Effect of Garlic and Licorice Extracts on Vegetative Growth and Leaf Anatomy of Strawberry Plants Cultivated in Different Growing Media

This research was conducted to investigate the effect of garlic cloves extract (GCE) at 50 and 100 g l-1 and licorice root extract (LRE) at 25 and 50 g l-1 as foliar spray treatments on the vegetative growth and leaf anatomy of strawberry plants cultivated in different growing media, i.e. traditional soil (silt : sand 1:1 v/v), solid substrates (Peatmoss, Perlite and vermiculite 1:1:1 v/v/v), hydroponic (DFT technique) during 2017 and 2018 seasons. The growth of strawberry plants cv. festival cultivated in the three assigned growing media was significantly enhanced by the applied GCE and LRE treatments.  Significant increases in the fresh and dry weights of root and shoots, root size, number of leaves and total leaves area / plant were obtained with all GCE and LRE treatments, while a significant reduction in roots / shoots ratio was occurred. In addition, both treatments caused a significant increase in the leaf content of photosynthetic pigments, nitrogen, phosphorous, potassium, calcium, magnesium and crude protein compared with the untreated plants. Anatomically, the applied concentrations of both GCE and LRE led to obvious increases in the thickness of mid vein, length and width of main vascular bundle, thickness of phloem and xylem tissues, number of xylem vessels/ bundle and thickness of lamina and its  tissue components  (upper and lower epidermis and mesophyll tissue). Furthermore, these positive effects of GCE and LRE treatments on the vegetative growth, chemical composition and leaf anatomy were most pronounced with the plants cultivated in solid substrate mixture followed by the plants cultivated hydroponically then those cultivated in traditional soil. Also, LRE at 50 g l-1 was the most effective treatment in this respect followed by LRE at 25 g l-1 then GCE at 50 g l-1 while GCE at 100 g l-1 was the least effective. Therefore, the present study strongly confirm the use of GCE and LRE as healthy safe and eco-friendly treatments to improve growth of strawberry plants whether cultivated in traditional soil or in soil alternatives and also to reduce the risks of using growth regulators for clean and safe agriculture.