Sex-specific differences in floral display and resource allocation in Australian alpine dioecious Aciphylla glacialis (Apiaceae)

2000 ◽  
Vol 48 (1) ◽  
pp. 81 ◽  
Author(s):  
Catherine Marina Pickering
Keyword(s):  
Resource Allocation ◽  
Dry Weight ◽  
Large Female ◽  
Floral Display ◽  
Dioecious Species ◽  
Male And Female ◽  
Structural Support ◽  
Allocation Patterns ◽  
Number Of Stems ◽  
Floral Displays

In one of the few dioecious species in the Australian alpine region, Aciphylla glacialis (F.Muell.) Benth. (Apiaceae) flowering and resource allocation patterns were found to differ between males and females, potentially a response to sex-specific selection under the limited conditions for growth and reproduction imposed by the alpine environment. Sex ratios were male biased with approximately 1.49 males to each female in each of five populations of A. glacialis. Male plants had larger floral displays than female plants, producing four times as many flowers per inflorescence and an average of 3.5 inflorescences per plant, compared to 2.9 inflorescences for females. Male and female plants commenced flowering within a few days of each other (average 18 January for males, 19 January for females) but female plants completed flowering earlier, finishing at the end of January, while males were still flowering well into February. Male and female plants did not differ in size as estimated by the number of stems per plant, nor in the proportion of resources allocated to reproduction compared with above ground vegetative structures. However, they did differ in the way resources were allocated to vegetative and floral structures, particularly among larger plants. Large female plants produced heavier stems and infloresences than males. Heavier inflorescences in females may be associated with the need for greater structural support for inflorescences when fruiting, while the increased dry weight of stems may reflect differences in the ways in which the sexes match growth and resource demands for flowering.

scholarly journals Sexual ratio and floral biology of the dioecious Neea theifera Oerst. (Nyctaginaceae) in a cerrado rupestre of central Brazil

2011 ◽  
Vol 25 (4) ◽  
pp. 785-792 ◽  
Author(s):  
Felipe Wanderley Amorim ◽  
Clesnan Mendes-Rodrigues ◽  
Pietro Kiyoshi Maruyama ◽  
Paulo Eugênio Oliveira
Keyword(s):  
Resource Allocation ◽  
Sex Ratio ◽  
Reproductive Biology ◽  
Reproductive Strategy ◽  
Pollen Viability ◽  
Floral Biology ◽  
Pollinator Limitation ◽  
Dioecious Species ◽  
Male And Female ◽  
Pollination Success

Dioecy is characterized by a complete separation of sexual functions on male and female plants. It has evolved many times in flowering plants and is widespread among distinct Angiosperm families. It is viewed as a reproductive strategy to reduce endogamy, and to promote optimal resource allocation between male and female sexual functions. Neea theifera is a common species in Cerrado, neotropical savannas in Brazil, but information regarding its reproductive biology is still incomplete. In order to investigate how environmental conditions possibly affect this dioecious species, we studied its floral biology, sex ratio and spatial distribution of sexual morphs along a soil-altitudinal gradient. The sex ratio did not significantly deviate from the expected 1:1 ratio. However, flower abundance in the population was significantly biased towards staminate flowers. Female individuals were larger than male individuals and plant size was negatively correlated with altitude, but did not differ between sexual morphs. The population did not show spatial segregation of sexes and male individuals were sexually mature earlier than female ones. Staminate flowers were larger than pistillate flowers and presented high pollen viability. Meliponini bees, small flies and thrips were potential pollinators, but pollination success was very low. Dioecy in N. theifera corroborates many general features of this reproductive strategy, such as woody habit, inconspicuous flowers, pollination by small generalist insects and differential resource allocation between male and female plants. However, reproduction in this species seems to be impaired by pollinator limitation. The results showed that the soil-altitude gradient influenced the growth pattern of the species and may play an important role in its reproductive biology but did not affect dioecy directly.

Reproductive ecology and the effect of altitude on sex ratios in the dioecious herb Aciphylla simplicifolia (Apiaceae)

2002 ◽  
Vol 50 (3) ◽  
pp. 289 ◽  
Author(s):  
Catherine Marina Pickering ◽  
Wendy Hill
Keyword(s):  
Sexual Dimorphism ◽  
Sex Ratios ◽  
Reproductive Ecology ◽  
Flowering Phenology ◽  
Specific Pattern ◽  
Floral Display ◽  
Vegetation Zone ◽  
Dioecious Plants ◽  
Male And Female ◽  
Floral Displays

The reproductive ecology of the dioecious herb Aciphylla simplicifolia (F.Muell.) Benth. (Apiaceae, Mountain Aciphylla) was examined in Kosciuszko National Park. Differences in floral display and flowering phenology between male and female plants were consistent with predictions based on theories concerning sexual dimorphism in dioecious plants. For example, male plants had larger floral displays than females at the alpine sites sampled. Male inflorescences had four times as many flowers as females and more than three times the area of floral display. In addition to differences in floral display, there was a sex-specific pattern in flowering phenology at six alpine sites. At these sites, there were more male inflorescences with buds and flowers and more female inflorescences finished flowering than would be expected if gender did not affect flowering phenology. To determine whether increasingly severe conditions associated with higher-altitude sites were associated with male-biased sex ratios, the number of male and female plants were compared for 20 sites over a 600-m altitudinal range from montane to alpine (total 4274 plants). As altitude increased and as the vegetation zone changed from subalpine to alpine, the sex ratio became increasingly male-biased, with sites in the alpine ranging from 1.45 males per female to 8.53 males per female. Sexual dimorphism in floral display, flowering phenology and sex ratios was consistent with what would be predicted for plants with sex-specific differences in resource allocation.

Resource allocation in young plants of two perennial species of Plantago

1978 ◽  
Vol 56 (20) ◽  
pp. 2533-2537 ◽  
Author(s):  
W. R. Hawthorn ◽  
P. B. Cavers
Keyword(s):  
Resource Allocation ◽  
Seed Production ◽  
Dry Weight ◽  
Growth Patterns ◽  
Plantago Major ◽  
Perennial Species ◽  
Plant Parts ◽  
Allocation Patterns ◽  
Number Of Leaves ◽  
Perennial Herbs

Growth patterns and biomass allocation to component plant parts in Plantago major and P. rugelii were compared under greenhouse conditions. Within 3 months of germination individuals of P. major were larger and had devoted more dry weight to seed and production of ramets than those of P. rugelii regardless of the number and kind of neighbours. No significant differences in percent resource allocation to roots, caudex, leaves, and spikes were observed between plants of P. major subjected to increased interference, although the actual biomass and number of leaves and spikes were reduced. Mean reproductive (spike) allocation in P. major was about 21%. Although the root biomass within a treatment was similar for the two species, the percent allocation to roots in P. rugelii was two and one-half times greater. Growth of P. major was depressed more by intraspecific neighbours and of P. rugelii by interspecific neighbours. These perennial herbs exhibit disparate allocation patterns as young plants that suggest adaptations to different temporary environments. Plantago major, with its early and sustained diversion of biomass to seed production, is distinctly adapted to exploitation of frequently disturbed sites, while P. rugelii, because of its more extensive root allocation and delayed seed production, seems better adapted to less frequent disturbance.

scholarly journals Male and Female Plants of Salix viminalis Perform Similarly to Flooding in Morphology, Anatomy, and Physiology

Forests ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 321 ◽  
Author(s):  
Fei-fei Zhai ◽  
Hai-dong Li ◽  
Shao-wei Zhang ◽  
Zhen-jian Li ◽  
Jun-xiang Liu ◽  
...  
Keyword(s):  
Photosynthetic Pigment ◽  
Primary Root ◽  
Photosynthetic Apparatus ◽  
Dry Weight ◽  
Normal Operation ◽  
Salix Viminalis ◽  
Dioecious Species ◽  
Positive Role ◽  
Male And Female ◽  
Production Ratio

Salix viminalis L., a dioecious species, is widely distributed in riparian zones, and flooding is one of the most common abiotic stresses that this species suffers. In this study, we investigated the morphological, anatomical, and physiological responses of male vs. female plants of S. viminalis to flooding. The results showed that the plant height and root collar diameter were stimulated by flooding treatment, which corresponded with higher dry weight of the stem and leaf. However, the dry weight of the underground part decreased, which might be due to the primary root having stopped growing. The little-influenced net photosynthesis rate (Pn) under flooding treatment could guarantee rapid growth of the aboveground part, while the unaffected leaf anatomical structure and photosynthetic pigment contents could ensure the normal operation of photosynthetic apparatus. Under a flooding environment, the production ratio of superoxide free radical (O2∙-) and malondialdehyde (MDA) contents increased, indicating that the cell membrane was damaged and oxidative stress was induced. At the same time, the antioxidant enzyme system, including superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX), and osmotic adjustment substances, involving proline (Pro) and solute protein (SP), began to play a positive role in resisting flooding stress. Different from our expectation, the male and female plants of S. viminalis performed similarly under flooding, and no significant differences were discovered. The results indicate that both male and female plants of S. viminalis are tolerant to flooding. Thus, both male and female plants of S. viminalis could be planted in frequent flooding zones.

scholarly journals Deviation from Hardy–Weinberg proportions in finite populations

1996 ◽  
Vol 68 (3) ◽  
pp. 249-257 ◽  
Author(s):  
Jinliang Wang
Keyword(s):  
Sampling Error ◽  
Random Mating ◽  
Random Selection ◽  
Stochastic Simulations ◽  
Gene Frequencies ◽  
Dioecious Species ◽  
Male And Female ◽  
Census Size ◽  
Genotype Frequencies ◽  
Gene Frequency Difference

SummaryFor a finite diploid population with no mutation, migration and selection, equations for the deviation of observed genotype frequencies from Hardy–Weinberg proportions are derived in this paper for monoecious species and for autosomal and sex-linked loci in dioecious species. It is shown that the genotype frequency deviation in finite random-mating populations results from the difference between the gene frequencies of male and female gametes, which is determined by two independent causes: the gene frequency difference between male and female parents and the sampling error due to the finite number of offspring. Previous studies have considered only one of the causes and the equations derived by previous authors are applicable only in the special case of random selection. The general equations derived here for both causes incorporate the variances and covariances of family size and thus they reduce to previous equations for random selection. Stochastic simulations are run to check the predictions from different formulae. Non-random mating and variation in census size are considered and the applications of the derived formulae are exemplified.

TEMPORAL PATTERNS OF PARENTAL RESOURCE DISTRIBUTION IN THE RED-NECKED GREBE: EQUALIZING THE SHARE OF THE SURVIVORS

Behaviour ◽  
2001 ◽  
Vol 138 (11-12) ◽  
pp. 1355-1370 ◽  
Author(s):  
Janusz Kloskowski
Keyword(s):  
Resource Allocation ◽  
Dominance Hierarchy ◽  
Food Distribution ◽  
Brood Reduction ◽  
Male And Female ◽  
Investment Allocation ◽  
Parental Aggression ◽  
Competition For Food ◽  
Podiceps Grisegena ◽  
Over Time

AbstractFood distribution within brood and parental aggression to chicks were studied in the asynchronously hatching red-necked grebe Podiceps grisegena throughout the whole period of parental care. When carrying young - during the first two weeks after hatching - parents did not interfere in sibling competition for food. The proportions of food received by each brood member reflected the dominance hierarchy. After this period, parents showed aggression to offspring, especially to the older chicks and the within-brood hierarchy of received food was gradually reversed. Junior chicks were also longer cared for than their older sibling. Male and female parents did not differ in the food apportionment among differentrank chicks. It is suggested that red-necked grebe parents change the within-brood investment allocation over time. In the first weeks after hatching, they allow biased food distribution and in consequence even brood reduction. Later, they intervene in resource allocation and attempt to equalize the post-fledging survival of all chicks. Parental aggression appears to be a means both for counteracting the competitive advantage of older sibs and for forcing the chicks to independence.

Population variation in Sorghum halepense, Johnson grass, at the northern limits of its range

1984 ◽  
Vol 62 (9) ◽  
pp. 1781-1790 ◽  
Author(s):  
S. I. Warwick ◽  
B. K. Thompson ◽  
L. D. Black
Keyword(s):  
New York ◽  
Dry Weight ◽  
Population Variation ◽  
Sorghum Halepense ◽  
Johnson Grass ◽  
Allocation Patterns ◽  
Cultivated Species ◽  
Relationship Of ◽  
The Relationship ◽  
Enzyme Patterns

Thirteen populations of Sorghum halepense, Johnson grass, were sampled from fields in Ontario, Canada, and Ohio and New York, United States. Only four of these populations were reported to overwinter as rhizomes. The morphology, phenology, resource allocation patterns, and growth of seedling and mature plants of the overwintering and the non-overwintering populations were compared. Field-collected specimens from the nonoverwintering populations had wider culms and leaves and larger seeds and inflorescences. Analysis of material grown in a 5-month greenhouse trial indicated similar differences. Greenhouse plants from the nonoverwintering populations were also characterized by greater percent emergence, larger and faster growing seedlings, earlier flowering, larger culms and seeds, greater reproductive dry weight per plant, and about 1/10th the rhizome dry weight of overwintering plants. Differences between populations within a biotype were evident for both biotypes, although there was little within-population variation, except in rhizome production, where certain individuals of some nonoverwintering populations did not produce extended rhizomes. Among the five enzymes which were examined electrophoretically, only one, phosphoglucomutase (PGM), showed variable isozyme patterns. No differences in enzyme patterns were apparent between the overwintering and the nonoverwintering biotypes. The relationship of the nonoverwintering populations to the cultivated species, Sorghum bicolor and S. almum, an introgressant between S. halepense and S. bicolor, is discussed.

Resource allocation patterns of two California-Sonoran desert ephemerals

Oecologia ◽  
1980 ◽  
Vol 46 (1) ◽  
pp. 86-91 ◽  
Author(s):  
D. D. Clark ◽  
J. H. Burk
Keyword(s):  
Resource Allocation ◽  
Sonoran Desert ◽  
Allocation Patterns

scholarly journals Male and female reproductive success in natural and anthropogenic populations of Malaxis monophyllos (L.) Sw. (Orchidaceae)

2015 ◽  
Vol 39 (1) ◽  
pp. 37-44 ◽  
Author(s):  
Edyta Jermakowicz ◽  
Beata Ostrowiecka ◽  
Izabela Tałałaj ◽  
Artur Pliszko ◽  
Agata Kostro-Ambroziak
Keyword(s):  
Reproductive Success ◽  
Fruit Set ◽  
Natural Populations ◽  
Floral Display ◽  
Natural Habitats ◽  
Female Reproductive Success ◽  
Male And Female ◽  
Demographic Processes ◽  
Preliminary Study ◽  
Effective Pollinators

Abstract In the presented study, male and female reproductive success was analyzed in relation to the population size, floral display and pollinators’ availability in natural and anthropogenic populations of the orchid Malaxis monophyllos (L.) Sw. Our results indicated significant differences between all investigated populations in parameters of floral display, including heights and number of flowers per inflorescence, as well the number of flowering individuals and their spatial structure. Additionally, populations differed both in male (pollinia removal) and female (fruit set) reproductive success, but only the fruit set clearly differentiated anthropogenic and natural populations. Despite the average flower number per plant being significantly higher in two of the anthropogenic populations, it was not related to the fruits set, which was significantly lower there. Moreover, our preliminary study concerning the potential pollinators of M. monophyllos showed a higher contribution of flies in natural habitats than in anthropogenic ones. Thus, we can suspect that the main factors influencing the level of female reproductive success in M. monophyllos populations are abundance of effective pollinators, as well as flower visitors, which may have resulted in a different level of pollen discounting in populations. Therefore, further studies concerning breeding system and pollination as important forces that shape demographic processes in M. monophyllos populations are necessary. Our results also indicate that suitable conservation methods in M. monophyllos should always include the preservation of potential pollinators, especially in these new, secondary habitats.

Sign in / Sign up

Export Citation Format

Share Document