Shoot Ratio Research Articles

Physiological and anatomical responses of Passiflora tripartita var. mollissima (Passifloraceae) in water deficit

Introduction: Passiflora tripartita var. mollissima (banana passionfruit) is one of the most promising exotic tropical fruits from the diversity of the Passifloraceae family in South America, because of its organoleptic properties and antioxidant activity. Objective: To evaluate the physiological and anatomical responses of banana passionfruit plants under water deficit to better understand the mechanisms that mitigate this stress and affect the production of crops subject to climate change and global warming. Methods: Three-month-old seedlings of banana passionfruit were subjected to a soil water deficit through an irrigation reduction at 70 % for 49 days under greenhouse conditions. Morphology (leaf area, height, and number of leaves) and physiological (stomatal conductance, Fv/Fm, total chlorophyll content) measurements were made through time, and after the irrigation treatments were measured biomass parameters and anatomical foliar traits. Results: The plants experienced a decrease in height, leaf area, number of leaves, leaf area index, and relative water content, that are common responses in plants subjected to reduced irrigation. Additionally, the plants exhibited certain mechanisms that can be attributed to water deficit tolerance such as higher root: shoot ratio, stomatal closing, an increase in stomatal density, a reduction in mesophyll tissue thickness, and a decrease in the number of vessels and its diameter as they enable the banana passionfruit to reduce water loss and decrease the probability of cavitation in xylem vessels. Conclusions: banana passionfruit plants could implement strategies against water scarcity, allowing them to survive and endure challenging environmental conditions

Tropical root responses to global changes: A synthesis.

Tropical ecosystems face escalating global change. These shifts can disrupt tropical forests' carbon (C) balance and impact root dynamics. Since roots perform essential functions such as resource acquisition and tissue protection, root responses can inform about the strategies and vulnerabilities of ecosystems facing present and future global changes. However, root trait dynamics are poorly understood, especially in tropical ecosystems. We analyzed existing research on tropical root responses to key global change drivers: warming, drought, flooding, cyclones, nitrogen (N) deposition, elevated (e) CO2, and fires. Based on tree species- and community-level literature, we obtained 266 root trait observations from 93 studies across 24 tropical countries. We found differences in the proportion of root responsiveness to global change among different global change drivers but not among root categories. In particular, we observed that tropical root systems responded to warming and eCO2 by increasing root biomass in species-scale studies. Drought increased the root: shoot ratio with no change in root biomass, indicating a decline in aboveground biomass. Despite N deposition being the most studied global change driver, it had some of the most variable effects on root characteristics, with few predictable responses. Episodic disturbances such as cyclones, fires, and flooding consistently resulted in a change in root trait expressions, with cyclones and fires increasing root production, potentially due to shifts in plant community and nutrient inputs, while flooding changed plant regulatory metabolisms due to low oxygen conditions. The data available to date clearly show that tropical forest root characteristics and dynamics are responding to global change, although in ways that are not always predictable. This synthesis indicates the need for replicated studies across root characteristics at species and community scales under different global change factors.

Respon Pertumbuhan dan Produksi Tanaman Selada Romaine terhadap Otomasi Aerasi pada Sistem Hidroponik Rakit Apung

Romaine lettuce is a nutritious leaf vegetable with a high selling price and its production can be increased using a hydroponic system. Floating raft hydroponics is a hydroponic system with plants floating on styrofoam and their roots submerged in a nutrient solution. Providing aeration using an aerator connected to a timer switch is necessary to increase dissolved oxygen in the nutrient solution to optimize plant growth and production. This research aims to analyze the effect of aeration automation and the best aeration duration on the growth and production of romaine lettuce plants in a floating raft hydroponic system. The research was conducted at Greenhouse UG Technopark in May-June 2023. This experiment used a one-factor Completely Randomized Design with 4 aeration duration treatments: no aeration (control), 6 hours aeration/day, 15 hours/day aeration, and 24 hours/day aeration. Each treatment was repeated 5 times so that there were 20 experimental units and consisted of 5 samples for a total of 100 samples. The results of this research show that aeration 24 hours/day has a real influence on the parameters of plant height in the 3rd week, leaf length, leaf width, leaf wet weight, and root shoot ratio (P<0,05). Aeration 24 hours/day provides the best results for the growth and production of romaine lettuce plants. Aeration automation of 15 hours/day can be used as an alternative from the producer's side to reduce electricity use.

Deep tillage combined with straw biochar return increases rice yield by improving nitrogen availability and root distribution in the subsoil

ContextAfter over 20 years of practicing shallow rotary tillage combined with straw direct return in the middle and lower Yangtze regions of China, the yield potential has gradually disappeared, and new alternative tillage practices are required to continuously increase rice yield. ObjectiveThis paper investigates the yield effect and mechanism of deep tillage combined with straw return through two consecutive years of a field experiment. MethodsThree tillage depths (shallow tillage 6–7 cm, ST; medium tillage 12–14 cm, MT; and deep tillage 25–28 cm, DT) plus three straw management methods (no straw return, NR; straw direct return, SR; and straw biochar return based on the same amount of carbon input as SR, BR) were set up as experiment treatments. The aboveground and belowground growth traits of rice and soil nitrogen (N) status were determined. ResultsCompared with ST and MT, the DT enlarged rice root distribution and increased soil N content in the middle and lower soil layers (7–28 cm) and decreased the root–shoot ratio at the flowering stage, which was conducive to absorbing more soil nutrients from the subsoil and allocating more photosynthetic products to the aboveground parts and grain. The MT and DT increased spike number and rice yield compared with ST. Compared with NR, both SR and BR increased soil total and available N contents, and the remaining soil available N content at the harvest stage of BR was lower than that of SR. Straw return (SR and BR) improved rice yield by increasing spike number and kernels per spike, and the effect of BR on increasing rice yield was greater than that of SR. ConclusionsThe DT combined with BR increased root distribution and N content in the subsoil, promoted the utilization of subsoil's nutrients, and increased rice yield. It is therefore a promising tillage practice for achieving high rice yields.

Plant metabolic responses to soil herbicide residues differ under herbivory in two woodland strawberry genotypes

The use of glyphosate-based herbicides (GBHs) to control weeds has increased exponentially in recent decades, and their residues and degradation products have been found in soils across the globe. GBH residues in soil have been shown to affect plant physiology and specialised metabolite biosynthesis, which, in turn, may impact plant resistance to biotic stressors.In a greenhouse study, we investigated the interactive effects between soil GBH residues and herbivory on the performance, phytohormone concentrations, phenolic compound concentrations and volatile organic compound (VOC) emissions of two woodland strawberry (Fragaria vesca) genotypes, which were classified as herbivore resistant and herbivore susceptible. Plants were subjected to herbivory by strawberry leaf beetle (Galerucella tenella) larvae, and to GBH residues by growing in soil collected from a field site with GBH treatments twice a year over the past eight years.Soil GBH residues reduced the belowground biomass of the susceptible genotype and the aboveground biomass of both woodland strawberry genotypes. Herbivory increased the belowground biomass of the resistant genotype and the root–shoot ratio of both genotypes. At the metabolite level, herbivory induced the emission of several VOCs. Jasmonic acid, abscisic acid and auxin concentrations were induced by herbivory, in contrast to salicylic acid, which was only induced by herbivory in combination with soil GBH residues in the resistant genotype. The concentrations of phenolic compounds were higher in the resistant genotype compared to the susceptible genotype and were induced by soil GBH residues in the resistant genotype.Our results indicate that soil GBH residues can differentially affect plant performance, phytohormone concentrations and phenolic compound concentrations under herbivore attack, in a genotype-dependent manner. Soil GBH altered plant responses to herbivory, which may impact plant resistance traits and species interactions. With ongoing agrochemical pollution, we need to consider plant cultivars with better resistance to polluted soils while maintaining plant resilience under challenging environmental conditions.

Dark septate endophytes enhance the drought tolerance of Haloxylon ammodendron in sterilized and nonsterilized soil

Dark septate endophytes (DSEs) are a type of endophytic fungus that commonly colonize plant root systems in extreme environments, and play a role in enhancing resistance to drought stress. To investigate the potential applications of DSEs in improving drought tolerance of desert plants, three DSE strains isolated from Haloxylon ammodendron for strong drought tolerance - Alternaria tellustris (AT), Cladosporium sp. (CL), and Paraphoma radicina (PR) - were screened through pure culture in vitro. Pot experiments of H. ammodendron were then conducted with different DSE, water, and soil treatments. In both sterilized and nonsterilized soil, DSEs showed growth-promoting and drought-resistant properties, with a stronger effect observed under sterilized soil treatment. The results showed that in sterilized soil, AT and CL increased root biomass, total biomass and root shoot ratio under high drought treatment, while PR effectively enhanced branch number and root biomass under normal water treatment. Physiologically, DSEs improved plant drought tolerance by increasing soluble sugar content and superoxide dismutase activity. Notably, DSE inoculation facilitated the uptake and utilization of soil nutrients such as available phosphorus, nitrate nitrogen, and free amino acids by plants in both sterilized and nonsterilized soil. Overall, our study highlights the potential of DSEs in improving drought resistance and promoting the growth of desert plants.

Elevational variation in morphology and biomass allocation in carpathian snowbell Soldanella carpatica (Primulaceae).

Plants growing along wide elevation gradients in mountains experience considerable variations in environmental factors that vary across elevations. The most pronounced elevational changes are in climate conditions with characteristic decrease in air temperature with an increase in elevation. Studying intraspecific elevational variations in plant morphological traits and biomass allocation gives opportunity to understand how plants adapted to steep environmental gradients that change with elevation and how they may respond to climate changes related to global warming. In this study, phenotypic variation of an alpine plant Soldanella carpatica Vierh. (Primulaceae) was investigated on 40 sites distributed continuously across a 1,480-m elevation gradient in the Tatra Mountains, Central Europe. Mixed-effects models, by which plant traits were fitted to elevation, revealed that on most part of the gradient total leaf mass, leaf size and scape height decreased gradually with an increase in elevation, whereas dry mass investment in roots and flowers as well as individual flower mass did not vary with elevation. Unexpectedly, in the uppermost part of the elevation gradient overall plant size, including both below-and aboveground plant parts, decreased rapidly causing abrupt plant miniaturization. Despite the plant miniaturization at the highest elevations, biomass partitioning traits changed gradually across the entire species elevation range, namely, the leaf mass fraction decreased continuously, whereas the flower mass fraction and the root:shoot ratio increased steadily from the lowest to the highest elevations. Observed variations in S. carpatica phenotypes are seen as structural adjustments to environmental changes across elevations that increase chances of plant survival and reproduction at different elevations. Moreover, results of the present study agreed with the observations that populations of species from the 'Soldanella' intrageneric group adapted to alpine and subnival zones still maintain typical 'Soldanella'-like appearance, despite considerable reduction in overall plant size.

Clonal integration benefits Calystegia soldanella in heterogeneous habitats

Abstract Land-use change and tourism development have seriously threatened the ecosystems of coastal protection forests and beaches. Light and nutrients are spatially heterogeneously distributed between the two ecosystems. Clonal plants, such as Calystegia soldanella, which play a crucial role in maintaining the ecological stability of coast habitats, are likely to encounter diverse environments. In this study, we investigated clonal integration and the division of labor in C. soldanella under heterogeneous (high nutrient and low light [HNLL]; low nutrient and high light [LNHL]) and homogeneous habitats. We cultivated pairs of connected and severed ramets of C. soldanella in these environments. Our results showed the total biomass (TB) of connected ramets was higher than that of severed ramets in heterogeneous environments, suggesting clonal integration enhances growth in heterogeneous habitats. The root shoot ratio was significantly lower in HNLL than in LNHL conditions for connected ramets, demonstrating a division of labor in growth under heterogeneous conditions. However, parameters of clonal propagation of C. soldanella did not significantly differ between connected and severed ramets in heterogeneous environments, indicating no division of labor in clonal propagation. In homogeneous environments, the growth of C. soldanella did not benefit from clonal integration. Connected ramets in heterogeneous habitats exhibited higher TB than in homogeneous habitats. The TB of one ramet in HNLL was consistently higher than that in LNHL, irrespective of ramet’s states, which suggests that high soil nutrients may enhance the growth. We conclude that C. soldanella has the capability of clonal integration to achieve high biomass in heterogeneous but not in homogeneous conditions, and the establishment of coastal protection forests (high nutrient and low light) may foster the growth of C. soldanella.

Root and shoot studies of summer cowpea (Vigna unguiculata) and baby corn (Zea mays) under intercropping system with different levels of fertility and stress-mitigating chemicals

An experiment was conducted during summer seasons of 2019 and 2020 at College of Agriculture (Agriculture University, Kota), Ummedganj, Rajasthan, to study the root and shoot of summer cowpea [Vigna unguiculata (L.) Walp.] and baby corn (Zea mays L.) under intercropping system with different levels of fertility and stress-mitigating chemicals. The experiment was laid out in a split-split plot design with 4 replications having 30 treatment combinations with 5 intercropping systems [sole cowpea; sole baby corn; cowpea + baby corn (2:1); cowpea + baby corn (3:1); and cowpea + baby corn (4:1)] in the main plot and 3 fertility levels, viz. 100; 125; and 150% RDF (Recommended dose of fertilizer) in subplot and 2 stress mitigating chemicals (0.5% CaCl2 and 1% KNO3 at flowering and pod development stage of cowpea) in sub-sub plot. Results revealed significant increase in shoot weight, root weight, root-to-shoot ratio, cowpea equivalent yield (CEY) and number and dry weight of nodules in 2:1 row cowpea + baby corn intercropping system over other row ratios. The 2:1 row ratio significantly increased root:shoot ratio of cowpea by 20.9, 15.2, and 7.3% over sole cowpea, 4:1 and 3:1 row ratio, respectively, and resulted in the highest root-to-shoot ratio for baby corn, recording 18.3, 14.5, and 6.8% increase over sole baby corn, 4:1, and 3:1 row ratios of cowpea and baby corn, respectively. Further shoot weight, root weight, root:shoot ratio in cowpea and baby corn, CEY and the number and dry weight of nodules in cowpea exhibited a notable increase in 150% RDF as compared to lower fertility levels (100 and 125% RDF). Applying 150% RDF resulted in a significantly higher root:shoot ratio for both cowpea and baby corn, with increases of 11.3 and 4.5% over 100 and 125% RDF for cowpea, and 11.6 and 5.5% over 100 and 125% RDF for baby corn, respectively. Foliar application of 0.5% CaCl2 at the flowering and pod-developing stages significantly augmented all the aforementioned parameters for both cowpea and baby corn.

Optimum Plant Density Improved Cotton (Gossypium hirsutum L.) Root Production Capacity and Photosynthesis for High Cotton Yield under Plastic Film Mulching

Optimum Plant Density Improved Cotton (Gossypium hirsutum L.) Root Production Capacity and Photosynthesis for High Cotton Yield under Plastic Film Mulching

Zinc-loaded mesoporous silica nanoparticles mitigate salinity stress in wheat seedlings through silica-zinc uptake, osmotic balance, and ROS detoxification

Abiotic stresses like salinity and micronutrient deficiency majorly affect wheat productivity. Applying mesoporous silica nanoparticles (MSiNPs) as a smart micronutrient delivery system can facilitate better stress management and nutrient delivery. In this purview, we investigated the potential of MSiNPs and Zn-loaded MSiNPs (Zn-MSiNPs) on the growth and physiology of wheat seedlings exposed to salinity stress (200 mM NaCl). Initially, the FESEM, DLS, and BET analysis portrayed nanoparticles' spherical shape, nano-size, and negatively charged mesoporous surface. A sustained release of Zn+2 from Zn-MSiNPs at 30 °C, diffused light, and pH 7 was perceived with a 96.57% release after 10 days. Further, the mitigation of NaCl stress in the wheat seedlings was evaluated with two different concentrations, each of MSiNPs and Zn-MSiNPs (1 g/L and 5 g/L), respectively. A meticulous improvement in the germination and growth of wheat seedlings was observed when treated with both MSiNPs and Zn-MSiNPs. A considerable increase in chlorophyll, total protein, and sugar content was in consort with a substantial decline in MDA, electrolyte leakage, and ROS accumulation, showcasing the nanomaterials' palliating effects. Most importantly, the K+/Na+ ratio in shoots increased significantly by 3.43 and 4.37 folds after being treated with 5 g/L Zn-MSiNPs, compared to their respective control sets (0 and 200 mM NaCl). Therefore, it can be concluded that the Zn-MSiNPs can effectively restrain the effects of salinity stress on wheat seedlings.

Effect of basal and foliar application of diammonium phosphate in cognizance with phosphate-solubilizing bacteria on growth, yield and quality of rainfed chickpea (Cicer arietinum)

A rainfed experiment was conducted during the winter (rabi) seasons of 2011–12 and 2012–13 at Kumarganj, Faizabad, Uttar Pradesh to study the effect of diammonium phosphate (DAP) applied through soil and foliage in conjunction with phosphate-solubilizing bacteria (PSB) on growth characters, yield attributes and yield, seed protein content, nutrient uptake and phosphorus-use efficiency (PUE) of chickpea (Cicer arietinum L.). The application of 50 kg DAP/ha as basal + 50 kg DAP/ha as foliar in 2 splits 45 and 60 days after sowing + PSB significantly increased the growth attributes (plant height, primary branches/plant, leaf area/plant, number and dry weight of nodules/plant, root and shoot dry weight/plant, root: shoot ratio), yield attributes and yield (pods/plant, 1,000-seed weight, seed yield, biological yield), seed protein content, N and P uptake and PUE of chickpea. However, seeds/ pod and harvest index were not affected significantly due to the application of DAP in cognizance with PSB. Thus, split application of 100 kg DAP/ha (½ through soil + ½ through foliage in 2 splits at 45 and 60 DAS) in conjunction with PSB proved effective in enhancing growth, yield (1,486 kg/ha; 102% increase over the control) and quality of chickpea grown under rainfed conditions.

Biochar Application Combined with Water-Saving Irrigation Enhances Rice Root Growth and Nitrogen Utilization in Paddy Fields

To improve nitrogen use efficiency (NUE) during rice cultivation, it is essential to comprehend the morphological and physiological traits of rice roots. However, in high-fertility black soil regions of Northeast China, the effects of combining biochar application with water-saving irrigation (WSI) conditions on rice root development and nitrogen utilization are still unknown. To address this knowledge gap, a combination of field experiments and 15N tracer micro-area investigations was conducted in this study. Four treatments were implemented: (i) controlled irrigation without biochar application (CB0); (ii) controlled irrigation with 2.5 t ha−1 biochar application (CB1); (iii) controlled irrigation with 12.5 t ha−1 biochar application (CB2); and (iv) controlled irrigation with 25 t ha–1 biochar application (CB3). Flooded irrigation conditions without biochar treatment (FB0) were used as the control. The primary objective of this research was to identify the mechanisms by which combined WSI conditions and biochar application affect rice root development and nitrogen utilization. Biochar application enhanced rice root morphological and physiological characteristics. Optimal biochar application increased the longest root length (RL), root volume (RV), root fresh weight (RFW), root active absorption area, root bleeding intensity, and root activity (RA) of rice while also optimizing the root–shoot ratio and facilitating nitrogen absorption by roots. These changes in root morphological and physiological characteristics facilitated the absorption of fertilizer-15N and soil nitrogen by rice roots, ultimately leading to improvements in rice yields and NUEs. Notably, the rice yields, NUE, nitrogen agronomic efficiency (NAE), and nitrogen partial factor productivity (NPFP) of CB2 plants were 16.45%, 39.42%, 24.48%, and 16.45% higher than those of FB0 plants, respectively. These results highlight the effectiveness of biochar application as a strategy to ensure food security and enhance NUE under WSI conditions. Furthermore, this study suggests that the recommended optimal application amount of biochar for the black soil area of Northeast China is 12.5 t ha−1.

ULTRAPETALA 1 regulates the growth and development of rice plants to promote resilience to salinity stress

Rice, one of the most important agronomically crops, when challenged by high salinity affects its growth at the seedling stage and reproductive phase. Thus, investigating the intricate molecular mechanisms that regulate its developmental process throughout its life cycle is essential for better stress resilience. We have investigated the role of rice trithorax group factor ULTRAPETALA1 (OsULT1) that orchestrates rice development and stress response. A genome-wide chromatin immunoprecipitation analysis revealed OsULT1 enrichment at transcription regulators, oxidative stress signaling, ROS scavengers, and K+ uptake transporters, during salinity stress. Interestingly, loci associated with root development, plant height, inflorescence development, panicles, spikelet numbers, and seed development showed OsULT1 occupancy under control and salt stress. Expression of these genes was regulated by chromatin modifications such as H3K4me3 and H3K27me3. Further, DNA binding analysis showed OsULT1 binding at AP2/ERF core motif A/GCCGAC during salinity stress. OsULT1 overexpression causes developmental changes with enhanced plant height, increase in basal internode length, robust root architecture, and increase in tiller and panicle numbers. Moreover, OsULT1OE showed salinity tolerance with enhanced seed germination, reduced ROS content, low Na+/K+ ratio in shoot and root tissue, and improved post-stress recovery. Collectively, our results indicate that ULT1 regulates different plant developmental pathways for better protection and adaptation against environmental stress.

Do proportions of rooting ramets in the clone affect the overall growth of the stoloniferous clonal plant Zoysia japonica?

AbstractIt is naturally common that different proportions of ramets in a clone lose rooting conditions due to habitat stress or obstacles, which potentially affects the overall growth of the clonal plant to different extents. However, so far, little attention has been paid to such phenomena and much less to the underlying ecological mechanisms. Taking Zoysia japonica as material, through an experiment with two nutrition levels in the habitats and five rooting ramet proportions in the clones, the impacts of proportions of rooting ramets in the clone on the overall growth were tested and the ecological mechanisms were analyzed. The results showed that there was no significant difference in the total clonal biomasses among the clones with five rooting ramet proportions under high and low nutrition levels, except for that with 0% rooting ramet proportion. Under both high and low nutrition levels, the lower rooting ramet proportions (0% and 25%) in the clones significantly decreased the number of the so‐called A‐ and B‐ramets, root biomass, stolon length per unit biomass, and root–shoot ratio, but significantly increased the stolon biomass of the clones. Stolon elongation was promoted under high nutrient level, and biomass allocations to stolons and roots increased under low nutrition levels. A‐ramet biomasses accounted for about 50% and 30% of the total biomasses of the whole clone under high and low nutrition levels, respectively. These results might be reasonably explained in terms of clonal integration, compensatory growth, division of labor, and bet‐hedging strategy.

A calmodulin-like protein PvCML9 negatively regulates salt tolerance

Calmodulin-like proteins (CMLs) are unique Ca2+ sensors and play crucial roles in response to abiotic stress in plants. A salt-repressed PvCML9 from halophyte seashore paspalum (Paspalum vaginatum O. Swartz) was identified. PvCML9 was localized in the cytoplasm and nucleus and highly expressed in roots and stems. Overexpression of PvCML9 led to reduced salt tolerance in rice and seashore paspalum, whereas downregulating expression of PvCML9 showed increased salt tolerance in seashore paspalum as compared with the wild type (WT), indicating that PvCML9 regulated salt tolerance negatively. Na+ and K+ homeostasis was altered by PvCML9 expression. Lower level of Na+/K+ ratio in roots and shoots was maintained in PvCML9-RNAi lines compared with WT under salt stress, but higher level in overexpression lines. Moreover, higher levels of SOD and CAT activities and proline accumulation were observed in PvCML9-RNAi lines compared with WT under salt stress, but lower levels in overexpression lines, which altered ROS homeostasis. Based on the above data, mutation of its homolog gene OsCML9 in rice by CRISPR/Cas9 was performed. The mutant had enhanced salt tolerance without affecting rice growth and development, suggesting that OsCML9 gene is an ideal target gene to generate salt tolerant cultivars by genome editing in the future.

Water Use Strategies and Shoot and Root Traits of High-Yielding Winter Wheat Cultivars under Different Water Supply Conditions

Drought is the most important factor limiting winter wheat yield in the North China Plain (NCP). Choosing high-yielding cultivars is an important measure to minimize the negative effects of drought stress. Field studies were conducted with 10 cultivars in the 2020–2022 seasons under three irrigation treatments (I0, without irrigation; I1, irrigated at jointing stage; I2, irrigated at jointing and anthesis stages) in the NCP to examine the water use strategies and root and shoot traits of high-yielding cultivars under different water supply conditions. The results showed that yield variation among cultivars was 21.2–24.6%, 23.7–25.9% and 11.6–15.3% for the I0, I1 and I2 treatments, respectively. Under water deficit conditions (I0 and I1), high-yielding cultivars reduced water use during vegetative stages and increased soil water use during reproductive stages, especially water use from deeper soil layers. Those cultivars with higher root length density (RLD) in deep soil layers exhibited higher water uptake. Each additional millimeter of water used after anthesis from the 100–200 cm soil layers increased grain yield by 23.6–29.6 kg/ha and 16.4–28.5 kg/ha under I0 and I1, respectively. This water use strategy enhanced dry matter accumulation after anthesis, decreased canopy temperature (CT) and increased relative leaf water contents (RLWC), which ultimately improved grain yield. For winter wheat grown under I2, cultivars that decreased water use after anthesis had higher water productivity (WP). Root length (RL), root weight (RW) and root:shoot ratio were each negatively correlated with grain yield, while above-ground biomass was positively correlated with grain yield. Therefore, higher dry matter accumulation and smaller root systems are two important traits of high-yielding cultivars under sufficient water supply conditions (I2) in the NCP.

Light Intensity: A Key Ecological Factor in Determining the Growth of Pseudolarix amabilis Seedlings

The notable absence of juvenile Pseudolarix amabilis trees in forest understories suggests their vulnerability to ecological niche competition, leading to limited survival prospects. This study examines the key factors limiting the growth of P. amabilis seedlings by investigating the effects of five ecological factors: light intensity, rainfall, groundwater level, soil type, and type of fertilization, on the growth of one-year-old P. amabilis seedlings. Our results demonstrate that increasing the light intensity promotes plant growth by augmenting the leaf count, leaf biomass, plant height, stem biomass, root biomass, and total biomass. Further analysis reveals that increased light intensity influences biomass allocation, reducing the specific leaf area and leaf–stem biomass ratio, and favoring root and stem growth over leaf investment. Rainfall, groundwater level, fertilization type, and rhizosphere soil type primarily influence root growth by impacting the soil’s physicochemical properties. Specifically, rising groundwater levels lower the soil temperature and increase the soil moisture, total potassium content, and soil pH, leading to reductions in root biomass, plant height, net height increment, leaf number, and total biomass. When groundwater levels reach 21 cm and 28 cm, submerging the surface soil layer, root biomass decreases by 1.6 g/plant (−51.6%) and 2.3 g/plant (−74.2%), respectively. Further analysis reveals a gradual decrease in the root–shoot ratio above the 14 cm groundwater level, while the specific leaf area and leaf–stem biomass ratio remains unaffected, indicating stronger belowground root stress compared to aboveground stem and leaf components. The results highlight light intensity as the key ecological factor determining the growth of P. amabilis seedlings. These findings underscore the importance of considering light intensity in the management of natural stands, the cultivation of artificial forests, and the nursery cultivation of endangered P. amabilis.

Effects of drought stress on the functional traits and rhizosphere microbial community structure of Cyperus esculentus

AbstractDrought is a major factor limiting plant growth. Plants cope with stress via morphophysiological responses. Rhizosphere‐related bacteria, fungi and other microorganisms can help plants cope with drought via various mechanisms. We conducted a pot experiment on Cyperus esculentus wherein we subjected it to various drought levels and analyzed the functional traits of its aboveground and belowground organs. High‐throughput sequencing was used to study the structure and diversity of the microbial community in the rhizosphere. Drought stress substantially lowered the densities of the leaves, stems, roots and seeds relative to the untreated control. Drought stress inhibited the growth and reduced the yield of C. esculentus. The leaves and seeds have higher water content and are more sensitive to drought stress than the roots. With the aggravation of drought stress, the plant height of C. esculentus decreased significantly, the root:shoot ratio increased and the specific leaf weight had no significant difference. Change in shoot height was the most evident response of C. esculentus to drought stress. Plants under drought stress reduced their leaf area and assumed a specific leaf weight to maintain photosynthetic performance. Rhizosphere fungi were more sensitive to drought stress than rhizosphere bacteria. Drought stress increased the relative abundances of Bacteroidetes, Verrucomicrobia, Patescibacteria, Actinobacteria and Nitrospirae. Drought‐stressed C. esculentus maintained their photosynthetic performance by reducing shoot height and leaf area while assuming a stable specific leaf weight. Drought stress exerted a significantly stronger negative impact on rhizosphere fungi than rhizosphere bacteria. The results clarified the response strategies of functional traits and rhizosphere microorganisms of C. esculentus to drought stress.

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

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