Iranian Journal of Seed Research

The purpose of this study was to evaluate the effect of Nano TiO₂ and Nano CNT on some germination indices and growth parameters of some hulled barley cultivars. The experiment was conducted in a laboratory at Shahrekord University during 2014. The study was a factorial, adopting a completely randomized design with four replications. Treatments consisted of titanium dioxide nanoparticles and carbon nanotube (CNT) in four concentrations (0, 10, 30 and 60 mg.l^-1) which were applied to seeds of hulled barley cultivars such as Bahman, Makoii and Nosrat. The traits measured were the dry weight of seedling and seedling length, germination percentage, germination rate, mean germination time, the percentage of resistance of radical, seedling vigor length and weight index. The results showed that carbon nanotubes treatments with 60 mg.l^-1 had a significant impact on germination percentage, germination rate, seedling vigor length and weight index and seedling dry weight, as compared with other treatments. In this experiment, the highest percentages of resistance of radicle, seedling vigor weight index and seedling dry weight of Nosrat Cultivar were obtained under 60 mg.l^-1 carbon nanotube treatment, which was 70, 122.2 and 64.9%, respectively, as compared with control treatment. In addition, 60 mg.l^-1 carbon nanotube treatment increased the seedling vigor of Makoii cultivar by 39.8%, as compared with the control treatment. The findings were that in terms of seedling vigor length and weight index, seedling length, seedling dry weight and the percentage of resistance of radical, the Nosrat Cultivar showed better morphological characteristics than Bahman and Makoii cultivars, under laboratory conditions.
 

In order to study the effects of different levels of salinity on germination components of wheat cultivars, a factorial experiment was conducted based on a completely randomized design with three replications. Experimental factors were wheat cultivars at eight levels (Saysons, Gaspard, Finkan, MV-17, Chamran, Sardari, Atila-4 and Azar-2) and six levels of salinity (0, 25, 50, 100, 150 and 200 mM NaCl). The results indicated that salinity had significant effects on all of the traits studied (i.e., radicle length and dry weight, plumule length and dry weight, remaining seed weight after germination, seedling weight, the longest radicle and plumule, number of radicle per seed, ratio of radicle weight to plumule weight and rate, and uniformity and percentage of germination). All of these traits declined with an increase in the salinity (except the ratio of radicle weight to plumule weight, remaining seed weight after germination and seedling weight). The highest ratio of radicle weight to plumule weight, remaining seed weight after germination and seedling weight were recorded in the salinity of 200 mM NaCl. The cultivars showed significant effects on all of the traits studied (except remaining seed weight after germination and seedling weight). Chamran cultivar showed the highest number of radicle per seed, the ratio of radicle weight to plumule weight, rate and percentage of germination. The highest radicle length and the longest radicle were obtained from the Sardari cultivar while in Azar-2 cultivar it was vice versa in plumule. Atila-4 cultivar showed the highest radicle and plumule weight. It seems that compared with other cultivars, out of the cultivars studied, Chamran, Azar-2, Sardari and Atila-4 were more resistant to salinity stress.

 
 Highlights:

1. Introduction of wheat cultivars with more tolerance to salinity conditions at germination stage.
2. Study of eight different wheat cultivars in terms of germination indices under salinity stress conditions.

The present study sought to compare the effect of seed priming by hydropriming, ascorbate and calcium chloride (CaCl₂) versus different concentrations of silver nanoparticles on two Iranian rice cultivars (Hashemi and Shiroodi) under drought stress. The experimental design, which was factorial, was completely randomized. The first factor was control (without priming), hydro-priming, 20 mg.L^-1 calcium chloride, 20 mg.L^-1 ascorbates and 20, 40 and 80 mg.L^-1 of silver nanoparticles. The second factor was the drought stress, including control, -1.48 and -4.91 bars created by polyethylene glycol 6000 solutions. In plants without drought stress, the time required to reach 50% germination (T₅₀) reduced to 34 and 54 percent under ascorbate and CaCl₂ priming in the Hashemi and Shiroodi cultivars, respectively.  In the drought stress condition, ascorbate and hydropriming pretreatments decreased T₅₀ and the time required to reach 90% germination (T₉₀) more than silver nanoparticles, especially in the Shiroodi cultivar. On the other hand, in comparison with other pretreatments, CaCl₂ had an important role in increasing the growth factors in all of the drought stress treatments. Although 40 mg.L^-1 silver nanoparticles increased the growth factors to some extent, it seems that higher levels of silver nanoparticles cause stress in seeds and therefore decrease the seed germination and growth of seedlings. By decreasing reactive oxygen species, Ascorbate improves the germination and by increasing plasma membrane efficiency, CaCl₂ enhances the seedling growth under drought stress.

Highlights:

1. Silver nanoparticles increased the effect of stress on the seedlings of rice cultivars.
2. Ascorbate and calcium chloride improved the germination and seedlings growth of the rice cultivars, respectively under drought stress conditions.

Extended abstract
Introduction: Nowadays exploitation of hetrotoxic characteristics  of hetrotoxic plants regarding  harmful effects of synthetic herbicides can most important role in weeds management and their control. In fact chemical compounds which is released by root, stem, leaf, flowers, seeds pollen, fruit and seeds can be used as bio herbicides and bio pesticides. The purpose of this srudy was evaluation of hetrotoxicity potential of Datura stramonium L. shoots on germination traits and photosynthetic pigments of wheat cultivars.
Materials and Methods: An experiment was conducted to evaluate hetrotoxicity potential of aqueous extract of different organs of Datura stramonium L. such as stem, leaf, fruit and mixed of them on germination traits and photosynthetic pigments of two cultivars of wheat (Kohdasht and N8720) as factorial experiment based on compeletly randomized design in three replications in Weeds Scince Laboratory of Gonbad-e- Kavous University in 2017. Datura stramonium shoot was collected at fruit formation stage in the Moghan plain and seprated into stem, leaf and fruit firstly. Five ml of studied extracts as well as mixed of them were added on 25 disinfected seeds of studied cultivars separately.
Results: Results showed that wheat cultivars had a different response to organs extract and this difference also were significant for various organs extract as well as interaction effect of cultivars in organs extract. Mean comparison of interaction of cultivars and organs showed that germination percent of Kohdash were decreased under experimental treatments. The highest decrease effect was obtained in the leaf extract about 98.33%. In return, stem, fruit and mixed organs had an increase effect on germination percent of N8720 about 5.72, 5.72 and 1.41% respectively. Result of the germination rate was similar with result of germination percent. Radicle and shoot length of both cultivars under experimental treatments were decreased. Leaf extract had an highest inhibition effect on radicle and shoot length about 96.70 and 89.21% respectively. Content of total chlorophyll of both cultivars of Kohdast and N8720 were increased under aqueous extract of stem (24.64%) and fruit (14.62%). Where as, extract of other organs and mixed of them had a decrease effect on studied trait. The result of carotenoid also was similar with result of total chlorophyll. Persumably, difference in allelochemicals concentration in various organs of Datura stramonium and physiological chracteractics of studied traits in cultivars caused different behavior.
Conclusions: According to the results, use of Datura stramonium biomass esspecially leaf, it is suggested as natural herbicides and strategy of non- chemical management. To accomplish this need to analyze phytochemical compounds of this weed.
 
Highlights:

1. Extract of different parts of Datura stramonium weed had a different effect on germination traits and content of chlorophyll and carotenoids  of both cultivars of Kohdast and N8720.
2. Leaf extract of Datura stramonium significantly decrease germination traits and content of chlorophyll and carotenoids of Kohdasht cultivar seedlings.

3- Use of Datura stramonium can be a good option for appearance of natural herbicides.