Cardinal Temperatures For Germination Research Articles

In Vitro Studies on Seed Germination of the Mediterranean Species Anthyllis barba-jovis to Facilitate Its Introduction into the Floriculture Industry

Anthyllis barba-jovis is a salt and drought tolerant evergreen shrub, native of the western-central Mediterranean coasts, with ornamental characteristics that make it worthy to be exploited for commercial use as an ornamental and landscape plant. Therefore, the present study aimed to determine germination as affected by seed-coat, temperature, photoperiod, and seed storage period, as a first approach to introduce the species into the floriculture industry. Seeds scarified or non-scarified, recently harvested or after storage at room temperature in the dark for 12, 24, or 36 months were placed for germination in vitro on Murashige and Skoog (MS) medium, under 16 h photoperiod (LD) or continuous darkness, at 5–35 °C, at 5 °C intervals. Seed pre-treatment by mechanical scarification with sandpaper highly promoted their germinability. Seeds germinated in all treatments at varying percentages. Photoperiod had no significant effect on germination. Cardinal temperatures for germination were defined at 35 °C and 5 °C (possibly even lower, particularly for up to 1-year-old seeds, which germinated at 30–58% at 5 °C when scarified). Temperatures from 15 to 25 °C were optimal for germination of recently harvested or 1-year-old seeds (82–98% when scarified), whereas older seeds germinated at higher percentages at 20 °C (65–97% when scarified), thus long storage affected both the range of optimal temperatures for germination and the germination percentage. Storage reduced germination mostly of non-scarified seeds. Three years after harvesting A. barba-jovis seeds germinated at high percentages (77%) at 20 °C and LD when scarified, while without scarification germination was less than 10% in all treatments.

Dormancy and cardinal temperatures for germination in seed from nine quinoa genotypes cultivated in Chile

AbstractIn Chile, two quinoa ecotypes are grown: salares, also present in the highlands of Bolivia, and coastal, in central and southern areas of the country, at sea level. Genotypes from the coastal ecotype have characteristics that differentiate them from the most popular quinoa genotypes grown in the Andean Region of South America. The objectives of this study were: (1) to determine the cardinal temperatures for seed germination in quinoa genotypes from coastal and salares ecotypes cultivated in Chile, and (2) to study the presence of physiological dormancy (PD) in these genotypes. Seed germination from nine quinoa genotypes, two from salares and seven from coastal ecotypes, was evaluated in a gradient of temperatures between 11 and 42°C. Germination was also evaluated at 20°C at 0, 7 and 15 months from harvest. Results showed that seed from the nine genotypes germinated at their maximum percentage between 11 and 35°C. However, their faster germination occurred between 25 and 35°C. There was a significant difference between optimum temperature for germination between genotypes from coastal (28°C) and salares (30°C). An increase in germination rates after 7 months of storage suggested the presence of a non-deep PD in seeds from coastal ecotype, which may be useful to improve pre-harvest sprouting resistance in quinoa breeding programmes.

CARDINAL TEMPERATURES FOR GERMINATION OF THE MEDICINAL ANDDESERT PLANT, Calotropis procera

ABSTRACT Calotropis procera, Apocynaceae, is a wild perennial shrub that originated in the Persian deserts. It is known to provide key resources in degraded ecosystems to about 80 animal species. C. procera is regenerated by seed and produces lots of small seeds that are dispersed by wind; nonetheless, its density is very low. The purpose of this study is to estimate the cardinal temperatures including the base, optimum, and maximum temperatures of Calotropis procera looking at two different ecotypes in the Iranian desert. The germination behavior of C. procera seeds was tested at temperature regimens of 0, 5, 10, 15, 20, 25, 30, 35 and 40oC and was analyzed using linear regression models. The rate of germination increased between base and optimum thermal conditions, and decreased between optimum and maximum thermal conditions. The base, optimum and maximum temperatures for germination of C. procera seeds were estimated at 19.10, 30.75 and 47.80 oC for the Fars and 20.00, 31.82 and 49.69oC for the Zahedan desert, respectively. Temperature and germination were rated to determine the seeding dates of the C. procera. Overall, cardinal temperatures for germination were dependent on local climate characteristics for the range of adaptations in plant growth of the given species.

The influence of temperature during seed development on the germination characteristics of millet seeds

Abstract. The cardinal temperatures, rate of germination and final percentage germination of pearl millet seeds were measured for seeds raised in greenhouses maintained at mean air temperatures of 19, 22, 25, 28 and 31°C. The results showed that cardinal temperatures for germination are unaffected by the temperature during seed development and growth. However, the conditions during seed growth did affect seed size and, subsequently, germination rate and seed viability.

Germination of the conidia of Peziza ostracoderma

Conidia ofPeziza ostracodermaKorf, washed by centrifugation and decantation, germinated in a high percentage in glass-distilled water and various nutrient solutions. They also germinated on a wide variety of agar media and in citratephosphate buffers from pH 3 through 8. The conidia first swell to twice their original size, and then emit one cylindrical germ tube. The cardinal temperatures for germination were: minimum, below 3° C; optimum, 20°–33° C; maximum, between 38° and 42° C. A liquid film of water was required for germination.