JOURNAL OF PLANT PROCESS AND FUNCTION
Year:2017 | Volume:6 | Issue:20|Papers Count:8

Lemon balm (Melissa officinalis L.), a member of Lamiaceae family, is an important medicinal plant that has many useful properties. Micronutrients are necessary in low dose for the growth and the development of plants. Present research was conducted to study the effects of micronutrients including manganese (Mn) and copper (Cu) on morpho-physiological traits and essential oil of lemon balm. Field trials were carried out in 2015 at Shahrekord (50o56/ E 32 o18/ N) South Western Iran.Experiments were arranged in a randomized complete block design with a factorial layout and three replications.Micronutrients concentrations (Cu and Mn in 0, 150 and 300 ppm) were employed form time of planting to beginning of flowering of plants. Of the two micro nutrients, copper was more effective in stimulating the accumulation of Caryophyllene b, Citronellal, Geranial, Geraniol, Geranyl Acetate, Linalool and Neral. At 150 ppm, micro nutrients enhanced the production of citronellal, Chavicol. Although combination of Cu2+ and Mn2+ at 300 ppm in some of essential oils like neral, ecaryophyllene, caryophyllene oxide and 14-hydroxy-Z-caryophyllene were more produced than 150 ppm combinations most of essential oils significantly increased in 150 ppm concentration of micronutrients. Trans-piperitone epoxide was upper extracted in 300 ppm concentration of Mn2+ but in much combination this essential oil was not extracted in little concentration. Geranial, Geraniol, (E-) Caryophyllene, Caryophyllene oxide and Neral were the main components in all treatments.

The effects of selenium (Se) on growth and antioxidant activity in Spirulina platensis were investigated. S. platensis was grownin zarrouk medium containing three different concentrations of selenate (Na2SeO4) (0 as a control, 5 and 10 mg l-1) for 7 days.Selenate, at the concentration of 5 mg l-1 was found to improve S. platensis growth. However, selenate was toxic to S. platensisat the concentration of 10 mg l-1. Selenium increased the activity of enzymatic (peroxidase and catalase) and non-enzymatic(carotenoids) antioxidants when Se was applied to the microalgae at low concentration (5 mgl-1). Phenolic compounds were significantly increased in Se-treated samples. The contents of chlorophyll a and carotenoids in Se-treated S. platensis did not significantly change as compared to control. The FTIR analysis clearly indicated that the spectra of cells grown on different Se concentrations did not significantly change as compared to control. In addition, the variety of different compounds such as aromatic, phosphine, alcohols and carboxylic acids were synthesized in all examined treatments. The present results suggested that Se at low concentration had suitable effects on the physiology of S. platensis.

Induction of hairy roots in Perovskia abrotanoides Karel, a medicinally important member of the Lamiaceae family, was evaluated using different strains of Agrobacterium rhizogenes and various carbon sources. An efficient Agrobacterium mediated transformation system was established for the first time for this plant species using the bacterial strains of ATCC15834, TR105, and R1000. Meanwhile, the effects of acetosyringone and carbon sources on both rooting and root biomass production were investigated and the potential of hairy root cultures for producing tanshinones was explored. Hairy root induction in the nodes of intact seedlings was found to be successful with all the bacterial strains tested but R1000 was found to be more effective than TR105. The highest transformation frequency belonged to the nodes infected with ATCC15834 (47.33%). Moreover, transformation frequency increased by up to 60.99% when 100 mM of acetosyringone was added. The strain ATCC15834 recorded the highest root dry and fresh weights per 50 mL of the nutrient medium (0.149 and 1.996 g, respectively) and root length (34.45 cm) in a medium containing 3% sucrose. However, R1000 induced maximum lateral root density in hairy roots (7.1 branches cm-1) in a medium containing 3% glucose. PCR analysis using rolC specific primer with an amplicon of 612 bp confirmed the transgenic nature of the hairy roots. Finally, HPLC analysis revealed that the cryptotanshinone and tanshinone IIA levels in the hairy roots induced by TR105 (clone T7) were 53.17±0.26 and 14.48±0.30 mg g-1 DW, respectively.

Micronutrient deficiency is characteristic of drought stress conditions and the remedy lies in the administration of nutrients with boron and zinc supplements for the crops to tolerate and survive drought conditions. This study evaluated the effects of zinc and boron foliar application on the physiological traits of sesame under different irrigation regimes. The experiment was conducted in 2013 as a split plot in a randomized complete block design with three replications at Fars Research Center for Agriculture and Natural Resources. The main factors included three irrigation levels (irrigation after 75, 110, and 145 mm evaporation levels from class A evaporation pan) and the sub-factors included foliar sprays of water, zinc sulphate, boric acid, and the mixture of zinc sulphate and boric acid. Results showed that leaf proline content increased significantly as a result of foliar application of boric acid in the 75-mm evaporation treatment and by boric acid and the mixture of zinc sulphate and boric acid in the 110- and 145-mm evaporation treatments. Maximum glycinebetaine content was attained with the foliar application of zinc sulphate at all the three irrigation levels. Foliar application of zinc sulphate and boric acid led to the highest leaf relative water content as compared with that of the control. Maximum seed zinc content in the 75-mm evaporation treatment was obtained when either zinc sulphate or the mixture of zinc sulphate and boric acid were applied.Generally, results showed that foliar application of zinc sulphate and boric acid improved both the physiological traits of sesame and its tolerance to drought stress.

This investigation was carried out with the aim of determining the effect of polyethylene glycol 6000 (PEG; 0, 3%, 6% and 9% w/v) treatment on six cultivars of Medicago sativa. PEG treatment significantly decreased the germination index incultivars of Isfahani, Hamedani, Bami, Baghdadi, Yazdi and Ghare-Medicago, with the highest reduction in Ghare-Medicago and Hamedani cultivars by about 50% and 44%, respectively. PEG treatment significantly decreased germination percentage and germination rate in two cultivars of Ghare-Medicago (22% and 20%, respectively) and Hamedani (28% and27%, respectively) while increased mean germination time. The seedlings height, fresh weight and water content significantlydecreased in all PEG-treated cultivars. The highest reduction in the mentioned factors was observed in Ghare-Medicago(43%, 24% and 55%, respectively) and Hamedani (57%, 23% and 53%, respectively), while the lowest reduction wasobserved in Yazdi, by about 28%, 9% and 17%, respectively. Data showed that PEG treatment reduced seedling dry massonly in Ghare-Medicago and Hamedani cultivars by about 16% in both cultivars. PEG treatment significantly decreased thechlorophyll a, b and total, anthocyanins, phenols and a-tocopherol contents of six Medicago cultivars. The results ofgreenhouse experiments showed that PEG treatments resulted in a significant reduction in fresh weight, dry weight andwater content of all studied cultivars. In conclusion, the findings of both petri dish and greenhouse experiments suggested that Ghare-Medicago and Hamedani cultivars can be regarded as drought sensitive cultivars while Yazdi is a drought tolerant cultivar. It should be noticed that Bami and Baghdadi cultivars were also relatively drought tolerant. Also, our studyon paclobutrazol (PBZ) treatment showed that PBZ effectively decreased the negative effect of drought stress on growth ofall cultivars of Medicago.

The objective of this study was to investigate the effect of exogenous nitric oxide on cellular response and production ofsecondary metabolites in Catharanthus roseus callus. The cell suspension and callus of C. roseus were treated with sodiumnitroprusside, and then cell viability, morphology, the amount of H2O2, proline, lipid peroxidation, the activity of superoxidedismutase, catalase and peroxidase were evaluated. Also production of total antioxidant, alkaloid, flavonoid and phenoliccompounds were estimated. A Significant (p<0.05) reduction was observed in viability according to the dose of treatment.Also, the amounts fo H2O2, proline, total antioxidant, alkaloid, flavonoid, total phenolic compounds and the activity of theinvestigated enzymes increased significantly. Malondialdehyde level as a lipid peroxidation indicator was increase dsignificantly in response to treatment. In conclusion, we may announce that the sodium nitroprusside caused cellular membrane damage due to oxidative stress, but an increase in the production of secondary metabolites was observed too.Exogenous NO treatment might be a useful way to increase production of alkaloids at cellular level.

Effects of accelerated aging and seed priming treatments were studied on milk thistle seeds during germination process. Anexperiment was performed in a factorial based on Completely Randomized Design (CRD). Treatments were Salicylic acidconcentrations (0, 500, 1000, 1500 and 2000 mg. L-1) and accelerated aging for (0, 48, 96 and 144 hours under 45oC and 95%humidity) with three replications. Our results showed that salicylic acid dramatically enhanced seed germination, seedlingvigor and primary seedling growth. Catalase, polyphenol oxidase and peroxidase activity were increased by seed priming.Reduction in germination parameters were observed by increase in accelerated aging durations. The highest antioxidant activity, germination percentage and daily germination rate and seed vigour were observed at primed seeds with 1000 mg. L-1 Salycilic acid on non-aged seeds. Salicylic acid treatment with a concentration of 1000 mg. L-1 had the greatest impact on healing harmful effects aging.

Selenium (Se) at high concentrations can cause toxic effects in plants, whereas at low concentrations, enhances resistance to certain abiotic stresses. The possible mechanisms of the Se-enhanced tolerance of plants to salinity stress remain elusive. In this work, effect of Se supplementation at 0, 0.1, 1 and 10 mg l-1 sodium selenate was studied in Lallemantia iberica plants subjected to salt stress. In pre-experiment design, the toxicity threshold for selenate was measured at the concentration of 10 mg l-1, as the biomass of L. iberica plants decreased selenate concentrations in the growth medium reached 10 mg l-1.Thereafter, we used 0.1 mg l-1 Se to mitigate salt stress in L. iberica plants. Se at low concentration (0.1 mg l-1) mitigated saltinduced oxidative stress because the NaCl-induced lipid peroxidation was smallest in the plants treated with Se, and was highest in the plants grown without Se addition. This occurred as a result of glutathione (GSH) accumulation in Se-supplied plants. Additionally, Se-supplied plants exhibited higher glutathione peroxidase (GSH-Px) activity after 2 days salt stress.These data provided the first evidence that the low-level Se pretreatment alleviated salt stress in L. iberica by increasing GSH levels and by decreasing ROS production; and therefore less reduction of biomass production during salt stress.