Seed mass and dormancy of annual plant populations and communities decreases with aridity and rainfall predictability

2011 ◽  
Vol 12 (8) ◽  
pp. 674-684 ◽  
Author(s):  
Danny Harel ◽  
Claus Holzapfel ◽  
Marcelo Sternberg
Keyword(s):  
Seed Mass ◽  
Annual Plant ◽  
Plant Populations

Does dose-dependent petal damage affect pollen limitation in an annual plant?

Botany ◽  
2010 ◽  
Vol 88 (6) ◽  
pp. 601-606 ◽  
Author(s):  
Andrew C. McCall
Keyword(s):  
Pollen Limitation ◽  
Annual Plant ◽  
Selective Force ◽  
Plant Populations ◽  
Pollinator Service ◽  
Nemophila Menziesii ◽  
The Impact ◽  
Dose Dependent ◽  
Floral Damage

Damage to flowers by herbivores, or florivory, can have direct impacts on gamete survival and can also indirectly affect fitness by reducing pollinator service. While recent studies have examined the impact of natural or artificial floral damage, very few researchers have manipulated both damage and pollen addition to see whether pollen limitation is enhanced by damage, and no workers, to my knowledge, have examined whether pollen limitation is dependent on the levels of florivory used. I used a pollen addition treatment and six levels of artificial floral damage to investigate whether damage increases pollen limitation and whether that pollen limitation becomes more severe with increasing numbers of petals damaged in Nemophila menziesii Hook. & Arn. I found that artificial floral damage that mimics natural florivore damage increases pollen limitation, and that this pollen limitation generally increased with increasing numbers of petals damaged. The treatment with the heaviest amount of damage did not suffer the most pollen limitation, perhaps because flowers in this treatment remained radially symmetric. These findings suggest that florivory may decrease pollen import through pollinator deterrence and could thus serve as a selective force on either floral or defense traits in outcrossing plant populations.

scholarly journals Internal Seed Structure of Alpine Plants and Extreme Cold Exposure

Data ◽  
2019 ◽  
Vol 4 (3) ◽  
pp. 107 ◽  
Author(s):  
Ganesh K. Jaganathan ◽  
Sarah E. Dalrymple
Keyword(s):  
Climate Change ◽  
Snow Cover ◽  
Seed Mass ◽  
Soil Surface ◽  
Crystal Formation ◽  
Ice Crystal ◽  
Seed Structure ◽  
Plant Populations ◽  
Extreme Cold ◽  
Angiosperm Species

Cold tolerance in seeds is not well understood compared to mechanisms in aboveground plant tissue but is crucial to understanding how plant populations persist in extreme cold conditions. Counter-intuitively, the ability of seeds to survive extreme cold may become more important in the future due to climate change projections. This is due to the loss of the insulating snow bed resulting in the actual temperatures experienced at soil surface level being much colder than without snow cover. Seed survival in extremely low temperatures is conferred by mechanisms that can be divided into freezing avoidance and freezing tolerance depending on the location of ice crystal formation within the seed. We present a dataset of alpine angiosperm species with seed mass and seed structure defined as endospermic and non-endospermic. This is presented alongside the locations of temperature minima per species which can be used to examine the extent to which different seed structures are associated with snow cover. We hope that the dataset can be used by others to demonstrate if certain seed structures and sizes are associated with snow cover, and if so, would they be negatively impacted by the loss of snow resulting from climate change.

Spatial Dynamics and Critical Patch Size of Annual Plant Populations

1998 ◽  
Vol 190 (3) ◽  
pp. 277-285 ◽  
Author(s):  
J. Latore ◽  
P. Gould ◽  
A.M. Mortimer
Keyword(s):  
Patch Size ◽  
Spatial Dynamics ◽  
Annual Plant ◽  
Plant Populations ◽  
Critical Patch Size

Effect of rotation and cultivation systems on establishment and persistence of annual medics

1989 ◽  
Vol 29 (2) ◽  
pp. 183 ◽  
Author(s):  
EJ Crawford ◽  
BG Nankivell
Keyword(s):  
Lower Proportion ◽  
The Other ◽  
Annual Plant ◽  
Plant Populations ◽  
The Third ◽  
Permanent Pasture ◽  
Seed Reserves ◽  
Annual Medics ◽  
Annual Medicago ◽  
Medicago Species

The persistence and annual and seasonal regeneration of 3 annual Medicago species, M. rugosa cv. Paragosa, M. scutellata cv. Robinson and M. truncatula cvv. Cyprus and Jemalong, were compared between 1978 and 1985 over 3 rotation systems, permanent pasture (R1); pasture, barley, pasture, barley repeated (R2) and pasture, fallow, wheat, barley, repeated (R3). Ploughing practices adopted for the various rotations affected persistence and regeneration. Not all ofthe seed that was produced in 1978 produced seedlings. A much lower proportion of the seed reserve of cv. Paragosa produced seedlings compared with cv. Robinson and cvv. Cyprus and Jemalong. The poorer re-establishment of cv. Paragosa could have been due to its more permeable seed compared with the other cultivars. Seed reserves persisted for a maximum of 7 years. Annual re-establishment was greater for all cultivars under the system of permanent pasture than under either the pasture, barley or the pasture, fallow, wheat, barley rotations which disturbed the soil. Unlike the other cultivars, germination and establishment rates of cv. Robinson were low following the first autumn rains in all years. Germination of this cultivar usually occurred from June to November following a delayed breakdown in hardseededness. It also responded to cultivation so that with the exception of R2 in 1980, the highest annual plant populations in R2 and R3 were in the cropping and/or fallowing phases rather than the pasture phases. Although cv. Paragosa produced the highest seed yield in the year of sowing, its reserves were exhausted by the third year in all rotations, whereas the harder seeded cultivars maintained adequate seed reserves to enable good plant re-establishment in the sixth year under all rotations, except in the continuous pasture rotation, where seed reserves of cv. Robinson were exhausted by the fifth year. Cultivation and consequent pod burial in the 2 cropping rotations preserved seeds longer than did the continuous pasture system. Jemalong maintained higher (P< 0.05) seed reserves than cvv. Cyprus and Robinson in the sixth year.

scholarly journals Does seed mass drive interspecies variation in the effect of management practices on weed demography?

2020 ◽  
Author(s):  
Kazakou Elena ◽  
Fried Guillaume ◽  
Cheptou Pierre-Olivier ◽  
Gimenez Olivier
Keyword(s):  
Seed Bank ◽  
Management Practices ◽  
Seed Mass ◽  
Demographic Parameters ◽  
Weed Species ◽  
Plant Populations ◽  
Interspecies Variation ◽  
Weed Population Dynamics ◽  
Do So

AbstractOptimizing the effect of management practices on weed population dynamics is challenging due to the difficulties in inferring demographic parameters in seed banks and their response to disturbance. Here, we used a long-term plant survey between 2006 and 2012 in 46 French vineyards and quantified the effects of management practices (tillage, mowing and herbicide) on colonization, germination and seed survival of 30 weed species in relation to their seed mass. To do so, we used a recent statistical approach to reliably estimate demographic parameters for plant populations with a seed bank using time series of presence–absence data, which we extended to account for interspecies variation in the effects of management practices on demographic parameters. Our main finding was that when the level of disturbance increased (i.e., in plots with a higher number of herbicide, tillage or mowing treatments), colonization and survival in large-seeded species increased faster than in small-seeded species. High disturbance through tillage increased survival in the seed bank of species with high seed mass. The application of herbicides, considered as an intermediate disturbance, increased germination, survival and colonization probabilities of species with high seed mass. Mowing, representing habitats more competitive for light, increased the survival of species with high seed mass. Overall, the strong relationships between the effects of management practices and seed mass provides an indicator for predicting the dynamics of weed communities under disturbance.

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