نوع مقاله : مقاله پژوهشی
نویسندگان
1 دانشجوی سابق کارشناسی ارشد دانشگاه کشاورزی و منابع طبیعی رامین خوزستان
2 دانشیار دانشگاه کشاورزی و منابع طبیعی رامین خوزستان
3 استادیار دانشگاه کشاورزی و منابع طبیعی رامین خوزستان
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسندگان [English]
Arbuscular mycorrhizal fungi are the most important symbiotic fungi that increase plant growth by improving nutrient uptake, particularly phosphorus (P) uptake, and by alleviating the detrimental effect of environmental stresses on the host plant. In this research, the effects of arbuscular mycorrhiza fungi and drought stress levels on root growth, proline accumulation, P, potassium (K), sodium (Na) and zinc (Zn) concentrations in three leek genotypes were studied. The experiments had a randomized complete block design with treatments arranged in factorial combination. The treatments with 4 replications were three soil moisture levels (the pots were watered when 40, 60, and 80 percent of the available water was consumed), two mycorrhizal status (with and without mycorrhiza), and three leek genotypes (Shadegan, Esfahan and Carantan 2). The results showed that drought stress significantly decreased root growth (root dry weight, total root length colonized, and percentage of root colonization). However, mycorrhizal colonization increased root growth at all drought stress levels. The percentage of mycorrhizal dependency increased as drought stress was increased. This increase was affected by morphological root characteristics and plant genotype. Among the leek genotypes, Shadegan genotype with a poor root system had the greatest mycorrhizal dependency compared with the other two genotypes at all drought stress levels. This is in agreement with the Baylis’s hypothesis even in drought stress condition. Drought stress significantly decreased leaf phosphorus concentration and content. In non-mycorrhizal treatment, proline accumulation, K, Na, and Zn concentrations in leaves increased as drought stress was increased. Mycorrhizal fungus significantly increased the uptake of P, K, and Zn, while proline and sodium concentrations decreased. The results of this study clearly indicated that mycorrhizal colonization improved drought tolerance of the host plants not by osmotic adjustment, but by increasing P, K, and Zn uptake.
کلیدواژهها [English]