Effect of methanol and drought stress on germination indices of bean (Phaseolus vulgaris L. cv COS16)

Beans in many developing countries as an important source of protein for numerous plants. Bean cultivation in Iran is about 240 thousand hectares with an average yield of 150 kg/he. Germination is an important stage in the life cycle of the plant and can have a significant impact on production and yield. Quality of seed germination has a significant impact on plant growth traits. It is reported that germination of legumes such as beans directly affected by unfavorable environmental conditions such as drought and salinity are located. In several studies, the use of methanol as a carbon source for growth and crop yield under drought stress conditions is recommended. Methanol external application directly with the metabolic processes of plant growth and development, as well as the processes associated with defense mechanisms such as the activation of genes involved in the biosynthesis of jasmonic acid is linked. Some studies have shown that intake of methanol can improve the efficiency of nutrient uptake, especially in the face of growing environmental stress. Given that, there are numerous reports in connection with a positive impact on the vegetative phase methanol plant in Iran; however, few studies exist on the effects of methanol on germination indices. The aim of this study was to investigate the effects of methanol on indices of bean seed germination under drought stress.
To investigate the effects of methanol and drought stress caused by PEG 6000 on germination indicators beans (cv. COS16) experiment factorial basis of completely randomized design in the summer at the Khatam Alanbia University of Technology. Parameters studied include different levels of ethanol contains: control (0), 10, 20 and 30 percent by volume and drought stress caused by PEG 6000 (0, -3 and -6 Bar). Drought stress using PEG 6000 at 25 ° C and the equation was applied Michael and Kaufman. Visiting of the samples once daily for 14 days and the number of germinated seeds were recorded at each visit. On the final day of testing, root and shoot were separated from the seeds and the germination indices such as germination percent, germination speed, radicle length, plumule length, radicle dry weight, plumule dry weight and endosperm consumption were measured.
Analysis of variance showed a significant effect of drought stress and the use of methanol on germination percent, germination speed, radicle length, plumule length, radicle dry weight, plumule dry weight and endosperm consumption. The results showed that the interaction effects at all levels of drought stress, levels of 20 and 30 percent methanol lead to a significant reduction in germination indices bean. Drought stress at -6 bar, leading to a significant decrease in germination percentage, germination speed, radicle length, plumule length, radicle dry weight, plumule dry weight and endosperm consumption in comparison with treatment without water stress. In general, the results of this study showed that the use of methanol at germination stage was not involved not only in reducing the negative impacts of drought stress, but also non-drought stress conditions, the germination of beans had negative effects.
In this study, the results showed that aqueous solution of methanol under water stress treatments (0, -3 and -6 bar) leads to a significant reduction in all parameters evaluated in bean plants. According to research showing that methanol, seedling stage and flowering plants increased the productivity and yield. In this study, it was found that an aqueous solution of methanol in addition to no role in reducing the negative impacts of drought stress on germination of beans, but also leads to germination indices were lower.