Stem Length Ratio Research Articles

Performance Evaluation of Maize Cob Harvester in Chhattisgarh, India

Maize is one of the vital crops after rice and wheat in India and is a widely produced cereal. Maize contributes only 2.4 percent of total world production. Maize occupied 22.98 lakh hectares, with a production of 36.61 MT in India. The average yield per hectare during 2020- 21 was 2804 kg per hectare. The performance of the maize cob harvester was tested to know the effect of three independent parameters like forward speed of operation (1.7 km/h, 1.9 km/h, 2.1 km/h), snipper speed (55 m/min, 62 m/min, 68 m/min), Variety of maize crop (Dhania- 9965, Sartaj-765, D-9081) on different dependent parameters like stripping loss, ratio of stem length before and after harvesting and machine parameter like actual field capacity, field efficiency. It was also observed that the machines work satisfactorily at forward speed 1.9 km/h and snipper speed 62 m/min. crop parameters stripping losses 0.197%, ratio of length of stem before and after harvesting are 825 mm and 113.33 mm and machine parameter actual field capacity is 0.081 ha/h, field efficiency 75.7%. The cost of operation of machine was found as Rs.337.65 per hour, breakeven point was found as 149.64 h and payback period was 2.5 years (approx.) The total output of machine is 75 q/ha.

Light grazing intensity enhances ecosystem services in semi-arid grasslands through plant trait associations

Grasslands provide multiple ecosystem services (ESs) including provisioning, regulating, supporting, and cultural services that are largely affected by livestock grazing. Linking plant functional traits (PFTs) to ecosystem processes and functions has attracted extensive ecological research to explore the responses and inter-relations of ecosystem services to environmental and management changes. However, little information is available on the links between PFTs and ESs in most ecosystems. We conducted a grazing experiment to investigate the response of PFTs at different levels, including in plant organs (leaves and stems), individual plants, and the overall community in a typical steppe region of Inner Mongolia. Additionally, we examined the effect of animal grazing at four intensities (nil, light, moderate, and heavy) and explored the dynamic interconnections between PFTs and ecosystem services in grasslands. Our analysis revealed that the highest total ecosystem service and provisioning service were achieved under light- and moderate-grazing treatments, respectively. Heavy grazing also increased provisioning service but with a large decline in regulating and total ecosystem services. These changes in ESs were closely associated with grazing-induced variations in PFTs. Compared to no grazing, light grazing increased plant size-related functional traits, such as height, leaf length, leaf area, stem length, and the ratio of stem length to diameter. In contrast, heavy grazing decreased these PFTs. Provisioning and regulating services were determined by plant above-ground community function and structural properties, while supporting service was jointly affected by the below-ground community and soil properties. Our results indicate that light grazing should be recommended for the best total ESs, although moderate grazing may lead to high short-term economic benefits. Moreover, PFTs are powerful indicators for provisioning and regulating services. These findings provide a valuable reference for developing effective management practices to achieve targeted ESs using PFTs as indicators.

Exploring agro-morphological diversity of Algerian hot pepper (Capsicum annuum L.) accessions using multivariate statistics

Pepper is an inevitable constituent in the diets of Algerian population. Unfortunately, the local landraces are endangered by both genetic erosion and pollution. This study aimed to perform agro-morphological characterization of hot peppers (Capsicum annuum L.) accessions. Twenty one accessions collected from the east and south of Algeria were evaluated for 24 quantitative and 38 qualitative morphological characters under green-house conditions. The trial was conducted in a Randomized Complete Block Design (RCBD), with four replicates at the experimental station of the Department of agronomical sciences of Biskra University in Southeast Algeria. Significant variations in most of the traits were strikingly demonstrated using variance analysis and coefficients of variation and the number of modalities, frequencies and Shannon–Weaver diversity index (H′) values for the quantitative and qualitative characters respectively indicating the heterogeneity of the studied accessions. The correlations between the studied quantitative variables showed that the yield parameters were correlated with the variables related to the vegetative part of the plant. The first five PCs explained 76.877 % of the total variation and identified the most discriminant variables related particularly to yield and fruit characteristics contributing to PC1: fruit width; fruit index; fruit weight, number of locules; placenta length, pedicel length, anther length, leaf width and plant height /stem length ratio. For several qualitative traits, an important degree of variability was observed. The first factorial dimension explained 42.5% of the variance and was mostly associated with: plant height; growth habit; flower position; corolla shape; number of flower per axil and fruit shape at pedicel attachment and at blossom end; calyx margin. Cluster analysis of the combined data grouped the pepper landraces into four clusters regardless of the localities and the closest accessions belonged to different localities and/or provinces. This study notably confirms the presence of considerable genetic diversity within and between accessions of hot pepper in Algeria and provides a basis for its active conservation and future selection to develop improved local pepper populations

Wave Attenuation Analysis for Artificial Coral Reefs Using a Physical Modelling Approach

Kim, T.; Kwon, Y.; Hong, S.; Kim, J.; Kwon, S., and Lee, J., 2021. Wave attenuation analysis for artificial coral reefs using a physical modelling approach. In: Lee, J.L.; Suh, K.-S.; Lee, B.; Shin, S., and Lee, J. (eds.), Crisis and Integrated Management for Coastal and Marine Safety. Journal of Coastal Research, Special Issue No. 114, pp. 529–533. Coconut Creek (Florida), ISSN 0749-0208. Due to global warming and coastal development, the damages in coastal such as sea level rise and changes in coastline caused by scour and erosion are increasing, Various types of breakwaters are applied to prevent the coastal erosion, however, the problem such as scour around the structure is exacerbated, therefore a fundamental solution is needed. In this study, two-dimensional laboratory experiments were conducted in the wave flume to investigate the wave transmission phenomena of artificial coral reef. Experiments are conducted by analyzing wave transmission dependents on ratio of stem length to water depth(ls/h), wave height and wave period. Wave attenuation appeared to be most dependent on stem length to water depth(ls/h) and structure width. As incident wave height increased and the wave period decreased, the wave attenuation also increased, however, it was insignificant compared to the influence of the inundation rate. Wave attenuation increases dependents on incident wave height and period, however showed insignificant effect compared to submergence rate. In addition wave attenuation rate also affects wave energy reduction in order of ls/h > H0/h > h/L0. Based on results, we analyzed correlation between KC and CD of artificial coral reef to suggest the equation on empirical relationship. As a result, it is judged that estimating wave transmission rate and drag coefficient of artificial coral reef dependents on sectional specification can be utilized properly in working design and application.

Humeral stress shielding following cemented endoprosthetic reconstruction: An under-reported complication?

The proximal humerus is a common location for primary and non-primary tumors. Reconstruction of the proximal humerus is commonly performed with an endoprosthesis with low rates of structural failure. The incidence and risk factors for stress shielding are under reported. Thirty-nine (19 male, 20 female) patients underwent resection of the proximal humerus and reconstruction with a cemented modular endoprosthesis between 2000 and 2018. The mean resection length was 12 ± 4 cm and was most commonly performed for metastatic disease (n = 26, 67%). Stress shielding was observed in 9 (23%) patients at a mean of 29 (6-132) months postoperatively. Patients with stress shielding were noted to have shorter intramedullary stem length (87 vs. 107 mm, p < .001), longer extramedullary implant length (16 vs. 14 cm, p = .01) and a higher extramedullary implant to stem length ratio (2.1 vs. 1.1, p < .001). The incidence of stress shielding was higher (p = .003) in patients reconstructed with 75 mm stem (n = 6, 67%) lengths. Stress shielding of the humerus was associated with the use of shorter stems and long extramedullary implants. The long-term ramifications of stress shielding on implant stability, complications at the time of revision surgery, and overall patient outcomes remain unknown.

Growth and development of Easter lily in response to container substrate with biochar

ABSTRACTA greenhouse study was conducted to evaluate the growth and flowering of Easter lily (Lilium longiflorum Thunb.) grown in a commercial substrate (Sunshine Mix #1) amended with biochar at 0 (control), 20, 40, 60, or 80% (by volume) and fertigated at four different regimes (constant feeding at 200 or 300 mg L−1 N, or at every third watering with 200 or 300 mg L−1 N). The experimental design was a split-plot design with fertigation regime as the main plot and the biochar percentage as the subplot. There was no interaction between fertigation regime and the biochar percentage on growth or development parameters. Neither fertigation regime nor the biochar percentage affected the number of days before full flower, the number of flowers, total shoot dry weight, the number of leaves, and leaf gas exchange rate. Plants grown in 80% biochar had the highest ratio of stem length with green leaves to total stem length. Plants in the two constant feeding groups had higher SPAD readings than those fertigated at every third watering in week 17. In summary, up to 80% biochar could be used as a component to peat-based container substrate without significant changes in Easter lily growth and development.

三峡水库长期水淹条件下耐淹植物甜根子草的资源分配特征

PDF HTML阅读 XML下载 导出引用 引用提醒 三峡水库长期水淹条件下耐淹植物甜根子草的资源分配特征 DOI: 10.5846/stxb201403030363 作者: 作者单位: 三峡库区生态环境教育部重点实验室,三峡库区生态环境教育部重点实验室,三峡库区生态环境教育部重点实验室,三峡库区生态环境教育部重点实验室,三峡库区生态环境教育部重点实验室 作者简介: 通讯作者: 中图分类号: 基金项目: 国家重点基础研究发展计划项目(2012CB723205);国家自然科学基金资助项目(31370443,31070474,30440035);教育部高校博士点基金课题(20100182110022);中央高校基本科研业务费专项资金项目(XDJK2013A003) Effects of long-term submergence on resource allocation of Saccharum spontaneum Linn. in Three Gorges reservoir Author: Affiliation: Key Laboratory of Eco-environments in Three Gorges Reservoir RegionMinistry of Education,Chongqing Key Laboratory of Plant Ecology and Resources Research in Three Gorges Reservoir Region,College of Life Science,Southwest University,Key Laboratory of Eco-environments in Three Gorges Reservoir RegionMinistry of Education,Chongqing Key Laboratory of Plant Ecology and Resources Research in Three Gorges Reservoir Region,College of Life Science,Southwest University,Key Laboratory of Eco-environments in Three Gorges Reservoir RegionMinistry of Education,Chongqing Key Laboratory of Plant Ecology and Resources Research in Three Gorges Reservoir Region,College of Life Science,Southwest University,Key Laboratory of Eco-environments in Three Gorges Reservoir RegionMinistry of Education,Chongqing Key Laboratory of Plant Ecology and Resources Research in Three Gorges Reservoir Region,College of Life Science,Southwest University,Key Laboratory of Eco-environments in Three Gorges Reservoir RegionMinistry of Education,Chongqing Key Laboratory of Plant Ecology and Resources Research in Three Gorges Reservoir Region,College of Life Science,Southwest University Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:为研究历经三峡水库长期水淹的驯化后,不同海拔高程之间相同种源的甜根子草的生物量分配特征是否发生改变,进而探讨该物种对水淹胁迫表现出的适应性进化特征,试验于2008年初选育相同种源的甜根子草同龄幼苗栽植于三峡水库消落区甜根子草种植试验示范区,并考察了2012年、2013年不同海拔高程甜根子草植株的形态和生物量特征.试验共设置3个海拔高程,即水淹高程168、172m和不受水淹对照高程176m.试验结果表明:(1)较低高程的甜根子草植株较矮小细弱,168m高程的甜根子草植株主茎长和主茎基径显著低于对照176m高程(P < 0.05);平均节间长度随高程的降低而缩短;与之相反,主茎长/主茎基径随高程的降低而增大.(2)甜根子草的叶片厚度、叶片长/叶片宽、叶片长/叶鞘长均随海拔高程的降低而减小;与之相反,比叶面积随高程的降低而增大.(3)水淹前,甜根子草近端成熟节间的质量密度随高程的降低而增大;水淹后,其地上存活茎段基部成熟节间的质量密度在各高程之间无显著差异(P > 0.05).以上研究结果表明,甜根子草历经三峡水库长期水淹的驯化后,生物量分配特征在不同海拔高程之间发生了改变,表现出了相应的驯化特征.相较于高高程的甜根子草植株而言,低高程的植株生长缓慢,采取低株高下的高向生物量投资策略;对叶的物质投资大部分分配到叶面积的增加、叶鞘的伸长生长和叶片的直立生长上,以加强植株的光合生产. Abstract:To reveal the biomass allocation response of Saccharum spontaneum Linn. at different elevations to long-term submergence in Three Gorges Reservoir, the adaptability of S. spontaneum to submergence was studied. Similar-sized seedlings of S. spontaneum with the same provenance were planted at different elevations in our study area located in the hydro-fluctuation zone of the Three Gorges reservoir region in 2008. The morphological traits and biomass of the plants were examined in 2012 and 2013. Three elevations (in the submerged area: 168 m and 172 m; non-submerged area: 176 m) were measured. The results showed that: (1) The plants at the lower elevation were shorter, and the length and basal diameter of stems at 168 m elevation were significantly lower than those at 176 m elevation (P < 0.05). The ratio of stem length to basal diameter significantly increased with decreasing elevation, while the average internode length decreased with decreasing elevation. (2) The leaf blade thickness, the ratio of leaf length to leaf width, and the ratio of leaf length to sheath length decreased with decreasing elevation, but specific leaf area increased with decreasing elevation. (3) The mass density in basal internodes showed no significant difference at different elevations after submergence (P > 0.05), although there was a significant increment with decreasing elevation before submergence. These results demonstrated that S. spontaneum could decrease the growth of seedlings, increase leaf area and sheath elongation, and increase the hyponastic growth of leaves to adapt to long-term submergence at different elevations. This suggests that the alteration of biomass allocation might be a survival strategy for S. spontaneum when exposed to long-term submergence. 参考文献 相似文献 引证文献

Wave attenuation by flexible, idealized salt marsh vegetation

Wave attenuation by vegetation is a highly dynamic process and its quantification is important for understanding shore protection potential and modeling coastal hydrodynamics. Data documenting the interactions of Spartina alterniflora, represented by polyolefin tubing, and single- and double-peaked irregular waves were collected in a large-scale laboratory flume. The laboratory provided a controlled environment to evaluate wave attenuation, including the parameters of stem density, submergence, wave height, and peak period. Wave attenuation appeared to be most dependent on stem density and the ratio of stem length to water depth. Wave attention increased slightly with wave height while no clear trend with respect to wave period was seen. Treating double-peaked spectra as superimposed wave systems revealed a preferential dissipation of the higher-frequency wave system relative to the lower-frequency wave system under emergent conditions. Wave energy loss occurred at all frequencies of both spectral types, with dissipation increasing with frequency above the spectral peak. Parameterizing the spectral equilibrium range as a function of frequency showed a steepening of the spectral tail compared to the −4 power law under emergent conditions. An empirical relationship defining the bulk drag coefficient for S. alterniflora as a function of the stem Reynolds number is found to serve as a first estimate for engineering applications.

Bryophyte mass to stem length ratio: A potential metric for eco-physiological response to land use

Methods of analysis are needed that quantitatively characterize the response of organisms to anthropogenic disturbance. Herein a method is presented that characterizes bryophyte morphological variability in response to timber harvest treatments (clearcut and partial cut). Samples (n = 6196) of the semi-aquatic bryophyte Brachythecium frigidum were collected from clearcut, partial cut and full forest stream reaches between August 2003 and October 2005 and analyzed to obtain mass to stem length ratios (M:SL). Results show that relative to a full forest (i.e. full canopy cover condition), average M:SL ratios were reduced approximately 18% in the partial cut and 37% in the clearcut, indicating a decrease in biomass per unit stem length with increasing harvest intensities. Increased light intensities and higher air temperatures resulting from decreased canopy cover in the harvest treatments corresponded to lower M:SL ratios (0.31 and 0.24 for the partial cut and clearcut, respectively). Results quantify the morphological response of B. frigidum to habitat perturbation, thereby validating the method as a useful assessment of anthropogenic disturbance in post-timber harvest environments. Additional work should be conducted to test the method in other physiographic regions and to isolate bryophyte response to alterations of distinct environmental variables.

Relative Importance of Modularity and Other Morphological Attributes on Different Types of Lithic Point Weapons: Assessing Functional Variations

The specific using of different prehistoric weapons is mainly determined by its physical properties, which provide a relative advantage or disadvantage to perform a given, particular function. Since these physical properties are integrated to accomplish that function, examining design variables and their pattern of integration or modularity is of interest to estimate the past function of a point. Here we analyze a composite sample of lithic points from southern Patagonia likely formed by arrows, thrown spears and hand-held points to test if they can be viewed as a two-module system formed by the blade and the stem, and to evaluate the degree in which shape, size, asymmetry, blade: stem length ratio, and tip angle explain the observed variance and differentiation among points supposedly aimed to accomplish different functions. To do so we performed a geometric morphometric analysis on 118 lithic points, departing from 24 two-dimensional landmark and semi landmarks placed on the point's contour. Klingenberg's covariational modularity tests were used to evaluate different modularity hypotheses, and a composite PCA including shape, size, asymmetry, blade: stem length ratio, and tip angle was used to estimate the importance of each attribute to explaining variation patterns. Results show that the blade and the stem can be seen as “near decomposable units” in the points integrating the studied sample. However, this modular pattern changes after removing the effects of reduction. Indeed, a resharpened point tends to show a tip/rest of the point modular pattern. The composite PCA analyses evidenced three different patterns of morphometric attributes compatible with arrows, thrown spears, and hand-held tools. Interestingly, when analyzed independently, these groups show differences in their modular organization. Our results indicate that stone tools can be approached as flexible designs, characterized by a composite set of interacting morphometric attributes, and evolving on a modular way.

Stem Architectural Effect on Leaf Size, Leaf Number, and Leaf Mass Fraction in Plant Twigs of Woody Species

This study is to examine the effect of stem architecture on biomass allocation between leaf and stem and between leaf size and number in plant twigs of woody species. We investigated leaf size, leaf number, stem length, stem diameter, and mass for 282 woody species of subtropical evergreen broad‐leaved forests in southwest China. Both stem diameter and stem length were positively correlated with individual leaf mass and area but were negatively associated with leaf number per unit stem mass and leaf number per stem length. This suggests that these stem architecture traits can be a physiological mechanism underlying the leaf size versus leaf number trade‐off. The ratio of stem length to stem diameter (LDR) was negatively correlated with leaf size and leaf number per stem length, due to the difference in the strength of the effects of stem length and stem diameter on leaf size and leaf number. Similarly, both stem diameter and stem length were positively correlated with leaf mass and stem mass. LDR was negatively correlated with leaf biomass fraction (the ratio of leaf mass to twig mass), due to the difference in the strength of the effect of stem length and stem diameter on leaf mass and stem mass. This indicates that stem architecture can significantly influence biomass allocation between leaf and stem. These relationships were generally strong when expressed as correlated evolutionary divergences. In addition, LDR was generally larger in the high‐rainfall habitat than in the low‐rainfall site. Accordingly, LDR can be regarded as a functional trait and an important component of the leading dimension of leaf size–twig size spectrum in plants.

RESPONSE OF TOMATO TRANSPLANT TO NITRATE PHOSPHATE CONDITIONING: EFFECTS ON DEVELOPMENT, GROWTH AND EARLY YIELD

RESPONSE OF TOMATO TRANSPLANT TO NITRATE PHOSPHATE CONDITIONING: EFFECTS ON DEVELOPMENT, GROWTH AND EARLY YIELD

Structural variation in current-year shoots of broad-leaved evergreen tree saplings under forest canopies in warm temperate Japan

Stem length and leaf area of current-year shoots were measured in saplings of eight broad-leaved evergreen tree species growing under a forest canopy. Stem length varied over a range of one to two orders of magnitude within each species. In all species, both the number of leaves and the mean stem length between successive leaves were greater in longer shoots. Mean leaf size and stem length were not correlated in six of eight species, and only weakly positively correlated in the other two species. Thus, total leaf area per stem increased with stem length, but not in direct proportion: leaf area per stem length was smaller in shoots with long stems and larger in shoots with short stems. I conclude that the within-species variation in the leaf-stem balance of current-year shoots is related to variation in shoot functional roles, as has been observed for long and short shoots in many deciduous tree species: shoots with long stems are extension oriented and contribute to the framework of the crown, whereas shoots with short stems serve mainly for leaf display. Among species, large differences were found in the leaf area per stem length ratio. In the species with larger leaf area per stem length ratios, leaves had narrower blades or longer petioles, or both, resulting in a reduction of mutual shading among the leaves on the shoot.

Stem swelling of stem mustard, as affected by temperature and growth regulators

Changes in the levels of zeation + zeatin ribosides (ZRs) and indole acetic acid (IAA) were determined in plants grown either in the greenhouse (25°C constant temperature) or in a tunnel (ambient temperature, 4–15°C) from the beginning of stem swelling until harvest. The plant fresh weight (FW) was lower at 25°C than at ambient temperature, stem swelling was almost completely suppressed and levels of ZRs and IAA were lower. Under ambient temperature, stem swelling occurred and ZRs and IAA levels were higher in both leaves and stem. At the end of the experiment, plants at high temperature had a long stem, tended to bolting, and the ratio of stem length to diameter was 4.1. Plants at ambient temperature formed a swollen stem, with a stem length diameter ratio of 0.8. Microcuttings were cultured in Murashige and Skoog (MS) media containing various concentrations (1–5 mg 1 −1) of 6-benzylaminopurine (BA) and α-naphthaleneacetic acid (NAA). The stem diameter of microcuttings was significantly promoted by BA in the absence of NAA. Addition of NAA counteracted stimulatory effect of BA on stem diameter. NAA increased the stem length of microcuttings more than BA. The promotive effect of NAA on the stem length was counteracted by BA supplement to the medium.