فصلنامه گیاه و زیست فناوری ایران
سال هجدهم شماره 1 (بهار 1402)

The poisonous substances in plants are mostly alkaloids, glycosides, organic acids, resins, resinoids, and mineral compounds. A poisonous plant is a plant that can be harmful or fatal to humans or other animals if touched or eaten in sufficient quantity. If used in small amounts and in the right proportion, these plants can be used as herbal medicines with medicinal properties. The beauty of these plants hides their toxicity. Scientific understanding of plant toxins and their effects has greatly increased. Poisonous plants that cause serious problems or even death are considered as "plant biological weapons". Knowledge about poisonous plants is still insufficient and it is very important to identify some species that cause poisoning and death in humans. The purpose of this article is to provide information about poisonous plants, existing toxic compounds and symptoms when consumed, as well as their medicinal uses.

Recently, the pretreatment of seeds with helium-neon laser has attracted the interest of the scientific community as one of the safest ways to enhance seed germination, seed growth and increase the resistance of plants to stresses. Due to the sensitivity of phytochromes to red light, the activity of enzymes related to growth and flowering can be increased by irradiating plant seeds with He-Ne laser light at a wavelength of 632.8 nm. In this study, the effect of laser on the morphological and physiological characteristics of Verbascum songaricum under normal conditions and under water stress was investigated. First, the effect of helium-neon laser with durations (0 and 30 minutes) and water deficit stress at two normal irrigation levels and water deficit stress (irrigation at 50% soil capacity) on seed germination in an experiment in the form of chopped plots in the form of a block design Complete randomization was evaluated in four replicates in the conditions of the research field of Azad University, Isfahan branch, and it showed the best plant stem height, root length, number of main stem flowers in the interaction effect of laser and water deficit stress. Helium-neon laser improved seed germination, flowering and seed growth of safflower in a time-dependent pattern under all water stress conditions.

Today, various organic and mineral materials are used as a culture medium. Each of these materials has unique characteristics. In general, these materials should have water retention capacity, sufficient ventilation, proper drainage, and high cation exchange capacity, and they should not have any adverse or harmful effects on the plant. In order to investigate the possibility of replacing the cocopeat and perlite culture medium with new and inexpensive culture mediums obtained from waste organic materials and mineral compounds in the cultivation of Rosaline gerbera cuttings, a research was conducted based on a completely randomized block statistical design with 7 treatments and 3 replications. The treatments used include cocopit 50% + perlite 50% (control), cocopit 50% + leaf soil 50%, perlite 50% + leaf soil 50%, perlite 50% + vermicompost 50%, garden soil 35% + perlite 15% + cocopit 50%, garden soil 35% + perlite 15% + leaf soil 50% and garden soil 35% + perlite 15% + vermicompost 50%. The measured traits were: flower persistence on the plant, stem diameter, stem height, leaf area, number of flowers and number of leaves. Based on the obtained results, the highest number of leaves and flowers, height and stem diameter were observed in the culture medium (50% cocopeat + 50% leaf soil) and the highest amount of leaf surface in the culture medium (50% perlite + 50% vermicompost). In general, the results of this research indicated that the cultivation substrates (cocopit 50% + leaf soil 50%) and (perlite 50% + vermicompost 50%) can be introduced for the cultivation of gerbera cv. rosalin.

In order to study the effect of foliar application of yeast and seaweed extract on the yield and quality of safflower seeds under drought stress conditions, an experiment was conducted in the research farm of the Faculty of Agriculture of Azad University, Sanandaj branch in 2018. The experiment was carried out as split plots in the form of randomized complete blocks design in three replications. The main factor was water stress at two levels (control: no stress or full irrigation and the stress of interruption of irrigation from the stemming stage to the end of the growing season) and the second factor was foliar spraying of growth stimulants in three types (control: distilled water, yeast and seaweed extract). The results showed that the traits of number of pods per plant, number of seeds per plant, weight of 1000 seeds, seed yield and protein percentage were significantly different under the influence of irrigation interruption stress. So that all the mentioned traits, without protein percentage, decreased under the influence of irrigation interruption. The percentage of protein also increased under the influence of irrigation interruption. Also, in this experiment, foliar spraying of growth stimulants showed a significant effect on the traits of number of pods per plant, number of seeds per pod and seed yield. So that the maximum values of the above traits were obtained under the influence of yeast extract foliar spraying. The results of interaction effects were also significant regarding the number of heads per plant and the maximum amount was obtained under the influence of full irrigation and foliar spraying of yeast and seaweed extract.

Selenium is a beneficial element with antioxidant properties that increases plant growth and tolerance under environmental stress. This study was conducted to investigate the effect of selenium nanoparticles on some germination characteristics of cherry tomato plant (Solanum lycopersicum L. var.cerasiforme) under normal irrigation conditions and water stress in a completely randomized design with application of 4 treatment levels (zero, 2, 4 and 10 Mg/l) and the interaction of selenium on drought (4% PEG) was repeated 3 times. For this purpose, after disinfecting the seeds, they were placed in plates containing filter paper and soluble selenium with certain concentrations (sodium selenate as control of bulk and nano selenium) was added to the seed growth medium every three days. 2 days after the second selenium treatment, water stress was applied with 4% polyethylene glycol. The evaluated traits included percentage and speed germination, root and shoot length, fresh and dry weight of seedlings. The results showed that the highest shoot length, seed germination and fresh weight in 4 Mg/l selenium treatments (sodium selenate and nano selenium) under normal irrigation and water stress conditions and the lowest shoot length, root shoot, seed germination, weight Wet, percentage and germination rate were observed at high concentrations of selenium (10 Mg/l) compared to the control under normal irrigation and water stress conditions. In general, 4 Mg/l selenium treatment increased plant tolerance to drought stress and seedling growth. 

This study performed in order to evaluate the effects of drought stress and Nitrogen fertilizer on growth indices and yield of four chickpea cultivars. The experiment was done as a split-factorial using randomized complete block design with three replications. Drought stress treatment consisting of no drought stress, moderate drought stress and severe drought stress stand in main plots. Combination of Nitrogen fertilizer (in two levels) and cultivar treatment (Azad, Bivanij, Hashem and ILC482) stand in sub plots. Results showed that, the effect of drought stress on all treats excluding CGR and LAR was significant. Drought stress reduced the procedure of LAI, CGR, RGR and NAR and decreased accumulation of dry matter and seed yield. Performance of irrigation and application of Nitrogen fertilizer increased leaf area, net assimilation and in final accumulation of dry matter and seed yield. Bivanij cultivar with highest CGR, NAR and LAR produced highest seed yield.