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Ineke Stulen - One of the best experts on this subject based on the ideXlab platform.
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Effect of NaCl salinity on nitrate uptake in Plantago maritima L
Phyton-annales Rei Botanicae, 2005Co-Authors: Michael Rubinigg, Freek Posthumus, J.t.m. Elzenga, Ineke StulenAbstract:Exposure of plants to NaCl salinity reduces the rate of nitrate net uptake by the roots. Previous studies showed that this effect was due to a reduced nitrate influx, which could only partially be explained by a lower demand of nitrate for growth. In the present work we tested the hypothesis that the observed decrease in nitrate net uptake rate is specific for nitrate and that this effect is due to a competitive or non-competitive inhibition of the nitrate transport system at the root plasma membrane. We conclude that NaCl induced reduction in nitrate net uptake rate was specific as it did not affect the uptake of other anions such as sulphate or phosphate. We could rule out that competitive or non-competitive inhibition of the nitrate transport system by external Cl- was responsible for the reduction of nitrate influx.
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NaCl salinity affects lateral root development in Plantago maritima
Functional plant biology : FPB, 2004Co-Authors: Michael Rubinigg, J.t.m. Elzenga, Julia Wenisch, Ineke StulenAbstract:Root growth and morphology were assessed weekly in hydroponically-grown seedlings of the halophyte Plantago maritima L. during exposure to 0, 50, 100 and 200 mm NaCl for 21 d. Relative growth rate was reduced by 25% at 200 mm NaCl. The lower NaCl treatments did not affect relative growth rates. Primary and lateral roots responded differently to NaCl. While primary-root length increased at all NaCl concentrations, total lateral-root length increased at 50 and was not affected at 100 mm but was considerably reduced at 200 mm NaCl. NaCl concentrations of 50 and 100 mm, which had no effect on relative growth rate or total lateral-root length, severely affected root branching pattern in that the number of first, second and third order laterals was reduced. At 200 mm NaCl third order laterals were not formed at all. However, mean lateral-root length was increased at all NaCl concentrations and was highest at 200 mm NaCl. We conclude that the increase in total lateral-root length in plants at 50 and 100 mm NaCl was mainly caused by increased length growth, while the decrease in total lateral-root length at 200 mm was the consequence of inhibition of lateral root primordia and / or the activation of apical meristems rather than reduced length growth.
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Effects of NaCl salinity on ^15N-nitrate fluxes and specific root length in the halophyte Plantago maritima L.
Plant and Soil, 2003Co-Authors: Michael Rubinigg, Freek Posthumus, J.t.m. Elzenga, Melanie Ferschke, Ineke StulenAbstract:The effect of salinity on nitrate influx, efflux, nitrate net uptake rate and net nitrogen translocation to the shoot was assessed in a ^15N steady state labelling experiment in the halophyte Plantago maritima L. raised for 14 days on solution supplied with 50, 100 and 200 mol m^−3 sodium chloride or without sodium chloride. Additionally, salinity induced changes in root morphology were determined. Specific root length increased upon exposure to elevated sodium chloride concentrations due to variations in biomass allocation and length growth of the tap root. Changes in root morphology, however, had a minor effect on nitrate fluxes when expressed on a root fresh weight basis. The decreased rate of nitrate net uptake in plants grown on elevated levels of sodium chloride was almost entirely due to a decrease in nitrate influx. Expressed as a proportion of influx, nitrate efflux remained unchanged and was even lower at the highest salinity level. At all sodium chloride concentrations applied the initial rate of nitrogen net translocation to the shoot decreased relative to the rate of nitrate net uptake. It is concluded that under steady state conditions the negative effect of sodium chloride on the rate of nitrate net uptake at non growth-limiting salinity levels was due to the interaction between sodium chloride and nitrate transporters in the root plasma membrane and/or processes mediating the translocation of nitrogen compounds, possibly nitrate, to the shoot.
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Effects of NaCl salinity on N-15-nitrate fluxes and specific root length in the halophyte Plantago maritima L.
Plant and Soil, 2003Co-Authors: Michael Rubinigg, Freek Posthumus, J.t.m. Elzenga, Melanie Ferschke, Ineke StulenAbstract:The effect of salinity on nitrate influx, efflux, nitrate net uptake rate and net nitrogen translocation to the shoot was assessed in a 15N steady state labelling experiment in the halophyte Plantago maritima L. raised for 14 days on solution supplied with 50, 100 and 200 mol m−3 sodium chloride or without sodium chloride. Additionally, salinity induced changes in root morphology were determined. Specific root length increased upon exposure to elevated sodium chloride concentrations due to variations in biomass allocation and length growth of the tap root. Changes in root morphology, however, had a minor effect on nitrate fluxes when expressed on a root fresh weight basis. The decreased rate of nitrate net uptake in plants grown on elevated levels of sodium chloride was almost entirely due to a decrease in nitrate influx. Expressed as a proportion of influx, nitrate efflux remained unchanged and was even lower at the highest salinity level. At all sodium chloride concentrations applied the initial rate of nitrogen net translocation to the shoot decreased relative to the rate of nitrate net uptake. It is concluded that under steady state conditions the negative effect of sodium chloride on the rate of nitrate net uptake at non growth-limiting salinity levels was due to the interaction between sodium chloride and nitrate transporters in the root plasma membrane and/or processes mediating the translocation of nitrogen compounds, possibly nitrate, to the shoot.
Emil K. Nilsson - One of the best experts on this subject based on the ideXlab platform.
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Six polymorphic microsatellite markers for Plantago maritima
Molecular Ecology Notes, 2006Co-Authors: Emil K. Nilsson, Niclas Gyllenstrand, Kirsten WolffAbstract:Plantago maritima displays an extraordinary variation in breeding system. In northern Europe, the species occurs as either self-incompatible or self-compatible, and as unisexual females or co-sexual hermaphrodites. The isolation of polymorphic codominant markers will provide the necessary tools to investigate the proportion of self-fertilized seeds and levels of inbreeding depression in natural populations of this species. Isolation of microsatellite loci was achieved using a membrane-enrichment method for four loci, and a streptavidin-coated-beads method for two loci. Primers were designed in microsatellite flanking sequences and were analysed using fluorescent labels.
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Population size, female fecundity, and sex ratio variation in gynodioecious Plantago maritima
Journal of evolutionary biology, 2006Co-Authors: Emil K. Nilsson, Jon ÅgrenAbstract:Theory predicts that the sex ratio of gynodioecious populations (in which hermaphrodites and females coexist) will be affected by the relative female fitness of females and hermaphrodites, and by founder events and genetic drift in small populations. We documented the sex ratio and size of 104 populations of the gynodioecious, perennial herb Plantago maritima in four archipelagos in eastern Sweden and western Finland (from latitude 53 to 64 degrees N). The sex ratio varied significantly both among and within archipelagos (range 0-70% females, median 6.3% females). The frequency of females was highest in the northernmost archipelago and lowest in the southernmost archipelago. As predicted, females were more frequently missing from small than from large populations, and the variance in sex ratio increased with decreasing population size. The relative fecundity of female plants (mean seed output per female/mean seed output per hermaphrodite) ranged from 0.43 to 2.16 (median 1.01, n = 12 populations). Among the 12 populations sampled for seed production (four in each of three archipelagos), the frequency of females was positively related to relative fecundity of females and negatively related to population size. The results suggest that the local sex ratio is influenced both by the relative fecundity of females and hermaphrodites and by stochastic processes in small populations.
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Population density and seed output in self-compatible and self-incompatible populations of the wind-pollinated herb Plantago maritima
2005Co-Authors: Emil K. Nilsson, Vanessa Coronel, Jon ÅgrenAbstract:In this thesis, I examined variation in sex expression and mating patterns in the sexually polymorphic, wind-pollinated herb Plantago maritima. With a combination of field studies, greenhouse experiments, and genetic analyses, I (a) examined factors influencing sex ratio variation in gynodioecious plants (in which hermaphrodites and females coexist), (b) discovered variation in breeding system, (c) investigated density-dependence of seed production, and (d) documented genetic variation within and among populations close to the northern range margin in Europe. In a survey of 104 P. maritima populations, I documented considerable variation in sex ratio (range 0-70% females, median 6.3% females). As predicted, females were more frequently missing from small than from large populations, and the variance in sex ratio increased with decreasing population size. Among twelve populations sampled for seed production, the frequency of females was positively related to relative fecundity of females and negatively related to population size. The results suggest that the local sex ratio is influenced both by the relative fecundity of females and hermaphrodites, and by stochastic processes in small populations.A comparative field study showed that plant fecundity decreased with increasing distance to nearest pollen donor both within and among populations in an archipelago in southern Sweden, where self-incompatibility was confirmed in controlled crosses. In contrast, plant fecundity was overall higher and was not density-dependent in the Skeppsvik archipelago in northern Sweden, where controlled crosses showed that plants are self-compatible. The results were consistent with the prediction that evolution of self-fertility should reduce density-dependence of pollination success.I quantified the genetic structure within and among populations from eastern Sweden and western Finland based on variation at four polymorphic microsatellite loci. The genetic diversity was low in northern Sweden, which may be the result of a history of small population sizes and periods of frequent self-fertilization.
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Mating system evolution in the wind-pollinated herb Plantago maritima: loss of self-incompatibility close to the northern range margin in Europe
2005Co-Authors: Emil K. Nilsson, Kirsten Wolff, Jon ÅgrenAbstract:In this thesis, I examined variation in sex expression and mating patterns in the sexually polymorphic, wind-pollinated herb Plantago maritima. With a combination of field studies, greenhouse experiments, and genetic analyses, I (a) examined factors influencing sex ratio variation in gynodioecious plants (in which hermaphrodites and females coexist), (b) discovered variation in breeding system, (c) investigated density-dependence of seed production, and (d) documented genetic variation within and among populations close to the northern range margin in Europe. In a survey of 104 P. maritima populations, I documented considerable variation in sex ratio (range 0-70% females, median 6.3% females). As predicted, females were more frequently missing from small than from large populations, and the variance in sex ratio increased with decreasing population size. Among twelve populations sampled for seed production, the frequency of females was positively related to relative fecundity of females and negatively related to population size. The results suggest that the local sex ratio is influenced both by the relative fecundity of females and hermaphrodites, and by stochastic processes in small populations.A comparative field study showed that plant fecundity decreased with increasing distance to nearest pollen donor both within and among populations in an archipelago in southern Sweden, where self-incompatibility was confirmed in controlled crosses. In contrast, plant fecundity was overall higher and was not density-dependent in the Skeppsvik archipelago in northern Sweden, where controlled crosses showed that plants are self-compatible. The results were consistent with the prediction that evolution of self-fertility should reduce density-dependence of pollination success.I quantified the genetic structure within and among populations from eastern Sweden and western Finland based on variation at four polymorphic microsatellite loci. The genetic diversity was low in northern Sweden, which may be the result of a history of small population sizes and periods of frequent self-fertilization.
Jon Ågren - One of the best experts on this subject based on the ideXlab platform.
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Population size, female fecundity, and sex ratio variation in gynodioecious Plantago maritima
Journal of evolutionary biology, 2006Co-Authors: Emil K. Nilsson, Jon ÅgrenAbstract:Theory predicts that the sex ratio of gynodioecious populations (in which hermaphrodites and females coexist) will be affected by the relative female fitness of females and hermaphrodites, and by founder events and genetic drift in small populations. We documented the sex ratio and size of 104 populations of the gynodioecious, perennial herb Plantago maritima in four archipelagos in eastern Sweden and western Finland (from latitude 53 to 64 degrees N). The sex ratio varied significantly both among and within archipelagos (range 0-70% females, median 6.3% females). The frequency of females was highest in the northernmost archipelago and lowest in the southernmost archipelago. As predicted, females were more frequently missing from small than from large populations, and the variance in sex ratio increased with decreasing population size. The relative fecundity of female plants (mean seed output per female/mean seed output per hermaphrodite) ranged from 0.43 to 2.16 (median 1.01, n = 12 populations). Among the 12 populations sampled for seed production (four in each of three archipelagos), the frequency of females was positively related to relative fecundity of females and negatively related to population size. The results suggest that the local sex ratio is influenced both by the relative fecundity of females and hermaphrodites and by stochastic processes in small populations.
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Population density and seed output in self-compatible and self-incompatible populations of the wind-pollinated herb Plantago maritima
2005Co-Authors: Emil K. Nilsson, Vanessa Coronel, Jon ÅgrenAbstract:In this thesis, I examined variation in sex expression and mating patterns in the sexually polymorphic, wind-pollinated herb Plantago maritima. With a combination of field studies, greenhouse experiments, and genetic analyses, I (a) examined factors influencing sex ratio variation in gynodioecious plants (in which hermaphrodites and females coexist), (b) discovered variation in breeding system, (c) investigated density-dependence of seed production, and (d) documented genetic variation within and among populations close to the northern range margin in Europe. In a survey of 104 P. maritima populations, I documented considerable variation in sex ratio (range 0-70% females, median 6.3% females). As predicted, females were more frequently missing from small than from large populations, and the variance in sex ratio increased with decreasing population size. Among twelve populations sampled for seed production, the frequency of females was positively related to relative fecundity of females and negatively related to population size. The results suggest that the local sex ratio is influenced both by the relative fecundity of females and hermaphrodites, and by stochastic processes in small populations.A comparative field study showed that plant fecundity decreased with increasing distance to nearest pollen donor both within and among populations in an archipelago in southern Sweden, where self-incompatibility was confirmed in controlled crosses. In contrast, plant fecundity was overall higher and was not density-dependent in the Skeppsvik archipelago in northern Sweden, where controlled crosses showed that plants are self-compatible. The results were consistent with the prediction that evolution of self-fertility should reduce density-dependence of pollination success.I quantified the genetic structure within and among populations from eastern Sweden and western Finland based on variation at four polymorphic microsatellite loci. The genetic diversity was low in northern Sweden, which may be the result of a history of small population sizes and periods of frequent self-fertilization.
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Mating system evolution in the wind-pollinated herb Plantago maritima: loss of self-incompatibility close to the northern range margin in Europe
2005Co-Authors: Emil K. Nilsson, Kirsten Wolff, Jon ÅgrenAbstract:In this thesis, I examined variation in sex expression and mating patterns in the sexually polymorphic, wind-pollinated herb Plantago maritima. With a combination of field studies, greenhouse experiments, and genetic analyses, I (a) examined factors influencing sex ratio variation in gynodioecious plants (in which hermaphrodites and females coexist), (b) discovered variation in breeding system, (c) investigated density-dependence of seed production, and (d) documented genetic variation within and among populations close to the northern range margin in Europe. In a survey of 104 P. maritima populations, I documented considerable variation in sex ratio (range 0-70% females, median 6.3% females). As predicted, females were more frequently missing from small than from large populations, and the variance in sex ratio increased with decreasing population size. Among twelve populations sampled for seed production, the frequency of females was positively related to relative fecundity of females and negatively related to population size. The results suggest that the local sex ratio is influenced both by the relative fecundity of females and hermaphrodites, and by stochastic processes in small populations.A comparative field study showed that plant fecundity decreased with increasing distance to nearest pollen donor both within and among populations in an archipelago in southern Sweden, where self-incompatibility was confirmed in controlled crosses. In contrast, plant fecundity was overall higher and was not density-dependent in the Skeppsvik archipelago in northern Sweden, where controlled crosses showed that plants are self-compatible. The results were consistent with the prediction that evolution of self-fertility should reduce density-dependence of pollination success.I quantified the genetic structure within and among populations from eastern Sweden and western Finland based on variation at four polymorphic microsatellite loci. The genetic diversity was low in northern Sweden, which may be the result of a history of small population sizes and periods of frequent self-fertilization.
Michael Rubinigg - One of the best experts on this subject based on the ideXlab platform.
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Effect of NaCl salinity on nitrate uptake in Plantago maritima L
Phyton-annales Rei Botanicae, 2005Co-Authors: Michael Rubinigg, Freek Posthumus, J.t.m. Elzenga, Ineke StulenAbstract:Exposure of plants to NaCl salinity reduces the rate of nitrate net uptake by the roots. Previous studies showed that this effect was due to a reduced nitrate influx, which could only partially be explained by a lower demand of nitrate for growth. In the present work we tested the hypothesis that the observed decrease in nitrate net uptake rate is specific for nitrate and that this effect is due to a competitive or non-competitive inhibition of the nitrate transport system at the root plasma membrane. We conclude that NaCl induced reduction in nitrate net uptake rate was specific as it did not affect the uptake of other anions such as sulphate or phosphate. We could rule out that competitive or non-competitive inhibition of the nitrate transport system by external Cl- was responsible for the reduction of nitrate influx.
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NaCl salinity affects lateral root development in Plantago maritima
Functional plant biology : FPB, 2004Co-Authors: Michael Rubinigg, J.t.m. Elzenga, Julia Wenisch, Ineke StulenAbstract:Root growth and morphology were assessed weekly in hydroponically-grown seedlings of the halophyte Plantago maritima L. during exposure to 0, 50, 100 and 200 mm NaCl for 21 d. Relative growth rate was reduced by 25% at 200 mm NaCl. The lower NaCl treatments did not affect relative growth rates. Primary and lateral roots responded differently to NaCl. While primary-root length increased at all NaCl concentrations, total lateral-root length increased at 50 and was not affected at 100 mm but was considerably reduced at 200 mm NaCl. NaCl concentrations of 50 and 100 mm, which had no effect on relative growth rate or total lateral-root length, severely affected root branching pattern in that the number of first, second and third order laterals was reduced. At 200 mm NaCl third order laterals were not formed at all. However, mean lateral-root length was increased at all NaCl concentrations and was highest at 200 mm NaCl. We conclude that the increase in total lateral-root length in plants at 50 and 100 mm NaCl was mainly caused by increased length growth, while the decrease in total lateral-root length at 200 mm was the consequence of inhibition of lateral root primordia and / or the activation of apical meristems rather than reduced length growth.
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Effects of NaCl salinity on ^15N-nitrate fluxes and specific root length in the halophyte Plantago maritima L.
Plant and Soil, 2003Co-Authors: Michael Rubinigg, Freek Posthumus, J.t.m. Elzenga, Melanie Ferschke, Ineke StulenAbstract:The effect of salinity on nitrate influx, efflux, nitrate net uptake rate and net nitrogen translocation to the shoot was assessed in a ^15N steady state labelling experiment in the halophyte Plantago maritima L. raised for 14 days on solution supplied with 50, 100 and 200 mol m^−3 sodium chloride or without sodium chloride. Additionally, salinity induced changes in root morphology were determined. Specific root length increased upon exposure to elevated sodium chloride concentrations due to variations in biomass allocation and length growth of the tap root. Changes in root morphology, however, had a minor effect on nitrate fluxes when expressed on a root fresh weight basis. The decreased rate of nitrate net uptake in plants grown on elevated levels of sodium chloride was almost entirely due to a decrease in nitrate influx. Expressed as a proportion of influx, nitrate efflux remained unchanged and was even lower at the highest salinity level. At all sodium chloride concentrations applied the initial rate of nitrogen net translocation to the shoot decreased relative to the rate of nitrate net uptake. It is concluded that under steady state conditions the negative effect of sodium chloride on the rate of nitrate net uptake at non growth-limiting salinity levels was due to the interaction between sodium chloride and nitrate transporters in the root plasma membrane and/or processes mediating the translocation of nitrogen compounds, possibly nitrate, to the shoot.
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Effects of NaCl salinity on N-15-nitrate fluxes and specific root length in the halophyte Plantago maritima L.
Plant and Soil, 2003Co-Authors: Michael Rubinigg, Freek Posthumus, J.t.m. Elzenga, Melanie Ferschke, Ineke StulenAbstract:The effect of salinity on nitrate influx, efflux, nitrate net uptake rate and net nitrogen translocation to the shoot was assessed in a 15N steady state labelling experiment in the halophyte Plantago maritima L. raised for 14 days on solution supplied with 50, 100 and 200 mol m−3 sodium chloride or without sodium chloride. Additionally, salinity induced changes in root morphology were determined. Specific root length increased upon exposure to elevated sodium chloride concentrations due to variations in biomass allocation and length growth of the tap root. Changes in root morphology, however, had a minor effect on nitrate fluxes when expressed on a root fresh weight basis. The decreased rate of nitrate net uptake in plants grown on elevated levels of sodium chloride was almost entirely due to a decrease in nitrate influx. Expressed as a proportion of influx, nitrate efflux remained unchanged and was even lower at the highest salinity level. At all sodium chloride concentrations applied the initial rate of nitrogen net translocation to the shoot decreased relative to the rate of nitrate net uptake. It is concluded that under steady state conditions the negative effect of sodium chloride on the rate of nitrate net uptake at non growth-limiting salinity levels was due to the interaction between sodium chloride and nitrate transporters in the root plasma membrane and/or processes mediating the translocation of nitrogen compounds, possibly nitrate, to the shoot.
Patrik Dinnétz - One of the best experts on this subject based on the ideXlab platform.
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Spatial distribution of male sterility in Plantago maritima
Oikos, 1998Co-Authors: Patrik Dinnétz, Lenn JerlingAbstract:Sexual polymorphism in angiosperms can be explained both by the functional responses of male and female function to autogamy and geitonogamy, and by the conflict between the nuclear and cytoplasmic genomes. In predominantly hermaphrodite species, cytoplasmically determined male sterility may persist in a population because of maternal inheritance, i.e. the loss of male function does not change the fitness of the cytoplasmic genome. However, in populations with cytoplasmic male sterility. male fertility is often restored by nuclear genes. Therefore, in populations with genetical substructure, the frequencies of the different sex-morphs will fluctuate depending on the presence of both the male sterile cytoplasms, and of their specific nuclear restorer genes. In Plantago maritima, we showed that the frequencies of male sterility were highest in regions with the highest population turnover rates and that male sterile individuals were more frequently found in the lower, less dense parts of the meadows. This indicates that male sterile cytoplasms have their highest probabilities to escape their nuclear restorer genes during recolonisation in disturbed regions within populations. We also found that male sterile individuals dispersed their seeds a little bit further than did the hermaphrodites. This can be interpreted as an adaptive response to the local occurrence of nuclear restorer genes.
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Male sterility, protogyny, and pollen-pistil interference in Plantago maritima (Plantaginaceae), a wind-pollinated, self-incompatible perennial.
American journal of botany, 1997Co-Authors: Patrik DinnétzAbstract:Evolution and maintenance of male sterility in seed plants can be explained by the maternal inheritance of mitochondria, which encode the trait, and by adaptive functions that enhance female fecundity in male-sterile compared to hermaphrodite individuals. Protogyny and male sterility can independently decrease the negative effect of pollen‐pistil interference in selfincompatible species. In Plantago maritima, which possesses both traits, protogyny increases seed set in hermaphrodite individuals. This is shown both by a significantly positive association between seed set and retarded dehiscence of the anthers and by a more than 50% reduction in seed set following self-pollination. Male sterility does not seem to increase seed set further, as female and hermaphrodite plants do not differ significantly in mean seed set per capsule. Bagging experiments demonstrate strong self-incompatibility in the study populations. Hence, in P. maritima male sterility seems neither to prevent selfing nor to reduce the effect of pollen‐pistil interference. Females had significantly larger stigmas than hermaphrodites, but seed set varied negatively with stigma length among females, indicating that the evolution of unisexuality in P. maritima is not due to prefertilization sex allocation. I therefore conclude that the genetical system of nucleocytoplasmic determination of gender is the main cause for maintenance of male sterility in P. maritima. The evolution and maintenance of females in gynodioecious species depend critically on whether male sterility is a nuclear or cytoplasmic trait. With nuclear male sterility, females must produce at least twice as many
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gynodioecy in Plantago maritima l no compensation for loss of male function
Acta Botanica Neerlandica, 1997Co-Authors: Patrik Dinnétz, Lenn JerlingAbstract:Size, allocation of biomass, seed production of hermaphrodites and male steriles as well as germination, growth rate and survival among their progeny were compared between male fertile and male ste ...