Interactive Effects of Salinity and Water Stress on Germination of Sunflower (Helianthus annuus L.)
Keywords:
salinity, water stress, germination inhibition, sunflowerAbstract
Salinity and water deficit are major abiotic stresses limiting seed germination in semi-arid regions. This reduces agricultural productivity in the region and the world at large. Plant’s response to salinity and water stress vary in physiological and biochemical processes. The study investigated the effects of salt and water stress on the germination of sunflower. This was carried out in Maiduguri a Sudano-Sahelian Savannah vegetation of Nigeria. Maiduguri has both rainy (June-October) and dry seasons (November-May) of a tropical climate. The experimental design was a Completely Randomized Block Design (CRBD), A total of fifteen (15) (S1(2.2dS/m) S4I1-S4I3, S2I1, S2(2.8dS/m) S2I1, S2I2, S2I3 S3(3.5dS/m) S3I1, S3I2, S3I3, S4(4.6dS/m) S4I1, S4I2, S4I3; S5(8.2dS/m) S5I1, S5I2, S5I3) treatments were used in the experiment. Seeds at 8.2dS/m salinity did not germinate (P>0.05) significantly. The result showed that control treatment had the highest germination percentage of 93.33% and treatments S4I1-S4I3 had the lowest germination percentage of 53.33%. The result showed a decrease in germination percentage with increase in salt stress and no change with increase in water stress. The result indicated that sunflower has a lower water demand for germination as seeds germinated under three (3) water stress levels. The result further showed that salt stress has a more negative effect on germination of sunflower seeds, as no germination was recorded in the highest salinity level of 8.2dS/m. The results also indicated that germination was significantly (P >0.05) reduced by salt stress. The plants under the highest salt and water stress level accumulated more proline (12.01 µg/ml), compared to the control (2.18 µg/ml), at P> 0.05. Generally, salt and water stress negatively affect the germination of Sunflower.
