scholarly journals Size-Dependent Flowering in relation to Grazing in a Short-Lived Monocarpic Perennial

2014 ◽  
Vol 2014 ◽  
pp. 1-7
Author(s):  
Diana E. Marco ◽  
Jonathan Silvertown
Keyword(s):  
Generation Time ◽  
Growing Season ◽  
Vegetative Period ◽  
Relative Growth ◽  
Size Dependent ◽  
Size Growth ◽  
Monocarpic Perennial ◽  
Winter Grazing ◽  
Flowering Probability ◽  
Seasonal Grazing

In short-lived monocarpic perennials flowering probability depends on size and relative growth. Reproducing at a smaller size results in a higher prereproductive survival and shorter generation time but also may lead to lower fecundity. Conversely, reproducing at a larger size allows greater fecundity but leads to higher mortality during the prolonged vegetative period. Herbivory may influence the above described relationships via alterations in size at reproduction and survival. Here we use field data to explore in detail the reproduction of the short-lived monocarpic perennial C. vulgare under seasonal grazing. Vegetative plants were marked in paddocks with and without winter grazing, and their size, growth, and flowering status were recorded during a growing season in a field grazing experiment. Grazing increased both survival of vegetative plants and flowering probability, but it did not affect flowering size. The increase in flowering probability is a result of differential plant growth and size and may be related to greater resource availability, including light (necessary for flowering induction in C. vulgare) in grazed paddocks.

scholarly journals Seed mass effects on germination and growth of diverse European Scots pine populations

1994 ◽  
Vol 24 (2) ◽  
pp. 306-320 ◽  
Author(s):  
P.B. Reich ◽  
J. Oleksyn ◽  
M.G. Tjoelker
Keyword(s):  
Growth Rate ◽  
Relative Growth Rate ◽  
Scots Pine ◽  
Field Experiments ◽  
Seed Mass ◽  
Growing Season ◽  
Turkish Population ◽  
Dry Mass ◽  
Relative Growth ◽  
Mass Effects

Seedlings of 24 European Scots pine (Pinussylvestris L.) populations were grown in controlled environment chambers under simulated photoperiodic conditions of 50 and 60°N latitude to evaluate the effect of seed mass on germination and seedling growth characteristics. Seeds of each population were classified into 1-mg mass classes, and the four classes per population with the highest frequencies were used. Photoperiod had minimal influence on seed mass effects. Overall, seed mass was positively related to the number of cotyledons and hypocotyl height. Populations differed significantly in seed mass effect on biomass. In northern populations (55–61°N), dry mass at the end of the first growing season was little affected by seed mass. However, dry mass in 9 of 15 central populations (54–48°N) and all southern (<45°N) populations correlated positively with seed mass. Relative growth rate was not related to seed mass within or across populations, and thus early growth is largely determined by seed mass. Relative growth rate also did not differ among populations, except for a geographically isolated Turkish population with the highest seed mass and lowest relative growth rate. After one growing season, height was positively correlated (r2 > 0.6) with seed mass in 15 populations. To check the duration of seed mass effects, height growth of 1- to 7-year-old field experiments established with the same seed lots were compared. Seed mass effects on height were strongest for 1-year-old seedlings and declined or disappeared by the age of 5–7 years among central and southern populations, but remained stable over that time in northern populations.

Growth and Development of Organic Arsenical-Susceptible and -Resistant Common Cocklebur (Xanthium strumarium) Biotypes Under Noncompetitive Conditions

1994 ◽  
Vol 8 (1) ◽  
pp. 154-158 ◽  
Author(s):  
William E. Haigler ◽  
Billy J. Gossett ◽  
James R. Harris ◽  
Joe E. Toler
Keyword(s):  
Growth Rate ◽  
Leaf Area ◽  
Plant Height ◽  
Growth And Development ◽  
Reproductive Potential ◽  
Dry Weight ◽  
Growing Season ◽  
Xanthium Strumarium ◽  
Relative Growth ◽  
Growth Development

The growth, development, and reproductive potential of several populations of organic arsenical-susceptible (S) and -resistant (R) common cocklebur biotypes were compared under noncompetitive field conditions. Plant height, leaf area, aboveground dry weights, and relative growth rate (RGR) were measured periodically during the growing season. Days to flowering, bur dry weight, and number of burs per plant were also recorded. Arsenical S- and R-biotypes were similar in all measured parameters of growth, development, and reproductive potential. Populations within each biotype varied occasionally in plant height, leaf area, aboveground dry weights, and reproductive potential.

Conventional and molecular genetic analysis of factors contributing to variation in the timing of heading among spring barley (Hordeum vulgare L.) genotypes grown over a mild winter growing season

2003 ◽  
Vol 54 (12) ◽  
pp. 1277 ◽  
Author(s):  
W. J. R. Boyd ◽  
C. D. Li ◽  
C. R. Grime ◽  
M. Cakir ◽  
S. Potipibool ◽  
...  
Keyword(s):  
Genetic Analysis ◽  
Spring Barley ◽  
Molecular Genetic ◽  
Phenotypic Expression ◽  
Heading Date ◽  
Growing Season ◽  
Transgressive Segregation ◽  
Molecular Genetic Analysis ◽  
Vegetative Period ◽  
Developmental Variation

Factors contributing to variation in heading date in spring barley were examined in several studies commencing with a survey of developmental variation in a large collection of genotypes and concluding with the molecular genetic analysis of 7 doubled haploid populations. Genotypes varied considerably in their specific responses to photoperiod and vernalisation, and in the duration of a pre-inductive (or juvenile) phase defined in this paper as a 'basic vegetative period'. The latter includes differential genotype responses to ambient temperature and their interaction with photoperiod. Combinations of these largely independent environmental variables account for variation in heading date associated with differences in growing season conditions, particularly geographic region, sowing dates, and cultivar adaptation. Under extended and natural (short) photoperiods, in both summer and winter field plantings, conventional genetic analysis was characterised by simple Mendelian segregation combined with considerable transgressive segregation within distinct early and late flowering subpopulations. Equivalent transgressive segregation characterised molecular genetic analysis that identified 16 quantitative trait loci (QTLs) with contributions ranging from >50% of the variation recorded to <10%. These were dominated by 2 QTLs located on chromosome 2, one of which on 2HS was associated with response to extended photoperiod and the other, located near the centromere, with variation in the duration of the basic vegetative period. As only one population segregated for response to vernalisation, all analyses were restricted to parents and progeny homozygous for no response. Three other QTLs on 1HL, 3HL, and 5HL were primarily associated with vernalised parents and progeny characterised by prostrate seedling growth habits, which questions any assumption of a pleiotrophic association between genes for vernalisation and growth habit.The potential for exploiting markers for selection is considered to be limited by the considerable transgressive segregation observed in lines homozygous for parental alleles, and the limited understanding of the causes of variation in the phenotypic expression of the QTLs identified. Such markers would be useful in the selection of backcrossed progeny and in developing materials for investigating fundamental mechanisms contributing to developmental variation.

Growth and Development of Dinitroaniline-Susceptible and -Resistant Goosegrass (Eleusine indica) Biotypes Under Noncompetitive Conditions

Weed Science ◽  
1986 ◽  
Vol 34 (5) ◽  
pp. 704-710 ◽  
Author(s):  
Tim R. Murphy ◽  
Billy J. Gossett ◽  
Joe E. Toler
Keyword(s):  
Growth And Development ◽  
Growth Parameters ◽  
Flag Leaf ◽  
Dry Weight ◽  
Growing Season ◽  
Leaf Length ◽  
Relative Growth ◽  
Eleusine Indica ◽  
Flag Leaf Length ◽  
Weight Number

A comparative study of the growth and development of several populations of dinitroaniline-susceptible (DS) and -resistant (DR) goosegrass [Eleusine indica(L.) Gaertn. # ELEIN] biotypes was conducted under noncompetitive field conditions. Plant height and width, number of tillers, aboveground dry weight, relative growth rate (RGR), number of inflorescences/plant, total inflorescence dry weight, individual inflorescence dry weight, number of spicate branches/inflorescence, and flag leaf length and width were recorded periodically during the growing season. There were no significant differences between biotypes in most characteristics with the exception of total inflorescence dry weight. The DS biotype produced more total inflorescence dry weight than the DR biotype at 8 and 13 weeks after transplanting. Significant variation among DS and DR populations occurred in 37 and 33 of 56 evaluations, respectively. When variation existed within a biotype, populations exhibited broad ranges of response for the various growth parameters. With the exception of total inflorescence dry weight, DS and DR biotypes generally exhibited similar ranges of variability.

Rapid juvenile development in old forest lichens

Botany ◽  
2011 ◽  
Vol 89 (1) ◽  
pp. 65-72 ◽  
Author(s):  
Per Larsson ◽  
Yngvar Gauslaa
Keyword(s):  
Growth Rates ◽  
Generation Time ◽  
Population Biology ◽  
Limiting Factors ◽  
Noninvasive Method ◽  
Relative Growth ◽  
Relative Growth Rates ◽  
Generation Times ◽  
Young Forests ◽  
Juvenile Development

Generation time and juvenile growth rates are important but poorly known parameters in lichen population biology. By using a noninvasive method, we aimed to quantify these variables in juvenile thalli of Lobaria pulmonaria (L.) Hoffm., L. scrobiculata (Scop.) D.C., and Pseudocyphellaria crocata (L.) Vain., in situ, on twigs of Picea abies (L.) H. Karst in boreal rainforests. Growth was monitored during the summer months (May–August, 106 d), as well as in the remaining part of the year (259 d), for each of two sequential years, by means of repeated photography and imaging analysis. The mean relative thallus-area growth rates were 0.53 ± 0.02, 0.41 ± 0.02, and 0.57 ± 0.04 mm2·mm–2·year–1 (mean ±SE), respectively, in the three species, equivalent to a yearly growth of 101 ± 5%, 70 ± 6%, and 121 ± 12%. Growth was much slower during the winter (0.09–0.12 mm2·cm–2·d–1) than in summer (0.19–0.27 mm2·cm–2·d–1). Relative growth rates significantly declined with increasing thallus size. Estimated generation times in L. scrobiculata and P. crocata, based upon the first observed formation of reproductive structures, were 15–22 and 9–13 years, respectively. Studied L. pulmonaria thalli produced no diaspores during the experiment, consistent with a generation time >17 years. The relative growth rates we measured and our estimated generation times are faster than those earlier recorded. Thus, our noninvasive method can estimate parameters needed to model population growth within a reasonable period of time. The rapid juvenile development implies that the growth rates and generation times are unlikely to be the limiting factors that exclude these lichens from young forests.

Water Relations of Beans I. Effects of Water Stress on Growth and Flowering

1969 ◽  
Vol 5 (3) ◽  
pp. 195-207 ◽  
Author(s):  
A. H. El Nadi
Keyword(s):  
Growth Rate ◽  
High Temperature ◽  
Water Stress ◽  
Plant Growth ◽  
Relative Growth Rate ◽  
Broad Bean ◽  
Day Length ◽  
Vegetative Period ◽  
Relative Growth ◽  
Made In

SummaryExperiments were made in glasshouses, growth cabinets and growth rooms to study the differential responses of the broad bean to water stress during the vegetative and flowering phases of growth. Plants in the flowering phase proved to be more sensitive to drought than in the vegetative period, and there were different responses (Relative Growth Rate) to temperature at different stages of plant growth. Day length and temperature influenced the position of the earliest flower initials on the stem, and intensity of flower shedding was aggravated by high temperature.

Carbon and nitrogen allocation patterns of Douglas-fir seedlings fertilized with nitrogen in autumn. II. Field performance

1986 ◽  
Vol 16 (5) ◽  
pp. 903-909 ◽  
Author(s):  
H. A. Margolis ◽  
R. H. Waring
Keyword(s):  
Free Amino ◽  
Shoot Growth ◽  
Field Performance ◽  
Growing Season ◽  
Frost Damage ◽  
Douglas Fir ◽  
Summer Drought ◽  
Tree Roots ◽  
Relative Growth ◽  
Relative Growth Rates

October-fertilized and unfertilized 2-0 Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) seedlings were outplanted the following February. Half of each planting block was seeded with grass to induce water stress during the typical summer drought. Sucrose was applied to soil around each seedling to limit availability of nitrogen to tree roots. Fertilized seedlings broke bud 9–10 days earlier, produced more shoot growth, and, as shown in later harvests, had higher relative growth rates than unfertilized seedlings. However, initial differences in growth response were due primarily to the earlier budbreak. Seedlings growing with grass had predawn water potentials of −1.5 MPa by early August; by September 3, unfertilized seedlings growing with grass were significantly more stressed than any others. Although free amino acid and total nitrogen concentrations were higher in fertilized than unfertilized seedlings when planted, they became equal by the end of one growing season. However, fertilized seedlings contained more free amino acids and nitrogen because of their greater size. Grass competition affected both seedling nitrogen and carbohydrate chemistry. After one growing season, fertilized seedlings had greater height increment, shoot growth, leaf area, relative growth rate, and production per unit nitrogen. Although autumn fertilization benefited these Douglas-fir seedlings, negative effects could result from carbohydrate depletion because of increased respiration or from frost damage because of earlier budbreak.

Response of red alder (Alnus rubra) seedlings to a woolly alder sawfly (Eriocampa ovata) outbreak

1998 ◽  
Vol 28 (4) ◽  
pp. 591-595 ◽  
Author(s):  
John H Markham ◽  
C P Chanway
Keyword(s):  
Growth Rate ◽  
Positive Relationship ◽  
Negative Relationship ◽  
Growing Season ◽  
High Elevation ◽  
Alnus Rubra ◽  
Herbivore Damage ◽  
Red Alder ◽  
Relative Growth ◽  
High Degree

We monitored the effect of an outbreak of Eriocampa ovata L.on experimental Alnus rubra Bong. seedlings during the year of the outbreak (1993) and the following growing season. Seedlings planted on low-elevation sites had significantly more of their leaves damaged (>50% per tree) than plants on high-elevation sites (<25% per tree), with significant differences between low-elevation sites during the year of the outbreak. There was a positive relationship between the amount of herbivore damage and plant relative growth rate early in the growing season and a negative relationship by August. This suggests that the sawflies attacked the largest and fastest growing plants, reducing their growth by midsummer. Plants with the highest degree of herbivore damage were the largest by the end of the growing season with no effects on plant growth the following year. Leaves from plants that had previously been defoliated were less palatable to E. ovata in 1994, but plants with a high degree of herbivore damage in 1994 were likely plants that had a high degree of damage in 1993.

scholarly journals Adaptation of silage maize varieties under extreme northern growing condions in Finland

1979 ◽  
Vol 51 (1) ◽  
pp. 197-209
Author(s):  
Seppo Pulli ◽  
P. M. A. Tigerstedt ◽  
Osmo Kara
Keyword(s):  
Weather Conditions ◽  
Growing Season ◽  
Limiting Factor ◽  
Vegetative Period ◽  
Average Temperature ◽  
Silage Maize ◽  
Maize Varieties ◽  
Growing Conditions ◽  
The University

Trials with maize varieties from various places in the world were started in 1975. In preliminary trials in 1975, 280 varieties were tested. Between 19 and 23 varieties were selected for ordinary variety tests in 1976—78 at the University farm in Siuntio. Weather conditions, particularly average daily temperatures in 1975 were better than the long term averages, and in 1976—78 far below the average growing conditions. Dry matter yields of the seven harvested silage varieties in 1975 varied between 5.8 and 11.5 tons/ha. In 1976—78 the variation in DM yields was 3.8—8.0 tons/ha among 19—23 varieties. In 1975, 44 varieties out of 280 produced mature seed. Only one variety matured in 1978, but none in 1976—77. The developmental stage of silage maize is primarily determined by ear percentage and secondarily by DM %. In 1975 the average ear % of seven varieties was 49.1 %, in 1978 18.1 % and in 1976—77 only 4.0—5.7 % in DM. As a result of the variety tests promising varieties from Yugoslavia, France and Germany could be found. It can be concluded from the long term temperature data that with very early hybrid varieties a mature grain yield can be harvested twice in ten years. Good quality silage material can be harvested six times in ten years and a satisfactory crop can be obtained eight times in then years. The limiting factor for the growth and development of maize in Finland is the low average temperature of the growing season. Important but less significant is the length of the vegetative period, which is determined by the first killing frost in the fall. The temperature deficit is particularly critical at the beginning of the growing season.

scholarly journals Intensity of grass stand formation on simulation models of pastures for different seasons of use

2020 ◽  
Vol 202 (11) ◽  
pp. 37-44
Author(s):  
S. Turko ◽  
K. Trubakova
Keyword(s):  
Plant Growth ◽  
Plant Height ◽  
Simulation Models ◽  
Growing Season ◽  
Specific Rate ◽  
Main Role ◽  
Average Growth ◽  
Vegetative Period ◽  
Grass Stand ◽  
The Relationship

Abstract. The purpose of the research is to substantiate the relationship between the parameter of the greatest growth of plants with a specific rate of grazing of animals on pasture. It is necessary to solve problems with the intensity of animal grazing, and also to establish, according to the data, a statistical relationship between the parameters of the logistic equation that describes the average statistical growth of plants on natural pastures. Research methods. The experiments were carried out at the research sites of the lysimetric complex of the FSC of Agroecology RAS with various soil substrates (Kumskiy sand, Bazhiganskiy sand, chernozem-like sandy loam substrate). Sowing mixtures of multicomponent herbs of the Stavropol selection was performed for further analysis of plant growth and development, taking into account the different season of use. Results. The article presents the equation of the course of growth of the grass stand for the growing season, which proves that even after the removal of part of the phytomass, the plant growth law is preserved according to the principle of the sigmoid curve. The maximum plant height after simulating phytomass etching was recorded on a lysimeter No. 6 and averaged: with phytomass removal of ⅓ – 121 cm, ½ – 97 cm, ⅔ – 61 cm. The smallest average plant height was noted on lysimeter No. 13 – 64 cm. The highest height on this lysimeter was 110 cm with ⅓ removal. The average growth at the end of the growing season of plants for all simulation models was distributed as follows: with the withdrawal of 33 % – 73 %; 50 % – 53 %; 67 % – 31 %. The experiments showed that it is not recommended to remove more than ⅓ of the plant phytomass. The main role is played by the rate of phytomass removal (grazing rate) for the stable restoration of the grass stand of degraded pastures, and it is also necessary to take into account the vegetative period of the plant. Scientific novelty. The relationship between plant growth parameters has been established. It allows you to predict the characteristics of further growth, improve the natural degraded grass stands, establish the sequence of grazing in different areas in accordance with the species composition of plants.

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