Tagged: Seeds


Variable seed dormancy and germination in Hibbertia

Variable seed dormancy and germination in Hibbertia

Several ecologically important plant families in Mediterranean biomes have seeds with morphophysiological dormancy. Hidayati et al. study four species of the intractably dormant Australian genus Hibbertia (Dilleniaceae) and find that although they are congeneric, sympatric and produce seeds of identical morphology, they show a remarkable level of variation in dormancy-break and germination requirements. The results have important implications for current classification systems of seed dormancy and highlight the difficulties, and caution required, in extrapolating dormancy requirements in biodiverse regions such as the south-west Australian biodiversity hotspot.

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Friedrich Justin Bertuch, Bilderbuch für Kinder, 1790–1830.

Phytophoenixism

In biology, matters are rarely either good or bad; oftentimes they may be both at once (albeit usually for different organisms). Take for instance hydrogen cyanide, which is widely regarded to be rather bad since it is a potent poison that can kill most living things by ‘interfering’ (that’s a euphemism!) with respiration. However, it seems that cyanide also has a good side. Apart from its role in deterring would-be herbivores, Gavin Flematti et al. propose that it may also act as an important stimulus for the germination of some seeds (Nature Communications). The Australia-based group showed that burning plant...

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A fascinating conservation problem and a failure of my imagination

The January 2011 Annals of Botany is out and I had hoped to put together a press release for one of the papers. Seeds of alpine plants are short lived: implications for long-term conservation by Mondoni et al is one of those papers that states the obvious, but does so in a way that makes you realise that some simple solutions aren’t going to work. The problem is based around seed banks. These are banks where seeds are stored in cool conditions to prevent them from germinating. The one that grabs a lot of the headlines is the Svalbard Global...

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Functionality of marcescent corollas

Functionality of marcescent corollas

Functionality of marcescent corollas Persistence of withered corollas after anthesis (‘corolla marcescence’) is widespread in angiosperms, yet its functional significance does not seem to have been explored. Herrera examines seed production in two southern Spanish insect-pollinated plants, Viola cazorlensis and Lavandula latifolia, and shows that removal of the corollas increases mean number of seeds per fruit in the former, but decreases the proportion of flowers that produce ripened fruit in the latter as a result of higher insect seed predation. Thus marcescent corollas should not be dismissed a priori as biologically irrelevant left-overs from past floral functions.

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Osmotic and salinity effects on germination

Osmotic and salinity effects on germination

Osmotic and salinity effects on germination Seeds in saline environments face a dilemma between allocating reserves to either osmotic balance or growth and development.  Zhang et al. show that barley seeds incubated in saline solutions germinate more rapidly than seeds in iso-osmotic PEG solutions. This suggests that barley seeds use salt as a metabolically cheap cellular osmotica, facilitating rapid germination under moderately saline conditions.

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Hormones and sugar network signalling in seeds

Hormones and sugar network signalling in seeds

Hormones and sugar network signalling in seeds Endospermic legumes are abundant in tropical forests and their establishment is closely related to the mobilization of storage polysaccharides and proteins. Tonini et al. adopt a systems approach to evaluate the effects of abscisic acid (ABA), ethylene and sugars on mobilization in Sesbania virgata during the period of establishment. They find that ABA appears to repress enzyme action and retard degradation of storage protein whilst ethylene has the opposite effect. Changes in concentrations of glucose and sucrose during this period suggest that ABA, ethylene and sugars interact to control the process of storage...

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Spikelet seed position-dependent effects on life history - Eremopyrum distans

Spikelet seed position-dependent effects on life history

The cold desert annual grass Eremopyrum distans exhibits position-dependent effects of seeds in the spikelet. Wang et al. (pp. 95–105) find that seeds from three positions in a spikelet differ in morphology, mass and in percentage and rate of seed germination, and the plants derived from them differ in growth and seed production. Distal seeds appear to represent a ‘high-risk’ life history strategy and basal seeds a ‘low-risk’ strategy.

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