Root Morphological Parameters Research Articles

Effects of different phosphorus and potassium supply on the root architecture, phosphorus and potassium uptake, and utilization efficiency of hydroponic rice

Phosphorus (P) and potassium (K) affect seedling growth, root configuration, and nutrient uptake in hydroponic rice, but there are few studies on all growth stages of rice. The purpose of this experiment was to determine the response characteristics of root morphology, plant physiology, and P and K uptake and utilization efficiency to different supplies of P and K. Two local conventional rice varieties (Shennong 265 and Liaojing 294) were used as experimental materials across four treatments, including HPHK (sufficient P and K supply), HPLK (sufficient P supply under low K levels), LPHK (sufficient K supply under low P levels) and LPLK (low P and K levels) in a hydroponic setting. The results showed that HPHK and HPLK significantly decreased the acid phosphatase activity of leaves and roots from full heading to filling stages when compared to LPHK and LPLK. Sufficient supply of P or K significantly increased the accumulation of P and K (aboveground, leaves, stem sheath, and whole plant) and root morphological parameters (root length, root surface area, total root volume, and tips) during major growth stages when compared to LP or LK levels. HPHK was significantly higher than other treatments in terms of dry weight and the root activity at the main growth stage, P and K uptake rates in nutrient solutions at various stages, related P and K efficiency at the maturity stage, yield, effective panicle number, and grain number per panicle. In addition, the effect of HPHK on the above indexes were significantly greater than those of single sufficient supply of P or K. In conclusion, HPHK can improve plant configuration, increase plant P and K absorption and root activity, and increase rice yield and related P and K utilization efficiency.

The Effects of Soil Acidity and Aluminium on the Root Systems and Shoot Growth of Lotus pedunculatus and Lupinus polyphyllus.

Lotus pedunculatus (lotus) and Lupinus polyphyllus (Russell lupin) persist in the upland grasslands of New Zealand, where soil acidity and associated aluminium (Al) toxicity impede conventional pasture legumes. This experiment investigated the response of lotus and Russell lupin to soil acidity and Al. The species were sown in 20 cm tall 1.2 L pots of acidic upland soil. A mass of 4.5 or 6.7 g lime (CaCO3)/L was added to either the top or bottom or both soil horizons (0-9 cm and 9-18 cm), resulting in six treatments across six randomised blocks in a glasshouse. The soil pH was 4.4, 4.9, and 5.4; the exchangeable Al concentrations were 24, 2.5, and 1.5 mg/kg for 0, 4.5, and 6.7 g lime/L. At 16 weeks post-sowing, the plants were divided into shoots and roots at 0-9 cm and 9-18 cm. Root morphology, shoot and root dry matter (DM), shoot nitrogen (N), and nodulation were measured. The total plant DM and shoot-to-root DM ratio were higher, and the shoot %N was lower for the lotus plants than the Russell lupin plants for the various lime rates (13.2 vs. 2.9 g plant-1, 5.6 vs. 1.6, and 2.4 vs. 3.3%, p < 0.05). No response to lime in terms of total DM or total root morphology parameters was exhibited in either species (p > 0.05). Root morphology adjustments in response to acidity between soil horizons were not observed. The results indicated that lotus and Russell lupin are tolerant to high soil acidity (pH 4.4-5.4) and exchangeable Al (1.5-24 mg kg-1), highlighting their considerable adaptation to grasslands with acidic soils.

Root morphology parameters and nutrient acquisition capabilities of grafted tomato plants in root-restricted conditions are subject to salinity and rootstock characteristics

ABSTRACT A tomato cultivar ('Izmir F1') grafted onto six commercially available rootstocks ('Arnold', 'Dohkko', 'Emperador', 'He-man', 'Kaiser', and 'Suzuka') together with self-grafted plants of the tomato cultivar (Izmir/Izmir) were included in a pot experiment. Growth, root morphology and nutrient uptake parameters were evaluated under different salinity conditions (0 and 50 mM NaCl). Grafting increases root length, specific root length, and root length ratio, which enhances the capabilities of hetero-grafted plants to exploit a larger volume of soil or otherwise increase root density under root restriction conditions. Since the root traits and nutrient concentrations in hetero-grafted variants were less impacted by a change in the salinity level, the use of specific rootstocks (‘Arnold,’ ‘Dohkko,’ ‘Kaiser’) could contribute to a steadier growth and yield of tomato plants under fluctuating salinity levels in the irrigation water. The hetero-grafted tomato plants (Dohkko/Izmir, Suzuka/Izmir) demonstrated higher Na sequestration/compartmentalization capabilities than the self-grafted (Izmir/Izmir) plants which helps to maintain a more appropriate K+/Na+ ratio. By exhibiting lower translocation indexes of some heavy metals (Al, Ni, Zn, and Cd), appropriate rootstock/scion combinations might be a useful tool for reducing the risk of their accumulation in edible plant organs.

Mechanisms and Applications of Pseudomonas monteilii SX001: A Promising Agent for Improving Cucumber Tolerance to Salt Stress

To investigate the effects of Pseudomonas monteilii SX001 on various parameters of cucumber plants under salt stress, the salt-sensitive cucumber variety “Jinyou No. 4” was used as the test material, and coconut bran was used to simulate salt stress by applying NaCl solution. The results indicated that salt stress significantly reduced the morphological structure, relative growth rate, root morphology, and photosynthetic parameters of the cucumber plants. Leaf starch, soluble sugar, and sucrose contents significantly increased, whereas their levels in roots decreased. Cell membrane damage leads to the accumulation of reactive oxygen species and malondialdehyde, with notable increases in the activities of major antioxidant enzymes such as SOD, CAT, and POD. Nitrogen metabolism was disrupted, as evidenced by a significant decrease in nitrate nitrogen content and an increase in ammonium nitrogen content, as well as a significant reduction in the activity of NR enzymes involved in nitrogen metabolism. The enzyme activity in the cucumber rhizosphere soil decreased. However, Pseudomonas monteilii SX001 significantly enhanced the growth of cucumber seedlings under salt stress, improved photosynthetic efficiency, and facilitated sugar transformation and transport via glucose metabolism. Additionally, Pseudomonas monteilii SX001 reduced the reactive oxygen content and increased antioxidant enzyme activity. It also increased the activity of substrate enzymes and decreased the diversity of rhizosphere soil microorganisms but also increased the abundance of Asticcacaulis, Acinetobacter, Brevundimonas, Pseudomonas, and Enterobacter. These findings demonstrate that Pseudomonas monteilii SX001 is a promising bioinoculant for alleviating salt stress in cucumber production and improving soil health.

Effects of Bacillus subtilis on Cucumber Seedling Growth and Photosynthetic System under Different Potassium Ion Levels.

Potassium deficiency is one of the important factors restricting cucumber growth and development. This experiment mainly explored the effect of Bacillus subtilis (B. subtilis) on cucumber seedling growth and the photosynthetic system under different potassium levels, and the rhizosphere bacteria (PGPR) that promote plant growth were used to solubilize potassium in soil, providing theoretical support for a further investigation of the effect of biological bacteria fertilizer on cucumber growth and potassium absorption. "Xinjin No. 4" was used as the test material for the pot experiment, and a two-factor experiment was designed. The first factor was potassium application treatment, and the second factor was bacterial application treatment. The effects of different treatments on cucumber seedling growth, photosynthetic characteristics, root morphology, and chlorophyll fluorescence parameters were studied. The results showed that potassium and B. subtilis had obvious promotion effects on the cucumber seedling growth and the photosynthesis of leaves. Compared with the blank control, the B. subtilis treatment had obvious effects on the cucumber seedling height, stem diameter, leaf area, total root length, total root surface area, total root volume, branch number, crossing number, gs, WUE, Ci, and A; the dry weight of the shoot and root increased significantly (p ≤ 0.05). Potassium application could significantly promote cucumber growth, and the effect of B. subtilis and potassium application was greater than that of potassium application alone, and the best effect was when 0.2 g/pot and B. subtilis were applied. In conclusion, potassium combined with B. subtilis could enhance the photosynthesis of cucumber leaves and promote the growth of cucumber.

Ridge-furrow film mulch with nitrogen fertilization improves grain yield of dryland maize by promoting root growth, plant nitrogen uptake and remobilization

Soil mulch has been widely applied to enhance crop yields in (semi-)arid and semi-humid regions on the globe. However, how different mulch practices influence root growth, plant nitrogen (N) uptake, remobilization and allocation remains unclear, especially under different N fertilization rates. A two-season (June–October in 2021 and 2022) field experiment was performed on dryland summer maize in a semi-humid but drought-prone region of northwest China. There were six mulch practices: flat cultivation without mulch (Flat), flat cultivation with straw mulch (Flat-Straw), flat cultivation with black film mulch (Flat-Film), flat cultivation with transparent film mulch (Flat-Trans), ridge-furrow cultivation with black film mulch on the ridge (Ridge-Film), ridge-furrow cultivation with transparent film mulch on the ridge (Ridge-Trans), and two N fertilization rates: 0 kg N ha−1 (N0) and 180 kg N ha−1 (N1). The results showed that film mulch significantly (p<0.05) improved root morphological parameters compared to Flat. Plant N uptake significantly (p<0.05) increased due to improved root growth under film and straw mulch, with grain N uptake increasing by 78.2% under Ridge-Film, 66.2% under Ridge-Trans and 39.6% under Flat-Film compared to Flat. The significant (p<0.01) increases in pre-anthesis N remobilization and post-anthesis N uptake under film and straw mulch compared to Flat achieved synergistic increases in grain yields. The contributions of total N remobilization to grain N dramatically increased by 31.2%, 27.5%, 17.0% and 11.2% under Ridge-Film, Ridge-Trans, Flat-Film and Flat-Trans compared to Flat, respectively. Meanwhile, film-mulched practices significantly (p<0.01) reduced soil nitrate-N residual due to improved plant N uptake, by 21.7% under Flat-Film, 16.9% under Flat-Trans, and 33.6% under Ridge-Film compared to Flat. The contributions of various mulch practices to grain yield ranked as Ridge-Film > Flat-Film > Ridge-Trans > Flat-Trans > Flat-Straw. The Ridge-Film with N fertilization significantly (p<0.05) increased N use efficiency, N agronomic efficiency, N recovery efficiency, N harvest index and grain yield by 10.8%, 124.9%, 147.1%, 19.8% and 120.0% compared to FlatN0, respectively. The structural equation modeling indicated that the differences in post-silking N uptake and pre-silking N remobilization caused by different mulch practices and nitrogen rates could directly explain at least 48.0% and 52.0% of grain yield differences. The ridge-furrow cultivation with film mulch, especially black film mulch, along with 180 kg N ha−1 is favorable for improving grain yield and N use efficiency of dryland summer maize in the semi-humid but drought-prone region of northwest China.

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.

Humalite enhances the growth, grain yield, and protein content of wheat by improving soil nitrogen availability and nutrient uptake

AbstractBackgroundThe application of synthetic chemical inputs in current agricultural practices has significantly increased crop production, but their use has caused severe negative consequences on the environment. Humalite is an organic soil amendment that is rich in humic acid and found in large deposits in southern Alberta, Canada. Humic products can enhance nutrient uptake and assimilation in plants by reducing nutrient losses and enhancing bioavailability in the soil.AimHere, we evaluated the effects of different humalite rates in the presence of nitrogen, phosphorus, potassium (NPK) at recommended rates on soil nitrogen availability, wheat growth, grain yield, seed nutritional quality, and nitrogen use efficiency (NUE) under controlled environmental conditions.MethodsA series of studies were conducted by applying five different rates of humalite (0, 200, 400, 800, and 1600 kg ha−1) with NPK at recommended rates. Soil nitrogen availability and shoot and root growth parameters were recorded at flowering stage. NUE was calculated based on the grain yield at maturity stage.ResultsPlants grown in the presence of humalite augmented root morphological parameters (root length, volume, and surface area), plant biomass (shoot and root), and nutrient uptake (N, P, K, and S) compared to the plants supplied with recommended fertilizer alone. Furthermore, humalite application significantly increased grain yield (14%–19%), seed protein content (23%–30%), and NUE (14%–60%) compared to the fertilizer application alone.ConclusionThese findings suggest that humalite can be used as an organic soil amendment to reduce synthetic fertilizer application and improve plant growth and yield while enhancing fertilizer use efficiency.

Biomass‐based lateral root morphological parameter models for rapeseed (Brassica napus L.)

AbstractLateral roots, including adventitious roots, are the main component of rapeseed roots with support, absorb, and synthesis functions and their morphological parameters directly affecting the plant's aboveground growth and yield. Root biomass, as a material base for lateral root growth, can be used as a link between plant phenotypes and their physiological processes, as well as to enhance root 3D growth model mechanisms and accuracy. To quantify the relationships between lateral root morphological indices and the corresponding organ biomass for rapeseed, we used two cultivars, NY 22 (conventional) and NZ 1818 (hybrid), and conducted cultivar and fertilizing cylindrical tube experiments during the 2016–2019, with two fertilizer levels, no fertilizer, and 180 kg N ha−1 fertilizer. The lateral root biomass and morphological parameters were determined during the whole growth period. The biomass‐based lateral root morphological parameter models were developed by analyzing the quantitative relationship between the lateral root morphological indices and their corresponding biomass, and the descriptive models were verified with independent experimental data. The results showed that the correlation (r) of simulated and observed values for the lateral root morphological parameters are all greater than 0.9 with significant levels at p &lt; 0.001. The absolute values of the average absolute difference (da) of simulated and observed values for the lateral root length (LLR), lateral root average diameter (ADLR), lateral root surface area (SALR), and lateral root volume (VLR) are −30.408 cm, −0.003 mm, 12.902 cm2, and 0.039 cm3, respectively. The RMSE values are 175.183 cm, 0.010 mm, 59.710 cm2, and 1.513 cm3, respectively. The ratio of da to the average observed values (dap) for the LLR and VLR are all less than 5%, and the ADLR and SALR are all &lt;6%. The models developed in this paper have good performance and reliability for predicting lateral root morphological parameters of rapeseed. The study provides a mechanistic method for linking the rapeseed growth model with the morphological model using corresponding organic biomass and laying a good foundation for establishing a 3D morphological model for rapeseed root system based on biomass.

Response of faba bean (Viciafaba L.) varieties to lime application in wolaita zone, Southern Ethiopia

Soil acidity and scarcity of faba bean varieties adapted to lower pH soils are major factors that limit faba bean production in Ethiopia. Therefore, an experiment was conducted to find the lime rate and faba bean can improve the yield of the crop. Four rates of lime (0, 2, 4, and 6 t ha–1) and five-faba bean varieties (local, Dosha, Gebelecho, Tumsa, and Bobicho) were used as treatments, which laid out as CRD with six replications. The main and interaction effects of lime rates and varieties significantly (P &lt; 0.05) influenced all growth, yield components, and yield parameters. Nevertheless, root morphological parameters were significantly (P &lt; 0.05) affected by the main effects of the lime rate. Accordingly, the most significant high aboveground biomass of 47.92 g pot–1, and seed yields of (19.16 g pot–1) were obtained in response to the interaction of the Tumsa variety with 3 g pot–1lime rate (2 t ha–1). The lowest aboveground biomass of (32.08 g pot–1) and seed yield of (12.84 g pot–1) were obtained in response to the local variety planted with no lime application. Overall, in terms of seed yield, the Gebelcho and Tumsa varieties performed best by attaining their maximum seed yields in response to the application of 3 g lime pot–1 (2 t ha–1). Thus, 3 g pot–1 (2.0 t ha–1) liming rate with the Gebelcho and Tumsa varieties was found to be the best-combined treatment to improve the yield of the crop in the study area. The results of the study indicated the need to ameliorate soil acidity and select acid-tolerant faba bean varieties for enhancing the yield of the crop.

Effects of aeration treatments on root and rhizome growth parameters of Phyllostachys violascens (Lei bamboo) under intensive cultivation: A field study

Aeration through underground tunneling in mulched Phyllostachys violascens (Lei bamboo) forests can improve soil quality. Nevertheless, the effect of soil ventilation on the growth of bamboo roots and rhizomes at different distances, directions and depths of the forest are still unclear. In a field experiment, four treatments including organic mulching without aeration (MNA), organic mulching with aeration (MA), non-mulched with aeration (NMA), and non-mulched and non-aeration treatment (control) were set up to investigate the effects of soil aeration treatment on bamboo root and rhizome growth at different depths and radii distances from the bamboo trunk in both perpendicular (PD) and horizontal (HD) aeration directions. The results show that root and rhizome quantity and quality decreased vertically and linearly in the soil layers and this trend was more significant in the PD direction and near the trunk. MA treatment induced the most significant effects on the determined root and rhizome growth parameters. At 10 cm depth, the number of rhizomes in CK was 70.8 %, 77.1 %, and 18.8 % higher than that in MA, NMA, and MNA plots, respectively. However, fewer rhizomes appeared in CK and MNA plots at 20 and 30 cm depths relative to 10 cm while the number was increased by 149 % in MA and 151 % NMA plots at 20 cm. This suggest that in CK and MNA plots, soil hypoxia and soil acidification were prevalent which inhibited rhizome growth by inducing rhizome up-floating and preventing root elongation, respectively. Also, the root morphological parameters including lengths, surface areas, and volumetric areas were significantly increased in MA and MNA treatments compared to the control and NMA. For example, root length, surface area, and volumetric area in MA were increased by 56 %, 44.9 %, and 28.3 % while that in MNA increased by 40 %, 55.8 %, and 81.0 % compared with roots from the control plot. This study provides both a theoretical and practical guide for improving soil quality and bamboo growth under intensive management using aeration treatment.

Unraveling plant adaptation to single and combined nutrient deficiencies in a dicotyledonous and a monocotyledonous plant species

Nutrient deficiencies considerably limit agricultural production worldwide. However, while single deficiencies are widely studied, combined deficiencies are poorly addressed. Hence, the aim of this paper was to study single and combined deficiencies of iron (Fe) and phosphorus (P) in barley (Hordeum vulgare) and tomato (Solanum lycopersicum). Plants were grown in hydroponics and root exudation was measured over the growing period. At harvest, root morphology and root and shoot ionome was assessed. Shoot-to-root-ratio decreased in both species and in all nutrient deficiencies, besides in -Fe tomato. Barley root growth was enhanced in plants subjected to double deficiency behaving similarly to -P, while tomato reduced root morphology parameters in all treatments. To cope with the nutrient deficiency barley exuded mostly chelants, while tomato relied on organic acids. Moreover, tomato exhibited a slight exudation increase over time not detected in barley. Overall, in none of the species the double deficiency caused a substantial increase in root exudation. Multivariate statistics emphasized that all the treatments were significantly different from each other in tomato, while in barley only -Fe was statistically different from the other treatments. Our findings highlight that the response of the studied plants in double deficiencies is not additive but plant specific.

Root Growth and Defense Response of Seedlings against Fusarium oxysporum in Sand Culture and In Vitro—A Comparison of Two Screening Approaches for Asparagus Cultivars

Two rapid asparagus (Asparagus officinalis L.) screening methods, in sand culture and in vitro, were tested to evaluate the response of young seedlings against F. oxysporum f. sp. asparagi (isolate Foa1). Root morphological parameters were evaluated and correlated with the symptomatology and expression of the defense-related genes at 5 and 7 dpi. In sand cultivation, the Foa1-inoculated cultivars showed no visible disease symptoms on their roots until 7 dpi. Two-factorial ANOVA statistics found no significant interaction between the cultivars and treatments for most root parameters but some differences between the cultivars. The in vitro Foa1-inoculated cultivars showed high susceptibility according to their symptomatology and differed greatly in the length of the primary root at 5 dpi. In some cultivars, the primary root length and root surface area were higher upon Foa1 inoculation. The expression changes were very different among the cultivars, with significant induction of PR1, POX, and PAL at 5 dpi in all cultivars in vitro but only in two cultivars in sand cultivation. The in vitro screening method, although more artificial, seemed to be more reliable than sand cultivation since the fungus was able to develop well in the culture medium. In sand-filled pots, the fungus may have been hindered in its development, even though a considerable higher amount of Foa1 was inoculated. In addition, the fungal growth was easily trackable in tubes, while in sand cultivation, the results were only visible after pulling the seedlings out of the pots 12 dpi.

Deciphering the mechanisms of microbe mediated drought stress alleviation in wheat

Drought stress adversely influences the crop plants. Herein, present research was designed to elucidate the role of plant growth promoting bacteria for amelioration of water stress in wheat. A pot experiment was conducted for screening the microorganisms on the basis of plant growth, chlorophyll and proline content under water stress. Bacillus sp. BT3 and Klebsiella sp. HA9 were found to be more promising strains that positively influenced the plant growth, chlorophyll and proline status of seedlings under water stress condition. Further, Bacillus sp.BT3 and Klebsiella sp. HA9 along with check strain (BioNPK) were used for elucidating their detailed effect on morphological, biochemical, physiological and molecular traits to mitigate water stress in wheat. Microbial inoculation significantly improved plant height, fresh weight and dry weight of root and shoot, relative water content, chlorophyll content and root morphological parameters over the uninoculated water stressed (30% FC) control. Likewise, sugar content, protein content and antioxidant enzymes were also significantly enhanced due to microbial inoculation under water stress (30% FC). Microbial inoculation significantly decreased proline, glycine betaine, lipid peroxidation, peroxide and superoxide radicals in wheat over the uninoculated water stressed (30%FC) control. Quantitative real-time (qRT) PCR analysis revealed that Bacillus sp. BT3, Klebsiella sp. HA9 and BioNPK inoculation significantly upregulated stress responsive genes (DHN, DREB, L15 and TaABA-8OH) over the uninoculated water stressed (30% F.C.) control. The study reports the potential of Bacillus sp. BT3 and Klebsiella sp. HA9 along with BioNPK in water stress alleviation in wheat which could be recommended as effective bioinoculants.

Critical shoot phosphorus concentrations for changes in root morphology to improve phosphorus uptake in cotton

AbstractBackgroundIn recent years, the response of cotton (Gossypium hirsutum L.) root morphology and rhizosphere processes to phosphorus (P) deficiency have attracted extensive attention. However, the dynamics of root morphology and physiology to shoot P concentration (SPC) under various P conditions remain unclear.AimWe aimed to determine the changes in root morphology and physiology and their relationships with SPC under different levels of P supply.MethodThe cotton cultivars XLZ13 and XLZ19 were grown in a hydroponic experiment with seven rates of P supply (0–2.0 mM P L−1) and in a root box experiment with seven P levels (0–400 mg P kg−1). Root morphological and physiological parameters were determined 60 days after planting (hydroponic experiment) and 75 days after transplanting (root box experiment).ResultsCotton plant growth, P uptake, and root morphology differed significantly between the two genotypes and among the P levels. Cotton plants had the maximum shoot biomass when the SPC of XLZ13 and XLZ19 were 4.6–5.9 mg g−1 and 3.9‐5.0 mg g−1, respectively. Total and specific root lengths initially increased with increasing SPC and peaked at an SPC of XLZ13 and XLZ19 about 6.0–7.0 mg g−1 and 4.0‐5.0 mg g−1, respectively. Root physiological responses (rhizosphere acidification, acid phosphatase [Apase] activity) decreased as the SPC increased.ConclusionsThe critical SPC for optimal root morphology were 5–6 mg g−1. P deficiency did not induce rhizosphere acidification but promoted root and rhizosphere APase activity.

Lead accumulation and biochemical responses in Rhus chinensis Mill to the addition of organic acids in lead contaminated soils.

Adding organic acid is an effective approach to assist phytoremediation. The effects of organic acids on phytoremediation efficiency are unknown in Rhus chinensis. This study aimed to evaluate the effect of citric acid (CA) and oxalic acid (OA) on the lead phytoremediation potential of R. chinensis with significantly inhibited growth in Pb-contaminated soil. The experimental pot culture study evaluated the long-term physiological response and metal accumulation patterns of R. chinensis grown in varying Pb-treated soil, and examined the effects of 0.5 and 1.0 mmol L-1 CA and OA on the growth, oxidative stress, antioxidant system, and Pb subcellular distribution of R. chinensis grown in pots with 1000 mg kg-1 Pb. Compared with the control, the biomass, leaf area, root morphological parameters, and chlorophyll concentration of R. chinensis decreased, whereas the carotenoid, malondialdehyde, H2O2, and O2˙- concentrations, and superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) activity increased under Pb stress. A copious amount of Pb was taken up and mainly stored in the cell walls of the roots. The application of CA and OA increased plant growth. The highest shoots and roots biomass increase recorded was 44.4 and 61.2% in 1.0 mmol L-1 OA and 0.5 mmol L-1 CA treatment, respectively. The presence of CA and OA increased SOD, POD, and CAT activities and decreased the H2O2, O2˙- and malondialdehyde content. A concentration of 0.5 mmol L-1 CA significantly increased the Pb concentration in the organs. The other organic acid treatments changed root Pb concentrations slightly while increasing shoot Pb concentrations. The translocation factor values from organic acid treatments were increased by 38.8-134.1%. Our results confirmed that organic acid could alleviate the toxicity of stunted R. chinensis and improve phytoremediation efficiency.

Influence of chicken feather waste derived protein hydrolysate on the growth of tea plants under different application methods and fertilizer rates.

Modern agriculture prioritizes eco-friendly and sustainable strategies to enhance crop growth and productivity. The utilization of protein hydrolysate extracted from chicken feather waste as a plant biostimulant paves the path to waste recycling. A greenhouse experiment was performed to evaluate the implications of different doses (0, 1, 2, and 3g L-1) of chicken feather protein hydrolysate (CFPH), application method (soil and foliar), and fertilizer rate (50% and 100%) on the growth performance of tea nursery plants. The highest dose of CFPH (3g L-1) increased the shoot and root dry weights by 43% and 70%, respectively over control. However, no significant differences were observed between 2 and 3g L-1 doses in plant dry weight, biometric, and root morphological parameters. Foliar application of CFPH significantly increased all the growth parameters compared to soil drenching except N, P, and K concentrations in leaves and roots. Plants grown under 100% fertilizer rate showed better growth performance than 50% fertilizer rate. Tea nursery plants treated with foliar 2g L-1 dose and grown under full fertilizer rate recorded the highest plant dry weight, root length, and root surface area. However, tea plants under 50% fertilizer rate and treated with foliar 2 and 3g L-1 doses sustained the growth similar to untreated plants under 100% fertilizer rate. The significantly higher N, P, and K concentrations in leaves were observed in plants treated with soil drenching of 2 and 3g L-1 CFPH doses under 100% fertilizer rate. Our results indicate that the application of CFPH as a foliar spray is highly effective in producing vigorous tea nursery plants suitable for field planting, eventually capable of withstanding stress and higher yield.

FeCl3 and Fe2(SO4)3 differentially reduce Cd uptake and accumulation in Polish wheat (Triticum polonicum L.) seedlings by exporting Cd from roots and limiting Cd binding in the root cell walls

Wheat grown in cadmium (Cd)-contaminated soils easily accumulates more Cd in edible parts than the Chinese safety limit (0.1 mg/kg). FeCl3 and Fe2(SO4)3 have been used to extract Cd from Cd-contaminated soils. Thus, we hypothesized that FeCl3 and Fe2(SO4)3, used as iron (Fe) fertilizers, can reduce Cd uptake and accumulation in wheat. Here, a hydroponic experiment was performed with three FeCl3 and Fe2(SO4)3 concentrations under 80 μM CdCl2 stress on dwarf Polish wheat (Triticum polonicum L., 2n = 4x = 28, AABB) seedlings. Compared with Fe deficiency, FeCl3 and Fe2(SO4)3 additions competitively reduced Cd concentrations. The reductions were not associated with changes in dry weight and root morphological parameters. FeCl3 and Fe2(SO4)3 additions reduced Cd concentrations in the following order from smallest to largest reduction: 25 μM Fe2(SO4)3 < 200 μM FeCl3 < 50 μM FeCl3 < 100 μM Fe2(SO4)3. Investigation of subcellular distributions showed that the four Fe fertilizers differentially reduced Cd binding in the root cell walls and enhanced root sucrose and trehalose. Cd chemical form analysis revealed that Fe fertilizer addition also differentially reduced root FE, FW, and FNaCl. Transcriptomic analysis revealed that addition of FeCl3 and Fe2(SO4)3 differentially up-regulated several genes that hydrolyze cell wall polysaccharides and metal transporter genes for Cd uptake (IRT1 and CAX19) and export (ZIP1, ABCG11, ABCG14, ABCG28, ABCG37, ABCG44, and ABCG48) reducing Cd uptake and accumulation. Our results demonstrated that FeCl3 and Fe2(SO4)3 can reduce Cd accumulation in wheat, and 50 μM FeCl3 is the most effective treatment.

Root cortical aerenchyma, characteristics and nutrient use efficiency of different maize hybrids during drought and rehydration process

AbstractThe importance of cortical aerenchyma in flood and drought resistance is well established. However, effects of the combination of the two factors remain unclear. We tested the hypothesis that under conditions of substantial water alteration, enhanced root cortical aerenchymas (RCAs) could not only exert a positive effect on root functions under drought periods but also influence nitrogen capture, soil exploration and compensation growth after rehydration. Three maize varieties, Yurui2 (YR2), Yunrui6 (YR6) and Yunrui167 (YR167), were grown under rainfed field conditions, and a subset was grown initially under well‐watered and extreme‐drought conditions, followed by the same simulated rainfed field conditions, in order to compare the effects on the RCAs during the growing season. Root morphology and function parameters were measured, and variation in the RCAs was induced by water stress. Under extreme drought, we found substantial variation in the RCAs (from 0% to 37%) and drought tolerance performance. During the rehydration stage, different RCA components exerted different effects on maize, recovery parameters and plant N use efficiency. YR6 showed resilient growth, whereas recovery was inhibited in YR167 and YR2, respectively, which possessed the lowest and highest RCA area percentages. The results support the hypothesis that RCA area percentage under drought periods are important for maize recovery after post‐drought rehydration.

Effect of Plant Growth Regulators on Cotton Seedling Root Growth Parameters and Enzyme Activity.

It is well known that the survival rate of cotton seedlings is low, and the growth and development status at this stage is crucial to improve productivity. Plant hormones are important factors that promote the growth and development of cotton seedlings. Growth regulators have the same function as plant hormones. The purpose of this research is to explore the effects of different concentrations of growth regulators on cotton root morphological parameters and enzyme activities, and to find suitable plant growth regulators and their optimal concentrations to improve the growth of the cotton seedling root system. Three cotton varieties, "Zhongmian 619" (Z619), "Xinluzao 27" (Z27), and "Xinluzao 39" (Z39), and three growth regulators, gibberellin (GA3), salicylic acid (SA), and paclobutrazol (PP333), at three concentrations were used in our experiment. In Z619 and Z27, 0.050 mg/L GA3 significantly increased the total root length. Similarly, 0.010 mmol/L SA significantly increased the root growth parameters of Z619 and Z39. In Z619, 0.1 mg/L PP333 significantly increased the total root length and total surface area and reduced the average root diameter. For all three cotton varieties, 0.050 mg/L GA3 increased peroxidase (POD) activity in the roots. In Z27 and Z39, 0.80 mg/L GA3 increased superoxide dismutase (SOD) activity in the roots. All SA concentrations increased SOD activity in roots of Z619 and Z27; 0.10 mg/L PP333 significantly increased SOD and POD activities in the roots of Z619 and significantly increased SOD activity in Z27. Principal component analysis indicated that 0.10 mmol/L SA was the optimal treatment for promoting the development of the roots of Z619 and 0.050 mmol/L SA was the optimal treatment for promoting the development of the roots of Z27 and Z39.