AbstractKey words: Gracilaria dendroides
A field experiment was conducted, June 2009 to study the effects of foliar applications of different concentrations of seaweed extract of Ulva lactuca (Ulvaceae) and Gracilaria dendroides (Gracilariaceae) on nutrient uptake, growth and yield of sunflower plant. There were five treatment control and two concentration 0.4 and 0.6 % w/v from each algal extract, this treatment applied at 3 times; first one at the seedling stage (20 days after sowing), the second at the flowering stage (40 days after sowing), while the third one before yield stage (70 days after sowing). Application of algal extract significantly increase fresh and dry weight of root and shoot, chlorophyll a, chlorophyll b and carotenoids rather than the control, especially with 0.6% extract of G. dendroides.
At harvest stage, application of seaweed significantly increase both root and shoot fresh and dry weight, plant height, head diameter, seed index (weight of 1000 seed), seed yield as compared to control. Also, the highest growth parameters were observed in plant treated by 0.6% extract of G. dendroides, except plant height.
Highest oil content was observed at 0.6 % G. dendroides extract, followed with 0.6% U. lactuca extract application (34.05 and 30.55%, respectively). The application of extract of 0.4 % and 0.6 % for both studied algae significantly increased seed yield of sunflower by 20.94, 40.31, 30.29 and 28.73%, respectively, compared to control.
Improved nutrient uptake (Na and K) was also observed with seaweed extract applications. Thus, foliar applications of seaweed extracts could be a promising option for yield enhancement and high oil yield production of sunflower plant.
, Oil content, Sunflower, Ulva lactuca