Greenhouse Plant Production Journal

Abstract Artificial light source is one of the most important factors for high quality and quantity vegetable production in a plant factory. Aiming to investigate the role of light spectra on growth, chlorophyll fluorescence, photosynthesis and stomata parameters in lettuce plants grown in a plant factory, a factorial experiment was conducted based on a completely randomized design with two lettuce cultivars (Lollo Rossa and Lollo Bionda) and four spectra LED illumination red (656 nm), red/blue (3:1) (656 nm), blue (450 nm) and white (449 nm). The results showed that the combination of red and blue LED light had the greatest effect on stomatal conductance (gs), number of stomata, length and width of stomata in both lettuce cultivars. Also the maximum substomatal CO2 concentration (Ci) was observed in both lettuce cultivars when they were treated with red LED light. The results also showed that the maximum CO2 assimilation rate (PN) was observed in Rossa variety under white LED and in Bionda cultivar under blue LED light. Contrary to the results related to some of photosynthetic parameters, the highest values of vegetative traits (plant height, dry and fresh mass of shoots and roots, leaf number and leaf area) of plants were observed in the treatment of red and blue light combination. It is concluded that plant growth, chlorophyll fluorescence characteristics, photosynthetic and stomatal properties can be affected by different spectra and cultivars of lettuce, so that the choice of proper lighting is a fundamental requirement for the cultivation of this plant

Abstract Snail medic (Medicago scutellata L.) is among the crucial medicinal legumes that exhibit minimal growth rates during the germination stage under salt and drought stresses. The objective of this study is to identify the sensitive components of seedling growth in response to salt and drought stresses. In the first experiment, seeds were subjected to magnetic field levels of 125 and 250 mT for varying durations (6, 12, 18, and 24 h). In the second experiment, ultrasonic waves were applied for durations of 3, 6, 9, 12, and 15 min. Both experiments were conducted using various osmotic pressures (OP) induced by NaCl (-3, -6, -9, and -12 MPa) and PEG 6000 (for similar OPs) with three replications. The results indicated that seedling growth rate (SGR), weight of mobilized seed reserve (WMSR), seed reserve depletion (SRDP), and seed reserve utilization efficiency (SRUE) were significantly affected by salt and drought stresses. Moreover, the maximum seedling dry weight (SLDW) of 0.195 mg was observed in the magnetic field treatments of 125 mT during 12 h, and the SRUE of 0.665 mg seed-1 was attained in ultrasonic wave treatments of 6 and 9 min. Under drought stress conditions, the maximum root length (22.84 mm), shoot length (8.09 mm), seed germination (49.93%), WMSR (0.096 mg per seed), and SRDP (43.1%) were obtained with the ultrasonic treatment of 9 min. Furthermore, the maximum SLDW of 0.09 mg was observed in the magnetic field treatment of 250 mT, and the maximum SRUE (0.516 mg seed-1) was obtained in the control treatment. For the improvement of salt and drought tolerances, priming with magnetic field and ultrasonic waves at 125 and 250 mT for 12 h and 9 min, respectively, can be efficiently used as pre-sowing treatments for snail medic seeds.

Abstract Salinity is one the major abiotic stresses that affect seed germination and establishment of plants in arid and semiarid regions. In order to investigate the effect of seed hydropriming on seed germination and seedling growth of Nitraria schoberi under salinity stress, an experiment was conducted in a completely randomized factorial design with three replications. The treatments included hydropriming at four levels (0, 2, 4, and 8 days) and salinity at five levels (0, 100, 200, 400, and 600 mM). The results showed that at lower levels of hydropriming, the percentage of germination and other germination components were minimal. The highest percentage of germination (50%) and rate germination, as well as seed vigor index, were obtained in the 8-day hydropriming treatment and 100 mM salinity level. Furthermore, with an increase in hydropriming duration, the root length and fresh and dry weight of the seedlings increased, indicating better establishment of the seedlings in the 8-day hydropriming treatment. On the other hand, based on the results, the seeds of this plant were sensitive to high salinity levels (600 mM) during the germination stage, and despite the hydropriming treatment, germination did not occur. it concluded that, the best treatment for germination and seedling growth of N. schoberi was the 8-day hydropriming treatment, particularly under mild salinity stress (100 mM NaCl), which improved the germination components.

Abstract Salinity stands as one of the major abiotic stresses impacting seed germination and plant establishment in arid and semiarid regions. To explore the effects of hydropriming on Atriplex seed germination components under salinity stress, an experiment was conducted following a completely randomized factorial design with three replications. The experiment involved hydropriming at four levels (0, 1, 2, and 4 days) and salinity at five levels (0, 100, 200, 400, and 600 mM). The findings indicate that salinity stress significantly reduced Atriplex seed germination. However, several germination components, such as germination percentage and rate, seed vigor index, and root length, did not significantly differ compared to the control treatment at the salinity level of 100 mM. The treatment with 600 mM salinity yielded the lowest percentage (1.2%) and rate (0.04 germinations/day) of germination, as well as the shortest root length (0.0083 cm) and shoot length (0.025 cm), alongside the lowest seed vigor index. Hydropriming treatment notably enhanced Atriplex seed germination, with increasing durations of hydropriming correlating to higher germination percentages and rates. The treatments with 0 and 4 days of hydropriming yielded the minimum and maximum germination percentages, respectively. Given that untreated seeds and short-term hydropriming led to limited germination, it appears that applying this treatment is essential for Atriplex seed germination under salinity stress conditions.

Abstract In vitro cultures provide a promising tool for large-scale multiplication of valuable plant species with an important role in the global ornamentals industry. In the current investigation, a rapid and efficient protocol was described for in vitro mass propagation of attractive ornamental plant Philodendron cv. Birkin through shoot tip culture. In shoot proliferation stage, 11 treatments of plant growth regulators were evaluated. The highest shoot multiplication was achieved by culturing explants in MS medium containing 3 mg/l benzyladenine (BA) and 0.5 mg/lit indole-3-butyric acid (IBA), resulting in average of 16.65 shoots per explant over a four weeks period. To induce adventitious root formation, the regenerated shoots were subsequently transferred to MS media supplemented with various concentrations of IBA and naphthalene acetic acid (NAA) (0.5-2 mg/l). In this regard, the superior performance of IBA compared with NAA was observed with the best response achieved using 1 mg/l IBA (resulting in a 95% rooting rate) with an average of 6.13 roots per shoot and the root length of 2.59 cm. Finally, the obtained plantlets were successfully acclimatized in a greenhouse, with 100% ex vitro survival rate. This established protocol can serve as an effective alternative to classical propagation methods for mass multiplication of this valuable decorative plant.

Abstract This experiment aims to compare the effect of deficiency of macro and micro nutrients and perlite particles size on radish, in the factorial experiment was conducted in a completely randomized design with three replications. Factors include deficiency of nutrient elements (control, nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, iron, boron, and zinc) and growing media tested were small, medium and large perlite particles size. The results indicated that dry and fresh weight of the taproot, dry and fresh weight of the root, dry and fresh weight of shoot, leaf area, numbers of leaves decreased under nutritional deficiencies as among the high consumption nutrients, the nitrogen deficiency had the greatest effect on reducing vegetative traits. The results also showed that the amount of total soluble sugars of leaves in nitrogen and boron deficiency respectively had the highest and lowest increase. Chlorophyll content and chlorophyll fluorescence indices also had the highest and lowest decrease under nitrogen and boron deficiency conditions respectively. The amount of vitamin C in the taproot also decreased under conditions of nitrogen, potassium, phosphorus, magnesium, calcium and iron deficiency. The results also showed that perlite particles size had a significant effect on the value of these indices and the big size of perlite particles caused a significant decrease in growth indices, mineral elements concentration and photosynthetic pigments. According to the results of this study, it seems that the small size of perlite in substrate was better to absorb the nutrients and therefore suitable for proper growth of radish.