توصيفگر ها :
گلگاوزبان اروپايي , تنش خشكي , همزيستي , قارچ مايكوريزا , فسفر
چكيده انگليسي :
Interest in cultivation and production of medicinal and aromatic plants as a reliable source for curing and remediation of human deseases is continuously increasing worldwide. Borage (Borago officinalis L.) is an annual medicinal plant species, but currently is cultivated for its oil-containing seeds. Its seed is one of the known sources of ɤ-linolenic acid (GLA), as from the 30-40% oil content of borage seeds, nearly 20-30% is GLA. Drought is one of the most serious environmental constraints to the plant growth and productivity, limiting the food production around the globe. An improved plant-microbe symbiotic relationship may lessen the drought stress damages to the physiological functions and hence improve plant drought tolerance. Mycorrhizal fungi are valuable symbiotic partners of many palnt species, as they enhance soil fertility, plant nutrition, and stress tolerance. Hence, two pot experiments were conducted at the Isfahan University of Technology, Isfahan, Iran, to shed light on the ameliorative effects of mycorrhizae (Funneliformis mosseae) on the drought-induced alterations in a wide range of attributes ranging from physiological to biochemical attributes and from root characteristics to shoot growth, and dry mass of two borage genotypes. The first pot experiment was a 3-replicate randomized complete block design, consisting of two borage genotypes (namely Pakan and Dashtyar), two levels of mycorrhizal inoculation (non-inoculated and inoculated soil), and three levels of irrigation (non-drought control, moderate drought, and severe drought). The second pot experiment was also a 3-replicate randomized complete block design consisting the two mentioned genotypes and two levels of mycorrhizal inoculation, and two levels of irrigation water (non-drought control and moderate drought). Drought resulted in suppressions in root mycorrhizal inoculation, leaf chlorophyll concentration, maximum quantum efficiency of photosystem II, relative water content, P concentration, membrane stability index, plant height, plant above-ground dry mass, root dry mass, and root volume. Though, it led to increases in the leaf carotenoids concentration, carotenoids/chlorophyll, proline
soluble sugars, total phenolics and flavonoids concentrations. Mycorrhizal inoculation mitigated some of the adverse effects of the drought, including leaf chlorophyll concentration, relative water content, membrane stability, P concentration, root volume and dry mass, and plant above-ground dry mass. These results taken together, suggest that mycorrhizae may help borage in acquiring soil P and water and consequently enhancing photosynthetic attributes, root and shoot growth, and dry mass, particularly under drought conditions.
