Seedling Height Growth Research Articles

Growth, Physiological, and Transcriptome Analyses Reveal Mongolian Oak Seedling Responses to Shading

Mongolian oak (Quercus mongolica) is a common building material and landscaping tree species in northern China, with significant economic and ecological value. Its seedling growth is inhibited by high light intensity, but the mechanism by which light stress affects the growth and development of its seedlings remains unclear. In this study, we investigated the phenotypes, physiological processes, and molecular responses of 3-year-old Mongolian oak seedlings under different light treatments: full light (Sck), light shading (S1; 40% light), moderate shading (S2; 20% light), and severe shading (S3; 3% light). Compared to Sck, the S1 and S2 treatments resulted in higher leaf area, photosynthetic pigment content, photosynthesis rates, soluble sugar contents, and soluble protein contents in Mongolian oak seedlings. The S1 and S2 treatments also promoted seedling height and diameter growth and resulted in lower degrees of membrane lipid peroxidation, cell membrane permeability, and antioxidant enzyme activity. In contrast, severe shading (S3) significantly inhibited seedling height and diameter growth due to the lower net photosynthetic rate, and exhibiting higher degrees of membrane lipid peroxidation and cell membrane permeability. Shading treatments (S1 and S2) alleviated the negative effects of strong light on the growth and development of Mongolian oak seedlings, with the S2 treatment having the greatest effect. However, severe shading (S3) inhibited growth and development. A total of 3726 differentially expressed genes (DEGs) were detected in leaves under different shading treatments in RNA sequencing analysis. Among these, 1691, 3150, and 824 DEGs were detected in the Sck-S1, Sck-S2, and S1-S2 comparison groups, respectively. The different shading treatments determined common expression regulation pathways, including carotenoid biosynthesis, photosynthetic antenna proteins, and mitogen activated protein kinase (MAPK) signal transduction. Shading induced increases in gene expression levels in light harvesting complexes, which are related to changes in gene expression in the photosynthetic system, leading to changes in photosynthetic physiology. The expression levels of genes related to reactive oxygen species signal perception and activation enzymes were upregulated in Sck. Together, these findings revealed the response mechanisms of Mongolian oak seedlings to different shading levels at the physiological and molecular levels, providing a scientific basis and technical support for the cultivation and large-scale production of Mongolian oak seedlings.

Endogenous Phytohormone and Transcriptome Analysis Provided Insights into Seedling Height Growth of Pinus yunnanensis

Plant height plays a crucial role in both the structure and quality of plants. Pinus yunnanensis is a distinctive species of the forest found in Southwest China, where the height of the plants significantly influences both yield performance and plant architecture. Although the phenotypes of P. yunnanensis seedlings with different plant heights were quite different at their seedling stage, the molecular mechanisms controlling the seedling differentiation remain poorly understood. This study is aimed to investigate the underlying mechanisms of P. yunnanensis seedling differentiation using phenotypic, transcriptomic, and endogenous phytohormone analyses. The P. yunnanensis seedlings were categorized into three grades, i.e., Grades A, B, and C, by mean ± 1/2 standard deviation method (H ± 1/2σ), and the seedling height and ground diameter were measured. We conducted the measurements of endogenous hormone levels in the young shoot apexes of seedlings at different grades during the fast-growth period (March). The DEGs were identified through transcriptome sequencing and analyzed by qRT-PCR validation. Significant differences were observed in the content and ratio of endogenous phytohormones among various grades of P. yunnanensis seedlings (p < 0.05). The ABA content in Grade A was prominently more than that in Grades B and C, and the order of the content of auxins was Grade B > C > A. Furthermore, when compared to Grade A, the ratios of auxins/CTKs, auxins/ABA, CTKs/ABA, and (auxins + CTKs)/ABA exhibited significant increases in Grades B and C. Moreover, GO functional annotation analysis indicated the more pronounced enrichment of DEGs in molecular functions. KEGG metabolic pathway analysis revealed notable differences in enrichment pathways between the pairwise comparisons. The “plant hormone signal transduction” pathway exhibited enrichment in the two groups, followed by “plant–pathogen interaction” pathway in the organism system that was enriched in the three groups. In addition, the results for endogenous phytohormone metabolism pathways indicate a significant up-regulation in the expression of AUX1, while AHP and PP2C exhibited significant down-regulation. To sum up, we aimed at investigating the underlying mechanisms of P. yunnanensis seedling differentiation using phenotypic, transcriptomic, and endogenous phytohormone analyses. The results suggested that individual phytohormones have a limited capacity to regulate gene expression, and seedling differentiation results from the combined regulation of multiple hormones. In addition, several candidate genes associated with phytohormone biosynthesis and signal transduction pathways were identified, including AUX1, GH3, AHP, B-ARR, PP2C, etc., which provided candidate genes for the following hormone-related gene overexpression and knockout experiments. These findings provide insights into the molecular genetic control of seedling height growth of P. yunnanensis.

Height increment patterns in Pinus pinaster seedlings emerging in naturally regenerated gaps

Abstract The group selection cutting system provides a promising technique for transforming monospecific even-aged stands into uneven-aged, mixed stands. However, this system has scarcely been used to regenerate Mediterranean shade-intolerant species. In this study, we analyze the height increment patterns of Pinus pinaster seedlings emerging in naturally regenerated gaps. P. pinaster is a shade-intolerant pine species distributed throughout the Mediterranean basin. An experimental trial was established in a 50-year-old P. pinaster (maritime pine) plantation located in the mountains of central Spain. Gaps of two different sizes (diameter equal to 1.5 and 2.5 times the dominant height of the stand, 26 and 44 m, respectively) were opened during winter 2017–18. A total of 531 subplots with a 1-m radius were installed in spring 2018, distributed within the gaps as well as in control plots adjacent to the gaps. Seedlings were tagged individually and variables including height, along with other ecological variables, were collected twice a year (in spring and autumn), providing six time intervals for the development of our models. We applied seemingly unrelated regression to analyze the height growth in this polycyclic species, allowing us to model spring and autumn height increments at the same time. Our results showed that seedling height growth depended on the silvicultural treatment, meteorological conditions during the spring growth season, inter-specific scrub competition, position within the gap, and seedling characteristics, such as the ontogenetic development or the size of the seedling itself. This work, along with germination and survival analysis, aims to provide a holistic perspective on the suitability of the group selection cutting system to regenerate maritime pine stands, taking into account current and future climate change scenarios.

Silviculture treatments hasten seedling growth on seismic disturbances in boreal treed fens

Seismic lines in western Canada's boreal region are linear disturbances that affect the habitat of threatened woodland caribou (Rangifer tarandus caribou). To hasten the return of forest cover and ultimately to restore caribou habitat, restoration managers use silviculture treatments in wet areas that involve the mechanical mounding of seismic lines to create artificial hummocks. Tree planting then takes place on top of these hummocks. However, the effectiveness of this silviculture technique for restoring seismic lines in peatlands is largely untested. Here we sampled incremental height growth of coniferous seedlings at 41 seismic line plots in poor and rich treed fens in northeast Alberta, Canada. We compared lines that had been treated with inverted mounding (a type of mechanical mounding) and subsequent tree planting, to nearby lines that were left untreated for natural recovery. We used generalized linear mixed models to test the effect of silviculture treatments on 5‐year growth increments of black spruce (Picea mariana) and tamarack (Larix laricina). Overall, we found that mounding and tree planting improved seedling growth compared to seismic lines regenerating naturally. However, growth responses were found to vary by species, ecosite, initial seedling size, and light availability. This suggests that site‐specific prioritization of mounding within peatlands may be more efficient considering the widespread nature of seismic lines. Future experiments testing growth responses to other mounding techniques that are designed to preserve the soil profile. It is also important for managers to weigh restoration goals beyond tree establishment and an accelerated return to forest cover.

Reclamation of abandoned magnesite site using amendments and plantation

This study aimed to determine the suitable reclamation ways of post‐mining magnesite. It was hypothesized that adding amendments and planting would decrease pH, increasing the nutrient availability and enhancing the soil microbial activity. Treatments included 200 g gypsum, 2 kg goat manure, and 200 g sulfur per square meter. Cedar (Cedrus libani A. Rich.), black locust (Robinia pseudoacacia L.), black pine (Pinus nigra J.F. Arnold), and sainfoin (Onobrychis sativa L.) were planted. Before and after the treatments, samples were taken from each experimental unit and analyzed. Analysis of the data indicated that the pH had decreased by 0.6 and 0.5 units on the gypsum + sulfur‐ and gypsum + manure‐treated experimental units, respectively, compared to the other treated plots. In addition, using manure significantly increased the organic matter N, P, and K content, by 3‐fold, 2.5‐fold, 7.5‐fold, and 2.5‐fold, respectively, and enhanced microorganism activity. The sulfur + manure treatment increased microbial C and N approximately twofold. Because the manure, sulfur, and gypsum treatments improved the tailings conditions for plant growth, the use of these amendments for mine tailing reclamation was strongly recommended. Across all treatments, cedar and black pine demonstrated 83 and 77% survival rates for the first 3 years of afforestation, respectively. For the same period, the black locust survival rate was 35% lower than that of the other species. The gypsum + manure application increased seedling height growth by about 20% for all three species compared to the other treatments.

High phenotypic variation found within the offspring of each mother tree in Fagus sylvatica regardless of the environment or source population

AbstractAimClimate change challenges temperate forest trees by increasingly irregular precipitation and rising temperatures. Due to long generation cycles, trees cannot quickly adapt genetically. Hence, the persistence of tree populations in the face of ongoing climate change depends largely on phenotypic variation, that is the capability of a genotype to express variable phenotypes under different environmental conditions, known as plasticity. We aimed to quantify phenotypic variation of central Europe's naturally dominant forest tree across various intraspecific scales (individuals, mother trees (families), populations) to evaluate its potential to respond to changing climatic conditions.LocationEurope.Time Period2016–2019.Major Taxa StudiedEuropean beech (Fagus sylvatica L.).MethodsWe conducted a fully reciprocal transplantation experiment with more than 9000 beech seeds from seven populations across a Europe‐wide gradient. We compared morphological (Specific Leaf Area), phenological (leaf unfolding) and fitness‐related (growth, survival) traits across various biological scales: within single mother trees, within populations and across different populations under the contrasting climates of the translocation sites.ResultsThe experiment revealed significant phenotypic variation within the offspring of each mother tree, regardless of geographic origin. Initially, seedling height growth varied among mother trees and populations, likely due to maternal effects. However, the growth performance successively aligned after the first year. In summary, we observed a consistent growth response in different beech populations to diverse environments after initial maternal effects.Main ConclusionsThe study strikingly demonstrates the importance of considering intraspecific variation. Given the surprisingly broad spectrum of phenotypes each mother tree holds within its juvenile offspring, we conclude that Fagus sylvatica might have the potential for medium‐term population persistence in face of climate change, provided that this pattern persists into later life stages. Hence, we also suggest further investigating the inclusion of passive adaptation and natural dynamics in the adaptive management of forests.

Effect of cow urine concentration and NPK fertilizer doses on the growth of oil palm seedlings (Elaeis guineensis Jacq)

Application of anorganic fertilizers can be reduced by using organic fertilizers such as cow biourine. This study aimed to see the combination of cow biourine and anorganic fertilizers (NPK fertilizer) on the growth of oil palm seedlings. Research was conducted at East Reuleut Village, Muara Batu District, and Agriculture Laboratory of Malikussaleh University on April to June 2021 using factorial Randomized Block Design. Concentration of cow biourine consisting 4 levels : control (U0), 50 cc/L (U1), 75 cc/L (U2), and 100 cc/L (U3). Doses of NPK fertilizer consisting 3 levels, control (N0), 2 g/polybag (N1), and 3 g/polybag (N2), each treatment replicated 3 times. Results showed the interaction between application of cow biourine concentration and NPK fertilizer doses increase plant height on 9 WAP, and number of leave on 11 WAP of oil palm seedlings. Single-dose cow biourine increases plant height growth, stem diameter, chlorophyll content, fresh weight and dry weight of oil palm seedlings. NPK fertilizer separately increases plant height growth, leaf chlorophyll of oil palm seedlings. Interaction between 100 cc/liter of cow biourine concentration + 2 grams/polybag of NPK fertilizer dose was the best combination.

KETERGANTUNGAN SEMAI JOHAR (Cassia siamea LAMK) TERHADAP FUNGI MIKORIZA ARBUSKULA PADA MEDIA TAILING TAMBANG EMAS

Tailings are the wastes resulting from mining activities in the amalgamation of mine ore from the ground, with extreme characteristics such as a sand-dominated texture, high Pb heavy metal content, very low availability of carbon and macro nutrients. Consequently, the plants may not able to grow well in the tailings. The application of Arbuscular Mycorrhyza Fungi (AMF) is expected to increase the ability of forest plant seedlings to grow and develop in tailings media. The research was carried out in a greenhouse using johar (Cassia siamea Lamk) seedlings which were inoculated with AMF inoculum: Glomus manihotis, Glomus etunicatum, and mix inoculan (mycofer), and planted in tailings media collected from Pongkor gold mine for 8 weeks. Johar seedlings were able to grow in tailings media and AMF colonization to the seedlings was observed. The compatibility of multi-species inoculum, mycofer, is higher than single AMF inoculum. The height, diameter and biomass growth of johar seedlings in tailings media significantly (p<0.05) increased with AMF inoculation. Johar seedlings have a high dependence on AMF, on tailings media, undicated by value of MIE > 50%, suggesting that the AMF application to johar is very necessary for revegetation activities in tailings media.

The role of secondary forest in the survival and growth of native species: Tree planting field experiment in the delta of the Paraná River (Argentina)

Secondary forests constitute 74% of the world's natural forests and, while the conservation value of primary forests is irreplaceable, secondary forests can provide important biological conservation services and secure the future of many species. In the frontal zone of the Paraná River delta (Argentina), post-abandonment secondary forests are developed, composed of exotic species, but in which regeneration of native plant species is observed. The objective of this study was to evaluate the role of secondary forest in the conservation of native trees. For this, the survival and growth of 60 seedlings, belonging to four native tree species and planted inside and outside a secondary forest, were analyzed for one year. Results indicates that the average survival within the secondary forest (89%) is significantly higher than outside it (66%) and that, in the range studied (6 to 41 cm), the survival odds increase by 10% with each centimeter that the seedling's initial height increases. Height growth of seedlings is, on average, 144% higher in the absence of forest cover and differs according to species, with Allophylus edulis and Myrsine parvula being the species with the highest growth and Lonchocarpus nitidus the lowest. After one year monitoring, it is noted that the secondary forest is an environment conducive to the survival of native tree seedlings, although it imposes growth limitations typical of environments with forest physiognomy. Also, that the planting of native trees can constitute an adequate ecological restoration technique for the recovery of native riparian forest in the frontal zone of the Paraná River delta.

Selection of Soil and Water Conservation Technologies and Native Tree Species for Rehabilitation of Degraded Arid Lands in Southeast Ethiopia

The large-scale commercial agriculture, mining, expansion of sedentary agricultural settlements, and overgrazing in Ethiopian pastoral areas have become a major cause of land degradation. Such activities reduce grazing capacities and impoverish already fragile living conditions of the pastoralists. Such an increase in land degradations necessitates urgent calls for interventions. The main objectives of this study were to select the best performing soil and water conservation technologies and native tree species to restore degraded lands of arid and semiarid conditions in Liben District of Guji Zone, Oromia Reginal State, Ethiopia. Four locally grown and locally preferred tree species, namely, Cordia africana, Acacia tortilis, Acacia goetzei, and Combretum molle, were planted in five soil and moisture conservation structures (control, half-moon, spot hoeing, mowing, and trench). The survival rate and height and root collar diameter (RCD) growth of planted tree species were collected two years after planting. A significantly higher survival rate, RCD, and height growth of planted seedlings were recorded from half-moon (52.44 ± 12.48%; 1.66 ± 0.31 cm; 51.57 ± 2.79 cm) and trench (64.00 ± 11.49%; 1.92 ± 0.27; 69.67 ± 2.62 cm) moisture conservation structures, respectively. Acacia tortilis (58.22 ± 12.38%) and Acacia goetzei (42.99 ± 8.81%) had better survival rate than Cordia africana (4.00 ± 1.91%) and Combretum molle (24.22 ± 7.34). Cordia africana attained the largest RCD (2.50 ± 0.34 cm) and height (95.83 ± 17.25 cm) growth, followed by Acacia tortilis and Acacia goetzei. It is concluded that Acacia tortilis and Acacia goetzei are better species to grow in degraded lands. The half-moon and trench moisture conservation structures have a great potential for degraded areas of the arid and semiarid conditions of Ethiopia for better tree establishment, survival, and enhanced growth thereby rehabilitation of degraded lands.

Manipulating overstory density and mineral soil exposure for optimal natural regeneration of Scots pine

In northern boreal region the growth of forests is slow, and yield and profit are low, which is why low reforestation costs are important for profitable forestry. If natural regeneration is successful, expensive artificial forest regeneration (planting or direct seeding) can be avoided. In this study, we look at the impact of overstory density and site preparation on natural regeneration and seedling growth of Scots pine. Study stands were established in different parts of Northern Finland and in each stand following treatments: 50, 150 and 250 trees ha−1 or unthinned control, where the stand density was ≥ 250 trees ha−1, were randomly allocated to experimental plots. In addition, site preparation (disc trenching, 4000–5000 m ha−1) was carried out on two experimental plots in which tree density was either 50 or 150 trees ha−1. In the experimental stands seedling number, age and growth were monitored for 11 years. Monitoring revealed that the number of seedlings increased with decreasing tree density. Average seedling height growth was very low or even non-existent in the unthinned control and in the densest (250 trees ha−1) treatment, but increased when the density of trees decreased. The highest seedling number and the highest growth were achieved when the tree density was 50 trees ha−1 and the soil was prepared to expose mineral soil. Achieving e.g. 2000 seedlings ha−1, would need about 40% exposition of mineral soil. The required low tree density implies that not only seed supply from seed trees and site preparation is important for regeneration success in northern boreal Scots pine forests but also the reduction of competition by mature trees.

Evaluating Ecklonia maxima water-soluble polysaccharides as a growth promoter of tomato seedlings and resistance inducer to Fusarium wilt

Alternatives to chemicals for plant management are increasingly used to reduce environmental pollution. Seed treatment with natural products may act as a priming effect by stimulating seedling growth and plant defence responses against fungal pathogens. In this framework, algae produce a wide variety of bioactive metabolites, which can be used in agriculture as biofertilizers or biostimulants. The purpose of this study was to investigate the possible role of water-soluble polysaccharides (WSPs) from the brown alga Ecklonia maxima applied on tomato seed in enhancing plant growth and inducing resistance to Fusarium oxysporum via modulation of multiple physiological parameters and metabolic pathways. Here, we first characterized the E. maxima WSPs by FT-IR spectroscopy, and then we tested the WSPs as growth promoters on tomato seedlings, and the physiological and defence responses of plants during pathogen infection. We found that WSP seed treatment without pathogen challenge stimulated seedling height and root growth by 24.5 and 62.9%, respectively. Under pathogen infection, plants exhibited long-lasting resistance against F. oxysporum until 46 days after seed treatment. The metabolic changes associated with resistance to Fusarium wilt in plant roots were related to an increase in phenols, flavonoids and protein contents as well as a higher chitinase and β-1,3-D-glucanase enzyme activity. Moreover, PR1a, PR3 and other defence gene expressions were significantly increased. Resistance to F. oxysporum as a result of WSP seed treatment was also supported by FT-IR analysis of tomato roots. Infected roots showed a decrease in the relative intensity of the bands due to the syringyl ring and amide I and amide II in proteins. In contrast, WSP treatment alone and in the presence of the pathogen exhibited a spectral profile similar to that of the control. This research emphasizes the potential role of algal polysaccharides applied by seed treatment in promoting seedling growth and priming plant resistance against soil-borne pathogens.

Invasive microstegium vimineum (Japanese stiltgrass) hinders growth and biomass of hardwood seedlings regardless of light and moisture regime

Limited natural oak (Quercus spp.) regeneration in current-day, closed-canopy upland oak forests across the eastern and central United States has prompted increased use of various silvicultural practices, including prescribed fire and/or thinning, to reduce competition from shade-tolerant, often fire-sensitive species, and ultimately, restore and/or maintain oak landscapes. However, these practices create disturbances that can promote the spread of invasive plants and complicate oak restoration attempts, especially if invasion differentially impacts oaks compared to competitor species during early seedling development. To evaluate if Japanese stiltgrass (Microstegium vimineum (Trin.) A. Camus), an invasive C4 grass common in the understory of these systems, impacts growth and biomass of hardwood seedlings in different light and moisture environments, we established a shadehouse experiment in May 2020 with one-year old seedlings of white oak (Quercus alba L.) and two competitor species, red maple (Acer rubrum L.) and sweetgum (Liquidambar styraciflua L.), in the following treatments: M. vimineum (MV) presence (with/without), light (40/10 % full irradiance), soil moisture (high/low), and their interactions. Monthly, from May to October 2020, we measured seedling height growth, stem basal diameter, and MV cover and height if present. In October 2020, we harvested a subset of seedlings and measured their above- and belowground biomass and aboveground MV biomass when present. At study cessation, regardless of light or moisture treatment, red maple and sweetgum were significantly shorter when grown with MV (17.9 and 15.6 cm, respectively) than without MV (33.5 and 22.3 cm, respectively) and had smaller basal diameters (with MV: 1.03 and 0.94, respectively; without MV: 1.34 and 1.25 cm, respectively) and ∼ two times less biomass. White oak basal diameter was 1.2 times lower with MV (0.77 cm) compared to without MV (0.93 cm), but MV had no impact on white oak height growth or biomass, likely because of its conservative growth strategy and high-water use efficiency. Light and moisture treatments had little impact on MV height and cover, but MV biomass was greater with high (462 dry wt m−2) compared to low (398 g dry wt m−2) moisture treatment and ∼ 1.3 times greater when grown without vs with tree competition. Thus, MV invasion into closed-canopy upland oak forests may have species-specific effects on early seedling growth, reducing growth of competitor seedlings with non-conservative growth strategies more than that of upland oaks, but long-term studies are needed to better understand the potential legacy effects of MV on growing conditions and tree regeneration.

Growth and Development Law of Annual Sown Seedings of <i>Photinia prunifolia</i> and Preliminary Exploration on Seeding Breeding Technology

In this paper, we studied the height and ground diameter growth of annual seedlings of <i>Photinia prunifolia, </i>and introduced its the morphological characteristic and geographical distribution. At the same time, through the seedling sowing and breeding experiment, we used the ordered sample clustering analysis method to analyze the high growth process of seedlings sown in <i>Photinia</i> <i>prunifolia</i>. We divided the growth of seedlings into four different growth periods, seedling stage, growth stage, rapid growth stage and later growth stage according to the experimental investigation. The seedling stage and growth stage of <i>Photinia prunifolia </i>were 30 days. The initial growth period lasted for about 48 days. The rapid growth stage lasted for 120 days, which was 10.1 times and 5.2 times higher than the seedling height and ground diameter growth in initial growth period, respectively. In later growth stage, the seedling height and ground diameter grew quite slowly. The simulation correlation coefficient was as high as 0.99 by simulating seedling height growth and seedling age. The fitting degree was high. It showed that the relationship seedling height growth and seedling age of <i>Photinia prunifolia</i> was highly consistent with the Logistic population growth model. Meanwhile, by using the Logistic population growth curve model to fit the high and diameter growth of <i>Photinia prunifolia</i>, we elucidated the growth law of annual seedlings. Since the seedlings grew in the rapid growth stage, that is, the high growth rate of seedlings grew rapidly with the increase of seedling age, enough nutrient fertilizer should be supplemented at this stage to satisfy the rapid growth of seedlings. Annal seedling biomass accounted for 62.5% of the total biomass, and the fresh-weight ratio of above-ground biomass was 1.67. Therefore, this species has better lodging resistance and is suitable for seedling afforestation. The study provided references for the rational cultivation and utilization of new afforestation tree species.

Organic Materials and AMF Addition Promote Growth of Taxodium ‘zhongshanshan’ by Improving Soil Structure

Soil salinization is considered a type of global-scale soil degradation, whereby excessive salinity severely diminishes soil health, which is primarily manifested through disrupted soil structures and reduced fertility. Furthermore, plant growth capacity is inhibited, and productivity is diminished. Consequently, the improvement of saline soils is regarded as a particularly important aspect of enhancing land production. To elucidate the roles of organic amendments and mycorrhizal fungi in the improvement of saline soils, seven treatments were set up, including biochar alone (B), straw alone (S), arbuscular mycorrhizal fungi alone (A), biochar in combination with arbuscular mycorrhizal fungi (BA), straw in combination with arbuscular mycorrhizal fungi (SA), and a control (CK). The results revealed that the seedling height growth rate under the BA treatment was significantly higher than that of the CK by 31.66%. The capillary porosity of the soil under the addition of BA was significantly higher than the CK by 3.17% in the 0–20 cm soil layer. The BA treatment reduced the fractal dimension of soil aggregates considerably by 19.06% in the 0–20 cm soil layer, and 13.71% in the 40–60 cm soil layer in contrast to the CK, respectively. In addition, the positive effects of the BA treatment were significant in the 20–40 cm soil layer. Overall, the application of biochar alone promoted the water stability of soil aggregates. The combination of arbuscular mycorrhizal fungi and biochar promoted plant growth, improved soil pore structures, promoted agglomerate water stability, and led to improved microbial activities. The results showed that organic amendments applied in conjunction with AMF improved the environment of salinized soil, which is a key factor in the promotion of plant growth and the long-term stability of soil health. This study provides a key technical basis for remediation of salinized soil.

Comparative growth and physiological performance of American chestnuts, oaks, hickories, and sugar maple across a silvicultural gradient in overstory retention

The development of a blight-tolerant transgenic American chestnut (Castanea dentata (Marsh.) Borkh.) would provide the potential for reintroducing this species into forests it historically dominated. However, we lack a silvicultural understanding of the environmental conditions most favorable to the growth and survival of American chestnut relative to species with which it historically co-existed. We examined effects of shelterwoods with variable residual densities on the growth and physiology of blight-tolerant chestnut seedlings relative to sugar maple (Acer saccharum Marsh.), and several oak (Quercus spp.) and hickory (Carya spp.) species across a broad range of light availabilities (gap light index; GLI; of 4–50%). To assess the hypothesis that American chestnuts are more physiologically plastic and responsive to light than oaks and hickories, we measured seedling relative diameter and height growth rates and photosynthetic light-response curves across a GLI gradient. The diameter and height growth of chestnut increased with GLI, while oaks and hickories did not. All species varied aspects of their photosynthetic physiology across the GLI gradient in an approximately equivalent manner; the dark respiration rate and light compensation point increased equivalently across species in response to increases in light availability. A multivariate analysis identified three major axes of variation across ten measured traits, largely reflecting differences in species averages and phenotypic plasticity across the GLI gradient. American chestnut seedlings were spread across these multivariate dimensions more than other species, consistent with the hypothesis of higher phenotypic plasticity in this focal species. These results suggest that low residual shelterwood densities may better promote the establishment of underplanted chestnut seedlings relative to associated tree species provided it does not result in detrimental increases in the productivity of competing understory species.

Evaluation the effect of different doses of mineral fertilizers on the height growth of forest seedlings: A case study of Chatkal ridge

This article describes the effects of different mineral fertilizer doses on the growth and development of seedlings of four forest-forming species grown with a closed root system on the western and southern slopes of the Chatkal ridge. The results show that different fertilizer doses have various effects on different types of seedlings. The effect of fertilizers on improving the growth of forest crops in the first year was not fully manifested, since growth buds were laid a year before fertilization against a natural background of growth conditions. Plants that had received more nutrients the year before grew the year ahead after fertilization, and a beneficial effect became apparent. The rate of fertilizer N90P90 K60 was more effective on pine growth on the western slope, while N120P180K60 showed high results on the southern. Oak on both slopes was better affected by a lower dose of fertilizer, hawthorn on both slopes by higher doses, and both doses had roughly the same effect on an apple tree. Therefore, for the apple trees, it can be recommended, as for oak, the depositing of a smaller dose due to the lower cost.

The Role of Trichoderma in The Early Growth of Rice and Soybean in Saline Soils

Optimizing the use of marginal saline soils to improve food security requires solutions that involve exploiting local potential resources, including the use of biological agents. This research aims to determine the ability of Trichoderma sp. Tc-31 and Aspergillus sp. As-27 to overcome salinity stress in rice and soybean seedlings. Both isolates were tested for their ability to grow in vitro in saline soil. Next, the ability to overcome saline soil stress during germination and initial growth of rice and soybean seedlings was tested. The experiment consisted of three types of treatment, namely the use of As-27, Tc-31, and the use of husks treated with complete basic fertilizer. The average inhibitory power of saline soil against As-27 and Tc-31 was (-)62.50±16.68% and (-) 52±3.54% respectively at 48 days of incubation. The application of biological agents had an effect on germination in rice 94.10-94.46% and soybeans 74.49-77.04%. Biological agents also influence the height growth of rice and soybean seedlings. These two fungal isolates have the potential to be used as biological agents to help rice and soybean seeds overcome salinity stress.

OsCSN1 regulates the growth of rice seedlings through the GA signaling pathway in blue light

Blue light can regulate the photomorphogenesis of plants through blue light receptors to influence seedling growth and development. The COP9 signaling complex (CSN), a vital regulator of photomorphogenesis, is a highly conserved protein complex. CSN1 is the largest and most critical subunit in the CSN with a complex N-terminal function that supports most of the functions of CSN1 and is mainly involved in plant growth and development processes. The CSN is also required in the blue light-mediated photomorphogenesis response of seedlings. In this study, the OsCSN1 subunit of Oryza sativa subsp. japonica (rice) was edited and screened, and OsCSN1 deletion mutant, OsCSN1 weak expression mutant and OsCSN1 overexpression mutant were constructed. The mechanism of OsCSN1 and its N-terminal effects on rice seedling growth and development under blue light conditions were investigated. The addition of exogenous hormone gibberellin (GA3) and gibberellin synthesis inhibitor paclobutrazol (PAC) caused aboveground phenotypic and protein (such as CUL4 and SLR1) changes. Blue light regulates the degradation of SLR1 through OsCSN1, which regulates the growth and development of rice seedling height, the first incomplete leaf, and the coleoptile. It is hypothesized that rice affects CRY-COP1 interactions after sensing blue light signals through the cryptochrome, and the nuclear localization of COP1 is regulated by the CSN complex. OsCSN1 is a negative regulator in response to blue light. The core structural domain of action that inhibits the growth of the aboveground part of rice seedlings is located at the N-terminal of OsCSN1. OsCSN1 regulates the nuclear localization of COP1 through the COP9 signaling complex and degrades SLR1 through CUL4-based E3 ligase. Ultimately, it affects the synthesis of the endogenous hormone GA, thereby inhibiting the aboveground growth and development of rice seedlings.

Assessing White-Tailed Deer Impacts to Tree Seedling Growth using Citizen Science Data in Minnesota, USA

Abstract White-tailed deer (Odocoileus virginianus Zimmerman) present numerous challenges for maintaining the health of forests in the US Lake States. Although many sources of data exist that provide coarse estimates of deer-browse impacts on plant survival and abundance (e.g., national forest inventories) or examine areas where deer are excluded (e.g., exclosures), few studies exist that use detailed tree seedling measurements across diverse stand conditions and forest types. This study evaluated four years of citizen science data collected in the Assessing Vegetation Impacts from Deer (AVID) program in Minnesota, USA. Results showed that average annual height growth of seedlings for nine browse-palatable species was 1.9 cm. For four of these tree species, annual height growth was not significantly different from zero. These results point to the challenges for the growth and survival of browse-palatable tree species in Minnesota under current deer population levels. Engaging the public through a citizen science project such as AVID showcases the importance of evaluating browse impacts on trees from white-tailed deer while simultaneously providing information to managers and decision makers about this important conservation concern. Study Implications: Citizen scientists can collect data on important conservation issues with ecological implications. This study showcases data provided by volunteers in Minnesota’s Assessing Vegetation Impacts from Deer (AVID) program. These results showed that the growth of nine browse-palatable species grew minimally over a four-year span. Citizen science data like these can be used by state wildlife agencies to better understand forest-wildlife interactions and establish wildlife population harvest goals. Measurements of deer browse can also assist researchers by reducing the costs of data collection and providing a geographically diverse data set with detailed measurements of deer impacts to forest vegetation.