Comparative use of cress seed germination and physiological parameters of Helianthus annuus L. to assess compost maturation

SUMMARY Seed germination of six sunflower (Helianthus annuus L.) hybrids was investigated across a range of eleven constant temperatures between 5°C and 45°C. Large temperature differences in germination rate 1/t (d-1), cardinal temperature (°C) and thermal time θ (°cd) were observed among hybrids. Base temperatures (Tb) varied between 3.3°C and 6.7°C whereas maximum germination temperatures (Tm) varied between 41.7°C and 48.9°C. Final germination fraction was attained at 15°C - 25°C whereas the maximum rate of germination was attained at 30.4°C - 35.6°C. The maximum germination rate of hybrid USDA 894, the cultivar with the slowest germination rate, was only 50% of that of hybrid EX 47. The low Tb and high Tm of sunflower appear to be one of the factors which explain the successful adaptation of sunflower to a wide range of temperature. These findings are discussed in relation to the origin of the crop and its wide adaptations in diverse habitats and climatic zones.

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Seed Germination and Physiological Response of Sunflower (Helianthus annuus L.) Cultivars under Saline Conditions

Bulletin of University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca Horticulture ◽

10.15835/buasmvcn-hort:003817 ◽

2018 ◽

Vol 75 (1) ◽

pp. 4

Author(s):

Carmen BEINSAN ◽

Renata SUMALAN ◽

Giancarla VELICEVICI ◽

Adriana CIULCA ◽

Radu SUMALAN

Keyword(s):

Seed Germination ◽

Helianthus Annuus ◽

Dry Matter ◽

Saline Stress ◽

Free Proline ◽

Radicle Growth ◽

Helianthus Annuus L ◽

Control Seed ◽

Germination Process

The purpose of the experiment was to highlight the germination of sunflower seeds affected by the presence of saline stress and the identification of tolerant genotypes. The biological material was represented by sunflower cvs. (Helianthus annuus L.): Coril, Select, Santiago and Fundulea-206. To simulate the saline conditions, germination solutions of sodium chloride (NaCl) were used with concentrations corresponding to the osmotic pressures -6 and -10 atm and the control seed hydration was performed with distilled water. Determination of seed germination, growth of seedling, percentage of plumules dry matter, chlorophyll content and free proline were performed. The experimental data obtained suppose the existence in the assimilation apparatus of sunflowers seedling subjected to stress a competitive chlorophyll/free proline biosynthesis processes. The experimental results regarding the effect of salinity on seed germination and seedling growth revealed important differences between genotypes. The radicle growth in the germination process were strongly affected by saline excess, with significant differences between cultivars. Saline stress results in significant reductions in the amount of chlorophyll, and high levels of free proline. It can be observed that with the increase of the stress level the percentage of the dry matter increases, indicating an accentuated water deficit.

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