Root Diameter Research Articles

Genome-wide identification of the SAUR gene family and screening for SmSAURs involved in root development in Salvia miltiorrhiza.

SmSAUR4, SmSAUR18, SmSAUR28, SmSAUR37, and SmSAUR38 were probably involved in the auxin-mediated root development in Salvia miltiorrhiza. Salvia miltiorrhiza is a widely utilized medicinal plant in China. Its roots and rhizomes are the main medicinal portions and are closely related to the quality of this herb. Previous studies have revealed that auxin plays pivotal roles in S. miltiorrhiza root development. Whether small auxin-up RNA genes (SAURs), which are crucial early auxin response genes, are involved in auxin-mediated root development in S. miltiorrhiza is worthy of investigation. In this study, 55 SmSAUR genes in S. miltiorrhiza were identified, and their physical and chemical properties, gene structure, cis-acting elements, and evolutionary relationships were analyzed. The expression levels of SmSAUR genes in different organs of S. miltiorrhiza were detected using RNA-seq combined with qRT‒PCR. The root development of S. miltiorrhiza seedlings was altered by the application of indole-3-acetic acid (IAA), and Pearson correlation coefficient analysis was conducted to screen SmSAURs that potentially participate in this physiological process. The diameter of primary lateral roots was positively correlated with SmSAUR4. The secondary lateral root number was positively correlated with SmSAUR18 and negatively correlated with SmSAUR4. The root length showed a positive correlation with SmSAUR28 and SmSAUR37 and a negative correlation with SmSAUR38. The fresh root biomass exhibited a positive correlation with SmSAUR38 and a negative correlation with SmSAUR28. The aforementioned SmSAURs were likely involved in auxin-mediated root development in S. miltiorrhiza. Our study provides a comprehensive overview of SmSAURs and provides the groundwork for elucidating the molecular mechanism underlying root morphogenesis in this species.

Distinct variations of soil infiltrability of contrasting root types in a temperate mosaic-pattern grassland in northern China

Soil infiltration capacity is an important factor affecting soil moisture, and is of great significance to plant growth and groundwater recharge in arid and semiarid areas. Patchiness of grasslands widely exist and have a crucial effect on hydrological processes in water-limited regions. This study investigated soil infiltrability under natural grasslands with patchy mosaic patterns based on a series of in-situ tests. Two dominated natural restoration vegetation communities (Bothriochloa ischaemum (B. ischaemum) with fibrous root systems and Artemisia gmelinii (A. gmelinii) with tap root systems) and abandoned land (as control) were selected in the loess hilly and gully region of the Loess Plateau, China. The results showed that natural restoration grasslands significantly improved soil infiltrability in both plant and bare patches, and the emergence of patchy mosaic patterns can result in infiltration heterogeneity to redistribute water on a hillslope scale. Compared to B. ischaemum, A. gmelinii are more likely to facilitate the formation of preferential flow, contributing to the increased soil infiltration rates. The initial, steady and average infiltration rates (IIR, SIR, and AIR, respectively) and soil infiltration capacity index (SIC) were all negatively correlated with both root length density (RLD) and root surface area density (RSAD) of fine roots (diameter < 2 mm) but positively correlated with those of coarse roots (diameter ≥ 2 mm). The main factors influencing the infiltration capacity were the mean weight diameter in the 10−20 cm layer and the RSAD of the fine roots in the 0−20 cm layer, which can explain 98.6 %, 81.7 %, 63.9 %, and 91.3 % of the total variance of IIR, SIR, AIR, and SIC, respectively. This work highlights the important roles of patchy mosaic patterns in affecting soil water redistribution and the stabilization of ecological systems, providing a scientific basis for vegetation selection in the process of vegetation restoration in water-limited regions.

Effects of Different Sources of Fertilizers on Growth and Yield of Radish (Raphanus sativus L.)

Radish is a widely cultivated root crop susceptible to chemicals for its growth and development. The experiment was conducted to study the effect of different sources of organic fertilizers on growth and yield parameters in the Tokinashi variety of radish. The experiment was laid out using one factorial completely randomized block design with six treatments replicated four times. Vermicompost, goat manure, chemical fertilizers (NPK), poultry manure, farmyard manure and control were the applied treatments. Various growth and yield parameters of radish were measured and assessed at 15-day intervals. Various growth and yield parameters of radish were measured and assessed at 15-day intervals. Growth parameters were observed at 15, 30, 45, and 60 days after sowing. For yield parameters, destructive samples were taken and observed at 30 DAS and 45 DAS and harvested at 60 DAS. The assessments of plant growth and yield parameters showed that poultry manure (PM) treatments were superior. At the time of harvesting, the treatment comprising poultry manure had considerably greater plant height (30.55 cm), leaf length (29.44cm), leaf breadth (10.78cm), leaf number per plant (9.23), root diameter (10.33cm) and root length (20.16cm) with superior yield per ha (33.59 mt ha-1). Poultry manure significantly enhanced root yield and was positively correlated with all growth parameters. The highest benefit-cost (B: C) ratio was recorded in chemical fertilizer (3.99), which was statistically at par with poultry manure (3.81), suggesting that poultry manure might potentially replace chemical fertilizers for the Tokinashi variety of radish cultivation.

Genotypic variations appear in fine root morphological traits of Cryptomeria japonica trees grown in a common garden

AbstractFine root morphological traits regulate the belowground resource acquisition strategies of trees. Therefore, investigating genotypic variations isolated from environmental variations within tree species helps in understanding how genotypic backgrounds affect intragenerational tree acclimation to the growing environment. Thus, this study aimed to clarify the effects of genotypic variations on the fine root morphology of three types of Japanese cedar (Cryptomeria japonica), which were derived from different provenances but were grown in a common garden. In the three geographically different provenances of C. japonica stands (Yanase, Yoshino, and Yaku), fine root morphological traits, such as root length and diameter and specific root length (SRL), were measured for each root up to the 4th branching order. Yaku cedar exhibited root traits distinct from the other provenances, such as growing longer and thinner roots in 1st root order to enhance root surface area. In addition, the SRL patterns with root orders and higher root tissue density suggested a resource conservation strategy. Yanase cedar demonstrated a significantly higher root branching ratio and specific root tips than the other provenances, indicating a strategy for investing resources in absorptive roots. Although Yoshino cedar had traits similar to those of Yanase cedar or intermediate between Yanase and Yaku cedars, high aboveground production may be achieved through nutrient acquisition with root exudates instead of absorptive root growth. Genotypic variations appeared in fine root morphological traits of C. japonica trees, even when grown in the same environments, implying distinct resource acquisition strategies characterized by each provenance.

GGE biplot analysis for yield performance and stability assessment of carrot genotypes (Daucus carota L.) under multi-environment trials (METs)

The stability of yield and contributing traits is a very important factor for long-term development and sustainability of cultivars. The genotype x environment (G × E) interaction on the yield stability in twenty-eight genotypes of carrot was studied under eight environments E1-E8 (different sowing dates) over the two years (2019–20 and 2020–21) at Vegetable Research Farm, Punjab Agricultural University, Ludhiana. The experiment was laid out in randomized complete block design with three replications under each environment. At each harvest, data was recorded for root yield (q acre−1), marketable yield (q acre−1), root length (cm), root weight (g), root-shoot ratio, root diameter (cm), core diameter (cm), shoot length (cm), shoot weight (g) and number of leaves plant−1. The data was analyzed with ANOVA, mixed models, BLUPs, GGE biplot and multi stability index for stability statistics. For all the traits, pooled analysis of variance revealed highly significant (p < 0.01) variations between genotypes, environments and genotype by environment (G × E interaction). The mean vs. stability view of GGE biplots revealed that genotype PC-171 (G6) performed better in the months of August and September of both the years (E1, E2, E5 and E6). PC-160 (G3) followed by Cartvar-2 (G25) performed better in the month of October (E3 and E7) for the root yield parameter. Mean across the environments and BLUP values of genotypes for all the traits showed similar results. Hence, GGE biplot graphically explained the interrelationships between the tested environments and genotypes, classified genotypes into three categories early, mid or late season based on their mean performance and stability in the given growing environment.

Physiological and Cellular Ultrastructural Responses of Isatis indigotica Fort. under Salt Stress

This study aimed to analyze the effects of salt stress on the growth physiology and plant-cell ultrastructure of Isatis indigotica Fort. (I. indigotica) to evaluate its adaptability under salt stress. The effects of different concentrations of salt (NaCl; 0, 25, and 300 mmol·L−1) on the agronomic traits, activities of related enzymes, ion balance, and mesophyll-cell ultrastructure of I. indigotica were studied in a controlled pot experiment. Results showed that compared with those of the control group, the aerial-part fresh weight, underground fresh weight, tiller number, root length, root diameter, plant height, and leaf area of salt-stressed I. indigotica increased at 25 mmol·L−1 and then decreased at 300 mmol·L−1. The changes in levels of superoxide dismutase, peroxidase, ascorbate peroxidase, and catalase showed a similar trend, with significant differences compared with control group. Salt stress altered the ion balance of I. indigotica, resulting in a significant increase in Na+ content and a significant decrease in K+ content. The contents of Ca2+ and Mg2+ changed to varying degrees. The analysis of the microstructure of the root showed that under salt treatment, the epidermal cells of the root significantly thickened and the diameter of the xylem decreased. The results of ultrastructural analysis of mesophylls showed that salt stress can cause cell-membrane contraction, cell-gap enlargement, disorder in the structures of chloroplasts and mitochondria, and an increase in the number of osmiophilic particles. These changes were aggravated by the increase in NaCl concentration. This study reveals the response of I. indigotica to salt stress and provides a basis for further study on the salt-tolerance mechanism of I. indigotica.

The Effectiveness of Eugenia Oleina in Protecting Tropical Residual Slope from Excessive Shear Failure

Introduction Slope stability and soil erosion are major concerns in geotechnical engineering and land management. This research investigates the relationship between soil type and root systems in stabilizing slopes. Methods The main aim is to measure the effectiveness of Eugenia Oleina as a bioengineering technique for slope protection. Laboratory tests were conducted to measure soil shear strength, root properties, and the factor of safety (FOS) of tropical slopes before and after plant root implementation. Results Results revealed significant differences in cohesion and angle of friction values between unrooted and rooted soil. Apart from that, it was observed that as the root diameter increased, the tensile strength decreased when the applied force increased. The FOS of unrooted soil was higher than rooted soil, indicating greater stability without any vegetation. Furthermore, this study also evaluated the use of bio-anchorage to prevent soil erosion, considering factors such as soil composition, vegetation, and external loads. Finite element analysis was carried out using Plaxis 3D simulations to assess the effectiveness of Eugenia Oleina in controlling slope erosion. Conclusion This study contributes valuable insights in choosing suitable plant species for erosion control in tropical soil and guides soil bioengineering practices for slope stability in various soil conditions.

Infra-Red Emission for Heat Radiation from Micro-Cone Textured Metallic Sheet Device with Semi-Regular Alignment

Abstract A micro-cone textured copper sheet was fabricated as an emitter of electromagnetic waves in the near-infrared (IR) to the far-IR wave lengths. This micro-cone texture was aligned in semi-regular by varying the micro-cone size parameters. The micro-cone height (H) was varied from 0.5 µm to 4 µm in average. SEM analysis was utilized to characterize the microstructure of micro-cone textures and to measure the population of micro-cone height (H), its root diameter (B) and pitch (D) with aid of the picture processing and computational geometry. This height population P (H) was compared to the IR emission spectrum, which was measured by the FT-IR (Fourier Transformation IR). Even varying the average height of micro-cone textures, the IR-emission wavelength (λ) abided by the resonance condition by λ ~ 2 x H within the standard deviation of heights and wavelengths. Through the heat radiation experiment in vacuum, the emitted heat flux was estimated to be 58 W/m2 by the one-dimensional heat balance between the heating rate of objective body and the radiated heat flux.

How Does No-till Affect Soil-Profile Distribution of Roots?

No-till (NT) often causes prominent stratification of C and nutrients in the soil profile relative to tilled systems. We hypothesize differences in root distribution within the soil profile between NT and tilled systems could be one factor contributing to stratification. We evaluated how NT affects root length density (RLD), root biomass yield (RBY), and root diameter compared with other tillage systems and factors that may affect root characteristics. We reviewed studies until 23 January 2024 where RLD, RBY, or root diameter were reported under NT and tillage. The data on RLD, RBY, and diameter were tabulated and the weighted log response ratio (MLRR) and confidence intervals computed. Our meta-analysis showed NT increased RLD in the 0-10 cm depth, but reduced RLD at 10-20 cm. It increased RBY and diameter in the 0-20 cm depth and reduced both characteristics at 20-30 cm. Regardless of root characteristic, NT had mixed effects below 30 cm. However, across the soil profile (minimum 50 cm depth), NT had no effect on RLD and RBY. No-till-induced changes in roots can be related to increased compaction at the tillage interface. No-till stratified both RLD and RBY compared with high intensity tillage systems, although there were some conditions where NT stratified only RLD or RBY. No-till did not induce stratification of RLD and RBY in dry regions, mild or hot climates, in medium-textured soils, or compared with intermediate intensity tillage systems. Overall, NT can result in stratification of both RBY and RLD compared with high intensity tillage systems.

Effect of Plant Density on Growth and Bioactive Compounds in Salvia miltiorrhiza

Danshen (Salvia miltiorrhiza) is an herbaceous plant widely used in the pharmaceutical industry. However, the majority of medicinal plants utilized in the US are imported, posing challenges such as fluctuations in bioactive compound concentrations and insufficient supply to meet demand. Determining the optimal plant density is a key management decision for danshen production. This study aimed to investigate the effects of different plant densities on the growth and bioactive compound content of danshen cultivated in Mississippi. A field experiment was conducted to investigate the effects of different plant densities on individual plant growth, photosynthesis, and the content of bioactive components in danshen in 2020 and 2021. Six plant densities were designed: 30 × 20 cm (between row spacing × within row spacing), 30 × 30 cm, 30 × 40 cm, 45 × 20 cm, 45 × 30 cm, or 45 × 40 cm. A plant density of 45 × 40 cm resulted in danshen plants exhibiting the highest Plant Growth Index (PGI), SPAD, root number, shoot number, shoot fresh and dry weight, maximum root diameter, maximum root length, net photosynthesis, intracellular CO2 concentration, tanshinone I, and cryptotanshinone, regardless of year. Plants spaced at 45 × 30 cm had similar root fresh weight, root dry weight, and tanshinone IIA and salvianolic acid B levels compared with plants grown at the 45 × 40 cm spacing, and both were significantly higher than other densities.

Genome-wide association studies of root system architecture traits in a broad collection of Brassica genotypes.

The root systems of Brassica species are complex. Eight root system architecture (RSA) traits, including total root length, total root surface area, root average diameter, number of tips, total primary root length, total lateral root length, total tertiary root length, and basal link length, were phenotyped across 379 accessions representing six Brassica species (B. napus, B. juncea, B. carinata, B. oleracea, B. nigra, and B. rapa) using a semi-hydroponic system and image analysis software. The results suggest that, among the assessed species, B. napus and B. oleracea had the most intricate and largest root systems, while B. nigra exhibited the smallest roots. The two species B. juncea and B. carinata shared comparable root system complexity and had root systems with larger root diameters. In addition, 313 of the Brassica accessions were genotyped using a 19K Brassica single nucleotide polymorphism (SNP) array. After filtering by TASSEL 5.0, 6,213 SNP markers, comprising 5,103 markers on the A-genome (covering 302,504 kb) and 1,110 markers on the C-genome (covering 452,764 kb), were selected for genome-wide association studies (GWAS). Two general linear models were tested to identify the genomic regions and SNPs associated with the RSA traits. GWAS identified 79 significant SNP markers associated with the eight RSA traits investigated. These markers were distributed across the 18 chromosomes of B. napus, except for chromosome C06. Sixty-five markers were located on the A-genome, and 14 on the C-genome. Furthermore, the major marker-trait associations (MTAs)/quantitative trait loci (QTLs) associated with root traits were located on chromosomes A02, A03, and A06. Brassica accessions with distinct RSA traits were identified, which could hold functional, adaptive, evolutionary, environmental, pathological, and breeding significance.

Identification of chili varieties (Capsicum annum) tolerance to root cutting based on stress selection indices and morphological traits planted in lowland area

Abstract. Kusumaningrum S, Sulistyaningsih E, Harimurti R, Dewi K. 2024. Identification of chili varieties (Capsicum annum) tolerance to root cutting based on stress selection indices and morphological traits planted in lowland area. Biodiversitas 25: 2063-2073. Root cutting is a potential technique for inducing root growth to increase chili yield. A set of four lowland chili varieties were evaluated under root cutting to identify tolerant variety. Stress selection indices such as stress tolerant level (TOL), Stress Susceptible Index (SSI), Stress Tolerance Index (STI), Yield Stability Index (YSI) and morphological traits responses were employed in screening of the variety. The research was arranged in randomized complete block design factorial, where the first factor was the lowland chili varieties ('Tanjung', 'Lembang-1', 'Tanjung-2', 'Ungara'), and the second factor was period of root cutting (0, 8, and 0 + 8 weeks after transplanting and no root cutting). The results showed that 'Kencana', 'Lembang-1', 'Ungara' were identified as the tolerant group under root cutting treatment and 'Tanjung-2' was identified as the intolerant group based on chili yield and stress selection indices. The tolerant group had chili yield increment under root cutting (0, and 8 WAT), which related to high root morphological traits (root diameter, root length, root surface area, and root dry weight density). Root cutting at 8 WAT gave the highest chili yield in tolerant group. The increased root growth in the tolerant group was contributed to promote shoot morphological traits (leaf number, leaf area, and plant height). Root cutting treatment in the intolerant group caused chili yield decrement, which was related to no increment of the root and shoot morphological traits. It was concluded that root cutting treatment at 8 WAT on tolerant group ('Kencana', 'Lembang-1', 'Ungara') can be used to increase chili yield in lowland areas.

Increased indexed proximal aortic diameter is a predictor of poor prognosis in maintenance hemodialysis patients

Background: Recent studies have shown that the baseline values of absolute aortic root diameter (ARD) and indexed diameter are associated with all-cause mortality and cardiovascular events in the general population, even in the absence of aneurysmal aortic disease. However, there is limited available data on the association between ARD and prognosis in end-stage renal disease (ESRD) patients receiving maintenance hemodialysis (MHD). Accordingly, the purpose of this study is to investigate the predictive value of ARD for all-cause mortality and cardiovascular events in this specific population.Methods: ARD was measured by echocardiography at the level of the sinuses of Valsalva at end diastole and indexed to body surface area (BSA). The primary endpoint was all-cause mortality. The secondary endpoint was major adverse cardiovascular events (MACE), including cardiovascular mortality, myocardial infarction and stroke. Cox proportional hazards models were conducted to evaluate the association between baseline ARD/BSA and clinical outcomes.Results: A total of 391 patients were included in this study. The primary endpoint occurred in 95 (24.3%) patients while the secondary endpoint occurred in 71 (18.2%) patients. Multivariate Cox regression analysis showed that ARD/BSA was an independent prognostic factor for all-cause mortality (HR, per 1-SD increase, 1.403; 95% CI, 1.118–1.761; p = 0.003) as well as MACE (HR, per 1-SD increase, 1.356; 95% CI, 1.037–1.772; p = 0.026).Conclusions: Our results show that ARD/BSA is predictive of all-cause mortality and MACE in MHD patients with ESRD and support the view that assessment of ARD/BSA may refine risk stratification and preventive strategies in this population.

Production of Seedlings of Corymbia citriodora Inoculated with Endophytic Bacteria

This study aimed to evaluate the effect of inoculants of endophytic bacteria producing indoleacetic acid (IAA) on the physiological quality of seeds and the production of seedlings of Corymbia citriodora (Hook.) KD Hill &amp; LAS Johnson. In the physiological quality test of the seeds, the treatments used were individual inoculation with Priestia megaterium, Exiguobacterium sibiricum, Pantoea vagans strain 45URP4-1, and Bacillus sp.; joint effect of the four strains (mix); inoculation only with the carrier (cassava starch and activated charcoal); carrier with 1.0 μg mL−1 of IAA; and non-inoculated control without IAA and without a carrier. In the production of seedlings in a greenhouse, the treatments were the same, except for the mix, which was replaced by P. vagans strain 7URP1-6 (Pvs7), as inoculation with the mix increased the number of abnormal seedlings. In the physiological quality test of seeds, seeds inoculated with the bacteria individually did not have the physiological quality impaired and the carrier created a microenvironment around the seeds, benefiting germination percentage, germination speed index, average germination time, and average germination speed. In the greenhouse, seedlings inoculated with Pvs7, P. megaterium and E. sibiricum were taller, with a larger stem diameter and dry mass of shoot, roots, and total. Seeds inoculated with E. sibiricum had higher averages for height, chlorophyll b content, and shoot and total dry mass, as well as a greater ability to colonize the rhizosphere and roots of C. citriodora, resulting in the production of higher-quality seedlings. Inoculation of seeds of C. citriodora with endophytic bacteria proved to be a promising alternative for plant development.

Impact of Fertilizer and Mulch on Growth, Yield and Quality of Carrot in Arecanut Cropping System Under Conservation Agriculture Practices

This study aims to comprehensively assess the influence of conservation agriculture techniques, encompassing reduced tillage, cover cropping (live mulch) and nutrient levels on a range of growth parameters and the ultimate yield of crop. As per the principles of conservation agriculture i.e., soil was disturbed minimally, berseem mulch was incorporated in the experiment and carrot was raised under arecanut plantation during rabi and it was succeeded by mint crop in pre-kharif season. Experiment was laid out in Randomized block design with seven treatments of different nutrient doses and mulch replicated thrice. Field experiments were conducted across two growing seasons i.e., 2019-20 and 2020-21 during Rabi (Winter) at Balindi research farm, Bidhan Chandra Krishi Viswavidyalaya, Mohanpur. Precise measurements and meticulous analyses were conducted on key parameters; Vegetative growth i.e., plant height and number of leaves, yield attributing parameters like root length, diameter, weight and total yield of crop. TSS and beta carotene was also estimated. These parameters unequivocally indicate that conservation agriculture practices exert a substantial influence on both the growth and yield. Among various nutrient levels, higher dose of fertilizer (T4 - 120:90:120 NPK kg ha-1) with berseem (Trifolium alexandrinum L.) as a cover crop in the interspaces showed maximum vegetative growth i.e., plant height and number of leaves plant-1 at all growth stages (30, 60 and 90 DAS) while decreasing trend was observed in yield parameters with higher levels of nutrient doses, medium level of fertilizer dose (T5 - 90:60:90 kg ha-1 + berseem (Trifolium alexandrinum) recorded highest root length, diameter, weight and projected yield of 18.5cm, 3.58 cm, 118.37 g plant-1 and 26.63 t ha-1 respectively. These findings underscore the considerable potential of conservation agriculture practices as a sustainable approach to optimize carrot crop production. This research contributes valuable scientific insights that hold significant implications for agricultural stakeholders, including farmers and practitioners, seeking to fine-tune carrot cultivation methodologies while concurrently fostering soil health and environmental sustainability.

Radiographic assessment of the quality of post and core restorations performed by general dental practitioners in Saudi Arabia

BackgroundDentists utilize various techniques and materials for post and core restoration of endodontically treated teeth, which remains a noteworthy health concern and can be addressed through interdisciplinary strategies to enhance outcomes. Therefore, this study aimed to evaluate the technical quality of the residual gutta-percha (GP) and posts by analysing the periapical radiographs of endodontically restored teeth. MethodsA total of 594 periapical digital radiographs were evaluated for tooth type, post material, post shape, design, diameter, length, residual GP, GP length, GP tapering, GP homogeneity, and final restoration. Frequency distribution and cross-tabulation of the variables were performed. ResultsMaxillary molars had the highest frequency of restorations, including posts, accounting for 27.4 %, followed by maxillary premolars (25.4 %) and maxillary anterior teeth (19.2 %). The prefabricated metallic posts were most commonly used (81.0 %), among these, 50.4 % were screwed posts. Tapered posts were the most commonly used (65.6 %). The percentage of posts with an acceptable length was 58.2 %. The most commonly used posts exhibited a width of one-third of the root diameter, accounting for 87.0 %. Suitable GP lengths were observed in 61.1 % of the restorations, and 62.8 % demonstrated adequate GP homogeneity. The findings of this study revealed that crown restoration accounted for 42.6 % of the studied sample. ConclusionsThe technical quality of the remaining GP after restoration was comparable to that of previous epidemiological investigations. However, the technical quality of the post was deemed suboptimal.

Low nitrate under waterlogging triggers exodermal suberization to form a barrier to radial oxygen loss in rice roots.

To acclimate to hypoxic waterlogged conditions, the roots of wetland plants form a radial oxygen loss (ROL) barrier that can promote oxygen diffusion to the root tips. We hypothesized that the low-nitrate concentrations that occur after molecular oxygen is consumed in waterlogged soils are an environmental trigger for ROL barrier formation in rice (Oryza sativa). We previously identified 128 tissue-specific up/downregulated genes during rice ROL barrier formation. The RiceXPro database showed that many of these genes were differentially regulated in response to nitrogen deficiency. Therefore, we assessed changes in the concentrations of ionic species of nitrogen under stagnant conditions, i.e. in a nutrient solution that mimics waterlogged soil conditions, and examined the effects of an increase or decrease of nitrate in the nutrient solution on ROL barrier formation and exodermal suberization. Preventing nitrate deficiency in the stagnant nutrient solution suppressed the formation of an ROL barrier. Conversely, a decrease in nitrate strongly induced ROL barrier formation, even under aerated conditions. In parallel with ROL barrier formation, suberin lamellae formed at the exodermis. Nitrate deficiency also promoted aerenchyma formation and the enlargement of root diameters. These findings suggest that the severe decline of nitrates under waterlogged conditions is an environmental cue for exodermal suberization to form an ROL barrier in rice roots.

Intelligent fertigation improves tomato yield and quality and water and nutrient use efficiency in solar greenhouse production

Intelligent fertigation is a sustainable solution for optimising water and fertiliser input, thus minimising environmental pollution in vegetable cultivation facilities and reducing labour costs in agricultural practices. It is important to optimise irrigation scheduling parameters to specific crops to ensure water and nutrient use efficiency. A field experiment was conducted in Shouguang, Shandong Province, to investigate the effects of irrigation scheduling with different treatments (farmer drip irrigation FI, intelligent irrigation II1, and intelligent irrigation II2) on tomato growth, irrigation water and nutrient use efficiency over two growth seasons. Intelligent irrigation II1 and II2 utilised FDR sensors to control the moisture range within 80–95% and 80–85% field capacity (FC) for automatic irrigation scheduling, respectively. Intelligent irrigation (II1 and II2 treatments) reduced irrigation rate by 24.3–63.8% in comparison with FI treatment, significantly increasing total dry matter accumulation, nutrient uptake, yield and fruit quality of tomato. II2 treatment further reduced the irrigation rate by 31.6–32.3% compared to II1 treatment, with no significant difference in tomato yield and quality. Root dry matter, root-shoot ratio, 0–2 mm diameter root length and root surface area, 0–1.5 mm diameter root tips, and >3.5 mm diameter root volume were significantly increased under intelligent irrigation treatments. Positive correlations between irrigation water productivity; nitrogen, phosphorus, and potassium use efficiency; and the indices of length, surface area, tips, and volume of roots were highly significant. Intelligent fertigation system (IFS) maintained soil moisture within a suitable range through high-frequency irrigation scheduling, promoted the growth of 0–2 mm diameter roots, which were responsible for absorbing, acquiring, and transporting water and nutrients in the soil, and reduced water loss and nutrient leakage. Taken together, the intelligent fertigation system presented herein is an effective fertigation strategy to improve irrigation water and nutrient use efficiency.

Influences of root fragments on soil thermal property measurements with heat pulse method

Heat pulse (HP) method has been widely applied for measuring thermal properties, heat fluxes, and soil–water evaporation for near-surface soil layers. In topsoil layers, the presence of roots violates the underlying assumption of HP method that the soil under test is homogeneous. In this study, numerical and laboratory experiments were conducted to test the influence of root fragments on soil thermal property measurement with HP sensors. Soybean root fragments, with a water content of about 0.74 m3 m−3 and diameters ranging from 0.5 to 4 mm, were carefully repacked into soil samples that were used for HP measurements. Results showed that the effects of roots on soil thermal property measurements depended on root size, root location and directions relative to the heater probe, and the thermal property differences between soil sample and root. Roots showed negligible influence on heat pulse data when the root fragments were positioned outside the HP measurement region (more than probe space away from heater probe), or root diameters (d) were less than 1 mm, or in oven-dried soil samples. On relatively wet soils (i.e., with water content of 0.05–0.25 m3 m−3), when root fragments were located in between the heater and sensing probes (parallel to the probe planes), (1) the heat capacity (C) and thermal conductivity (λ) differences between root-free soil and root-soil mixture increased proportionally with d increased from 1 mm to 4 mm; (2) the differences in absolute values of C and λ between the root-free soil and soil-root mixture were highly dependent on soil water content. The errors in soil C and λ estimates were larger when the root fragment was parallel with than perpendicular to or inclined 45 degrees to the probe plane, and the error overall decreased with a smaller ρb and sand fraction. When the root fragments were positioned within the HP measurement region, or d were larger than 1 mm, or in relatively wet soil samples, it is important to consider root effect when interpreting HP signals.

Comparing vegetative growth patterns of cultivated (Daucus carota L. subsp. sativus) and wild carrots (Daucus carota L. subsp. carota) to eliminate genetic contamination from weed to crop

Wild carrot is a problematic weed that can threaten the genetic purity of cultivated carrots by hybridization. Wild carrots must be controlled before flowering to avoid the undesirable crossing with cultivated carrots. Understanding wild carrot's vegetative growth pattern helps formulate sustainable weed management practices. However, little is known about the vegetative growth patterns of wild and cultivated carrots. A pot experiment was carried out to compare and model the vegetative growth pattern of different morphological traits in both wild and cultivated carrots. This study was executed in a glasshouse located in Palmerston North, New Zealand. A factorial randomized complete block design (RCBD) with two factors and four replications was used. The first factor was assigned to the carrot genotype (cultivated and wild) and the second factor to length of juvenile stages (12-weeks, 8-weeks, and 4-weeks). Plant height, leaf number, shoot fresh and dry weight, root fresh and dry weight, root diameter and root length were measured. Data were analyzed using analysis of variance (ANOVA), principal component analysis (PCA), correlation, and regression analysis. At the 8-week juvenile stage (9–11 leaves stage), wild carrot's shoot and root characteristics exhibited rapid growth. Correlation analysis indicated positive and significant (p < 0.05) correlations between above and below-ground morphological traits. PCA showed that morphological characteristics, except plant height, can be used to distinguish wild and cultivated carrots. To predict the vegetative growth pattern of most of the morphological traits of wild and cultivated carrots, power regression models were selected based on higher R2 and adj-R2 values and lower values of RMSE, AIC and BIC. The study showed wild carrots grew more quickly than cultivated carrots during the vegetative phase. It is recommended that appropriate weed management practices, such as hoeing, tilling, hand pulling, or herbicide spraying, be implemented before wild carrot leaf stages 9–11.