Predation by Insects Limits Seed Production in Banksia spinulosa var neoanglica (Proteaceae)

1990 ◽  
Vol 38 (4) ◽  
pp. 335 ◽  
Author(s):  
G Vaughton
Keyword(s):  
Seed Production ◽  
Reproductive Output ◽  
Seed Set ◽  
Control Group ◽  
Insecticide Treatment ◽  
Seed Predators ◽  
Flowering Season ◽  
Number Of Seeds

Application of insecticide to inflorescences of Banksia spinulosa var. neoanglica indicated that damage by flower and seed predators halved the number of seeds produced per plant. Both the proportion of inflorescences that produced fruits and the number of seeds produced per infructescence increased by 45% when insects were excluded. Infructescences in the insecticide treatment produced 28% more follicles than in the control group. Insects damaged the seed in 13% of follicles in the control group whereas there was no damage in the insecticide treatment. The proportion of follicles with aborted seed did not differ between the two groups. The greater seed set occurring when insects were excluded did not affect the weight of individual seeds or reproductive output in the next flowering season. Some inflorescences did not produce fruit even when insects were excluded suggesting that factors besides predation also limit fecundity of B. spinulosa.

What determines the number of seed produced in a flowering event? A case study of Calyptrogyne ghiesbreghtiana (Arecaceae)

2000 ◽  
Vol 48 (5) ◽  
pp. 659 ◽  
Author(s):  
Saul A. Cunningham
Keyword(s):  
Resource Allocation ◽  
Seed Production ◽  
Natural Variation ◽  
Seed Set ◽  
Plant Seed ◽  
Flower Production ◽  
Number Of Seeds ◽  
Female Flowers

Calyptrogyne ghiesbreghtiana Linden ex. H. Wendl. is an understorey palm that occurs at La Selva Biological Station, Costa Rica. In this paper I combine analysis of natural variation and results of experimental manipulations to ask (1) what limits seed production? and (2) what processes cause variation in seed production by C. ghiesbreghtiana? The number of seed produced per inflorescence ofC. ghiesbreghtiana was limited substantially by the loss of female flowers to floral herbivores. Much variation in the number of seed produced perinflorescence of C. ghiesbreghtiana was due to losses of developing fruits to predators. Together these phenomena illustrate the influential role of natural enemies in the reproductive success of this plant. Seed-set efficiency (number of seeds/number of female flowers) was highly variable in this species, and such high levels of variation appear to be common in other species. For species with highly variable seed-set efficiency, the role of resource allocation to flower production in determining differences in seed production among individual plants is likely to be relatively small.

The beneficial effect of ants on the reproductive success of Dyckia floribunda (Bromeliaceae), an extrafloral nectary plant

2003 ◽  
Vol 81 (1) ◽  
pp. 24-27 ◽  
Author(s):  
José L Vesprini ◽  
Leonardo Galetto ◽  
Gabriel Bernardello
Keyword(s):  
Seed Production ◽  
Reproductive Output ◽  
Fruit Set ◽  
Seed Set ◽  
Reproductive Organs ◽  
Extrafloral Nectaries ◽  
Perennial Herb ◽  
Seed Number ◽  
Total Seed ◽  
Mutualistic Association

Dyckia floribunda is a perennial herb from the Argentinian Chaco with extrafloral nectaries. Ants visited these nectaries while patrolling inflorescences and infructescences. We anticipated that ants attracted to extrafloral nectaries might protect the reproductive organs, increasing plant reproductive output. To evaluate the possibility of mutualism between D. floribunda and ant visitors, we determined whether ant-accessible plants showed a higher seed production than ant-excluded plants. Experimental fieldwork suggested a decrease in fruit set of ant-excluded plants compared with ant-accessible plants but the seed number per fruit was not affected by ant exclusion. Thus, total seed number per plant was highly reduced in treated spikes. Analyses of covariance confirmed these trends, indicating that total seed production per plant was strongly affected by ant exclusion. This study marks the first experimental report of this mutualistic association in Bromeliaceae.Key words: ant–plant interaction, Bromeliaceae, Chaco, Dyckia floribunda, fruit set, seed set, mutualism.

scholarly journals Self-Fertilization, Inbreeding, and Yield in Alfalfa Seed Production

2021 ◽  
Vol 12 ◽  
Author(s):  
Molly E. Dieterich Mabin ◽  
Johanne Brunet ◽  
Heathcliffe Riday ◽  
Lauren Lehmann
Keyword(s):  
Pacific Northwest ◽  
Seed Production ◽  
Inbreeding Depression ◽  
Seed Yield ◽  
Seed Set ◽  
Central Valley ◽  
Selfing Rate ◽  
Alfalfa Seed ◽  
The Impact ◽  
Number Of Seeds

Selfing (self-pollination) is the ultimate form of inbreeding, or mating among close relatives. Selfing can create yield loss when inbreeding depression, defined as a lower survival and reproduction of inbred relative to outbred progeny, is present. To determine the impact of selfing in alfalfa (Medicago sativa L.), we quantified the selfing rate of 32 alfalfa seed production fields located in three regions, namely, the Pacific Northwest (PNW), the Central Valley of California (CEV), and the Imperial Valley of California (IMP). Selfing rates (the proportion of selfed seeds) varied between 5.3 and 30% with an average of 12.2% over the 32 seed production fields. In both the parents and their progeny, we observed an excess of heterozygotes relative to Hardy–Weinberg expectations. We detected notable levels of inbreeding in parents (0.231 ± 0.007 parental inbreeding coefficient) and progeny (0.229 ± 0.005). There were a 15% decrease in the number of seeds per stem (seed set) and a 13% decline in the number of seeds per pod in selfed relative to outcrossed stems, but negligible inbreeding depression for pods per raceme and seed weight. The number of racemes on selfed stems increased significantly in fields with greater selfing rates, supporting the presence of geitonogamous or among flower selfing. Despite the significant level of inbreeding depression, seed set did not decrease in fields with higher selfing rates, where the greater number of racemes on the selfed stems increased the seed set. The effects of the field selfing rate on the seed yield metrics were mostly indirect with direct effects of the number of racemes per stem. Available data indicate that the majority of selfing in alfalfa is pollinator-mediated, and thus, eliminating selfing in alfalfa seed production would require the selection of self-incompatible varieties, which, by eliminating inbreeding depression, would provide a 15% potential increase in seed yield and an increase in future hay yield.

scholarly journals 950 PB 443 DOES WOUNDING BEFORE POLLINATION INCREASE SEED PRODUCTION IN SOLANACEOIJS PLANTS?

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 570a-570
Author(s):  
Ellen K. Muchmor ◽  
Loverine P. Taylor
Keyword(s):  
Natural Product ◽  
Seed Production ◽  
Pollen Germination ◽  
Seed Set ◽  
Pollen Grains ◽  
Inbred Lines ◽  
Nicotiana Tobacum ◽  
Solanaceous Plant ◽  
Number Of Seeds

Seed set is affected by many factors. One of the most important is the number of pollen grains that germinate on the stigma. Our research has shown that kaempferol (a plant natural product) is required for pollen germination. Pollen lacking kaempferol does not germinate, but this defect can be reversed by adding powdered kaempferol to the stigma at pollination. Within 24 hours of wounding the corolla or stamens of V26, a Petunia inbred, high levels of kaempferol accumulate in the stigma. The requirement for kaempferol in pollen germination, and the high levels that can accumulate in the stigma, suggested that seed set might be enhanced by wounding 24 hours before pollination. We tested this hypothesis in two inbred lines of Petunia, a Petunia outcross, and another solanaceous plant Nicotiana tobacum cv. Samsum. The number of seeds per capsule were correlated with the levels of kaempferol in the stigma in wounded and non-wounded flowers.

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.

The importance of recruitment patterns versus reproductive output in the persistence of a short-range endemic shrub in a highly fragmented landscape of south-western Australia

2012 ◽  
Vol 60 (7) ◽  
pp. 643 ◽  
Author(s):  
Neil Gibson ◽  
Colin Yates ◽  
Margaret Byrne ◽  
Margaret Langley ◽  
Rujiporn Thavornkanlapachai
Keyword(s):  
Short Range ◽  
Reproductive Output ◽  
Fruit Set ◽  
Seedling Recruitment ◽  
Fragment Size ◽  
Fragmented Landscape ◽  
Recruitment Failure ◽  
Degree Of Isolation ◽  
Number Of Seeds ◽  
Significant Mortality

Calothamnus quadrifidus subsp. teretifolius A.S.George & N.Gibson is a short-range endemic shrub whose habitat has been greatly reduced by clearing for agriculture. Reproductive output was high in all populations sampled, although there were large differences among populations in fruit set, the number of seeds per fruit and seed germination. These traits showed no relationship to population size, degree of isolation, or fragment size, which contrasts strongly with the patterns found in a widespread congener. Demographic studies in remnants with an intact understorey showed stable adult populations with continuous seedling recruitment. In contrast, there was consistent widespread failure of seedling and juvenile recruitment in degraded roadside remnants that also showed significant mortality of reproductive adults. In these degraded remnants, recruitment failure appears to be the primary cause of species decline.

scholarly journals Researches on the Main Characteristics of Red Clover Seedlings and their Influence in

2012 ◽  
Vol 69 (1) ◽  
Author(s):  
Marioara GREBENIȘAN ◽  
Doru PAMFIL ◽  
Dorottya Alice DOMOKOS
Keyword(s):  
Plant Breeding ◽  
Seed Production ◽  
Red Clover ◽  
Production Level ◽  
Seed Crop ◽  
Binding Process ◽  
Lower Variability ◽  
Clover Seed ◽  
Number Of Seeds

Concerning the red clover breeding, it is essential to choose as genitors those varieties that possess good characteristics. In order to identify potential genitors, two red clover varieties were studied at Cluj-Napoca: Roxana, diploid variety and Napoca-tetra, tetraploid variety. The analyzed traits comprised the number of capitula/plant, number of seeds/capitulum and the binding process, under the aspect of their contribution to the seed crop and the interaction between those components, in order to provide important clues about di-and tetraploid red clover seed production, for plant breeding. The highest variability (s%=30) presented regarding the number of flowers/capitulum, diploid variety comparatively with a lower variability (s%=26) regarding the number of flowers number/capitulum, tetraploid varieties. Several traits were compared between di-and tetraploid red clover varieties in order to find genitors which can be used for creating new genotypes with high seed production level.

scholarly journals SEED PRODUCTIVITY AND DEVELOPMENT OF PLANTLETS POPULUS × JRTYSCHENSIS CH. Y. YANG

2019 ◽  
pp. 51-57
Author(s):  
B. V. Proshkin ◽  
A. V. Klimov
Keyword(s):  
Filter Paper ◽  
Fruit Set ◽  
Control Group ◽  
Natural Hybrid ◽  
Seed Productivity ◽  
Model Trees ◽  
Fruit Number ◽  
Black Poplar ◽  
Petri Dishes ◽  
Number Of Seeds

The research explores the seed productivity and plantlets growth in the free pollination of the natural hybrid taxon P. × jrtyschensis. Fruits of P. × jrtyschensis were selected from four plants that grow in the collection ofResearchCenter“EducationalBotanical Garden” ofKemerovoStateUniversity. Four P. nigra model trees, randomly selected from theTomRiverfloodplain population, were applied as a control group. The authors used 30 fruit-bearing amentumsfrom each model. The researchers measured set of fruit (capsule); number of ovules per fruit; number of seeds per fruit; set of seeds.. Laboratory germination was determined by sowing Petri dishes on wet filter paper. The authors found out sowing germination by sowing 100 seeds in a box with soil and drainage. The energy of germination was determined on the second day while germination - on the fifth day. P. × jrtyschensis is characterized by a lower level of seed productivity (15-30%) compared to P. nigra. In terms of laboratory germination of seeds, the descendants of hybrids surpassed many P. nigra models, but their soil germination was 20-30% lower than that of black poplar. The observed variability in reproductive indices of both P. × jrtyschensis and P. nigra is mainly caused by specific features of their genotypes. Plantlets being developed, the authors observed no significant differences among the descendants of P. nigra and hybrids. The researchers highlighted plantlets that can stop growing and even more abnormal plants with one, three or four seeds in P. × jrtyschensis. This may be caused by underdevelopment of hypocotyl or germ root. The authors observed breaches in development of P. nigra just once. They outline high plantlets destruction when sowing hybrids on the first day after germination The share of destructed plants within a month (from the beginning of the experiment) reaches 66,0 %, and in P. nigra it does not exceed 40,0 %.

scholarly journals Influence of bee pollination on quality and quantity of onion (Allium cepa L.) seed

2020 ◽  
Vol 13 (2) ◽  
pp. 200-204
Author(s):  
Subhash B. Kandakoor ◽  
Jitendra Kumar S. Hilli
Keyword(s):  
Allium Cepa ◽  
Seed Weight ◽  
Seed Set ◽  
Maximum Activity ◽  
Major Contributor ◽  
Flowering Stage ◽  
Bee Pollination ◽  
Allium Cepa L ◽  
Bee Colonies ◽  
Number Of Seeds

The activity of bees pollination in onion was observed throughout the day. Numerically maximum activity was observed during afternoon hours (12.00 to 2.00 PM) with 7.00 numbers in rock bee, 5.40 in Indian bees, 11.60 in little bees and 7.80 in case of dammer be, respectively. Among the four species of bees, little bees were more in entire day with highest of 111.60 bees/10 inflorescence/ minute followed by dammer bee with 9.40 bees/10 inflorescence/ minute, Among the bees major contributor was little bee, this may be due to more colonies of little bees in that area and destruction of rock bee colonies. Also, the bee acitivty was observed maximum number at 100 per cent flowering stage. The observations on number of seeds per umbel, 1000 seed weight and per cent germination under the laboratory conditions. The results clearly indicated that, maximum number of seeds per umbel was observed in open pollinated flowers with 339.30 ± 60.27 seeds per umber where all the four species of bees were made visits regularly followed by in case of pollination in mesh cloth cage with bees with 330.00±35.80 and very least number of seed set was observed in case of pollination in mesh cloth cage without bees with only 60.70 seeds/umbel. Similarly, 1000 seed weight also differed significantly in case of pollination with bees and without bees. In case of with bees it weighed around 3.37 g/1000 seeds followed by 3.10 g/1000 seeds in onion with bee cage and least in case of control with only 1.97 g/1000 seeds.

Seed production in Cardiocrium cordatum: effects of nitrogen and dry mass availability of a plant

2006 ◽  
Vol 84 (5) ◽  
pp. 805-812
Author(s):  
Satoki Sakai ◽  
Akiko Sakai ◽  
Kohta Fujioka
Keyword(s):  
Mass Loss ◽  
Seed Production ◽  
Plant Size ◽  
Dry Mass ◽  
Stem Diameter ◽  
N Content ◽  
N Concentration ◽  
The Mean ◽  
Number Of Seeds

To clarify how seed production depends on the relative N and dry mass availability, we examined the number and size of seeds, and the loss of dry mass in Cardiocrium cordatum (Thunb.) Makaino plants that differed naturally in overall size and stem N content. After adjusting for plant size (basal stem diameter was used as a criterion of plant size), the amount of dry mass lost because of respiration in a plant decreased with an increase in the stem N content of the plant, whereas the total dry mass of seeds of a plant increased with an increase in the stem N content. Plants with a high stem N content relative to dry mass status used dry mass resources more efficiently in seed production by reducing the loss of dry mass. Plants with a higher stem N content produced a greater number of seeds, and the amount of dry mass lost decreased with an increase in the number of seeds of the plant, possibly because the resources allocated to seed production are consumed rapidly, if numerous seeds simultaneously absorb those resources. However, the stem N content of a plant had no influence on the mean seed dry mass, seed N content, and the seed N concentration, and the latter three parameters did not affect respiration loss of dry mass. We concluded that plants undergoing seed production reduce dry mass loss if their relative N to dry mass availability is high, through an increase in the numbers of seeds they produce.

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