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Caracterização morfológica de embriões por imagens de raios x e relação com a massa e a qualidade fisiológica de sementes de Tecoma stans L. Juss. ex Kunth (Bignoniaceae); Embryo morphological characterization by x-ray image and relation with mass and physiological quality of seeds of Tecoma stans L. Juss. ex Kunth (Bignoniaceae)

SOCOLOWSKI, Fábio; CICERO, Silvio Moure
Fonte: Associação Brasileira de Tecnologia de Sementes Publicador: Associação Brasileira de Tecnologia de Sementes
Tipo: Artigo de Revista Científica
POR
Relevância na Pesquisa
56.29%
As imagens obtidas pelos raios X vêm sendo utilizadas na análise da qualidade de sementes desde os anos 50 e, atualmente, vêm se destacando por ser um método rápido, de boa precisão e não destrutivo. Deste modo, o presente trabalho foi realizado com o objetivo de avaliar as características morfológicas dos embriões de sementes de Tecoma stans L. Juss. ex Kunth pertencentes a diferentes classes de massa através da análise de imagens obtidas pelo uso dos raios X, correlacionando-as com a germinação e morfologia das plântulas. Foram utilizadas sete classes de massa com trinta sementes em cada classe, que foram submetidas aos raios X para a obtenção das imagens dos embriões. Os embriões, de cada uma das classes, foram separados de acordo com suas características morfológicas em 4 categorias (embriões sem defeito, embriões com pequenos defeitos, embriões deformados e sementes sem embrião). As sementes das diferentes classes de massa foram colocadas para germinar (emissão da raiz primária) e após dez dias foi observado o número de plântulas normais em cada uma das categorias e classes de massa. A maioria das sementes das classes 1 e 2, mais leves, apresenta-se com embriões deformados ou sem embrião, enquanto que as de maior massa (classes 3 a 7) apresentam embriões sem defeitos...

Massa das sementes de Tecoma stans L. Juss. ex Kunth (Bignoniaceae): efeitos na emergência e desenvolvimento de suas plântulas no sol e na sombra; Seed mass of Tecoma stans L. Juss. ex Kunth (Bignoniaceae): effects on emergence and seedling development under full sun and shade

SOCOLOWSKI, Fábio; VIEIRA, Daniela Cristine Mascia; TAKAKI, Massanori
Fonte: Instituto Virtual da Biodiversidade | BIOTA - FAPESP Publicador: Instituto Virtual da Biodiversidade | BIOTA - FAPESP
Tipo: Artigo de Revista Científica
POR
Relevância na Pesquisa
56.15%
The aim of this study was to evaluate the effect of Tecoma stans L. Juss. ex Kunth seeds mass on initial emergence, growth and, seedling development under different light conditions. The seeds were separated in four mass classes and sowed in four replicates of 24 seeds for each class, under full sun and canopy shade. Under sun environment was observed a greater percentage of emergence. Heavy seeds presented the greater percentage of emergence under both environments, but a greater rate was observed under canopy shade. One month after the start of experiments, the seedlings at the shade environment presented 100% of mortality. The growth and development seedlings under full sun were noticed for five months. In this period, only in the first three months was possible to observe the effects of Tecoma stans seeds mass on capacity of seedlings to acquire dry mass. The seedlings biomass partitions were similar among the tested mass class. The seedlings of smaller mass tended to a high specific leaf area in relation to the seedlings from large seeds, mainly in the first three months, resulting in a great acquisition of dry mass by these seedlings. In the fourth month, the specific leaf area did not present any tendency. Because the biggest seeds to give rise seedlings with best initial development than smallest seeds can be considered as species reproductive strategy. To produce seeds of different sizes also can be considered as way of species to spread in many microhabitats.; Este estudo teve como objetivo avaliar o efeito da massa das sementes de Tecoma stans L. Juss. ex Kunth na emergência...

The role of seed mass on the caching decision by agoutis, Dasyprocta leporina (Rodentia: Agoutidae)

Galetti, Mauro; Donatti, Camila I.; Steffler, Carla; Genini, Julieta; Bovendorp, Ricardo S.; Fleury, Marina
Fonte: Sociedade Brasileira de Zoologia Publicador: Sociedade Brasileira de Zoologia
Tipo: Artigo de Revista Científica Formato: 472-476
ENG
Relevância na Pesquisa
46.19%
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); It has been shown that the local extinction of large-bodied frugivores may cause cascading consequences for plant recruitment and overall plant diversity. However, to what extent the resilient mammals can compensate the role of seed dispersal in defaunated sites is poorly understood. Caviomorph rodents, especially Dasyprocta spp., are usually resilient frugivores in hunted forests and their seed caching behavior may be important for many plant species which lack primary dispersers. We compared the effect of the variation in seed mass of six vertebrate-dispersed plant species on the caching decision by the red-rumped agoutis Dasyprocta leporina Linnaeus, 1758 in a land-bridge island of the Atlantic forest, Brazil. We found a strong positive effect of seed mass on seed fate and dispersal distance, but there was a great variation between species. Agoutis never cached seeds smaller than 0.9 g and larger seeds were dispersed for longer distances. Therefore, agoutis can be important seed dispersers of large-seeded species in defaunated forests.

Caracterização morfológica de embriões por imagens de raios x e relação com a massa e a qualidade fisiológica de sementes de Tecoma stans L. Juss. ex Kunth (Bignoniaceae)

Socolowski, Fábio; Cicero, Silvio Moure
Fonte: Associação Brasileira de Tecnologia de Sementes (ABRATES) Publicador: Associação Brasileira de Tecnologia de Sementes (ABRATES)
Tipo: Artigo de Revista Científica Formato: 200-208
POR
Relevância na Pesquisa
46.28%
As imagens obtidas pelos raios X vêm sendo utilizadas na análise da qualidade de sementes desde os anos 50 e, atualmente, vêm se destacando por ser um método rápido, de boa precisão e não destrutivo. Deste modo, o presente trabalho foi realizado com o objetivo de avaliar as características morfológicas dos embriões de sementes de Tecoma stans L. Juss. ex Kunth pertencentes a diferentes classes de massa através da análise de imagens obtidas pelo uso dos raios X, correlacionando-as com a germinação e morfologia das plântulas. Foram utilizadas sete classes de massa com trinta sementes em cada classe, que foram submetidas aos raios X para a obtenção das imagens dos embriões. Os embriões, de cada uma das classes, foram separados de acordo com suas características morfológicas em 4 categorias (embriões sem defeito, embriões com pequenos defeitos, embriões deformados e sementes sem embrião). As sementes das diferentes classes de massa foram colocadas para germinar (emissão da raiz primária) e após dez dias foi observado o número de plântulas normais em cada uma das categorias e classes de massa. A maioria das sementes das classes 1 e 2, mais leves, apresenta-se com embriões deformados ou sem embrião, enquanto que as de maior massa (classes 3 a 7) apresentam embriões sem defeitos...

Estimating seed mass and volume from linear dimensions of seeds

Casco, H.; Dias, L.S.
Fonte: Universidade de Évora Publicador: Universidade de Évora
Tipo: Artigo de Revista Científica Formato: 6343 bytes; application/pdf
ENG
Relevância na Pesquisa
56.23%
Seeds from eight species common in soil banks and covering two orders of magnitude of seed size were individually weighted and measured. Adopting simple but sound assumptions on seeds geometry, seed length and width together or not with thickness were found to be highly accurate estimators of seed mass and volume at intra- and inter-specific levels. Thereby, by abstracting the vast amount of published data of seed length and width, seed volume rather than seed mass only can be used to investigate ecological and functional aspects of seed size.

Seed production and seed quality of the dune building grass Panicum racemosum Spreng

Cordazzo,Cesar Vieira; Davy,Anthony John
Fonte: Sociedade Botânica do Brasil Publicador: Sociedade Botânica do Brasil
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/1994 EN
Relevância na Pesquisa
56.27%
Seed production, pollination requirement, seed characteristics related to quality and the relationship between number and mass of seeds were examined for Panicum racemosum in three successional populations in southern Brazilian coastal dunes. The seed production was generally low and declined further between the frontal dunes and the backdunes, dropping from 4.05 seeds per panicle in the former to 1.8 seeds in the latter. However fertility (% fertile florets) did not differ among the three habitats. Plants cross-pollinated in a glasshouse showed an increase in seed production to 41.4 seeds compared to no seed production in self-pollinated plants. Caryopses varied in mass from 3.2 to 12.2 mg with a mean of 7.98 mg. A strong negative correlation was found between mean individual seed mass and the total number of seeds per panicle in a natural population. However, this relationship did not persist in seeds produced by cultivated plants in the glasshouse. The causes of low seed production appear to be mainly pollen self-incompatibility and additionally competition for nutrients between sexual reproduction and allocation to clonal growth. Under conditions of nutrient shortage, Panicum racemosum probably allocates resources more to clonal growth and to fewer...

Effects of ovule and seed abortion on brood size and fruit costs in the leguminous shrub Caesalpinia gilliesii (Wall. ex Hook.) D. Dietr

Calviño,Ana
Fonte: Sociedade Botânica do Brasil Publicador: Sociedade Botânica do Brasil
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2014 EN
Relevância na Pesquisa
46.25%
For several plant species, brood size results from the abortion of ovules and seeds. However, these processes have rarely been studied together in wild plants. In some of the leguminous species studied, seed abortion has been found to depend on pollen quality and on the position of the ovule or fruit. The direct consequence for the mother plant is that fruit costs increase as the seed:ovule ratio decreases. However, because ovule abortion occurs earlier than does seed abortion, the former can reduce the biomass invested per seed (i.e., fruit costs) more efficiently than does the latter. Here, the frequencies of aborted ovules and seeds were analyzed in relation to the type of pollination treatment (open pollination vs. hand cross-pollination) and ovule/fruit position within pods of the leguminous shrub Caesalpinia gilliesii. The influence of ovule and seed abortion on fruit costs was analyzed by comparing the pericarp mass per seed between fruits with different frequencies of aborted ovules and seeds. The rate of ovule abortion was similar between hand cross-pollinated and open-pollinated fruits but was higher than that of seed abortion in one- and two-seeded fruits, as well as in those at stylar positions and in distal fruits. Hand cross-pollination reduced seed abortion but did not increase the seed:ovule ratio. In addition...

Effect of seed mass on germination and growth in three dominant species in southern Brazilian coastal dunes

CORDAZZO,C. V.
Fonte: Instituto Internacional de Ecologia Publicador: Instituto Internacional de Ecologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/08/2002 EN
Relevância na Pesquisa
46.27%
The effect of seed mass on germination and growth was tested in fresh-seeds of Blutaparon portulacoides, Panicum racemosum, and Spartina ciliata, selected at random in southern Brazilian populations. The seed mass varied within a population of the three species. Both B. portulacoides and P. racemosum showed normal frequency distribution of seed mass, while S. ciliata did not. Significant differences were observed in seed germination between large and small seeds of all species. In all species the capacity of seedling elongation was greater in seedlings of large seeds than those of small ones. Relative growth rate of seedlings of P. racemosum and S. ciliata decreased with time in all seed mass size-classes. On the other hand, the relative growth rate of B. portulacoides seedlings increased during the first 40 days. Seed mass is an important biological factor, affecting seed germination, seedling elongation, and growth of these species, and favoring large seeds, specially in areas of active sand accretion like coastal dunes.

The role of seed mass on the caching decision by agoutis, Dasyprocta leporina (Rodentia: Agoutidae)

Galetti,Mauro; Donatti,Camila I.; Steffler,Carla; Genini,Julieta; Bovendorp,Ricardo S.; Fleury,Marina
Fonte: Sociedade Brasileira de Zoologia Publicador: Sociedade Brasileira de Zoologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2010 EN
Relevância na Pesquisa
46.19%
It has been shown that the local extinction of large-bodied frugivores may cause cascading consequences for plant recruitment and overall plant diversity. However, to what extent the resilient mammals can compensate the role of seed dispersal in defaunated sites is poorly understood. Caviomorph rodents, especially Dasyprocta spp., are usually resilient frugivores in hunted forests and their seed caching behavior may be important for many plant species which lack primary dispersers. We compared the effect of the variation in seed mass of six vertebrate-dispersed plant species on the caching decision by the red-rumped agoutis Dasyprocta leporina Linnaeus, 1758 in a land-bridge island of the Atlantic forest, Brazil. We found a strong positive effect of seed mass on seed fate and dispersal distance, but there was a great variation between species. Agoutis never cached seeds smaller than 0.9 g and larger seeds were dispersed for longer distances. Therefore, agoutis can be important seed dispersers of large-seeded species in defaunated forests.

Control of seed mass by APETALA2

Ohto, Masa-aki; Fischer, Robert L.; Goldberg, Robert B.; Nakamura, Kenzo; Harada, John J.
Fonte: National Academy of Sciences Publicador: National Academy of Sciences
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
46.33%
Arabidopsis APETALA2 (AP2) encodes a member of the AP2/EREBP (ethylene responsive element binding protein) class of transcription factors and is involved in the specification of floral organ identity, establishment of floral meristem identity, suppression of floral meristem indeterminancy, and development of the ovule and seed coat. Here, we show that loss-of-function ap2 mutations cause an increase in seed mass relative to that of wild-type seeds. Analysis of an allelic series of ap2 mutations showed that increases in seed mass corresponded with the severity of defects in flower structure, indicating that AP2 activity directly influences seed mass. Experiments with male-sterile plants and deflowered wild-type plants showed that reduced fertility of ap2 mutant plants due to abnormal flower structure accounted for only part of the increase in seed mass caused by strong ap2 mutant alleles. Reciprocal cross experiments showed that AP2 acts maternally to control seed mass. The maternal effect of AP2 on seed mass involves the regulation of both embryo cell number and cell size. We show further that ap2 mutations cause changes in the ratio of hexose to sucrose during seed development, opening the possibility that AP2 may control seed mass through its effects on sugar metabolism. Together...

Factors that shape seed mass evolution

Moles, Angela T.; Ackerly, David D.; Webb, Campbell O.; Tweddle, John C.; Dickie, John B.; Pitman, Andy J.; Westoby, Mark
Fonte: National Academy of Sciences Publicador: National Academy of Sciences
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
46.24%
We used correlated divergence analysis to determine which factors have been most closely associated with changes in seed mass during seed plant evolution. We found that divergences in seed mass have been more consistently associated with divergences in growth form than with divergences in any other variable. This finding is consistent with the strong relationship between seed mass and growth form across present-day species and with the available data from the paleobotanical literature. Divergences in seed mass have also been associated with divergences in latitude, net primary productivity, temperature, precipitation, and leaf area index. However, these environmental variables had much less explanatory power than did plant traits such as seed dispersal syndrome and plant growth form.

Patterns of Cross-Continental Variation in Tree Seed Mass in the Canadian Boreal Forest

Liu, Jushan; Bai, Yuguang; Lamb, Eric G.; Simpson, Dale; Liu, Guofang; Wei, Yongsheng; Wang, Deli; McKenney, Daniel W.; Papadopol, Pia
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 11/04/2013 EN
Relevância na Pesquisa
46.36%
Seed mass is an adaptive trait affecting species distribution, population dynamics and community structure. In widely distributed species, variation in seed mass may reflect both genetic adaptation to local environments and adaptive phenotypic plasticity. Acknowledging the difficulty in separating these two aspects, we examined the causal relationships determining seed mass variation to better understand adaptability and/or plasticity of selected tree species to spatial/climatic variation. A total of 504, 481 and 454 seed collections of black spruce (Picea mariana (Mill.) B.S.P.), white spruce (Picea glauca (Moench) Voss) and jack pine (Pinus banksiana Lamb) across the Canadian Boreal Forest, respectively, were selected. Correlation analyses were used to determine how seed mass vary with latitude, longitude, and altitude. Structural Equation Modeling was used to examine how geographic and climatic variables influence seed mass. Climatic factors explained a large portion of the variation in seed mass (34, 14 and 29%, for black spruce, white spruce and jack pine, respectively), indicating species-specific adaptation to long term climate conditions. Higher annual mean temperature and winter precipitation caused greater seed mass in black spruce...

Does seed mass drive the differences in relative growth rate between growth forms?

Houghton, Jennie; Thompson, Ken; Rees, Mark
Fonte: The Royal Society Publicador: The Royal Society
Tipo: Artigo de Revista Científica
Publicado em 07/07/2013 EN
Relevância na Pesquisa
46.22%
The idea that herbaceous plants have higher relative growth rates (RGRs) compared with woody plants is fundamental to many of the most influential theories in plant ecology. This difference in growth rate is thought to reflect systematic variation in physiology, allocation and leaf construction. Previous studies documenting this effect have, however, ignored differences in seed mass. As woody species often have larger seeds and RGR is negatively correlated with seed mass, it is entirely possible the lower RGRs observed in woody species is a consequence of having larger seeds rather than different growth strategies. Using a synthesis of the published literature, we explored the relationship between RGR and growth form, accounting for the effects of seed mass and study-specific effects (e.g. duration of study and pot volume), using a mixed-effects model. The model showed that herbaceous species do indeed have higher RGRs than woody species, and that the difference was independent of seed mass, thus at all seed masses, herbaceous species on average grow faster than woody ones.

Effect of seed mass on germination and growth in three dominant species in southern Brazilian coastal dunes

Cordazzo, C??sar Vieira
Fonte: Universidade Federal do Rio Grande Publicador: Universidade Federal do Rio Grande
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
46.27%
The effect of seed mass on germination and growth was tested in fresh-seeds of Blutaparon portulacoides, Panicum racemosum, and Spartina ciliata, selected at random in southern Brazilian populations. The seed mass varied within a population of the three species. Both B. portulacoides and P. racemosum showed normal frequency distribution of seed mass, while S. ciliata did not. Significant differences were observed in seed germination between large and small seeds of all species. In all species the capacity of seedling elongation was greater in seedlings of large seeds than those of small ones. Relative growth rate of seedlings of P. racemosum and S. ciliata decreased with time in all seed mass size-classes. On the other hand, the relative growth rate of B. portulacoides seedlings increased during the first 40 days. Seed mass is an important biological factor, affecting seed germination, seedling elongation, and growth of these species, and favoring large seeds, specially in areas of active sand accretion like coastal dunes.; O efeito da massa das sementes sobre a germina????o e o crescimento foi testado com sementes de Blutaparon portulacoides, Panicum racemosum e Spartina ciliata coletadas aleatoriamente em popula????es no sul do Brasil. A massa das sementes variou dentro das popula????es das tr??s esp??cies. Ambas...

Seed production and seed quality of the dune-building grass Panicum racemosum Spreng

Cordazzo, C??sar Vieira; Davy, Anthony John
Fonte: Universidade Federal do Rio Grande Publicador: Universidade Federal do Rio Grande
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
56.26%
Seeel production, poIlination requirement, seed characteristics relateel to quality and the relationship between number anel mass of seeds were examineel for Panicum racemosum in three successional populations in so uthern Brazilian coastal dunes. The seed prod uction lVas generaIly low and eleclined further betlVeen the frontal dunes anel the backelunes, elropping from 4.05 seeds per panicle in the former to 1.8 seeds in the latter. HOlVever fettility (% fettile florets) eliel not differ among the three habitats. Plants cross-poIlinateel in a glasshouse showeel an in crease in seeel proeluction to 4 1.4 seeels compared to no seed production in self-poIlinated plants. Caryopses varied in mass from 3.2 to 12.2 mg lV ith a mean of 7.98 mg. A strong negative correlation was found between mean individual seed mass and the total number of seeds per panide in a natural population. However, this relation ship elid not persist in seeds proeluceel by cultivated plants in the glassho use. The causes of 101V seed production appear to be mainly poIlen se lf-incompatibility and additionally competition for nutrients between sexual reproduction and aIlocation to donal growth. Under conditions of nutrient shOltage, Panicllll1 raCell10SlIII1 probably aIlocates resources more to cIonal growth and to fewer...

Express??o relativa de genes, caracteriza????o qu??mica e estrutural de tegumentos e desempenho de sementes de soja com caracter??sticas contrastantes; Relative genes expression, chemical and structural characterization of seed coats and soybean seeds performance with contrasting traits

Bahry, Carlos Andr??
Fonte: Universidade Federal de Pelotas; Agronomia; Programa de P??s-gradua????o em Ci??ncia e Tecnologia de Sementes; UFPel; BR Publicador: Universidade Federal de Pelotas; Agronomia; Programa de P??s-gradua????o em Ci??ncia e Tecnologia de Sementes; UFPel; BR
Tipo: Tese de Doutorado Formato: application/pdf
POR
Relevância na Pesquisa
46.32%
Soybean seed coats perform as a modulator of the interactions between internal structures of seeds and the external environment, which are vital for its quality. In order to perform a deeper study, four tests were performed. In Test 1, the expression of eight genes was evaluated, possibly related to the quality of the seeds, and express on the seed coats; on Test 2, the seed coats chemical composition was determined; on Test 3, the internal structure of seed coats was analyzed and on Test 4, physical and physiological traits of seeds were evaluated. Four contrasting soybean genotypes were used for the seed coat traits, two yellow seed coats, BMX Pot??ncia RR and CD 202, and two black seed coats, TP and IAC. The relative expression of the genes VINV1, SCB1, SCS1, SBP, LEGINSULIN, CHIA1, SGF14c e CHS8* was evaluated through the qPCR technique in seven phases of seed coat development, on the 25, 30, 35, 40, 45, 50 and 55 days after anthesis. Concerning the chemical composition of the seed coats, the phenolic compounds concentration, antioxidant potential, anthocyanin, carotenoids and lignin were determined. For the structural characterization of the seed coats, two anatomic cuts of these in microtome and the documentation of the results were performed by the capture of images on the microscope. Seed quality was evaluated by the germination test and first counting...

Germination in Two Australian Species of Frankenia L., F. Serpyllifolia Lindl. and F. Foliosa J.M.Black (Frankeniaceae) - Effects of Seed Mass, Seed Age, Light, and Temperature

Easton, L.; Kleindorfer, S.
Fonte: Royal Soc South Australia Inc Publicador: Royal Soc South Australia Inc
Tipo: Artigo de Revista Científica
Publicado em //2008 EN
Relevância na Pesquisa
66.3%
We test the effects of seed mass, temperature (16°C, 24°C, 30°C), and seed age (1 year, 7 years, 20 years) on the germination rates of two arid zone plant species that differ in seed mass, but occur within the same genus (Frankenia) to determine whether these factors, or a combination of these factors, influence germination rates. Frankenia serpyllifolia sens. lat. produces one or two larger seeds per fruit whereas F. foliosa produces up to 27 smaller seeds per fruit. Both of these species co-occur geographically in northern South Australia and experience similar abiotic conditions (unpredictable rainfall, extremes in temperature, poor soil conditions). The results showed that germination success by Day 21 was similar between the species, whereas we found significant differences in germination rates during the first week. Frankenia serpyllifolia sens. lat. seeds germinated rapidly and were less temperature dependant for germination success. Frankenia foliosa seeds were relatively slower to germinate and germination rates were higher at lower temperatures. Differences in germination rates were demonstrated to result from an interaction between seed mass/seed age (ηp2 = 0.30), and an interaction between seed age/temperature (ηp2 = 0.19)...

Rapid Development of Adaptive, Climate-Driven Clinal Variation in Seed Mass in the Invasive Annual Forb Echium plantagineum L.

Konarzewski, Tara K.; Murray, Brad R.; Godfree, Robert C.
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 19/12/2012 EN
Relevância na Pesquisa
46.31%
We examined adaptive clinal variation in seed mass among populations of an invasive annual species, Echium plantagineum, in response to climatic selection. We collected seeds from 34 field populations from a 1,000 km long temperature and rainfall gradient across the species' introduced range in south-eastern Australia. Seeds were germinated, grown to reproductive age under common glasshouse conditions, and progeny seeds were harvested and weighed. Analyses showed that seed mass was significantly related to climatic factors, with populations sourced from hotter, more arid sites producing heavier seeds than populations from cooler and wetter sites. Seed mass was not related to edaphic factors. We also found that seed mass was significantly related to both longitude and latitude with each degree of longitude west and latitude north increasing seed mass by around 2.5% and 4% on average. There was little evidence that within-population or between-population variation in seed mass varied in a systematic manner across the study region. Our findings provide compelling evidence for development of a strong cline in seed mass across the geographic range of a widespread and highly successful invasive annual forb. Since large seed mass is known to provide reproductive assurance for plants in arid environments...

Global patterns in seed size

Moles, Angela T; Ackerly, David D; Tweddle, John C; Dickie, John B; Smith, Roger; Leishman, Michelle R; Mayfield, Margaret M; Pitman, Andy J; Wood, Jeffrey; Westoby, Mark
Fonte: Blackwell Publishing Ltd Publicador: Blackwell Publishing Ltd
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
56.19%
Aim: To provide the first global quantification of the slope and shape of the latitudinal gradient in seed mass, and to determine whether global patterns in seed mass are best explained by growth form, vegetation type, seed dispersal syndrome, or net prim

Seed-seedling allometry in tropical rain forest trees: seed mass-related patterns of resource allocation and the reserve effect.

Green, P; Juniper, P
Fonte: Blackwell Publishing Ltd Publicador: Blackwell Publishing Ltd
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
66.31%
1. The seedlings of larger seeded species generally perform better than those of smaller seeded species under a variety of hazards. The reserve effect proposes that larger seeded species retain a greater proportion of their initial seed resources and their seedlings are therefore better provisioned to cope with post-deployment resource deficits. 2. This hypothesis was tested with a suite of 32 Australian rain forest species with storage cotyledons, and seed reserve mass ranging from 36 mg to 25 g. Seedlings germinated in dim light were harvested as their first set of leaves became fully expanded, dissected into shoot, root and left-over cotyledons, dried and weighed. 3. In cross-species, allometric analyses, the mean mass of the shoot-plus-root scaled less than proportionately (slope c. 0.8), and mean cotyledon mass more than proportionately (slope c. 1.1) with either initial seed mass or seedling mass. These slopes were significantly different from each other. Both conditions for a reserve effect were therefore fulfilled. Cotyledons ranged from 45% of total seedling mass in the smallest species, to 92% in the largest. 4. Solid evidence for a reserve effect was detected within two of four families tested (Lauraceae and Myrtaceae), but only in 7 of the 22 species for which there were sufficient data. 5. Even if the reserve effect has present day utility for enhanced seedling performance in larger seeded species...