Physiological Responses of Hybrid Rose (Rosa hybrida L.) to Foliar Glycine and Licorice Root Extract Under Heat Stress Conditions

• Hadeia Abed Atiyah1*, Manal Zibari Sabti2 and Abdul-Kadhm N.S.Al-Showily3

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Roses Hybrid (Rosa hybrida L.) have shown sensitivity during development and blooming with regard to high temperature and high light. Foliar biostimulants can help in maintaining performance of plants under these stresses. This study evaluated the effects of shading, glycine, and licorice root extract on the vegetative growth and flowering of hybrid rose. Factorial experiments were carried out during both spring and fall seasons in which 162 potted plants were used. Treatment combinations included two shading rates (0 and 50%), three rates of glycine (0, 5, and 10 mg L⁻¹), and three rates of licorice root extract (0, 50, and 100 g L⁻¹). At 50% shading, there was an increase in flower number, branch number, leaf number, fresh and dry weight, length of main branch, and root length. Addition of glycine caused an increase in flower number, flower diameter, fresh and dry weight, and petals number. The licorice root extract caused an increase in leaf number, stem diameter, fresh and dry weight, and petals number. The highest flower number (8.33 plant⁻¹), branch number (3.33 plant⁻¹), leaf number (119.7 plant⁻¹), and root length (26.3 cm) were achieved when 50% shading, 10 mg L⁻¹ glycine, and 100 g L⁻¹ licorice root extract were combined. Moderately shaded plants, supplemented with glycine and licorice root extract, performed well in terms of growth and

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