بهنام صداقتی

Water deficit is one of the major limiting factors that influences the cultivation and production of agricultural crops in the world. Drought stress severely impairs plants growth and development through alterations in the physiological, morphological, biochemical, and molecular attributes (Cheng et al., 2018). Most of the world's farms are located in arid and semi-arid regions. In addition, drought conditions can be exacerbated by climate change and water scarcity. Therefore, it is important to find a way for increasing the adaptation potential of crops to water shortage (Asghari et al., 2020). Zeolite can act as water moderators and play a key role in plant growth and development under drought condition. The aim of this research was to investigate the effect of zeolite application on morphological traits and secondary metabolite biosynthesis of dill (Anethum graveolens L.) under drought stress.

This study was conducted as a factorial experiment in a completely randomized block design with three replications in the greenhouse. The experimental factors included irrigation regimes in 3 levels (40 %, 80 % and 100 % of filed capacity (FC), application of zeolite in 2 levels (0.0 and 2.5 g/ kg of soil) and plant ecotype (Naeen and Zavereh). Seeds of dill were obtained from Pakan Bazr Company, Isfahan, Iran. The seeds were cultured in pot containing sandy loam soil. When plants were fully established, drought treatment was started and continued until harvest. Then, we measured some morphological and biochemical attributes of dill plant. The obtained data were analyzed using analysis of variance (ANOVA) performed with SAS software. Duncan’s multiple range test was used to distinguish the differences in treatments.

The results showed that water deficit and zeolite application significantly affected morphological and biochemical properties of dill plant. Drought stress reduced plant height, leaf area, fresh ant dry weight of plant, number of umbrella per plant and 1000 grain weight but only amplified root length. Application of zeolite alleviated drought-related damages and promoted plant growth and development, which increased leaf area and the amount of grain per plant, and reduced root length and plant height. A similar effect of drought stress and zeolite treatment has reported in Dracocephalum moldavica (Gholizadeh et al., 2010). Our data demonstrated that mention attributes significantly influenced by the plant ecotype, and Naeen was more effective than Zavareh. The results illustrated that the severity of drought stress play a key role in the amount of phytochemical compounds of dill seeds. The highest amount of dill ether and alphaphellandrene was recorded under normal condition. While, the highest level of limonene was obtained in plants subjected to moderate drought stress. In addition, the severe water stress led to the highest accumulation of carvone and transdihydrocarvone in dill seeds. Zehtab Salmasi et al., (2016) reported that water shortage causes an increase in dill ether and limonene of dill plants.

Water deficit adversely affected normal growth and morphological properties of dill plants. The obtained results showed that dill plant could adapt to drought condition by raising its protective compounds and root length. Water stress significantly enhanced essential oil percentage of basil plant, leading to accumulation of dill ether, carvone, transdihydrocarvone and limonene in its seed. The exogenous usage of zeolite can successfully alleviate deleterious impacts of water shortage on dill plant by improving morphological characteristics and stimulating secondary metabolites production.

To evaluate the silicon effects on morphological characteristics as well as the percentage and composition of basil (Ocimum basilicum L.) essential oil under cadmium stress, a factorial greenhouse experiment was conducted in a completely randomized design. The treatments included cadmium metal (Cd) as the first factor at three levels of 0, 25, and 50 mg kg-1 soil and silicon (Si) as the second factor with concentrations of 0, 1, and 2 mM. The characteristics including root length, fresh and dry weight of roots, plant height, fresh and dry weight of stems, stem diameter, number of leaves, fresh weight of leaves, number of buds, number of sub-stems, and percentage and composition of essential oil were evaluated. The results showed that Cd had negative effects on all studied morphological characteristics and significantly decreased their values compared to the control. However, Si treatment improved all these traits and with increasing the concentration of this element, a significant increase in the values of these traits was observed. Application of Si in the concentration of 2 mM caused 63.8, 81, 61, and 61% increase in the number of sub-stems, root fresh weight, stem fresh weight, and number of buds compared to the control, respectively. The amounts of five major constituents of basil essential oil including 1,8-cineole, linalool, estragole, methyl eugenol, and eugenol were affected significantly with the Cd and Si treatments. However, the interaction of these two treatments showed a significant effect only on the three compounds 1,8-cineole, linalool, and methyl eugenol. The maximum amounts of 1,8-cineole (5.06%) and methyl eugenol (6.21%) were observed in the plants which simultaneously exposed to the highest concentrations of Cd and Si. The amount of linalool was also decreased with the presence of Cd and increased with the Si treatment. The Cd treatment increased the amount of estragole by 12.8% and decreased the amount of eugenol by 25.2%. The Si treatment also increased the amount of estragole by 23.9% and decreased the amount of eugenol by 18.3%.

 In this factorial study in a completely randomized design, the effect of different concentrations of colchicine (0, 15, 30, 45 and 60 mg/L) and different time intervals (12, 24 and 48 hours) on the amount of phenol and lignan production was investigated in the callus tissue of Linum usitatissimum L. For callus induction, cotyledon explants were cultured on solid MS medium supplemented with 2 mg/l 6-Benzylaminopurine (BAP) and 1 mg/l 1-Naphthaleneacetic acid (NAA).The total phenolic and lignan contents were measured by spectrophotometric method based on the standard curves of gallic acid and sesamin at 765 and 288 nm, respectively. The highest amount of fresh and dry weight of callus was related to 45 mg/l colchicine treatment. Maximum and minimum levels of lignin in experimental periods were obtained from 15 mg/l (in average 28.4 mg SE/ g DW) and 30 mg/l (in average 19.75 mg SE/ g DW) colchicine, respectively. According to the results, the highest (164 mg GA/g) and lowest (145.6 mg GA/g) levels of total phenol content were observed in 60 and 30 mg/l colchicine treatments, respectively. The results indicated that the production of valuable secondary metabolites such as phenol and lignan in flax callus were increased under some colchicine treatments.

Catharanthus roseus is a medicinal plantthat is important because of production of many alkaloids, including anticancer drugs, Vincristine and Vinblastine. Vincristine and Vinblastine are among the most important drugs for cancer treatment, but the performance of these two compounds is relatively low and the approximate amount of them in the plant is 0.0005%. Due to the high price of these compounds and small amount in this plant, efforts to increase the production of these compounds have led to extensive researches on this plant. In this experiment to study the effect of fungal extracts and time of the alkaloids production in Catharanthus roseuse cell suspension culture, test factorial randomized complete block designed with three replications. For this purpose, after preparation of cell suspensions, extracts of fungi P. indica, T. tomentosum and fungal extracts combined of P. indica and T. tomentosum at a concentration of 1% v/v was add to the cell suspension. Sampling in the time period (0, 24, 48, 72h) after the treatment were performed, and Vinblastine and Vincristine alkaloids were measured by using HPLC method. The results showed that three fungal extracts, P. indica, T. tomentosum and mixture of the fungal extract (P + T), increases the amount of Vinblastine, compared to the control and the greatest impact has been on fungal extract T. tomentosum. The average comparison of Vincristine between fungal extracts showed that the highest amount of Vincristine in the control samples and fungal extracts decrease the amount of Vincristine.

In micropropagation of Anthurium the most important and sensitive stage, is callus induction from explant. This experiment was conducted in a completely randomized design with factorial arrangement in 4 replications in Sari Agriculture Sciences and Natural Resources University (SANRU) in 2010. The cultivar used in this study is Fire and leaf segments with and without main nervure, were used as explants. Explants were cultured on mMS media with 2, 4-D (0.0, 0.04, 0.08, 0.12, 0.16, 0.20 and 0.24 mgL-1) and BA (1 mgL-1), 30% sucrose and 7% agar for callus induction. Calli were cultured in mMS media with BA (0.25, 0.5, 0.75 and 1 mgL-1), 206 mgL-1 NH4NO3, 20% sucrose and 7% agar for shoot regeneration. Four weeks after inoculation, callus induction initiated in explants with nervure. Regardless of 2, 4-D concentrations, leaf explants with the main nervure, showed highest callus induction (48.3%). The leaf explants with main nervure in mMS medium contain 0.16 mgL-1 2, 4-D showed the highest callus induction (83.7%) and the leaf explant without main nervure in mMS medium without 2, 4-D showed the lowest callus induction (12.5%). The best rate of BA for shoot regeneration (20.83%) was 1 mgL-1. The callus on mMS medium containing 1 mgL-1 BA showed the highest shoot regeneration (20.83 %) and the callus in mMS medium containing 0.25 mgL-1 BA showed the lowest shoot regeneration.