Effects of irrigation levels and soil properties modifiers on vegetative properties of Lycium depressum stocks in pot reproduction

The present research on Lycium depressum stocks aims to study the vegetative responses (leaf area, leaf specific weight, leaf specific area, dry weight ratio of root to shoot, dry weight of leaf, stem, and root) of the pasture shrub of Kam Tigh against drought stress and the effect of soil amendment on these responses. 

 The experiment was conducted in a factorial design based on a completely randomized design, including the main irrigation treatment at four levels (100, 75, 50, and 25% of crop capacity) and sub-treatment of soil conditioners under semi-controlled greenhouse conditions. The experiment involved five repetitions and 160 pots for each combined irrigation and soil amendment treatment. Sub-treatments of soil conditioners, including Stacosorb hydrogel, were added at 3 grams per kilogram of soil in each pot in the lower part of the plant roots. Mineral Zeolite in 8 grams per pot was placed in the lower part of the plant roots. Nitrobacter was added in the amount of 3 cc in each pot in the upper root area of the plant. Mycorrhiza at 10 grams per pot was added to the lower plant roots. 

Generally, a significant difference (p<0.05) was observed in all irrigation levels between the treatments in each soil amendment material. In zeolite with mycorrhiza, the highest stem dry weight and leaf-specific weight were obtained at a 50% irrigation level. With the increase in leaf-specific gravity and drought stress, plant dry weight increased, and proline content decreased in Nitrobacter and mycorrhizal treatment, which differed from the treatment. Measurements of leaf area revealed that leaf area decreased from 1450 mm2 in 100% and 75% irrigation to 900 mm2 in 25% irrigation. This indicated the impact of drought stress on the leaf area. The highest specific weight of leaves at 25% irrigation was related to Nitrobacter with mycorrhiza. This modifier increased the specific weight of leaves from 0.0025 g/m2 at 100% irrigation level to 0.0028 g/m2 at 25% irrigation level. Leaf surface area in Nitrobacter treatment with mycorrhiza during 100% irrigation decreased from 400 mm2/g to 350 mm2/g during 25% irrigation. In hydrogel treatment without mycorrhiza, the dry weight ratio of root to shoot at 100% irrigation level declined from 2 grams to 1.4 grams in 25% irrigation. The dry weight of the leaf decreased from 1.4 g in 100% irrigation to 1.3 g in 25% irrigation. 

Biofertilizers enhance plant resistance to drought stress by improving vegetative characteristics. Nitrobacter treatments without mycorrhiza, hydrogel, and zeolite with mycorrhiza are recommended for planting this plant due to improved growing conditions. Since the Kam Tig plant is considered a medicinal plant, it can be used as a soil conditioner in the pharmaceutical and medical industries. This will enable better cultivation of the species. All organizations related to the cultivation of Kam Tig species can use the results of this research to enhance cultivation projects.