Focal plants are considerably affected by their neighbouring plants,especially when growing in heterogeneous soils.A previous study on grasses demonstrated that soil heterogeneity and species composition affected plan...Focal plants are considerably affected by their neighbouring plants,especially when growing in heterogeneous soils.A previous study on grasses demonstrated that soil heterogeneity and species composition affected plant biomass and above-and belowground allocation patterns.We now tested whether these findings were similar for forbs.Three forb species(i.e.Spartina anglica,Limonium bicolor and Suaeda glauca)were grown in pots with three levels of soil heterogeneity,created by alternatively filling resource-rich and resource-poor substrates using small,medium or large patch sizes.Species compositions were created by growing these forbs either in monocultures or in mixtures.Results showed that patch size×species composition significantly impacted shoot biomass,root biomass and total biomass of forbs at different scales.Specifically,at the pot scale,shoot biomass,root biomass and total biomass increased with increasing patch size.At the substrate scale,shoot biomass and total biomass were higher at the large patch size than at the medium patch size,both in resource-rich and resource-poor substrates.Finally,at the community scale,monocultures had more shoot biomass,root biomass and total biomass than those in the two-or three-species mixtures.These results differ from earlier findings on the responses of grasses,where shoot biomass and total biomass decreased with patch size,and more shoot biomass and total biomass were found in resource-rich than resource-poor substrates.To further elucidate the effects of soil heterogeneity on the interactions between neighbour plants,we advise to conduct longer-term experiments featuring a variety of functional groups.展开更多
Aims We investigate the effect of position within a size-structured population on the reproductive allocation(RA)and flowering probability of individual plants of Sinapis arvensis.We also assess the effects of plant s...Aims We investigate the effect of position within a size-structured population on the reproductive allocation(RA)and flowering probability of individual plants of Sinapis arvensis.We also assess the effects of plant size and changing level of CO_(2) on both responses.Methods Sinapis arvensis L.,(field mustard),an annual agricultural weed,was grown in monoculture at six densities under ambient and elevated CO_(2) in a study with 84 stands.Individual aboveground biomass and reproductive biomass were measured.Varying density produced a wide range of mean plant sizes across stands and size hierarchies within stands.Many(;40%)individuals had zero reproductive biomass.Employing a novel modelling approach,we analysed the joint effects of position in stand size hierarchy,plant size and CO_(2) on RA and flowering probability of individuals.Important Findings We found a strong effect of position within the size hierarchy of individuals in a population:for an individual of a given size,greater size relative to neighbours substantially increased RA and flowering probability at a single harvest time.There was no other effect of plant size on RA.We found a positive effect of elevated CO_(2) on RA regardless of position within the size hierarchy.These observed patterns could impact doubly on the reproductive biomass(R)of small individuals.First,because RA is not affected by size,smaller plants will have smaller R than larger plants;and second,for smaller plants lower down in a population size hierarchy,their RA and hence R will be further reduced.These results suggest that size relative to neighbours may be independent of and more important than direct abiotic effects in determining RA.Further studies are required to evaluate how these observed patterns generalize to other populations in non-experimental conditions.展开更多
基金supported by the Open Fund of Key Laboratory of Biodiversity and Environment on the Qinghai-Tibet Plateau,Ministry of Education(KLBE2024002)a start-up fund from Lanzhou University(508000-561119213).
文摘Focal plants are considerably affected by their neighbouring plants,especially when growing in heterogeneous soils.A previous study on grasses demonstrated that soil heterogeneity and species composition affected plant biomass and above-and belowground allocation patterns.We now tested whether these findings were similar for forbs.Three forb species(i.e.Spartina anglica,Limonium bicolor and Suaeda glauca)were grown in pots with three levels of soil heterogeneity,created by alternatively filling resource-rich and resource-poor substrates using small,medium or large patch sizes.Species compositions were created by growing these forbs either in monocultures or in mixtures.Results showed that patch size×species composition significantly impacted shoot biomass,root biomass and total biomass of forbs at different scales.Specifically,at the pot scale,shoot biomass,root biomass and total biomass increased with increasing patch size.At the substrate scale,shoot biomass and total biomass were higher at the large patch size than at the medium patch size,both in resource-rich and resource-poor substrates.Finally,at the community scale,monocultures had more shoot biomass,root biomass and total biomass than those in the two-or three-species mixtures.These results differ from earlier findings on the responses of grasses,where shoot biomass and total biomass decreased with patch size,and more shoot biomass and total biomass were found in resource-rich than resource-poor substrates.To further elucidate the effects of soil heterogeneity on the interactions between neighbour plants,we advise to conduct longer-term experiments featuring a variety of functional groups.
文摘Aims We investigate the effect of position within a size-structured population on the reproductive allocation(RA)and flowering probability of individual plants of Sinapis arvensis.We also assess the effects of plant size and changing level of CO_(2) on both responses.Methods Sinapis arvensis L.,(field mustard),an annual agricultural weed,was grown in monoculture at six densities under ambient and elevated CO_(2) in a study with 84 stands.Individual aboveground biomass and reproductive biomass were measured.Varying density produced a wide range of mean plant sizes across stands and size hierarchies within stands.Many(;40%)individuals had zero reproductive biomass.Employing a novel modelling approach,we analysed the joint effects of position in stand size hierarchy,plant size and CO_(2) on RA and flowering probability of individuals.Important Findings We found a strong effect of position within the size hierarchy of individuals in a population:for an individual of a given size,greater size relative to neighbours substantially increased RA and flowering probability at a single harvest time.There was no other effect of plant size on RA.We found a positive effect of elevated CO_(2) on RA regardless of position within the size hierarchy.These observed patterns could impact doubly on the reproductive biomass(R)of small individuals.First,because RA is not affected by size,smaller plants will have smaller R than larger plants;and second,for smaller plants lower down in a population size hierarchy,their RA and hence R will be further reduced.These results suggest that size relative to neighbours may be independent of and more important than direct abiotic effects in determining RA.Further studies are required to evaluate how these observed patterns generalize to other populations in non-experimental conditions.
