Bean Germination and Saline free essay sample

This study was to observe the effects of increased saline (NaCl) concentrations in relation to the germination of P. vulgaris seeds. The hypothesis is that with each increase in saline concentration there will be less root development. Why do higher concentrations of saline inhibit germination? What does the higher concentrations of saline do to the P. vulgaris seed? Are seeds tolerant to higher concentrations of saline? â€Å"All soil contains salts, many of which are essential nutrients for plants. Salinity occurs when soluble salts (usually NaCl) are elevated in soil and water. Every continent is affected by salinized soil and water; approximately 7% of the world’s land area. † (Nerissa Hannink, 2005). â€Å"But why should we care about how a plant copes with excess salt? Once inside the cell, salt can cause ionic stresses, largely as Na+ (and Cl-) inhibit metabolic processes including protein synthesis. Na+ can rise to toxic levels in older leaves causing them to die. We will write a custom essay sample on Bean Germination and Saline or any similar topic specifically for you Do Not WasteYour Time HIRE WRITER Only 13.90 / page † (Dr. R. Munns, 2001) Since there is salt found in the soil naturally, and higher levels will cause ionic stress; what levels are considered to inhibit growth? Salt tolerance is defined when plants show little growth reduction at concentrations of 300mM NaCl or more. (M. Tester and R. Davenport, 2003) â€Å"Seedlings are the most vulnerable stage in the life cycle of plants and germination determines when and where seedling growth begins. † (A. Lianes, H. Reinoso, V. Luna, 2005). â€Å"There are contradictory reports in the literature as to the relative sensitivity of germination and seedling growth to salt stresses. According to Munns, salt stress decreases growth in most plants, including halophytes. † (R.Munns, 2002) â€Å"Salinity can affect germination of seeds either by creating osmotic potential which prevent water uptake, or by toxic effects of ions on embryo viability. † (A. Lianes, H. Reinoso, V. Luna, 2005). â€Å"Shoot growth was reduced by salinity due to the inhibitory effect of salt on cell division and enlargement in the growing point. (K. Mccue and A. Hanson, 1990) In results from M. Kaymakanova (2009) it was that show that; â€Å"Specific ionic effects were evident as different responses were obtained with different salt treatments at iso-molar concentrations. There should have been a higher root and shoot development of the P. vulgaris seeds in the 0%, 0. 025%, 0. 05%, and the 0. 1% saline solutions. Only the 0. 5% saline solution has shown any significant results. As shown in previous research higher concentrations of saline does in fact inhibit germination. It does so by retarding the roots so that they cannot take in water and minerals from the soil. In a similar experiment done with monk beans; all beans in a saline of 0. 50% or less germinated roots in five days. In a saline solution greater than 0. 0% the beans split and had little or no germination at all. (ABC Science, 2006) From this and other data the skewed results can only be from experimenter error. There should not have been greater germination in the P. vulgaris beans in the 0%, 0. 025%, 0. 05%, and the 0. 1% saline solutions. There was only minimal germination in the 0. 025% with only a 30% root growth; and in the 0. 5% with only 70% root growth. Possibly repeating the experiment several time would have given better results in the groups that showed no signs of germination. It is also possible that there was experimenter error in placing the wrong solutions or miss labeling the bags. Repeating the experiment at least three times with larger groups of beans would give better results.