Rhizome Diameter Research Articles

Morphological Traits and Biomass Allocation of Leymus secalinus along Habitat Gradient in a Floodplain Wetland of the Heihe River, China

Plant organ biomass allocation and morphological characteristics are important functional traits. The responses of plant root, stem, and leaf traits to heterogeneous habitats in floodplain wetlands are highly important for understanding the ecological adaptation strategies of riparian plants. However, the patterns of these responses remain unclear. In a floodplain wetland in the middle reaches of the Heihe River, we studied the responses of the root, stem, and leaf morphological traits and biomass allocation of Leymus secalinus to varying habitat conditions. We measured these traits in three sample plots, delineated based on distance from the riverbank: plot I (near the riparian zone, 50–150 m from the riverbank), plot II (middle riparian zone, 200–300 m from the riverbank), and plot III (far riparian zone, 350–450 m from the riverbank). The results showed that in plot I, L. secalinus tended to have slender roots and stems and small leaves, with a biomass allocation strategy that maximized the root–shoot ratio (RSR). In plot II, L. secalinus had thick stems and moderate leaf and root patterns, and the RSR values were between those of plot I and plot III. In plot III, L. secalinus had thin and short stems and large leaves; furthermore, among the root morphological structures, plot III had the shortest Rhizome length (RL) and longest Rhizome diameter (RD), and the RSR was the lowest. Moreover, there was a significant correlation between organ biomass and leaf thickness, stem length, RD, and RL in the three habitats (p < 0.05). By balancing the biomass allocation among organs, wetland plants in floodplains balance changes in root, stem, and leaf morphological characteristics to improve their environmental adaptation.

Estimation of Genetic Variability and Character Association Analysis of Underutilized Ornamental Canna Lily (Canna indica L.)

Background: Canna lily (Canna indica L.) is an edible herbaceous perennial plant in which flowers and rhizomes were commonly used as a food additive and its potentiality was not fully utilized in India. To stun these hindrances, morphological characterizations are needed to determine the genetic variability to improve flower quality and rhizome yield in canna lily. Methods: In the present research, a field experiment was conducted during 2022-2023 in Botanical Garden, Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu. Twelve accessions were investigated by using a randomized block design with 3 replications. All the observations for 23 quantitative traits were carried out at 0.05 and 0.01 probability. Results: The wide range of genetic variability was observed, a high genetic coefficient of variation ranged from 8.49 to 75.62 % and a phenotypic coefficient of variation ranged from 8.83 to 76.50 % was observed in 20 traits except in time taken for first flowering, rhizome diameter, number of nodes per rhizome. High heritability coupled with high genetic advance as a percent of mean was observed for 21 traits except in time taken for flowering and number of nodes per rhizome. Character association analysis revealed that stem diameter and inflorescence length showed highly significant and positively correlated with flower yield and rhizome yield per plant. Path analysis specified that the number of leaves per clump had a very high and positive direct effect on fresh flower yield per plant.

Evaluation of Different Arrowroot (Maranta arundinacea L.) Accessions for High Rhizome Yield with Good Quality and Starch Content

Aim: Arrowroot (Maranta arundinacea L) is an underutilized tuber crop belonging to the family marantaceae. This study mainly aims to evaluate different arrowroot accessions for quality starch and best yield.
 Study of Design: The field experiment was conducted in randomized block design with total ten accessions and three replications.
 Place and Duration of Research: The present investigation was undertaken at the College Orchard, Department of Vegetable Science, Horticultural College & Research Institute, TNAU, Coimbatore during the year 2022-2023.
 Methodology: In this study, ten arrowroot accessions viz.,TAr18-01, TAr18-02,TAr18-04,TAr18-05,TAr18-10, TAr18-11, TAr18-12, TAr18-13, TAr18-14 and Local were evaluated for their growth, yield and quality parameters.
 Results: The statistical results revealed that all the accessions significantly differ from each other. Results obtained as maximum height in the accession TAr18-14(132.01cm), maximum number of leaves in TAr18-10 (109.33), number of tillers in TAr18-14 (8.45) and biggest rhizome weight in TAr18-14(198.81g) respectively. The yield traits like rhizome length (25.49 cm), diameter (9.46cm) and number of rhizome per plant (30.00), rhizome yield per plant (1.49kg) were maximum in TAr18-10. The quality parameters viz., dry matter (%) was highest for TAr18-10(56.76%),TSS in TAr18-12 (27.83%), ash contents in TAr18-10 (3.88%). These parameters mainly decide the quality and nutritive value of Arrowroot. There is a significant variation in the quality parameters like starch, TSS, dry matter, protein, crude fiber. Among various accessions TAr18-04 recorded the highest starch (54.62%) and TAr18-14recorded highest protein content (6.194%). Amylose content (21.88%) was maximum in TAr18-01.
 Conclusion: It can be concluded from the following study that TAr18-10 recorded highest rhizome yield, dry matter content with quality starch and can be selected for further evaluation and exploitation in industrial applications.

Cytokinin and Metabolites Affect Rhizome Growth and Development in Kentucky Bluegrass (Poa pratensis).

Rhizome growth and development is regulated by phytohormone. However, endogenous phytohormones affect rhizome initiation, and sustained growth in perennial grass species remains elusive. In this study, we investigated the morphological characteristics and the content of indole-3-acetic acid (IAA), zeatin (ZT), gibberellic acid (GA3), and abscisic acid (ABA) in the rhizomes of two different Kentucky bluegrass. Using ultra-performance liquid chromatography/tandem mass spectrometry (UPLC-MS/MS), we performed metabolite analysis of two different rhizomes. In our study, the multi-rhizome Kentucky bluegrass material 'Yuzhong' had an average of 1113 rhizomes, while the few-rhizome material 'Anding' had an average of 347 rhizomes. The diameter of rhizome and length of rhizome internode in 'Yuzhong' were 1.68-fold and 1.33-fold higher than that of the 'Anding', respectively. The rhizome dry weight of 'Yuzhong' was 75.06 g, while the 'Anding' was 20.79 g. 'Yuzhong' had a higher ZT content (5.50 μg·g-1), which is 2.4-fold that of 'Anding' (2.27 μg·g-1). In contrast, the IAA, ABA, and GA3 content of rhizome were markedly higher in 'Anding' than 'Yuzhong'. Correlation analysis revealed significant correlations between ZT and ZT/ABA with the number of rhizomes, diameter of rhizome, and length of rhizome internode, whereas IAA, ABA, GA3, and IAA/ZT were opposite. In the metabolic profiles, we identified 163 differentially expressed metabolites (DEMs) (60 upregulated and 103 downregulated) in positive ion mode and 75 DEMs (36 upregulated and 39 downregulated) in negative ion mode. Histidine metabolism and ABC transporters pathways were the most significantly enriched in the positive and negative ion mode, respectively, both of which are involved in the synthesis and transport of cytokinin. These results indicate that cytokinin is crucial for rhizome development and promotes rhizome germination and growth of Kentucky bluegrass.

Dynamic transcriptome profiling provides insights into rhizome enlargement in ginger (Zingiber officinale Rosc.).

The rhizome is an economically important part of ginger (Zingiber officinale Rosc.). However, the mechanism of ginger rhizome enlargement remains unclear. In this study, we performed an integrated analysis of the hormone content and transcriptome of ginger at three rhizome enlargement stages: initial enlargement (S1), middle enlargement (S2), and peak enlargement (S3). With rhizome enlargement, the levels of the hormones zeatin (ZT), gibberellic acid (GA), indole acetic acid (IAA), and jasmonic acid (JA) were significantly increased, and this increase was positively correlated with rhizome diameter. Transcriptomic analysis identified a large number of differentially expressed genes (DEGs); the number of DEGs were 2,206 in the transition from S1 to S2, and 1,151 in the transition from S2 to S3. The expression of several genes related to hormone biosynthesis and signalling and cell division or expansion, and transcription factors was significantly altered, which suggests that these genes play essential roles in rhizome enlargement. The results of correlation analysis suggested that the process of ginger rhizome enlargement may be primarily related to the regulation of endogenous cytokinin, GA3, auxin, and JA biosynthesis pathways and signal transduction; GRAS, HB, MYB, MYB122, bZIP60, ARF1, ARF2, E2FB1, and E2FB2, which may regulate the expression of rhizome formation-related genes; and CYC2, CDKB1, CDKB2, EXPA1, and XTH7, which may mediate cell division and expansion. These results provide gene resources and information that will be useful for the molecular breeding in ginger.

Species‐specific acclimatization capacity of key traits explains global vertical distribution of seagrass species

AbstractAimThe global vertical depth distribution of seagrass species remains poorly understood. Locally, the abundance and distribution of seagrasses is determined by light penetration, but at global levels each seagrass species has very distinct maximum distributional depth ranges, indicating that plant‐associated traits must also influence their specific depth ranges. Seagrass‐specific attributes, such as plant size or architecture, growth or reproductive strategy and their physiological and/or morphological acclimatization potential, have been suggested to be responsible for this variety of vertical distributions. We investigate here whether these species‐specific traits drive differences in the global maximum vertical distribution of seagrasses.LocationGlobal.Time periodPublications between 1982 and 2020.Major taxa studiedSeagrasses (order Alismatales).MethodsWe tested whether the species‐specific maximum vertical distribution of seagrasses can be predicted by (1) their rhizome diameter (a proxy for plant size); (2) their functional resilience (growth/reproductive strategy); or (3) their acclimatization capacity. For the last aspect, we used a systematic review followed by meta‐analytical approaches to select key seagrass traits that could potentially acclimatize to extreme light ranges across different seagrasses.ResultsWe found that vertical distribution is best explained by the species‐specific acclimatization capacity of various seagrass traits, including saturation irradiance (physiological trait), leaves per shoot (morphological trait) and above‐ground biomass (structural trait). In contrast, our results indicate no predictive power of seagrass size or growth/reproductive strategy on the vertical distribution of seagrasses.Main conclusionsAcross the globe, the ability of seagrass species to thrive at a wide range of depths is strongly linked to the species‐specific acclimatization capacity of key traits at different organizational levels.

Unlocking the genetic diversity of Indian turmeric (Curcuma longa L.) germplasm based on rhizome yield traits and curcuminoids.

Turmeric is an important commercial crop widely grown in Asia due to its pharmacological and nutritional value. India is the centre of turmeric diversity and many turmeric accessions have good rhizome yield, varying curcuminoids content and are well-adapted to various agro-climatic zones. In the present study, we unravel the diversity among 200 Indian turmeric accessions based on rhizome yield traits and curcuminoids content. Clustering and correlation studies were also performed to group the turmeric accessions and to observe the relationship between the traits. Results revealed the presence of large variability among turmeric accessions including the major traits such as yield (24.77g p-1 to 667.63g p-1), dry recovery percentage (13.42% to 29.18%), curcumin (0.41% to 2.17%), demethoxycurcumin (0.38% to 1.45%), bisdemethoxycurcumin (0.37% to 1.24%) and total curcuminoid content (1.26% to 4.55%). The superior germplasm identified for curcuminoids content were as follows; curcumin (CL 157 - 2.17% and CL 272 - 2.13%), demethoxycurcumin (CL 253 - 1.45% and CL 157 - 1.31%), bisdemethoxycurcumin (CL 216 - 1.24% and CL 57 - 1.11%) and total curcuminoid content (CL 157 - 4.55% and CL 272 - 4.37%). Clustering based on dendrogram, grouped 200 accessions into seven clusters. Among seven clusters, the maximum number of accessions were grouped into cluster II while cluster VII showed maximum mean value for majority of the traits. Correlation analysis revealed a significant relationship between the traits where the total curcuminoid content is significantly and positively correlated with the primary rhizome core diameter and length of the secondary rhizome. The selection of these particular traits may result in the identification of germplasm with high total curcuminoid content. Taken together, it is the first report on the large screening of turmeric accessions for variation in the rhizome yield traits and curcuminoids content. The genetic diversity revealed in this study could be useful for further crop improvement programs in turmeric to develop new varieties with high rhizome yield coupled with high curcuminoids content.

Feasibility of Surfgrass Phyllospadix iwatensis Transplantation Along the Rocky Coasts of Shandong Peninsula, China.

Surfgrass Phyllospadix iwatensis is a dominant seagrass species along the east coast of Shandong Peninsula, China. Like other seagrasses in the world, surfgrass has been declining in the past decades. To assess the possibility of transplanting P. iwatensis in the coastal area, a new surfgrass transplant system was designed and applied to conduct a surfgrass transplantation experiment in a tide pool and a subtidal area, and its survival, morphological and physiological parameters were examined from May 2019 to June 2020. The results showed that after a year since transplantation, more than 65% of the transplants survived and the survival rate was higher in the subtidal site than in the tide pool. The morphological measurements including shoot height, leaf width, number of leaves per shoot, rhizome diameter and elongation rate, and number of roots per shoot were all higher in the subtidal area than in the tide pool, showing that the P. iwatensis transplants grew better in the subtidal area than in the tide pool in the study area. These results indicated that surfgrass can be transplanted in the two areas, and it is probably more suitable in subtidal area than in tide pool in the study area.

Growth and Development Responses of the Rhizome-Root System in Pleioblastus pygmaeus to Light Intensity.

Light, as a primary source of energy, directly or indirectly influences virtually all morphological modifications occurring in both shoots and roots. A pot experiment was conducted to assess the growth patterns of one-year-old Pleioblastus pygmaeus plants’ rhizome-root systems and their responses to different light intensities from 11 March to 26 December 2016. The experiment design scheme was 3.87% (L1), 11.25% (L2), 20.25% (L3), 38.76% (L4), 60.70% (L5), and 100% full sunlight (control CK). The results indicated that along the growing period from March to December, eight of the eleven studied parameters of the rhizome-root system showed significant variability and diverse growth patterns. In addition, light intensity is a key factor for determining P. pygmaeus plants’ rhizome and root growth. Specifically, the light intensity had a significant, positive, and linear/or almost linear impact on the number of old and new rhizomes, old rhizome length, new rhizome diameter, as well as the culm root diameter. A nonlinear and positive relationship was found between light intensity and the listed three parameters, i.e., new rhizome length, new rhizome internode length, and rhizome root length. The value of the above-mentioned three parameters significantly increased when affected from 0% to 40–60% of full sunlight and then gradually increased until 100% of full sunlight. The ratio of aboveground dry weight to underground dry weight (A/U ratio) showed a single peak curve with increasing light intensity and presented the highest value under ca. 55% full sunlight. Furthermore, 40% full sunlight (equal to an average light of 2232 lux) might be the threshold for P. pygmaeus rhizome-root system growth. When the light intensity was below 40%, the generalized additive models (GAMs) predicted value of most studied parameters decreased to lower than zero. In conclusion, current study provides a solid basis for understanding the dynamic growth and development of P. pygmaeus rhizome-root system, and its responses to different light conditions, which could be used as inputs to P. pygmaeus plant cultivation.

Effect of colchicine induced tetraploids of ginger (Zingiber officinale Roscoe) on cytology, rhizome morphology, and essential oil content

Ginger (Zingiber officinale Roscoe; 2 n = 22) is an important spice crop recognized for its medicinal benefits and pharmacological activities. The crop is said to have a narrow genetic base in the cultivated gene pool due to hinderance in sexual recombination. Polyploid induction is an efficient strategy to develop new cultivars in vegetatively propagated horticultural crops. In this study, successful induction of tetraploids (2 n = 44) in ginger ‘IISR Rejatha’ was achieved through colchicine treatment and the tetraploid plants were subsequently characterized. The 21 putative polyploids were identified by altered morphology, particularly plant height, leaf size, pseudostem height and thickness through colchicine treatment. The chromosome counts confirmed polyploidization in two of the tetraploid lines (2 n = 4x = 44), while that of the control diploid plants was 2 n = 2x = 22. Further, the ploidy levels of diploid and tetraploids were confirmed by flow cytometric analysis. The morphological characterization of the induced tetraploids revealed significant differences in leaf and pseudostem characters. Significantly larger rhizome diameter (3.26 cm) and higher yield per plant (418.65 g/plant) was recorded in Tetraploid 2 compared with Tetraploid 1 (2.88 cm, 320.81 g/plant) and diploid (2.00 cm, 280.33 g/plant). Overall, the colchicine induced tetraploids in ginger have larger rhizomes and greater source of essential oil.

Effects of growing Coptis chinensis Franch in the natural understory vs. under a manmade scaffold on its growth, alkaloid contents, and rhizosphere soil microenvironment.

BackgroundThe main planting modes currently used for the production of Coptis chinensis Franch are under the shade of a manmade scaffold or a natural understory. In this study, we analysed changes in the growth, development, and alkaloids of C. chinensis when grown in a natural understory compared with under a manmade scaffold. We also clarified the differences in the rhizosphere soil microenvironment, represented by soil physicochemical factors, enzyme activity, and microbial community structure of 1- to 5-year-old C. chinensis between the different planting modes. These results will provide theoretical guidance and scientific evidence for the development, application, and extension of ecological planting technologies for C. chinensis.ResultsThe results of this study showed that rhizome length, rhizome diameter, and rhizome weight all increased over time in both planting modes. The greatest rhizome length was reached in 4-year-old C. chinensis, while the greatest rhizome diameter and rhizome weight were obtained in 5-year-old C. chinensis. There was no significant difference in rhizome biomass between the two planting modes. The alkaloid content of the four common alkaloids in the rhizome of 5-year-old C. chinensis at the harvest stage met the standards found in the Pharmacopoeia of the People’s Republic of China; the berberine content and total alkaloids in the rhizomes were significantly higher with natural understory planting compared to planting under a manmade scaffold. A redundancy analysis revealed that the physicochemical factors and enzyme activity of rhizosphere soil were significantly correlated with variation in microbial community structure. Soil pH, available potassium, bulk density, available nitrogen, catalase, and peroxidase were all significantly correlated with bacterial and fungal community structures. Among these, soil pH was the most important factor influencing the structures of the fungal and bacterial community. In the two planting modes, the differences in soil enzyme activity and microbial community structure mainly manifested in the rhizosphere soil of C. chinensis between different growth years, as there was little difference between the rhizosphere soil of C. chinensis in a given growth year under different planting modes. The levels of nitrogen, phosphorus, potassium, and organic matter in the rhizosphere soil under either planting mode were closely associated with the type and amount of fertiliser applied to C. chinensis. Investigating the influence of different fertilisation practices on nutrient cycling in farmland and the relationship between fertilisation and the soil environment will be key to improving the yield and quality of C. chinensis medicinal materials while maintaining the health of the soil microenvironment.

Local Victory: Assessing Interspecific Competition in Seagrass From a Trait-Based Perspective.

Tropical seagrass meadows are formed by an array of seagrass species that share the same space. Species sharing the same plot are competing for resources, namely light and inorganic nutrients, which results in the capacity of some species to preempt space from others. However, the drivers behind seagrass species competition are not completely understood. In this work, we studied the competitive interactions among tropical seagrass species of Unguja Island (Zanzibar, Tanzania) using a trait-based approach. We quantified the abundance of eight seagrass species under different trophic states, and selected nine traits related to light and inorganic nutrient preemption to characterize the functional strategy of the species (leaf maximum length and width, leaves per shoot, leaf mass area, vertical rhizome length, shoots per meter of ramet, rhizome diameter, roots per meter of ramet, and root maximum length). From the seagrass abundance we calculated the probability of space preemption between pairs of seagrass species and for each individual seagrass species under the different trophic states. Species had different probabilities of space preemption, with the climax species Thalassodendron ciliatum, Enhalus acoroides, Thalassia hemprichii, and the opportunistic Cymodocea serrulata having the highest probability of preemption, while the pioneer and opportunistic species Halophila ovalis, Syringodium isoetifolium, Halodule uninervis, and Cymodocea rotundata had the lowest. Traits determining the functional strategy showed that there was a size gradient across species. For two co-occurring seagrass species, probability of preemption was the highest for the larger species, it increased as the size difference between species increased and was unaffected by the trophic state. Competitive interactions among seagrass species were asymmetrical, i.e., negative effects were not reciprocal, and the driver behind space preemption was determined by plant size. Seagrass space preemption is a consequence of resource competition, and the probability of a species to exert preemption can be calculated using a trait-based approach.

Impact of water turbidity to Seagrass (Enhalus acoroides) morphology

Seagrass meadows provide a range of important ecosystem functions that can be influenced by both natural and anthropogenic pressures. One water quality that important for seagrass growth and survival is turbidity. A study to observe impacts of high turbidity to seagrass morphometry was conducted in two islands i.e., Sabutung and Bangko-Bangkoang of Pangkep Regency. These two islands are influenced by sediment load from several rivers in Pangkep Regency. Water column turbidity impacts seagrass by reducing the quantity and quality of light available for photosynthesis. However, dense population of seagrass Enhalus acoroides was found buried under turbidity regimes in both Islands. Some seagrass morphological characteristics such as leaf sheath length, leaf length and width, rhizome diameter and internode length were varied among locations. This suggested that seagrass developed morphological plasticity in responding to reduced light. Seagrass may establish morphological acclimatization to respond to the minimum light availability.

Effect of different rhizome types and sizes on growth and yield of turmeric (Curcuma longa L.)

Curcuma longa L. is known as spice crop and have important medicinal properties due to presence of bioactive compounds. This study was carried out to determine the effect of mother and finger rhizomes size on growth and yield of turmeric. Rhizomes with three different sizes were used viz., T1: mother rhizome 15-25 g, T2: mother rhizome 25-35 g, T3: mother rhizome 35-45 g, T4: finger rhizome <10 g, T5: finger rhizome 15-25 g and T6: finger rhizome 25-35 g. This experiment was arranged according to randomized complete block design with three replications. Results showed that treatment T3 (mother rhizome 34-45 g) produced maximum plant height (82.57 cm), stem diameter (17.39 mm), number of tillers (10.31), number of leaves (16.04), leaf area (73.21 cm²), total number of rhizomes (28.01), number of primary rhizome (11.70), number of secondary rhizome (21.45), yield per plant (345.06 g/plant), rhizome length (25.93 mm), rhizome diameter (22.53 mm), and 8.11% curcumin content while the seedling emergence percentage was non-significant for all the treatments.

Submerged Aquatic Vegetation Species and Populations Within Species Respond Differently to Environmental Stressors Common in Restorations.

Submerged aquatic vegetation (SAV) improves environmental conditions by acting as a sediment stabilizer and nutrient retention tool; therefore, reintroduction of SAV is a common freshwater restoration goal. Initial plant establishment is often difficult in suboptimal conditions, and planting material with specific traits may increase establishment rates. Here we evaluate the variability in plant traits based on collection location. We find consistent differences in traits of plants collected from different natural water bodies, and those differences persist in plants grown from seeds under common garden greenhouse conditions-presumably because of genetic differentiation. In three separate mesocosm experiments, we tested the interactive impacts of collection location and environmental condition (control conditions, reduced light, elevated nutrients, or a combination of reduced light and elevated nutrients) on plant reproduction and on traits that might indicate future restoration success (plant height, number of leaves, and rhizome diameter). In most cases, plant traits at the end of the experiments varied by collection location, environmental condition, and an interaction between the two. The best performing plants also depended on response variable (e.g., plant height or number of new shoots produced). Together these results suggest that unpredictable environmental conditions at restoration sites will make selection of a single high-performing plant source difficult, so we suggest incorporating a diverse set of collection locations to increase the probability of incorporating desirable traits.

Field Capacity and Efficiency of a Turmeric Rhizome Planter in Response to Machine Speeds and Some Selected Crop Parameters

This study present variation in field capacity and efficiency of a turmeric rhizome planter in response to the machine speed and some selected turmeric parameters (dimension); turmeric rhizome length and diameter. This was done with a view to ascertaining the best condition under which the planter could perform optimally. The land area covered in a specific duration by the planter depends largely on the field capacity. The turmeric rhizome planter consists of trapezoidal hopper, grooved cylindrical metering devise, ground wheels made of mild steel, chain/sprocket drive system, three linkage point and frame. The experiment was randomized in a factorial design of three levels of rhizome lengths of 30, 45 and 60 mm, diameter of 25, 30 and 35 mm and operational speeds of 8, 10, and 12 kmh-1. The result of the study shows that increase in planter operational speed resulted in an increase in field capacity and efficiency of the planter, and had a significant effect on them. The turmeric rhizome lengths and diameter were found to have insignificant effects on the field capacity and efficiency of the planter.

Preliminary Application of Ground-Penetrating Radar for Reconstruction of Root System Architecture in Moso Bamboo

Root system architecture (RSA) refers to the geometric features and topology of the root system. Ground-penetrating radar (GPR) is a possible method of RSA reconstruction. However, because the topology of the root system is not directly accessible by GPR, GPR-based reconstruction must be complemented by manual connection of root points, resulting in limited accuracy. In this study, we used both GPR and direct excavation to obtain 3D coordinates (XYZ coordinates) and diameters of moso bamboo rhizomes on an orthogonal grid. A score function for selecting the best-connected root points was developed using rhizome diameter, depth, extension angle, and measured line spacing, which was then used to recover the topology of discrete root points. Based on the recovered topology, the 3D RSA of the rhizomes was reconstructed using a smoothing function. Based on the excavation data, the reconstructed RSA was generally consistent with the measured RSA, with 78.13% of root points correctly connected. The reconstructed RSA based on GPR data thus provided a rough approximation of the measured RSA, with errors arising due to missing root points and rhizome displacement. The proposed algorithm for reconstructing 3D RSA further enriches the application of ground-penetrating radar to root detection.

The growth and mortality of Pleioblastus pygmaeus under different light availability

Pleioblastus pygmaeus (Miq.) Nakai, as a dwarf bamboo, providing a high ornamental value in landscaping. Furthermore its well-developed and intricate root system lends its use for soil consolidation and slope protection. A pot experiment was performed to study the impact of different light intensity on the growth characteristics of P. pygmaeus seedlings. The light intensity was controlled by punching circular holes with different diameters in center of the plates cover the pots. The illuminance percentages of the pore diameter area to the inner diameter area of the pot in each treatment were 1.29% (A), 5.16% (B), 11.62% (C), 20.66% (D), 32.28% (E), and 100% (F). The average illumination intensity under treatment A, B, C, D and E is 3.87%, 11.25%, 20.25%, 38.76% and 60.70% of control F (100% of full sunlight), respectively. The results showed that the light intensity is a key factor influencing P. pygmaeus seedlings’ growth and mortality. Seedlings died when light is lower than 38.76%. As light intensity decreased, the mortality increased and the number of culms and total rhizomes, leaf-, aboveground- and underground-biomass significantly decreased, and the gap between the treatments and control significantly increased over the nine month growing period. The generalized additive model (GAM) explained the influence of illuminance and investigation time and indicated a lower determination coefficient on culm height, culm diameter, total rhizome length and total rhizome diameter compared with number of culms, number of total rhizomes and biomass. The diameter of culms showed a decreasing trend during the experiment while their lengths increased even under A treatment (3.87% of full sunlight), suggesting that nonstructural carbohydrates stored prior to the experiment was used for culm height growth under light/carbon limitation. In the case of the leaves, their growth was significantly inhibited under low light intensity (3.87–60.70% of full sunlight) as they are the primary component of the plant’s photosynthetic apparatus. As suppressed leaves could not independently provide enough carbon to the plant, P. pygmaeus seedlings adjust their plasticity to slow down rhizome growth, shoot emergence and biomass accumulation, eventually resulting in “Carbon starvation” and increased mortality. This study provides insights into how dwarf bamboos balance growth and survival under low light availability.

Comparison of phytochemical compounds of two Glycyrrhiza glabra L. populations and their relationship with the ecological factors

Glycyrrhiza glabra is an important herb throughout the World. Glycyrrhizin is the major constituent of the rhizomes of Glycyrrhiza glabra. Fars and Khorasan provinces are the production poles of licorice in Iran. The present study (with a randomized factorial design) was performed in tree replications to determine the variation in phytochemical composition and antioxidant capacity on the licorice rhizomes (less than 1 and 1–2 cm diameters) of Fars (FA) and Khorasan (KH) populations in 2016 and 2017. Glycyrrhizin, saponin, phenolic compounds, and the flavonoid content, as well as antioxidant capacity of the rhizomes, were evaluated. Moreover, the metabolite profile of these two licorice populations was detected by GC–MS analysis. The results showed that these factors were significantly influenced by environmental factors and rhizome diameter. The highest glycyrrhizin (43 mg/g) and saponin (47 g/100 g DW) contents belonged to the thicker rhizomes of Fars population. Flavonoid showed a significant negative correlation with saponin and glycyrrhizin (r2 = − 0.92 and 1− 0.87, respectively) while exhibiting a significant positive relationship with antioxidant activities (r2 = 0.77). The high antioxidant capacity (by DPPH) or IC50 values (the concentration showing 50% antioxidant activity) (0.66 mg/ml) were observed in the thinner rhizomes of the Khorasan population. Moreover, the constituents were isolated from the hydroalcoholic extract of the rhizomes of two licorice populations whose GC–MS results were different. The most abundant phytochemical compound was dihydro-p-coumaric acid in both populations. The results of PCoA, PCA-biplot, and cluster analysis revealed a low diversity between all the individuals of FA and KH populations. Phenolic compounds and flavonoid of the two populations had the largest amount of difference of traits. Thus, the different environmental conditions can dramatically influence the production of secondary metabolites and antioxidant capacity of G. glabra.

GPR based RTM imaging technology for estimating rhizome diameters and application in the western China mining area

The rhizome functions are of great significance to the ecological protection of the western China mining area, whose ecological management can be provided with technical support via accurate calculations of the rhizome biomass. The rhizome diameter is an important index parameter of rhizome biomass. In this study, we propose an estimation of rhizome diameters based on ground penetrating radar (GPR)-based reverse time migration (RTM) imaging technology. First, the spatial distribution of shallow rhizomes is simulated using the finite difference time domain method. The simulation data are examined via RTM imaging and single-channel rhizome analysis to obtain the rhizome index parameters: Δh, the width of the maximum positive peak amplitude measured at an amplitude of zero, and ΔH, the distance between the zero-amplitude position above the largest positive peak in the shallow region and the zero-amplitude position below the largest positive peak in the deeper region. The experiments of physical models verify the effectiveness of the two parameters (Δh and ΔH). and indicate that the values of Δh and ΔH are independent of the rhizome burial depth; instead, they are only related to the diameter of the rhizome. For both the numerical simulations and the physical model experiment, the estimation errors of Δh and ΔH for the rhizome diameters can be constrained to less than 6% and 5%, respectively, which shows that the estimation of the rhizome diameters using GPR based RTM imaging technology is reasonable and effective and its high estimation accuracy meets the technical requirements.