Perianth colour affects germination behaviour in wind-pollinated Salsola rubescens in Arabian deserts

Abstract

Salsola rubescens Franch. is a wind-pollinated halophytic shrub that produces fruits with red and yellow winged perianths. Germinability of seeds from both fruit types was determined under various light, temperature, and salinity treatments. Red seeds, with and without winged perianths, were heavier than yellow seeds. Germination percentage and germination rate index (speed) were significantly affected by the perianth colour, presence of wings, and temperature and light of incubation and most of their interactions. Germination percentage was greater for yellow-winged seeds than for red-winged seeds. Wing removal significantly enhanced the germination percentage and germination speed in the two types. The presence of wings enhanced germination at lower temperatures, but wing absence enhanced germination at higher temperatures. Wing removal enhanced germination to a greater degree in yellow than in red seeds. There was no light requirement during germination of red-winged seeds, but yellow-winged seeds germinated significantly more in light than in darkness. Red-winged and dewinged seeds were more tolerant to salinity than yellow seeds. Removal of wings significantly increased salinity tolerance for seeds of both wing colours. It is concluded that the showy perianth colours have an ecological role in wind-pollinated plants in regulating dormancy and germination behaviour in the heterogeneous unpredictable hyperarid deserts.Résumé : Le Salsola rubescens Franch., un arbuste halophyte pollinisé par le vent, produit des fruits avec périanthes ailés rouges ou jaunes. Les auteurs ont déterminé le potentiel germinatif des deux types de graines sous différents traitements de lumière, de temperature, et de salinité. Les graines rouges, avec ou sans périanthes ailés, sont plus lourdes comparativement aux graines jaunes. Le pourcentage de germination et l'index du taux de germination (vitesse) sont affectés de façon significative par la couleur du périanthe, la présence des ailes, ainsi que par la température et la lumière d'incubation incluant la plupart de leurs interactions. Le pourcentage de germination est plus grand chez les graines à ailes jaunes comparativement aux graines à ailes rouges. L'ablation des ailes augmente significativement le pourcentage et la vitesse de germination chez les deux types. La présence des ailes augmente la germination aux faibles températures, mais l'absence des ailes augmente la germination aux températures plus élevées. L'ablation des ailes augmente la germination à un plus fort degré chez les graines jaunes que chez les rouges. On n'observe pas de besoin en lumière au cours de la germination des graines à ailes rouges, mais les graines à ailes jaunes germent significativement plus à la lumière qu'à l'obscurité. Les graines rouges et les graines privées de leurs ailes s'avèrent plus tolérantes à la salinité que les graines jaunes. L'ablation des ailes augmente significativement la tolérance à la salinité chez les graines aux ailes des deux couleurs. On conclut que les couleurs voyantes des...

Perianth colour dimorphism is related to germination properties and salinity tolerance in Salsola vermiculata in the Arabian deserts

“…We also found that removal of the perianth wing significantly increased germination percentage and rate in both colour morphs. These results are in a line with previous studies on seed germination in S. vermiculata ( and ), S. villosa (), and S. rubescens (). Under natural conditions, the wings do gradually decompose in the soil and there might also be leaching of the chemicals that inhibit seed germination.…”

“…Several reproductive and ecological strategies are used by desert plants to survive under unpredictable climatic conditions (, , and ). Infrequent, variable seed germination and seedling establishment is one of the strategies adopted by desert species to survive extremes of high temperature, low rainfall and high salinity ().…”

Maternal habitat affects germination requirements of Anabasis setifera, a succulent shrub of the Arabian deserts

“…In order to enhance survival and fitness in such stressful environments, desert plants developed complementary sets of adaptation and survival strategies during different stages of their life cycles (Gutterman 2002;El-Keblawy 2004). For example, factors such as seed morphology, mass, wing size and persistence can all greatly affect the seed dispersal, dormancy and germination behavior of many desert plants (Xing et al 2013;El-Keblawy et al 2013;El-Keblawy & Bhatt 2015).…”

Seed colour affects light and temperature requirements during germination in two Lotus species (Fabaceae) of the Arabian subtropical deserts

“…Seed heterogeneity, which is the variations in size, colour and weight is a phenomena commonly reported in many species of the desert environment (Volis, & Bohrer, 2013;El-Keblawy, Bhatt, & Gairola, 2013). Heterogeneity in seeds mostly occurs due to physiological, environmental and genetic factors (Dickson, & Boettger, 1982;Atak et al, 2008).…”

“…in addition, the study aimed to assess the impact of seed colour on light and temperature requirements during germination for the two species. We assume that colours of structures surrounding seeds and seed colours would affect light filtering properties, which in turn affect germination requirements, especially light of incubation (xing et al 2013, El-Keblawy, Bhatt, & Gairola, 2013. Germination behavior of the two species was assessed through studying final germination percentage and germination rate.…”