Evaluation of Pre- or Postharvest Application of Some Minerals and Organic Agents on the Growth, Flowering and Vase Life of Rudbeckia hirta, L.

Abstract

<p>The experiments were carried out during 2014 and 2015 summer seasons at the greenhouses of the Experimental Farm of Faculty of Agriculture, Kafr El-Sheikh University. The experiments were conducted in two phases: First one (pre-harvest): <em>Rudbeckia hirta</em> seedlings were transplanted during the first week of May to 30 cm diameter plastic pots filled with a soil mixture of clay and sand (1:1, v:v). Pots were divided in two equal groups, the first one, plants were foliar sprayed with one of the following:- Distilled water for the control treatment, CaCl<sub>2</sub> (125, 250, 375 mg·L<sup>-1</sup>), NiSO<sub>4</sub> (30, 45, 60 mg·L<sup>-1</sup>), CoCl<sub>2</sub> (50, 75, 100 mg·L<sup>-1</sup>), K<sub>2</sub>SiO<sub>3</sub> (100, 150, 200 mg·L<sup>-1</sup>) and SA (100, 150, 200 mg·L<sup>-1</sup>) at 60, 45, 30 and 15 days before harvest. The second group was without pre-harvest application assay (untreated plants).</p><p>Second phase (postharvest) was conducted in two different methods as follows: First method, flower stems resulted from each pre-harvest treatment were preserved in 250 mL graduated test tube filled with 200 mL of standard holding solution consists of sucrose (4%) + 8-Hydroxyquinoline citrate (250 mg·L<sup>-1</sup>). The second method, flower stems resulted from plants without pre-harvest application preserved in holding solution consists of a constant sucrose (4%) and 8-Hydroxyquinoline citrate (250 mg·L<sup>-1</sup>) beside one of the following additives: Distilled water for the control treatment, CaCl<sub>2</sub> (125, 250, 375 mg·L<sup>-1</sup>), NiSO<sub>4</sub> (30, 45, 60 mg·L<sup>-1</sup>), CoCl<sub>2</sub> (50, 75, 100 mg·L<sup>-1</sup>), K<sub>2</sub>SiO<sub>3</sub> (100, 150, 200 mg·L<sup>-1</sup>) and Salicylic acid (100, 150, 200 mg·L<sup>-1</sup>). Results showed that, pre harvest spraying plants with higher levels of K<sub>2</sub>SiO<sub>3</sub> or CaCl<sub>2</sub> recorded the highest values for all plant vegetation characters. K<sub>2</sub>SiO<sub>3</sub> followed by SA excelled on others in most flowering aspects. At the post harvest stage, SA, K<sub>2</sub>SiO<sub>3</sub> and CaCl<sub>2</sub> exchanged the excellence between them for most vase life measurements. Flowers resulted from plants that preharvest treated was better than those that did not preharvest treated.</p>