scholarly journals Pre- dispersal seed loss of Ramorinoa girolae (Fabaceae) in Ischigualasto Provincial Park (San Juan, Argentina

2015 ◽  
Vol 50 (4) ◽  
pp. 585-594
Author(s):  
Sofía Papú ◽  
Susana Lagos Silnik ◽  
Claudia M. Campos
Keyword(s):  
Seed Predation ◽  
Mixed Models ◽  
Fruit Production ◽  
Great Loss ◽  
Explanatory Variables ◽  
Seed Loss ◽  
Adult Trees ◽  
Dispersal Stage ◽  
Provincial Park ◽  
Number Of Seeds

Ramorinoa girolae Speg. is a “vulnerable” tree endemic to Argentina. During the pre-dispersal stage, the seeds are predated by Anypsipyla univitella. The objectives of this study were to describe some reproductive parameters (size and number of fruits and seeds) of R. girolae, to quantify pre-dispersal seed loss by abortion and predation, and to test the effect on pre-dispersal seed predation of fruit production (per tree, of co-specific neighbors, and the sum of both), size of fruits, number of seeds per fruit, and number of predators per fruit. As seeds can be partially consumed by the predator, the viability of partially damaged seeds was assessed as well. At Ischigualasto Park, we sampled 17 adult trees from 3 stands spaced 4 km apart. For each focal tree, we quantified the number of co-specific neighbors and their fruits. We collected ten fruits from canopies and recorded their length and the number and states of seeds (intact, predated, and aborted). Generalized Linear Mixed Models were fitted to evaluate explanatory variables affecting the proportion of pre-dispersal predated seeds. R. girolae suffers great loss of seeds during the pre-dispersal stage, mainly by seed predation (58% of seeds). The proportion of predated seeds was most important relative to the number of predators, the number of seeds per fruit, and the size of fruits. Fruits containing more predators, more seeds, and smaller fruits had higher proportions of predated seeds. Seed abortion would not represent an important factor of seed loss (6% of seeds

Flowering, seed dispersal, seed predation and seedling recruitment in two pyrogenic flowering resprouters

2002 ◽  
Vol 50 (5) ◽  
pp. 545 ◽  
Author(s):  
Andrew J. Denham ◽  
Tony D. Auld
Keyword(s):  
Seed Dispersal ◽  
Seed Predation ◽  
Seedling Recruitment ◽  
Growth Conditions ◽  
Fruit Production ◽  
Seed Shadow ◽  
South Eastern ◽  
Seed Loss ◽  
Eastern Australia ◽  
South Eastern Australia

A few resprouting plants in fire-prone environments have no local seed bank (soil or canopy) when a fire occurs. These species rely on post-fire flowering and the production of non-dormant seeds to exploit favourable post-fire establishment and growth conditions. For two such pyrogenic flowering species (Doryanthes excelsa Correa and Telopea speciosissima (Smith) R.Br.), we examined the timing of seed release, patterns of fruit production, seed dispersal, seed predation and seedling establishment following a fire in the Sydney region of south-eastern Australia. Both species took some 19 months after the fire to flower and the first seeds were released 2 years after the fire. D. excelsa flowered and fruited only once after the fire. For T. speciosissima, plants also flowered at least once more in the subsequent 5 years, but produced seed in only the first three post-fire flowering years. Fruit production differed between species, with fruiting individuals of D. excelsa producing fewer infructescences, similar numbers of follicles, but many more seeds per follicle than fruiting individuals of T. speciosissima. Ultimately, D. excelsa produced approximately six times as many seeds per m2 and four times as many seeds per adult in one flowering season than T. speciosissima did after four flowering (three successful fruiting) seasons. Seeds were passively dispersed from fruits borne 3–4 m (D. excelsa) or 1–2 m (T. speciosissima) above the ground. Most seeds were found within 5 m (D. excelsa) or 3 m (T. speciosissima) of parent plants. The primary seed shadow of both species was a poor predictor of the distribution of seedlings, with more seedlings occurring further from the adults than expected from the distribution of seeds. Seed loss to predators was high in both species in exclusion experiments where mammals had access to clumps of seeds (77–88%). It was variable and generally lower (8–65%) in experiments where seeds were not locally clumped. However, for T. speciosissima, at one site, some 65% of seeds were lost to mammals and invertebrates in these latter experiments. At this site, these losses appeared to influence subsequent recruitment levels, as very low seedling densities were observed. For both species, germination of seedlings first occurred some 2.5–3 years after the passage of the fire. The percentage of seeds produced to seedlings successfully established was low in D. excelsa (2–3%) and more variable across sites and years in T. speciosissima (0–18%). Resultant post-fire seedling densities of D. excelsa (two sites) and T. speciosissima at one site were similar, but they were much lower at the T. speciosissima site that had high levels of seed predation. Both D. excelsa and T. speciosissima are amongst the slowest woody resprouting species to recruit seedlings after fire in south-eastern Australia and lag years behind species with soil or canopy seed banks.

Individual crop size increases predispersal predation by beetles in a tropical palm

2020 ◽  
pp. 1-4
Author(s):  
Morgana Maria Arcanjo Bruno ◽  
Klécia Gili Massi ◽  
Alexander V. Christianini ◽  
John du Vall Hay
Keyword(s):  
Seed Predation ◽  
Positive Influence ◽  
Reproductive Phenology ◽  
Individual Plant ◽  
Crop Size ◽  
Seed Predators ◽  
Plant Trait ◽  
Predispersal Seed Predation ◽  
Total Seed ◽  
Number Of Seeds

Abstract Predispersal seed predation is one of the main causes of seed mortality in plant populations, contributing to decreased plant recruitment. Seed loss has previously been found to be related to crop size. Thus, we examined the influence of individual crop size on predispersal seed predation by beetles in the palm Syagrus flexuosa in the Brazilian savanna. The study was carried out in three tropical woodland savanna sites, where we sampled the total seed crop of 46 fruiting palms and checked the presence of beetle larvae inside all seeds per plant. We observed predispersal seed predation of S. flexuosa from all sites and a high variation in the number of seeds preyed on per individual palm. Crop size had a positive influence on the number of seeds lost to predispersal seed predators. Variations in levels of predispersal seed predation may also be accounted for by the reproductive phenology of S. flexuosa. If fruits are not available at the same time, less resource is available for predators and therefore a high proportion of seeds may be preyed on. Thus, our study demonstrates that an individual plant trait, crop size, is an important predictor of beetle seed damage per palm and a driver of the number of seeds lost to predispersal seed predators.

scholarly journals Path analysis for selection of feijoa with greater pulp weight

2017 ◽  
Vol 47 (6) ◽  
Author(s):  
Joel Donazzolo ◽  
Vanessa Padilha Salla ◽  
Simone Aparecida Zolet Sasso ◽  
Moeses Andrigo Danner ◽  
Idemir Citadin ◽  
...  
Keyword(s):  
Path Analysis ◽  
Indirect Selection ◽  
Total Weight ◽  
Direct And Indirect Effects ◽  
Rio Grande Do Sul ◽  
Basic Variable ◽  
Explanatory Variables ◽  
Acca Sellowiana ◽  
Number Of Seeds ◽  
Selection Of

ABSTRACT: The objective of this paper was to identify the direct and indirect effects of feijoa fruits (Acca sellowiana) traitson pulp weight, in order to use these traits in indirect genotypes selection. Fruits of five feijoa plants were collected in Rio Grande do Sul, in the years of 2009, 2010 and 2011. Six traits were evaluated: diameter, length, total weight, pulp weight, peel thickness and number of seeds per fruit. In the path analysis, with or without ridge regression, pulp weight was considered as the basic variable, and the other traits were considered as explanatory variables. Total weight and fruit diameter had high direct effect, and are the main traits associated with pulp weight. These traits may serve as criteria for indirect selection to increase feijoa pulp weight, since they are easy to be measured.

scholarly journals Interaction between biological and chemistry fungicides and tomato pollinators

2018 ◽  
Vol 12 (2) ◽  
pp. 425-435
Author(s):  
Carlos De Melo e Silva-Neto ◽  
Anna Clara Chaves Ribeiro ◽  
Flaviana Lima Gomes ◽  
Jordana Guimarães Neves ◽  
Aniela Pilar Campos de Melo ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Mortality Rate ◽  
Fruit Size ◽  
Pollen Grains ◽  
Fruit Production ◽  
Control Treatment ◽  
Copper Hydroxide ◽  
Tomato Crop ◽  
Bite Marks ◽  
Number Of Seeds

The use of agrochemicals is harmful to bees visiting agricultural crops, reducing production gains from pollination, but the effect of fungicides on these bees is not known. The objective of this study was to verify the effect of bee visitation influenced by different fungicides on the tomato crop and on the deposition of pollen grains on the stigma, number of seeds, mass and fruit size. The experiment was conducted with 10 treatments: (T1) control treatment, without application of agrochemicals; (T2 and T3) Bacillus subtilis in different application frequencies; (T4) copper hydroxide; (T5) B. subtilis and copper hydroxide; (T6) acibenzolar-S-methyl; (T7) (trifloxystrobin+tebuconazole) and B. subtilis; (T8) copper hydroxide+Mancozeb; (T9) propineb+(trifloxystrobin+ tebuconazole); (T10) (trifloxystrobin+tebuconazole)+B. subtilis+copper hydroxide. The presence of the pollination mark on the flower, the pollen load of the stigmas, the number of seeds per fruit, and the size and mass of the fruits were determined in each treatment. Subsequently, the mortality rate of Melipona quadrifasciata (Hymenoptera, Apidae) exposed to four fungicides (trifloxystrobin+tebuconazole; manganese and zinc; copper hydroxide; Bacillus subtilis) was estimated. The mortality rate of M. quadrifasciata over 24 h of evaluation was higher in the treatments with copper hydroxide and trifloxystrobin+tebuconazole (75 and 50%, respectively). The mortality rate was lower in the treatments with manganese and zinc and Bacillus subtilis and in the control treatment. The treatments with trifloxystrobin+tebuconazole reduced the presence of bite marks on the flowers and of pollen grains on the flower stigma. The fruits of the control treatments and treatments with B. subtilis and copper hydroxide were larger and had greater mass, as compared to other agrochemicals. Thus, a higher number of pesticide applications on the tomatoes reduced bee visitation rates to the flowers and, consequently, reduced the amount of pollen grains deposited on the stigmas, also reducing the fruit production. 

Investigating Dispersion of Leaf Symbionts: Exploring Specific Symbioses

2019 ◽  
Vol 81 (1) ◽  
pp. 27-31
Author(s):  
Dave Shutler
Keyword(s):  
Poisson Distribution ◽  
Mixed Models ◽  
Distribution Data ◽  
Dispersion Pattern ◽  
Medical Practitioners ◽  
Explanatory Variables ◽  
Random Dispersion ◽  
Simple Fashion ◽  
The Way

Symbioses can range from mutualisms to parasitisms; the latter are the foci of this exercise. The way in which parasites are distributed among hosts (their dispersion) can have profound importance for how they and their hosts coevolve, and for many other facets of their biology. Accordingly, many researchers, including ecologists and medical practitioners, study dispersion of parasites in detail. Fungi are commonly observed parasites on leaves of trees. I describe one way to randomly sample leaves to quantify dispersion of such parasites and test whether dispersion is related to a variety of explanatory variables. Significant quantities of data can be generated in relatively short order and pooled for a class; many patterns can emerge that challenge students to find logical interpretations. Relatively sophisticated students could test whether parasites have a random dispersion pattern by comparing the histogram they generate to that of a Poisson distribution. Data can be analyzed in a simple fashion or via advanced mixed models.

scholarly journals People’s perception on agricultural vulnerabilities to climate change and SLR in Bangladesh: adaptation strategies and explanatory variables

2018 ◽  
Vol 8 (1) ◽  
pp. 70-78
Author(s):  
MA Islam ◽  
SK Paul
Keyword(s):  
Climate Change ◽  
Adaptation Strategies ◽  
External Support ◽  
Great Loss ◽  
Explanatory Variables ◽  
Climatic Hazards ◽  
People’S Perception ◽  
Relevant Variables ◽  
The Impact ◽  
Impacts Of Climate Change

The objective of this research is to evaluate people’s perception on vulnerabilities of agriculture and to explore effective adaptation options with identifying the underlying demographic, socio-economic and other relevant variables that influence the adaptation strategies in the sea level rise (SLR) hazard induced coastal areas of Bangladesh. The study finds that climate change and induced SLR are emerging threats to coastal agriculture of Bangladesh; hence, farmers are applying different adaptation strategies to reduce the vulnerabilities of coastal agriculture. Selection of effective adaptation strategies to vulnerabilities of agriculture depends not only on the magnitude, intensity and the impacts of climate change and SLR, but also perceptions and types of farmer, land, educational level, indigenous knowledge about adaptation, locational advantages, external support, community awareness and sharing of different effective mechanisms among the farmers. Effective adaptation strategies with high perceptions have significant influence to reduce the vulnerabilities of agriculture considering the adverse impacts of climate change and SLR. In time of extreme climatic hazards when a great loss in agriculture hamper the coastal agrobased economy, different effective indigenous local adaptation strategies through farmer awareness and community co-operation become vital for minimizing the impact of climatic hazards and reducing the vulnerabilities of coastal agriculture.Int. J. Agril. Res. Innov. & Tech. 8 (1): 70-78, June, 2018

Seed predation and patterns of fruit production in Asclepias syriaca L.

Oecologia ◽  
1983 ◽  
Vol 59 (2-3) ◽  
pp. 370-376 ◽  
Author(s):  
Susan E. Franson ◽  
Mary F. Willson
Keyword(s):  
Seed Predation ◽  
Fruit Production ◽  
Asclepias Syriaca

scholarly journals The influence of habitat conditions on the performance of two invasive, annuals — Impatiens glandulifera and Bidens frondosa

Biologia ◽  
2014 ◽  
Vol 69 (4) ◽  
Author(s):  
Kinga Kostrakiewicz-Gierałt ◽  
Maria Zając
Keyword(s):  
Seedling Recruitment ◽  
Riparian Forest ◽  
Fruit Production ◽  
Spatial And Temporal Variability ◽  
Habitat Conditions ◽  
Impatiens Glandulifera ◽  
Long Distance ◽  
Bidens Frondosa ◽  
Number Of Seeds ◽  
Invasive Annuals

AbstractThe investigations of habitat conditions on the variability of selected population features in the two invasive, annuals with different life-history traits were conducted in the years 2008–2010, in the Polish part of the Carpathian Mountains in communities characterized by the gradual decrease of light availability. The individuals of Impatiens glandulifera were surveyed along roadsides, in willow thickets, as well as inside and along the edges of the riparian forest, whereas the individuals of Bidens frondosa were observed in riverside gravels characterized by a different species composition. Each year, the number and density of individuals (stems) occurring in the particular sites were examined, as well as the height and the fruit production in 30 randomly chosen stems were surveyed. Moreover, the number of seeds per fruit, the diaspore dimensions and the seedling recruitment in laboratory conditions were examined during each season. As the values of height of individuals, number of fruits per stem, number of seeds per fruit, as well as the seedling abundance in some groups were not consistent with the normal distribution and the variances were not homogeneous, the non-parametric Kruskal-Wallis test was used in statistical analyses.Much greater number and density of individuals of Impatiens glandulifera were found in riparian forest, than in willow thickets and along the roadsides. In all sites the number and density of individuals increased steadily in consecutive seasons. The great number and density of Bidens frondosa individuals observed in shady and partly shady sites during the first year of studies raised in the second year and subsequently dramatically decreased in the third season. The lowest number and density of individuals noted in the first season in unshaded site raised substantially in subsequent years. The height of stems, as well as seed and fruit production of both taxa diminished with a decrease of height of neighboring plants. The seed dimensions presented the spatial and temporal variability, whereas the number of seedlings among consecutive years and in successive sites did not differ.The considerable height of the individuals of Impatiens glandulifera, high production of large fruits and seeds in open and dry roadside areas can contribute to more effective ballistic dissemination, while substantial seedling recruitment enables the colonization of new, perhaps more advantageous sites. On the other hand, lower individual height, as well as fruit and seed production and considerable seedling emergence allow the population to last and to gradually extend the area in forest communities. The considerable abundance of the high-statured Bidens frondosa individuals, substantial production of large capitula and achenes contribute to long persistence of populations in open and sun-lit sites. The gradually decrease in the height of the stems, achene number and size observed in partly-shaded and shaded places might allow to long-distance dispersal of seeds by animals, while substantial seedling recruitment might contribute to establishment in new areas.

Seed predation, pathogens and germination in primary vs. secondary cloud forest at Maquipucuna Reserve, Ecuador

2015 ◽  
Vol 31 (4) ◽  
pp. 375-378 ◽  
Author(s):  
Randall W. Myster
Keyword(s):  
Seed Predation ◽  
Human Disturbance ◽  
Secondary Forest ◽  
Cloud Forest ◽  
Primary Forest ◽  
Natural Disturbances ◽  
Seed Loss ◽  
Closed Canopy ◽  
Piper Aduncum ◽  
Maquipucuna Reserve

Abstract:Because the fate of the seed rain has long been shown to be critical to understanding forest recruitment and regeneration, seed predation, seed pathogens and germination among different species was examined in primary (closed-canopy vs. tree-fall gap) and in secondary (banana vs. sugarcane vs. seeded pasture) cloud forest at Maquipucuna Reserve, Ecuador. I found (1) seed predation took more seeds than either seed pathogenic disease or germination for all tree seed species and in both forests, where the level of seed loss to predation was greatest in the closed-canopy primary forest, second largest in the tree-fall gaps and less in recovering banana, sugarcane and pasture; (2) for pathogens these trends were reversed; and (3) most seeds, that were not taken by predators or pathogens, germinated. Cecropia sp. seeds in the tree-fall gaps and Otoba gordoniifolia seeds in both closed-canopy forest and tree-fall gaps were the most significantly different among all treatments in primary forest and Solanum ovalifolia seeds in banana fields and Piper aduncum in all fields were the most significantly different among all treatments in secondary forest. I conclude that forests may recover faster after human disturbance (here agriculture) than after natural disturbances (here tree-fall).

scholarly journals Seed Characteristics of Wild Pear Genotypes from the in situ Population of the Banja Luka Region

2019 ◽  
Vol 20 (4) ◽  
Author(s):  
Nada Zavišić ◽  
Jelena Davidović Gidas ◽  
Borut Bosančić
Keyword(s):  
Fruit Production ◽  
Pyrus Communis ◽  
Seed Germinability ◽  
Mother Plants ◽  
Banja Luka ◽  
Seed Characteristics ◽  
Number Of Seeds ◽  
Tetrazolium Test

Wild pear (Pyrus communis var. piraster (L.) Ehrh.) is widely used as a generative rootstock for pear grafting. Seeds for the production of this rootstock should be taken from the registered mother plants. The aim of this research was to select mother plants in wild pear population from three localities (Banja Luka, Manjača, and Potkozarje). Fruit bearing regularity of selected trees was observed from 2012-2016, and the number of seeds per fruit was analysed in 2013, 2015 and 2016. Seed germinability and vitality analysis was carried out on 14 selected tress (genotypes). Seed germinability was tested according to the ISTA guideline. Seed vitality was determined by the tetrazolium test (TT). Accessions from Banja Luka locality expressed the highest fruit production. The highest number of seeds was determined in the genotypes marked as No. 6 and No. 21, amounting to 7.53 and 7.21 seeds, respectively. Seeds of the tested wild pears have shown good vitality. The highest seed vitality and germination of 92% was obtained from the accession No. 20. On the basis of the results, accessions marked with numbers: '6', '8', '20', '25', '31' and '32' can be used as mother plants for pear rootstock production.

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