Deep-rooted maize plants utilize water and nutrients more effectively, particularly in compacted soil. However, the mechanisms by which different maize genotypes adjust root angles in response to compaction remain underexplored. We conducted a two-year study (2021-2022) on silty loam soils in the North China Plain. We tested two genotypes of maize [one with naturally deep roots (DR) and another with shallow roots (SR)] in compacted (C) and non-compacted (NC) soil. Soil compaction impeded shoot growth in both genotypes; however, DR exhibited better growth than SR. Under compacted conditions, DR maintained steeper root angles and demonstrated superior mechanical strength with larger root cortex areas (increased by 60 %) and stele (increased by 92 %), as well as higher cellulose concentration (up to 146 %). Notably, PIEZO1 gene expression increased significantly (up to 242 %) in DR under compaction, suggesting its role in root structural enhancement, unlike in SR where it remained unchanged. These findings underscore the importance of genetic, anatomical, and biochemical adaptations in maize roots, facilitating their resilience to soil compaction. Such insights could inform the breeding of maize genotypes that are better adapted to diverse soil conditions, potentially boosting agricultural productivity.

Waterlogging, or excessive accumulation of water in the soil, poses significant stress to riparian ecosystems and agroforestry, especially with increasing global rainfall. Cenchrus fungigraminus is a vital agricultural resource, biomaterial, and super-energy plant with high resistance and adaptability. This study examined its morphological and physiological responses under root and above-ground waterlogging for up to 30 days. Results showed that waterlogging significantly inhibited growth, reducing membrane permeability, and root activity, and accelerating leaf senescence (P < 0.05). Despite this, C. fungigraminus achieved 100 % survival after 30 days of waterlogging. The plant adapted to the hypoxic environment by enhancing oxygen channels through cortex cell loosening, lysigenous tissue formation, and adventitious root development. It also activated defense mechanisms, increasing the activities of antioxidant enzymes (SOD, POD, and CAT), levels of non-enzymatic antioxidants (AsA and GSH), osmotic regulators (SS, SP, and Pro), and anaerobic respiratory enzymes (PDC, ADH, and LDH), and hormones (ABA, IAA, GA, and ETH). Under two levels of waterlogging depth, the plant initially adopted the LowO2 escape strategy (LOES), but over time, it transitioned to the Low-O2 quiescence strategy (LOQS), while still retaining some features of the LOES. Our results revealed that C. fungigraminus demonstrates strong adaptability to waterlogging, especially in response to root waterlogging. By employing anatomical adjustments and exceptional cellular defense mechanisms, the species effectively mitigates damage, establishing itself as an excellent forage grass for slope protection under waterlogged conditions. These results offer valuable guidance for selecting waterlogging-tolerant species to restore and rehabilitate degraded riparian ecosystems in the Yellow River Basin, optimize land use in waterlogging-prone areas, and advance the genetic improvement of waterlogging tolerance in other forage varieties.

AimsHigh root tensile strength (RTS) is crucial for tree stability, windthrow resistance, soil reinforcement, and erosion control. However, RTS varies across species, and the underlying causes remain poorly understood. RTS is directly linked to anatomical structure and fiber morphology, which influence its resistance to stress. This study explores the relationship between xylem anatomy and RTS in four broadleaved species-Acer velutinum, Fagus orientalis, Quercus castaneifolia, and Carpinus betulus-from the Hyrcanian forests of Iran.MethodsRTS was measured, and fiber biometry, including fiber length, width, lumen width, and wall thickness, was quantified on macerated fibers. Vessel lumen fraction was also assessed through microscopic examination of root cross-sections.ResultsA. velutinum (Persian maple) exhibited the highest RTS, while F. orientalis displayed the lowest. A negative power relationship was observed between root diameter and RTS. Among fiber traits, fiber length and width had the strongest positive influence on RTS. Persian maple, as the species with strongest root, possessed the longest and widest fibers. Conversely, F. orientalis, the weakest one, displayed the shortest and thinnest fibers with the most robust cell walls. The relationship between quantitative vascular features of xylem and RTS was inconclusive, across species.ConclusionThis study revealed the complex interplay between xylem anatomical traits and RTS. Fiber characteristics, particularly a dense network of long, wide, and more flexible fibers, were found to strengthen root. Further research should explore the interplay of multiple anatomical features to provide a comprehensive understanding of RTS.

Grassland degradation and reduced yields are often linked to the root soil composite of perennial alfalfa roots. This study introduces a novel modeling approach to accurately characterize root biomechanical properties, assist in the design of soil-loosening and root-cutting tools. Our model conceptualizes the root as a composite structure of cortex and stele, applying transversely isotropic properties to the stele and isotropic properties to the cortex. Material parameters were derived from longitudinal tension, longitudinal compression, transverse compression, and shear tests. The constitutive model of stele was Hashin failure criteria, accounting for differences in tensile and compressive strengths. Results reveal that root tensile strength mainly depends on the stele, with its tensile properties exceeding compressive and transverse strengths by 4-10 times. In non-longitudinal tensile stress scenarios, like shear and transverse compression tests, the new model demonstrated superior accuracy over conventional models. Results of shear tests were further validated using non-parametric statistical analysis. This study provides a finite element method (FEM) modeling approach that, by integrating root anatomical features and biomechanical properties, significantly enhances simulation accuracy. This provides a tool for designing low-energy consumption components in grassland degradation restoration and conservation tillage.

Soil salinization has become one of the major problems that threaten the ecological environment. The aim of this study is to explore the mechanism of salt tolerance of hybrid walnuts (Juglans major x Juglans regia) under long-term salt stress through the dynamic changes of growth, physiological and biochemical characteristics, and anatomical structure. Our findings indicate that (1) salt stress inhibited seedling height and ground diameter increase, and (2) with increasing salt concentration, relative water content (RWC) decreased, and proline (Pro) and soluble sugar (SS) content increased. The Pro content reached a maximum of 549.64 mu g/g on the 42nd day. The increase in superoxide dismutase (SOD) activity (46.80-117.16%), ascorbate peroxidase (APX) activity, total flavonoid content (TFC), and total phenol content (TPC) under salt stress reduced the accumulation of malondialdehyde (MDA). (3) Increasing salt concentration led to increases and subsequent decreases in the thickness of palisade tissues, spongy tissues, leaves, and leaf vascular bundle diameter. Upper and lower skin thickness, root periderm thickness, root diameter, root cortex thickness, and root vascular bundle diameter showed different patterns of change at varying stress concentrations and durations. Overall, the study concluded that salt stress enhanced the antireactive oxygen system, increased levels of osmotic regulators, and low salt concentrations promoted leaf and root anatomy, but that under long-term exposure to high salt levels, leaf anatomy was severely damaged. For the first time, this study combined the anatomical structure of the vegetative organ of hybrid walnut with physiology and biochemistry, which is of great significance for addressing the challenge of walnut salt stress and expanding the planting area.

Background Seed aging, a natural and inevitable process occurring during storage. Oats, an annual herb belonging to the Gramineae family and pooideae. In addition to being a healthy food, oats serve as ecological pastures, combating soil salinization and desertification. They also play a role in promoting grassland agriculture and supplementing winter livestock feed. However, the high lipid and fat derivatives contents of oat seeds make them susceptible to deterioration, as fat derivatives are prone to rancidity, affecting oat seed production, storage, development, and germplasm resource utilization. Comparative studies on the effects of aging on physiology and cytological structure in covered and naked oat seeds are limited. Thus, our study aimed to determine the mechanism underlying seed deterioration in artificially aged 'LongYan No. 3' (A. sativa) and 'BaiYan No. 2' (A. nuda) seeds, providing a basis for the physiological evaluation of oat seed aging and serving as a reference for scientifically safe storage and efficient utilization of oats. Results In both oat varieties, superoxide dismutase and catalase activities in seeds showed increasing and decreasing trends, respectively. Variance analysis revealed significant differences and interaction in all measured indicators of oat seeds between the two varieties at different aging times. 'LongYan No. 3' seeds, aged for 24-96 h, exhibited a germination rate of < 30%, Conductivity, malondialdehyde, soluble sugar, and soluble protein levels increased more significantly than the 'BaiYan No. 2'. With prolonged aging leading to cell membrane degradation, reactive oxygen species accumulation, disrupted antioxidant enzyme system, evident embryo cell swelling, and disordered cell arrangement, blocking the nutrient supply route. Simultaneously, severely concentrated chromatin in the nucleus, damaged mitochondrial structure, and impaired energy metabolism were noted, resulting in the loss of 'LongYan No. 3' seed vitality and value. Conversely, 'BaiYan No. 2' seeds showed a germination rate of 73.33% after 96 h of aging, consistently higher antioxidant enzyme activity during aging, normal embryonic cell shape, and existence of the endoplasmic reticulum. Conclusions ROS accumulation and antioxidant enzyme system damage in aged oat seeds, nuclear chromatin condensation, mitochondrial structure damage, nucleic acid metabolism and respiration weakened, oat seed vigor decreased. 'LongYan No. 3' seeds were more severely damaged under artificial aging than 'BaiYan No. 2' seeds, highlighting their heightened susceptibility to aging effects.

Soil salinization has damaged the soil biological environment and chemical structure, resulting in a decline in soil quality and crop yields, which has caused harm to the ecological environment and human health, and severely hindered the development of the economy. In this experiment, using the 'Ningdan 33' maize seeds as materials, the maize was treated with histidine and salt stress (100 mM NaCl), and photosynthesis, photosynthetic enzyme activity, relative expression of photosynthetic genes of maize were measured. The anatomical structure of the leaves was also observed. The study explored the impact of exogenous histidine treatment on the photosynthesis of maize under salt stress. When the concentration of histidine sprayed on the leaves was 0.5 mM, it had the best effect on promoting photosynthesis in maize under salt stress. 0.5 mM histidine significantly improved the photosynthetic performance ( P N , g s , E , Chl a /Chl b ) of maize under salt stress, significantly improved photosynthesis efficiency (F v /F m , Delta F/F' m , q P were significantly increased. NPQ was significantly decreased), significantly increased the activity of photosynthetic enzymes (PEPC, NADP-ME, PPDK, Rubisco) and the relative expression of photosynthetic genes ( ZmPEPC , ZmNADP-ME , ZmPPDK , ZmRCA ), increased the length of the vascular bundle in the cross- of the leaf, played a certain protective role on the vascular bundle, and improved the efficiency of material transportation under salt stress. Based on the above analysis, 0.5 mM histidine can significantly improve the tolerance of maize under salt stress, which has great application value for planting maize in saline environments.

Widespread shrubification across the Arctic has been generally attributed to increasing air temperatures, but responses vary across species and sites. Wood structures related to the plant hydraulic architecture may respond to local environmental conditions and potentially impact shrub growth, but these relationships remain understudied. Using methods of dendroanatomy, we analysed shrub ring width (RW) and xylem anatomical traits of 80 individuals of Salix glauca L. and Betula nana L. at a snow manipulation experiment in Western Greenland. We assessed how their responses differed between treatments (increased versus ambient snow depth) and soil moisture regimes (wet and dry). Despite an increase in snow depth due to snow fences (28-39 %), neither RW nor anatomical traits in either species showed significant responses to this increase. In contrast, irrespective of the snow treatment, the xylem specific hydraulic conductivity (Ks) and earlywood vessel size (LA95) for the study period were larger in S. glauca (p < 0.1, p < 0.01) and B. nana (p < 0.01, p < 0.001) at the wet than the dry site, while both species had larger vessel groups at the dry than the wet site (p < 0.01). RW of B. nana was higher at the wet site (p < 0.01), but no differences were observed for S. glauca. Additionally, B. nana Ks and LA95 showed different trends over the study period, with decreases observed at the dry site (p < 0.001), while for other responses no difference was observed. Our results indicate that, taking into account ontogenetic and allometric trends, hydraulic related xylem traits of both species, along with B. nana growth, were influenced by soil moisture. These findings suggest that soil moisture regime, but not snow cover, may determine xylem responses to future climate change and thus add to the heterogeneity of Arctic shrub dynamics, though more longterm species- and site- specific studies are needed.

Wheat (Triticum aestivum) employs various strategies to defend against Fusarium oxysporum, a soilborne vascular fungal pathogen that disrupts structural integrity and metabolism. The purpose of this research was to ascertain the alterations of anatomical and biochemical responses in wild-type (WT) and DPA-treated wheat (T. aestivum) seedlings exposed to F. oxysporum. The WT and DPA-treated seedlings showed disorganization of parenchyma cells, sclerenchyma cells, vascular bundles (VBs), and lower numbers of xylem (Xy) and phloem (Ph) cells, and reduced thickness of the cuticle layer (C) at the epidermal layer of shoots. The content of chlorophyll (Chl), carbohydrate, and nucleic acid was reduced in WT and DPA-treated seedlings during infection. Enhanced defense responses through peroxidase (POD), and polyphenol oxidase (PPO) was observed to be high in WT as compared to DPAtreated seedlings under stress condition. In addition, the content of salicylic acid (SA) and phenolics was increased in WT than DPA under stress condition. However, the DPA-treated seedlings showed enhanced growth of fungal mycelia compared to WT during stress condition. Hence, the anatomical and biochemical aspects of DPA-treated seedlings decreased as compared to WT when exposed to F. oxysporum.

The morphology of a plant's root is strongly affected by the compaction of the growth medium, the size of its particles, or the presence of non -movable obstacles. However, little is known about the effect of these characteristics on root anatomy and mechanical properties of the root tissues. Anatomical features of maize roots grown in media that varied in density and/or structure (soil, glass beads, vermiculite) were analyzed on cross -sections through the elongation and maturation zones of the roots of 14 -day -old seedlings. The sections were stained for lignin and suberin to recognize the developmental stages of exodermis and endodermis. Cortex thickness, number of cortical cell layers, and diameter of the vascular cylinder (stele) were measured in both zones. The Young's modulus of the roots was determined using mechanical tensile tests. Assuming that the root can be considered a composite material, a model was used that allowed, for the first time, the estimation of the mechanical properties of the stele and cortex. While the cell arrangement of roots grown in a medium with high density and fine movable particles (soil) was regular, roots grown in a medium with low density and light particles (vermiculite) and a medium with high density and large unmovable particles (glass beads) showed early damage of the rhizodermis and impaired cell arrangement in the cortex and vascular cylinder. In these roots, the exodermis and endodermis matured closer to the root tip than in roots from the soil. The vermiculite roots were the most outliers in terms of morphometric parameters and mechanical properties. The Young's modulus of the stele was many times greater than the Young's modulus of the cortex in the roots of all variants. Of the media used in the experiment, the soil appears to be most favorable for the maize root growth and development.