root morphology traits, two important P-acquisition strategies in response to P deficiency, is unclear among B. napus genotypes. This study aimed to understand their relationship and how they affect P acquisition, which is crucial for the sustainable utilisation of agricultural P resources. This study showed significant genotypic variations in root-secreted APase activity per unit root fresh weight (SAP) and total root-secreted APase activity per plant (total SAP) among 350 B. napus genotypes. Seed yield was positively correlated with total SAP but not significantly correlated with SAP. Six root traits of 18 B. napus genotypes with contrasting root biomass were compared under normal Pi, low Pi and Po. Genotypes with longer total root length (TRL) reduced SAP, but those with shorter TRL increased SAP under P deficiency. Additionally, TRL was important in P-acquisition under three P treatments, and total SAP was also important in P-acquisition under Po treatment. In conclusion, trade-offs existed between the two P-acquisition strategies among B. napus genotypes under P-deficient conditions. Total SAP was an important root trait under Po conditions. These results might help to breed B. napus with greater P-acquisition ability under low P availability conditions.