Biology and control of Reseda lutea L. 1. Seed biology and seedling growth

1997 ◽  
Vol 48 (4) ◽  
pp. 511 ◽  
Author(s):  
J. W. Heap
Keyword(s):  
Seedling Growth ◽  
Control Strategies ◽  
Germination Rate ◽  
South Australia ◽  
Effective Control ◽  
Temperate Climate ◽  
Perennial Weed ◽  
Seed Biology ◽  
Early Seedling ◽  
And Control

Reseda lutea L. is a major perennial weed of alkaline cropping soils in South Australia. Seed biology and early seedling growth of R. lutea were studied in field and laboratory experiments to gain information needed for effective control strategies. Recovery of intact seeds buried for 4 years in the field at 50 and 150 mm was 77–96%. Germination of this seed was 33–63% (50 mm) and 0% (150 mm). Germination patterns differed markedly between seed collected from 2 populations. Seed germinated at all constant and fluctuating temperatures between 10 and 35° C with the maximum (88%) at 25°C constant. Mean temperature, rather than constancy or fluctuation, determined the germination rate. Light strongly inhibited germination. Seedling shoot growth was slow but tap root growth was rapid, reaching 350 mm within 28 days of emergence. Secondary roots arose 3–7 days after emergence and shoot buds formed on the roots within 28 days. R. lutea was found to be well adapted for persistence in cultivated fields with a temperate climate.

scholarly journals Effect of Environmental Factors on Seed Germination and Early Seedling Emergence of Carolina geranium (Geranium carolinianum)

2018 ◽  
Vol 36 ◽  
Author(s):  
X. LIU ◽  
T. ZONG ◽  
Y. LI ◽  
X. ZHOU ◽  
L. BAI
Keyword(s):  
Control Strategies ◽  
Germination Rate ◽  
Seedling Emergence ◽  
Burial Depth ◽  
Invasive Weed ◽  
Temperature Regimes ◽  
Dark Regime ◽  
Early Seedling ◽  
Effects Of Temperature ◽  
And Control

ABSTRACT: Carolina geranium (Geranium carolinianum) is an emerging invasive weed in rape and wheat fields in China. A better understanding of its germination and emergence ecology will enable the development of integrated weed control strategies. In this study, we investigated the effects of temperature, photoperiod, soil water content, salinity, and burial depth, on germination and emergence of Carolina geranium. Germination percentages were over 74% under 15/20 and 20/25 oC night/day temperature regimes. Germination rate was independent of light/dark regime. Increasing salinity reduced germination of Carolina geranium from 81.1% at 0 mM to 0% at 160 mM NaCl. Seeds germination was peaked at 50% soil moisture, but was completely inhibited at < 20% and > 90%. The seedling emergence above 82.2% was observed when seeds were placed at a depth from 0 to 1 cm, and no seedlings emerged from seeds placed at a depth of 7 cm. Current work provide the basic information to effectively prevent and control this invasive weed in Chinese rape and wheat fields.

Seed Fecundity, Persistence, and Germination Biology of Prairie Groundcherry (Physalis hederifolia) in Australia

Weed Science ◽  
2018 ◽  
Vol 67 (1) ◽  
pp. 77-82 ◽  
Author(s):  
Hanwen Wu ◽  
Rex Stanton ◽  
Deirdre Lemerle
Keyword(s):  
Seed Germination ◽  
Management Practices ◽  
Effective Control ◽  
Perennial Weed ◽  
Effective Strategies ◽  
Seed Biology ◽  
Temperature Regimes ◽  
Plant Fecundity ◽  
Soil Seedbank ◽  
Viable Seeds

AbstractPrairie groundcherry [Physalis hederifolia(A. Gray) var.fendleri(A. Gray) Cronquist] is an invasive perennial weed with the potential to become a significant summer weed across 409 million hectares in Australia. Current management practices do not provide effective control of established populations. A better understanding of the seed biology is needed to effectively manage this weed. A series of field and laboratory studies were conducted to determine plant fecundity, soil seedbank longevity, and the factors that affect seed germination.Physalis hederifoliahas the capacity to produce 66 to 86 berries plant−1, 51 to 74 seeds berry−1, and approximately 4,500 seeds plant−1, with the seeds potentially able to persist in the soil seedbank for 20 yr if buried in an intact dry berry pod. The bare-seed component of the soil seedbank can be virtually exhausted within 3 yr if cultivation is minimized to avoid burial of seed. Optimal temperature for germination is diurnal fluctuations of 15 C within the temperature range of 10 and 30 C. Increasing osmotic stress levels reduced the germination under all temperature regimes, with less than 6% germination occurring at −0.96 MPa.Physalis hederifoliaseed germination was not significantly affected by substrate pH 4 to 10 or salt levels less than 160 mM, while the germination was significantly reduced at NaCl concentrations above 160 mM. These results suggest thatP. hederifoliacan adapt to a range of substrate conditions. Stopping seed set, avoiding grazing plants with viable seeds, and minimizing seed burial in the soil are some effective strategies to control this weed.

EARLY IDENTIFICATION OF SALT TOLERANT GENOTYPES OF RICE (ORYZA SATIVA L.) USING CONTROLLED DETERIORATION

2006 ◽  
Vol 42 (1) ◽  
pp. 65-77 ◽  
Author(s):  
M. Z. ALAM ◽  
T. STUCHBURY ◽  
ROBERT E. L. NAYLOR
Keyword(s):  
Seedling Growth ◽  
Seed Quality ◽  
Oryza Sativa L ◽  
Germination Rate ◽  
Seed Vigour ◽  
Early Seedling Growth ◽  
Early Seedling ◽  
Controlled Deterioration ◽  
Rice Genotypes ◽  
Initial Seed

The response of germination and early seedling growth to levels of salinity (0, 50, 100, 150, 200 and 250 mM NaCl) were examined in single seed lots of ten modern rice genotypes. Unaged and deteriorated rice seeds were germinated in rolled paper towels and in Petri dishes. Initial seed quality, final germination, germination rate and early seedling growth were assessed. The samples of the rice genotypes differed in their initial seed quality (measured in terms of Ki). The effect of deterioration varied depending upon the initial seed quality and the severity of the treatment imposed. Ageing (using the technique of controlled deterioration, CD) for up to 24 h had no effect on final germination levels. Although CD for 30 h only reduced final germination slightly, ageing for 36 or 48 h reduced it greatly. Controlled deterioration for 36 h or longer reduced the final length and the rate of extension of both the plumule and radicle. Combining information about germination in salt solution with that about seed quality enabled a distinction to be made between varieties which performed poorly because they were genetically salt-susceptible from those which germinated poorly due to poor seed quality. It is argued that the seed vigour of seed lots used in genotype evaluation should be assessed in order to avoid discarding potentially useful genotypes because of poor physiological seed quality.

scholarly journals ​Influence of Temperature and Salinity Stress on Seed Germination and Seedling Growth of Soybean (Glycine max L.)

2021 ◽  
Author(s):  
Mustafa Çirka ◽  
Ali Rahmi Kaya ◽  
Tamer Eryiğit
Keyword(s):  
Seed Germination ◽  
Seedling Growth ◽  
Germination Rate ◽  
Petri Dish ◽  
Negative Effects ◽  
Randomized Design ◽  
Salt Level ◽  
Glycine Max L ◽  
Early Seedling ◽  
Lower Temperature

Background: The high salt level of a germinating environment can lead to reduced, delayed, and even complete inhibition of germination and seeding growth due to osmotic action and/or ion toxicity. Based on this viewpoint, the aim of this study was to investigate germination temperature and salinity effects on germination and early seedling growth of soybean, which can be sown as first and second crops. Methods: Soybean seeds were subjected to NaCl induced saline germinating media prepared in petri dishes under two different germination temperatures (20±2 and 25±2oC). Thirty sterilized seeds per petri dish were sown in ten salt treatments (0, 100, 150, 250, 750, 1000, 2250, 5000, 7500 and 10000 ppm NaCl L-1). The study was carried out according to the completely randomized design with four replications. Result: Lower temperature promoted seed germination, while the high temperature significantly inhibited the seed germination at all NaCl doses tested. As a result, 25oC temperatures, which can only be measured at the time of the second sowing, have been found to negatively affect germination and also increase the negative effects of salt. Due to the moderate tolerance of soybeans to salt stress, the germination rate was positively affected up to 750 ppm NaCl L-1 dose and resulted in severe reductions in subsequent doses. Also, the tolerance of soybean was negatively influenced by the interaction of temperature and NaCl concentration.

Trajectory control of a mobile manipulator in the presence of base disturbance

SIMULATION ◽  
2018 ◽  
Vol 95 (6) ◽  
pp. 529-543 ◽  
Author(s):  
RV Ram ◽  
PM Pathak ◽  
SJ Junco
Keyword(s):  
Mobile Robot ◽  
Dynamic Models ◽  
Control Strategies ◽  
Effective Control ◽  
Mobile Manipulator ◽  
Dynamic Interactions ◽  
Additional Task ◽  
Manipulator Arm ◽  
And Control ◽  
Base Disturbance

A mobile manipulator is typically an assembly of a mobile robot base and an on-board manipulator arm. As the manipulator arm is mounted over the mobile robot base, the controller has the additional task of taking care of the disturbances of the mobile robot due to the dynamic interactions between the mobile robot base and manipulator arm. In the present work, dynamic models for the manipulator arm and an omni-wheeled mobile robot base were developed separately and then both were combined. Two control strategies, namely only manipulator arm control (OMAC) and simultaneous manipulator and base control (SMBC) were developed for the effective control of tip trajectory. In both strategies, an amnesia recovery coupled with classical proportional integral and derivative (PID) control was used. The bond graph methodology was used for the development of the dynamic model and control for the mobile manipulator. Simulation results are presented to illustrate the efficacy of the two control strategies.

scholarly journals Seed Biology of Lepidium apetalum (Brassicaceae), with Particular Reference to Dormancy and Mucilage Development

Plants ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 333
Author(s):  
Keliang Zhang ◽  
Yin Zhang ◽  
Yusong Ji ◽  
Jeffrey L. Walck ◽  
Jun Tao
Keyword(s):  
Seed Development ◽  
Seedling Growth ◽  
Seed Coat ◽  
Outer Integument ◽  
Effective Control ◽  
Cold Stratification ◽  
Anatomical Changes ◽  
Seed Biology ◽  
Physiological Dormancy

Lepidium apetalum (Brassicaceae) is an annual or biennial weed widely distributed in Asia and Europe. The outer surface of L. apetalum seeds produces a large amount of mucilage. The primary aim of this study was to explore the dormancy characteristics and to determine how mucilage develops. The role of mucilage in water absorption/dehydration, the effects of after-ripening, gibberellin acid (GA3), cold stratification and seed coat scarification on germination, the role of mucilage in germination and seedling growth during drought, and the progress of mucilage production during seed development were investigated. The results indicate that the best temperature regime for germination was 10/20 °C. After-ripening, GA3 and seed coat scarification helped to break dormancy. Light promoted germination. Seedling growth of mucilaged seeds were significantly higher than those of demucilaged seeds at −0.606 and −1.027 MPa. Anatomical changes during seed development showed that mucilage was derived from the outer layer of the outer integument cells. Our findings suggest that seeds of L. apetalum exhibited non-deep physiological dormancy. The dormancy characteristics along with mucilage production give seeds of L. apetalum a competitive advantage over other species, and thus contribute to its potential as a weed. Effective control of this weed can be achieved by deep tillage.

scholarly journals Seed Germination and Early Seedling Growth of Barley at Negative Water Potentials

Agronomy ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 671
Author(s):  
Tim L. Springer ◽  
Dolores W. Mornhinweg
Keyword(s):  
Seed Germination ◽  
Water Potential ◽  
Seedling Growth ◽  
Germination Rate ◽  
Moisture Stress ◽  
Potential Treatment ◽  
Line Treatment ◽  
Plant Materials ◽  
Early Seedling ◽  
Line P

The impacts of climate change may increase the duration and frequency of droughts, which would have deleterious effects on crop establishment. The objectives of this study were to determine the effects of moisture stress on seed germination and seedling growth of six winter barley (Hordeum vulgare) lines and discuss how the data are used to select plant materials for rapid germination. Twenty-five seeds of each line were germinated in water of potentials of −2.0, −1.6, −1.2, −0.8, −0.4, and 0 MPa for 4- and 7-days. The experimental design was a factorial arrangement of treatments (barley lines and water potential treatments) in a randomized block replicated four times and repeated twice. The 4- and 7-day percentage seed germination varied with line (p < 0.01), water potential treatment (p < 0.01), and line × treatment interactions (p < 0.01). The seed germination rate varied with water potential treatment (p < 0.01), and line × treatment interactions (p < 0.01). The data indicated that enough variation was present to effectively select and breed cultivars for improved germination at a negative water potential. Studying seed germination under moisture stress is the first step for developing an effected selection pressure for identifying plant materials with rapid seed germination.

scholarly journals Effects of medical resource capacities and intensities of public mitigation measures on outcomes of COVID-19 outbreaks

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Xia Wang ◽  
Qian Li ◽  
Xiaodan Sun ◽  
Sha He ◽  
Fan Xia ◽  
...  
Keyword(s):  
Prevention And Control ◽  
Control Strategies ◽  
Control Measures ◽  
Mitigation Measures ◽  
Effective Control ◽  
Medical Resource ◽  
Key Factors ◽  
Medical Resources ◽  
Detection Rates ◽  
And Control

Abstract Background The COVID-19 pandemic is complex and is developing in different ways according to the country involved. Methods To identify the key parameters or processes that have the greatest effects on the pandemic and reveal the different progressions of epidemics in different countries, we quantified enhanced control measures and the dynamics of the production and provision of medical resources. We then nested these within a COVID-19 epidemic transmission model, which is parameterized by multi-source data. We obtained rate functions related to the intensity of mitigation measures, the effective reproduction numbers and the timings and durations of runs on medical resources, given differing control measures implemented in various countries. Results Increased detection rates may induce runs on medical resources and prolong their durations, depending on resource availability. Nevertheless, improving the detection rate can effectively and rapidly reduce the mortality rate, even after runs on medical resources. Combinations of multiple prevention and control strategies and timely improvement of abilities to supplement medical resources are key to effective control of the COVID-19 epidemic. A 50% reduction in comprehensive control measures would have led to the cumulative numbers of confirmed cases and deaths exceeding 590,000 and 60,000, respectively, by 27 March 2020 in mainland China. Conclusions Multiple data sources and cross validation of a COVID-19 epidemic model, coupled with a medical resource logistic model, revealed the key factors that affect epidemic progressions and their outbreak patterns in different countries. These key factors are the type of emergency medical response to avoid runs on medical resources, especially improved detection rates, the ability to promote public health measures, and the synergistic effects of combinations of multiple prevention and control strategies. The proposed model can assist health authorities to predict when they will be most in need of hospital beds and equipment such as ventilators, personal protection equipment, drugs, and staff.

scholarly journals The Salinity Effects on Germination and Early Seedling Growth of Bean Plants (Bean Phaseolus)

2020 ◽  
Keyword(s):  
Seedling Growth ◽  
Germination Rate ◽  
Petri Dish ◽  
Normal Weight ◽  
Bean Plant ◽  
Control Group ◽  
Early Seedling Growth ◽  
Bean Plants ◽  
Root And Shoot Length ◽  
Early Seedling

The study was conducted at Dilla University, in the laboratory of Biological sciences to see the effects of salinity on germination and early seedling. Objectives:Background: It is estimated that the world 20% of farming land and 50% of cropland is salt stressed and salinity decreases the germination of seed, retards the growth of plant and so it reduces the yield of crop. Objectives: The major objective of this research was to evaluate the effects of salinity on the germination and early seedling growth of bean plants. Specifically, to investigate salt tolerant efficiency, salt effect on seed germination and its rate and growth of bean plant at different concentration of NaCl. Methodology: The experiment required 21 groups, of which 20 of them were experimental with different salt concentrations ranging from 0.05M to 1.00M with 0.05M difference and one control group. Each group contain three bean seed measuring its weight using electronic balance machine, sterilized with 70% Alcohol solution for 15 seconds, rinsed with distilled water, placed in separate Petri dish using a forceps, 50ml of solution were added to each Petri dish with different concentration, all Petri dishes were covered with lids and kept into incubator at room temperature for 17 days, germinated seed were counted, seedlings root and shoot length were measured using a ruler. Finally, the Bean was transferred to non-saline condition, weight of germinated Bean were measured to compare with their normal weight and to determine the effects of salt on seed weight, which was conducted in triplicates. All necessary data was taken, analyzed and interpreted in the form of percentage, graph, tables and figures. Result: When the concentration of salt increased the Bean plant is extremely affected, germination rate decreased and the terminal weights of seed were become lower than the initial weight due to the absorption of water by seed. Conclusions: The rate of germination decrease when the salt concentration increased and late growth of length of root and shoot when the salt dosage is highest and also the weights of seed reduced as concentration of salt is raised. Generally, as the concentration of salt is increased the Bean plant is extremely affected.

scholarly journals Allelopathic activity of aqueous decomposed leaf litter extracts on the germination and early seedling growth of cowpea (Vigna unguiculata) in Aden, Yemen

2021 ◽  
Vol 10 (2) ◽  
pp. 191-195
Author(s):  
Hana A. Al-Quhbi ◽  
Amna A.I. Saeed ◽  
Abdul Nasser Al-Gifri
Keyword(s):  
Leaf Litter ◽  
Seedling Growth ◽  
Growth Parameters ◽  
Germination Rate ◽  
Germination Percentage ◽  
Allelopathic Effect ◽  
Early Seedling Growth ◽  
Early Seedling ◽  
The Difference ◽  
Radicle Length

Allelopathic effect of Aqueous decomposed leaf litter from four common trees and shrubs in Aden governorate, Yemen was investigated on the germination and early seedling growth of Cowpea, the test crop was subjected to four concentrations of 25, 50, 75 and 100% of the aqueous extract, while a control was maintained at 0% extract level. The study carried out in the laboratory of Botany at Faculty of Education, University of Aden. The Percentage of germination, Germination rate per plate, radicle length, plumule, (hypo and epicotyl lengths) observed. Data was recorded at 24 hours interval after germination for 15 days, the research revealed delayed germination rate per plate and a significant reduction in the radicle length and germination percentage (data was collected on percentage germination; plant height. Results obtained showed that significant reduction in the growth parameters considered at 100% and 75%, while at 50% and 25% the difference was not significant. From the result obtained, it can concluded that Conocarpus lancefolius and Thevetia peruviana possess allelopathic effect that inhibit the germination and early seedling growth of Cowpea, hence at 100% concentration.

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