scholarly journals How reproductive allocation and flowering probability of individuals in plant populations are affected by position in stand size hierarchy, plant size and CO2 regime

2008 ◽  
Vol 1 (4) ◽  
pp. 207-215 ◽  
Author(s):  
C. Brophy ◽  
D. J. Gibson ◽  
P. M. Wayne ◽  
J. Connolly
Keyword(s):  
Plant Size ◽  
Reproductive Allocation ◽  
Plant Populations ◽  
Size Hierarchy ◽  
Flowering Probability

scholarly journals Size-dependent allocation of biomass to ancillary versus flowers of the inflorescences of the epiphyte Tillandsia stricta Soland (Bromeliaceae)

2009 ◽  
Vol 23 (1) ◽  
pp. 130-135 ◽  
Author(s):  
André Mantovani ◽  
Ricardo Rios Iglesias
Keyword(s):  
Leaf Area ◽  
Plant Species ◽  
Vegetative Growth ◽  
Reproductive Investment ◽  
Plant Size ◽  
Reproductive Allocation ◽  
Heterogeneous Environment ◽  
Plant Resources ◽  
Total Leaf Area ◽  
Size Dependent

The amount of resources invested in reproduction is closely correlated to plant size. However, the increase in reproductive investment is not always proportional to the increase in vegetative growth, as the proportion of plant resources allocated to reproduction can increase, decrease or be maintained along different plant sizes. Although comprising thousand of species, epiphytes are poorly studied in relation to reproductive allocation (RA). We describe the variation in the RA of the epiphytic bromeliad Tillandsia stricta Soland with increasing plant sizes. Our goal is not only to evaluate the RA of the whole inflorescence but also quantify the contribution of ancillary structures in the final RA of this plant species. With increasing sizes of T. stricta the reproductive allocation of biomass to the whole inflorescence decreased significantly along plant sizes from 37% to 12%. Reproductive allocation to ancillary and to flowers decreased respectively from 30% to 9% and 10% to 3%. As leaves are the main source of water and nutrients absorption in atmospheric Tillandsia, the total leaf area and area per leaf were used as indicators of foraging capacity, that also increased with plant size. We discuss these results with respect to the capacity of T. stricta to reproduce in the heterogeneous environment of the canopies.

Is reproductive allocation in Senecio vulgaris plastic?

Botany ◽  
2009 ◽  
Vol 87 (5) ◽  
pp. 475-481 ◽  
Author(s):  
Jacob Weiner ◽  
Lars Rosenmeier ◽  
Emma Soy Massoni ◽  
Josep Nogués Vera ◽  
Eva Hernández Plaza ◽  
...  
Keyword(s):  
Reproductive Output ◽  
Plant Biomass ◽  
Seed Mass ◽  
Plant Size ◽  
Reproductive Allocation ◽  
Life Cycles ◽  
Nutrient Level ◽  
Significant Shift ◽  
Senecio Vulgaris ◽  
The Relationship

Several purported cases of plasticity in plant allocation patterns appear to be the effects of size and allometric growth (“apparent plasticity”). To ask whether there is true plasticity (i.e., a change in the allometric trajectory) in reproductive allocation in Senecio vulgaris  L., we grew S. vulgaris plants at high and low levels of water, nutrients, and competition, and analyzed the relationship between vegetative and seed biomass. Plant size was the major determinant of reproductive output, accounting for 83% of the variation in log (seed mass). There were also significant effects of the treatments that were not due to size, accounting for an additional 9% of the variation. The treatments affected the allometric coefficient (intercept), not the allometric exponent (slope) of the relationship, reflecting a small but significant shift in the efficiency of conversion of total plant biomass into reproductive biomass. In a second experiment, we grew S. vulgaris plants at three nutrient levels and allowed all individuals to complete their life cycles. Again, nutrient level had a small but significant effect on the allometric coefficient. Plasticity in reproductive allocation exists, but is very limited. The primary effects of the environment on the reproductive output of S. vulgaris occur via plant size.

Plant-size and fruit-position effects on reproductive allocation in Alliaria petiolata (Brassicaceae)

2000 ◽  
Vol 78 (11) ◽  
pp. 1398-1407 ◽  
Author(s):  
David J Susko ◽  
Lesley Lovett-Doust
Keyword(s):  
Seed Mass ◽  
Maternal Investment ◽  
Plant Size ◽  
Dry Mass ◽  
Reproductive Allocation ◽  
Alliaria Petiolata ◽  
Position Effects ◽  
Threshold Size ◽  
Linear Relationships ◽  
Total Seed

We examined the development of ovules and components of reproductive yield as they related to plant size and fruit position within plants of Alliaria petiolata (M. Bieb.) Cavara and Grande from three sites. We found that both factors affected fruit and seed production, and patterns of ovule fate. Larger plants were more fecund than their smaller counterparts, while proximally positioned flowers within an inflorescence produced more seeds. Maternal investment was regulated according to plant mass at two levels: among fruits (small plants had significantly lower fruit-set than did large plants), and within fruits (small plants had significantly fewer ovules and significantly higher proportions of aborted ovules per fruit than did large plants). All absolute measures of reproduction had positive linear relationships with plant size, but a threshold size for flowering was not found. Most proportional measures of reproduction were independent of plant size. Small plants produced the same relative proportions of total seed number and total seed mass per unit plant dry mass as large plants. Therefore, proportional reproductive allocation did not vary with plant size. However, small plants produced proportionately more flowers per unit dry mass. Small plants may be maximizing their overall fitness through increased allocation to male function (flower production).Key words: Alliaria petiolata, plant-size effects, fruit-position effects, reproductive allocation, patterns of ovule abortion, seed maturation.

scholarly journals 281 Impact of Plant Population, Nitrogen, and Variety on Early Fresh-market Sweet Corn Quality

HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 439E-440
Author(s):  
Anusuya Rangarajan ◽  
Betsy A. Ingall ◽  
Michael S. Orfanedes
Keyword(s):  
New York ◽  
Sweet Corn ◽  
Plant Stress ◽  
Plant Size ◽  
Early Spring ◽  
Plant Population ◽  
Fresh Market ◽  
Plant Populations ◽  
Upstate New York ◽  
Cool Conditions

Early fresh-market sweet corn expressed concern is prone to variability in ear length and quality due to uneven germination rates in cooler soils, smaller plant size of early corn, and single ear per stalk trait of early varieties. In an informal survey of current practices, growers reported using in-row spacings between 0.5 and 0.25 m (0.76 m between rows) for their first bare-ground corn, representing a range of plant populations from 86,000 to 43,000 plants/ha. However, no information had been gathered on the impacts of these various in-row spacings on early corn ear length and overall quality and how different sweet corn types (se, sh2, sweet breeds) might respond to these spacings under cool conditions of early spring. Four trials were conducted over the last 2 years, in upstate New York, examining three sweet corn types, five plant populations, and two nitrogen sidedress rates for effect ear length, quality, and uniformity. In general, results thus far indicate that all three parameters can influence ear quality and variability. Among treatments, ear length varied by up to 1 cm. The variety `Sweet Symphony' was less affected by high populations than `Temptation'. In 1998, no difference in ear length due to spacing was found. It is suspected that the warm spring in 1998, coupled with adequate moisture, reduced plant stress during early growth. Higher nitrogen sidedress rates reduced variability of early season corn, at all populations. In 1999, plant population was found to be the most important factor affecting ear physical characteristics.

Frequency distribution of shoot weight of plants in populations ofTrifolium repenspersisting by clonal growth in grazed pastures

1990 ◽  
Vol 115 (1) ◽  
pp. 41-47 ◽  
Author(s):  
M. J. M. Hay ◽  
V. J. Thomas ◽  
J. L. Brock
Keyword(s):  
Gini Coefficient ◽  
White Clover ◽  
Clonal Growth ◽  
Dry Weight ◽  
Plant Size ◽  
Size Hierarchy ◽  
Gini Coefficients ◽  
Shoot Dry Weight ◽  
The Gini Coefficient ◽  
Variable Nature

SUMMARYOver two years (1984/85 and 1986/87), monthly sampling of shoots of white clover plants compared the populations of white clover in mixed swards at Palmerston North, New Zealand, under set stocking, rotational grazing and a combination of both systems, at a common stocking rate of 22·5 ewe equivalents/ha.The frequency distributions of shoot (or stolon) dry weight per plant in each population over the study period was described by a log-normal model, which indicated that the populations consisted of many small individuals and few large individuals. Such inequality of shoot dry weight within populations is commonly termed size hierarchy; a statistic giving a measure of such size hierarchy is the Gini coefficient. The populations under different managements had similar Gini coefficients which differed little among seasons or between years. Lack of significant correlation between the Gini coefficient and mean shoot dry weight per plant of each population indicated that, in these white clover populations, size hierarchy was independent of mean plant size.These results were considered in relation to the clonal growth of white clover in grazed swards and it is suggested that the variable nature of death of older basal stolons makes an important contribution to the variability in size of individual plants and hence to size hierarchy. As size hierarchy, as assessed by Gini coefficients, was relatively stable in these populations over 3½ years, it appears that clonal growth of white clover incorporates sufficient variability within the growth and death processes at the individual plant level to maintain the size hierarchy, irrespective of variations in mean plant size of populations.

Seed yield and biomass allocation in Sorghum bicolor and F1 and backcross generations of S. bicolor × S. halepense hybrids

1994 ◽  
Vol 72 (4) ◽  
pp. 468-474 ◽  
Author(s):  
Jon K. Piper ◽  
Peter A. Kulakow
Keyword(s):  
Sorghum Bicolor ◽  
Seed Yield ◽  
Block Design ◽  
Seed Mass ◽  
Plant Size ◽  
Reproductive Allocation ◽  
Total Biomass ◽  
Plant Parts ◽  
Perennial Grains ◽  
High Seed Yield

The Land Institute is developing perennial grains to be grown in prairie-like mixtures. One approach involves the development of a perennial grain sorghum by crossing tetraploid Sorghum bicolor with wild S. halepense to combine high seed yield with overwintering ability via rhizome production. We grew tetraploid S. bicolor, F1 hybrid (BC0), and two backcross generations (BC1 and BC2) in a randomized block design to examine total biomass, seed yield, and allocation to plant parts within and across generations. Root, rhizome, stem and leaf, and total biomass decreased from the BC0 to BC2 to S. bicolor generations, whereas panicle mass, seed mass, and reproductive allocation were lowest in the BC0 generation (p < 0.05, ANOVA). Mean seed mass (g ∙ plant−1) was 39.1 in the BC0, 107.3 in the BC1, 84.1 in the BC2, and 92.7 for the S. bicolor parent, which translated into yields of 171.9, 471.6, 396.7, and 407.5 g ∙ m−2, respectively. Reproductive allocation varied from 14.7% in BC0 to 28.9% in BC2 compared with 33.5% in S. bicolor. Mean allocation to rhizomes was 2.71% in BC0 but negligible in BC1 and BC2. There was no relationship between rhizome mass and seed mass within any generation, but there was a positive correlation between total plant mass and rhizome mass in BC0. We divided the BC0 population into four groups with respect to rhizome production and found no significant differences among the groups in plant size or seed yield. Within each generation, reproductive allocation was inversely related to culm mass. The lack of an apparent trade-off between allocation to rhizome versus allocation to seed within any generation supports the possibility of combining within a population high seed yield and production of perennating belowground organs. Key words: backcross, hybrid, perennial grains, reproductive allocation, rhizome, seed mass, Sorghum bicolor, Sorghum halepense.

Problems of population structure exemplified by the invasive tropical shrub Parkinsonia aculeata l. in northern Australia

2004 ◽  
Vol 26 (2) ◽  
pp. 237 ◽  
Author(s):  
A. C. Grice ◽  
S. D. Campbell ◽  
J. R. McKenzie ◽  
L. V. Whiteman ◽  
M. Pattison ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Plant Size ◽  
Population History ◽  
Above Ground Biomass ◽  
Plant Populations ◽  
Cross Sectional ◽  
Frequency Distributions ◽  
Parkinsonia Aculeata ◽  
Ground Biomass ◽  
Class Frequency

Age-class frequency distributions are valuable means of describing plant populations because they can be used to infer population history. Variables other than age are also often used to describe plant populations, either because they more accurately reflect an attribute of interest, or because it is difficult to determine age. However, interpretation of frequency distributions based on variables other than age can be problematic. We discuss these problems and illustrate them using data from six populations of the invasive rangeland shrub Parkinsonia aculeata L. We used three different measures of plant size: height, canopy diameter and stem cross-sectional area. Structures based on these measures were compared with structures based on three different estimates of above-ground biomass derived from them. For each variable, structures differed greatly between populations, and for each population, they were strongly dependent on the variable used to describe it. Population structures based on three-dimensional variables (above-ground biomass) tend to be more strongly positively skewed than those based on two-dimensional (area) measures of plant size. These in turn are more strongly positively skewed than those based on one-dimensional (height, diameter) measures. The statistical basis of this general phenomenon is discussed. The results highlight the difficulties of deriving histories and projecting futures of populations from size-class frequency distributions without accompanying knowledge of the temporal patterns of change in size variables as plants grow.

scholarly journals Delayed effects of climate on vital rates lead to demographic divergence in Amazonian forest fragments

2021 ◽  
Author(s):  
Eric R Scott ◽  
Emilio Miguel Bruna ◽  
María Uriarte
Keyword(s):  
Amazon Basin ◽  
Life History Stage ◽  
Fragmented Landscape ◽  
Forest Fragments ◽  
Vital Rates ◽  
Climate Data ◽  
Plant Populations ◽  
Delayed Effects ◽  
Continuous Forest ◽  
Flowering Probability

Deforestation often results in landscapes where remaining forest habitat is highly fragmented, with remnants of different sizes embedded in an often highly contrasting matrix. Local extinction of species from individual fragments is common, but the demographic mechanisms underlying these extinctions are poorly understood. It is often hypothesized that altered environmental conditions in fragments drive declines in reproduction, recruitment, or survivorship. The Amazon basin, in addition to experiencing continuing fragmentation, is warming and experiencing changes in precipitation leading to altered frequency and intensity of droughts and unusually wet periods. Whether plant populations in tropical forest fragments are particularly susceptible to extremes in precipitation remains unclear. Most studies of plants in fragments are relatively short (1-6 years), focus on a single life-history stage, and often do not compare to populations in continuous forest. Even fewer studies consider delayed effects of climate on demographic vital rates despite the importance of delayed effects in studies that consider them. Using a decade of demographic and climate data from an experimentally fragmented landscape in the Central Amazon, we assess the effects of climate on populations of an understory herb (Heliconia acuminata, Heliconiaceae). We used distributed lag non-linear models to understand the delayed effects of temperature and precipitation on survival, growth, and flowering. We detected delayed effects of climate up to 36 months. Drought two dry seasons prior to the February census decreased survival and increased flowering probability while drought in the wet season a year prior to the census decreased flowering probability and increased growth. The effects of extremes in precipitation on survival and growth were more pronounced in forest fragments compared to continuous forest. The complex delayed effects of climate and habitat fragmentation in our study point to the importance of long-term demography experiments in understanding the effects of anthropogenic change on plant populations.

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